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Synthesis, Chiral Resolution, and Enantiopharmacology of a Potent 2,3-Benzodiazepine Derivative as Noncompetitive AMPA Receptor Antagonist
Abstract
This paper describes the synthesis of racemic 3,5-dihydro-5-methyl-7,8-methylenedioxy-4H-2,3-benzodiazepin-4-one (+/-)-5, attempted stereoselective synthesis of its enantiomers, chiral HPLC resolution of the racemate, and assignment of the absolute configuration. Enantiomer (5S)-(-)-5 is provided with an in vivo anticonvulsant activity 8 times higher than its enantiomer (5R)-(+)-5. This result is confirmed in the in vitro test by the ability to inhibit the kainate-induced increase of the [Ca(2+)](i) in a primary culture of rat cerebellar granule cells which express alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. Binding affinity of compound (+/-)-5 at the AMPA and N-methyl-d-aspartic acid (NMDA) receptors was also evaluated.
... 1-Aryl-2,3-benzodiazepine-4-ones (1, Scheme 1), which are structurally related to the previously introduced compounds, were also investigated in great detail as noncompetitive AMPA [2-amino-3-(3-hydroxy-5-methyliso xazol-4-yl)propionic acid] receptor antagonists with marked anticonvulsant activity [9][10][11][12][13][14][15]. ...
Previously synthesized 9-aryl-5H-imidazo[2,1-d][1,2,5]triazepin-6(7H)-ones have been used as starting materials for the synthesis of three new tricyclic ring systems, where an imidazotriazepine is condensed with an imidazole, triazole or tetrazole ring. These novel compounds could be potential drug candidates for central nervous system diseases because of their closely related structure to known tricyclic derivatives with anticonvulsant activity.
Graphical Abstract
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... lmol/kg for (À)-(S)-3 vs. 88.4 lmol/kg for (þ)-(R)-3, in the clonic phase). 9 On these basis, the objective of the present research was to optimize a chromatographic method to efficiently resolve and isolate the enantiomers of (6)-(R,S)-2, to determine the absolute configuration and to evaluate the anticonvulsant activity of the single enantiomers. ...
... There are several ways for the treatment of epilepsies, although antiepileptic drugs (AEDs) remain the most widely utilized treatment [2]. 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3benzodiazepine (GYKI52466, 1) is the first compound showed anticonvulsant that act via noncompetitive-AMPA receptor antagonist and was used as a lead for many studies [3][4][5][6][7][8][9][10]. Subsequently, talampanel (2) and CFM-2 (3) was identified, and showed highly active molecule with good results in various animal seizure models [11][12][13]. ...
... ).135 Scheme 62: Synthesis of 2,3-benzodiazepines from a ketoacid and hydrazine Alternatively, then precursor ketoester 206 can be prepared by Friedel-Crafts acylation of phenylacetic acid derivative 205 (scheme 63).136,137 Noteworthy, a solidsupported version of this strategy has been also developed.138 ...
... lmol/kg for (À)-(S)-3 vs. 88.4 lmol/kg for (þ)-(R)-3, in the clonic phase). 9 On these basis, the objective of the present research was to optimize a chromatographic method to efficiently resolve and isolate the enantiomers of (6)-(R,S)-2, to determine the absolute configuration and to evaluate the anticonvulsant activity of the single enantiomers. ...
The resolution of 1-(4-aminophenyl)-7,8-methylenedioxy-1,2,3,5-tetrahydro-4H-benzodiazepin-4-one (+/-)-(R,S)-2 was accomplished by chiral HPLC. The absolute configuration of (+)-2, determined by X-ray crystallographic analysis, was R. The in vivo anticonvulsant activity of the enantiomers (+)-(R)-2 and (-)-(S)-2 is reported. It has been also demonstrated that compound (+/-)-(R,S)-2 in vivo undergoes oxidative metabolism to derivative 1.
In this chapter, synthetic approaches to the preparation of seven-membered heterocycles such as azepines and benzodiazepines, oxazepines, thiazepines and dithiazepines are discussed. The data on the synthesis and biological properties of these heterocycles over the past 10–15 years are presented with an emphasis on one-pot preparation procedures. Two approaches are considered within the framework of one-stage synthesis of azepine derivatives – there are methods for recyclization of small and medium carbo-, oxa- or azacyclanes, as well as multicomponent heterocyclization reactions to prepare various compounds with azepine scaffolds.KeywordsAzepinesBenzodiazepinesDithiazepinesOxazepinesThiazepinesOne-pot synthesisBiomedical properties
Heterocycles including two adjacent nitrogen atoms were very popular in medicinal chemistry. More particularly, the five-membered ring pyrazole, as well as both six-membered rings pyridazine and 1,2,4-triazine, were extensively used in drug design. Indeed, thanks to the nitrogen atoms, these three aromatic scaffolds exhibit 2 to 3 H-bond acceptors, capable to interact with target proteins. Moreover, these nitrogen atoms allow to decrease the lipophilicity of these heterocycles in comparison with benzene. However, due to their aromatic character, these scaffolds have still a planar geometry, which constitutes a significant limitation in the search for complex molecular structures. In 2009, Franck Lovering from Wyeth proposed the concept “Escape from Flatland”, which means to avoid aromatics, in favour of saturated carbon bonds and chiral sp3 carbon atoms. The rational of this approach is that these non-planar molecules will be more natural product-like, and more amenable to explore additional areas of chemical space. Moreover, significant gains are expected in terms of ADME properties (solubility, biological selectivity, lipophilicity, etc). Despite the five-membered N-O heterocycles such as isoxazole or isooxazoline are well known, the corresponding six and seven-membered non-aromatic heterocycles exhibiting a N-O moiety are pretty rare in the literature. Besides the interesting non-planar geometry, the presence of the oxygen atom will strongly decrease the basicity of the adjacent nitrogen atom, endowing these N-O heterocycles particular physicochemical properties. Furthermore, the oximes ethers (=N-O-) possess a good resistance to protonation, which gives them better intrinsic stabilities towards hydrolysis than hydrazones or imines. Untill now, several alkoxyamides are under clinic trails. In this project, new non-planar N-O heterocycles, 3-amino-1,2,4-oxadiazine and benzo-2,3-oxazepin-4-one would be synthesized and their physicochemical properties would be measured. During this course, a radical reaction in water was established to introduce N-O moiety and a novel precatalyst was developed for Fukuyama cross-coupling reaction. Futhermore, we also attempted to synthesize the natural product alchornedine with the established synthetic methods for 3-amino-1,2,4-oxadiazine scaffold.
Heterocyclization of ethyl 2-acetyl(aroyl)-5-methylthieno[2,3-b]thiophene-3-acetates with hydrazine hydrate has been studied. A dependence of the reaction direaction on the nature of the substituent in the acyl fragment was established. The heterocyclization of ethyl 2-aroyl-5-methylthieno[2,3-b]thiophene-3-acetates leads to derivatives of thieno[3',2':4,5]thieno[2,3-d][1,2]diazepin-5-ones. The cyclization of ethyl 2-acetyl-5-methylthieno[2,3-b]thiophene-3-acetate with hydrazine hydrate forms a six-membered ring, viz. 2-aminothieno[3',2':4,5]thieno[2,3-c]pyridin-5(6H)-one.
A new synthetic approach to fused azepines was demonstrated on an example ofthe synthesis of 2-methyl-2,3,4,5-tetrahydro-1H-[1]benzothieno[2,3-c]azepine. The key stage of the synthesis is the formation of theazepine ring under the Eschweiler–Clark reaction conditions. The Gibbs energy ofactivation for the inversion of the azepine ring was determined by dynamic¹H NMR spectroscopy. Molecular modeling of thestructure and estimation of the ¹H and¹³C NMR chemical shifts were performed for2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine. The magnetic shielding tensors were calculated by thestandard GIAO method using the B3LYP/6-31G(d,p)-optimized molecular geometryparameters. The solvent effect was taken into account in the PCM approximation.The calculated ¹H and ¹³CNMR chemical shifts of 2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine are in good agreement with the experimental valuesobserved in the spectra of its DMSO-d6 solution.
In this study, substituted 2H‐indazolo[2,1‐b]phthalazine‐1,6,11‐trione compounds (4a–d) obtained via one‐pot three‐component condensation reaction of aromatic aldehydes, cyclic 1,3‐dione, and phthalhydrazide in ethanol catalyzed by Y(OTf)3 showed satisfactory inhibitory effects against some important enzymes. Also, these molecules had Ki values in the row of 185.92 ± 36.03‐294.82 ± 50.76 nM vs carbonic anhydrase I (CA I), 204.93 ± 46.90‐374.10 ± 83.63 nM against human CA II, 937.16 ± 205.82‐1021.83 ± 193.66 nM against α‐glycosidase (α‐Gly), respectively. For cholinesterase enzymes, the Ki values were found in the range of 47.26 ± 9.62‐72.05 ± 19.47 nM against acetylcholinesterase (AChE) and 65.03 ± 9.88‐102.83 ± 25.04 nM against butyrylcholinesterase (BChE), respectively. The inhibition effects of these compounds against enzymes whose name are AChE, BChE, α‐Gly, hCA I, and hCA II, were compared with control molecules like tacrine, acarbose, and acetazolamide.
Background
Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used therapeutics; they are competitive inhibitors of cyclooxygenase (COX), the enzyme which mediates the conversion of arachidonic acid to inflammatory prostaglandins.
Objective
In this study, new benzodioxol derivatives with different core cycles and functional groups (i.e., aryl acetate, aryl acetic acid and diazepine) were designed, synthesized, identified and evaluated for their analgesic and anti-inflammatory activity, as a preliminary screening study to identify the most potent and more selective groups.
Methods
The synthesized compounds were identified using FTIR, HRMS, 1H-NMR and 13C-NMR, and evaluated for their inhibitory activity against ovine COX-1 and COX-2 using an in-vitro cyclooxygenase (COX) inhibition assay kit.
Results
Six compounds were synthesized as a preliminary screening study to identify which was the most potent and more selective group towards COX-2 versus COX-1, compared to ketoprofen as nonselective NSAIDs. The compounds have three different groups: aryl acetate, aryl acetic acid and diazepine. The results showed that the most potent compound against the COX-1 enzyme was 4b (which has diazepine and 2-chlorophenyl) with IC50 = 0.363 µM, and the selectivity ratio of 4b was found to be better than ketoprofen. In contrast, compound 4a (which has diazepine and 3- chlorophenyl) was the most selective with a COX-1/COX-2 ratio value of 0.85 in comparison with a ketoprofen ratio value of 0.20.
Conclusion
In general, the synthesized library has moderate activity against both enzymes (i.e., COX-1 and COX-2). Moreover, all six compounds have better COX-2 inhibition selectivity compared to the commercial drug ketoprofen.
2,3-Benzodiazepine compounds are an important family of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) antagonists that act in a noncompetitive manner. Due to the critical role of AMPARs in the synapse and various neurological diseases, significant scientific interest in elucidating the molecular basis of the function of the receptors has spiked. The analogues were synthesized to assess the functional consequence of removing the amine group of the phenyl ring, the potency and efficacy of inhibition by substituting a halogen group at the meta vs ortho position of the phenyl ring, and layout the prediction of potential drug candidates for AMPAR hyperactivation. Using the whole-cell patch-clamp technique, we assessed the effect of the derivative on the amplitude of various AMPA-type glutamate receptors and calculated the desensitization and deactivation rates before and after treatment of HEK293 cells. We noticed that the amino group is not necessary for inhibition as long as an electron-withdrawing group is placed on the meta position of the phenyl ring of BDZ. Furthermore, compound 4a significantly inhibited and affected the desensitization rate of the tested AMPARs but showed no effect on the deactivation rate. The current study paves the way to a better understanding of AMPARs and provides possible drug candidates of 2,3-BDZ different from the conventional derivatives.
We report the first example of the construction of chiral 2,3-benzodiazepine compounds which are of biologic and pharmaceutical relevance by asymmetric catalysis. Catalyzed by a thiazolium derived carbene and a palladium-chiral bidentate phosphine complex in sequence, one-pot reaction between 1-(2-(2-nitrovinyl)aryl)allyl esters 1 with azodicarboxylates 2 took place efficiently at ambient temperature to produce 4-nitro-1-vinyl-1H-2,3-benzodiazepine-2,3-dicarboxylates 5 in good to excellent yields with an enantiomeric ratio up to 95 : 5.
A novel, fast and economic chiral HPLC method was developed and validated for the resolution of the four isomers of tofisopam. The separation capacity of eleven different chiral columns: six polysaccharide‐type including three amylose‐based (Chiralpak AD, Chiralpak AD‐RH and Chiralpak AS) and three cellulose‐based (Chiralcel OD, Chiralcel OJ and Lux Cellulose‐4); three cyclodextrin‐ (Quest‐BC, Quest‐C2 and Quest‐CM) and two macrocyclic glycopeptide antibiotic‐type (Chirobiotic T and Chirobiotic TAG) were screened using polar organic or reversed‐phase mode. Chiralpak AD, based on amylose tris(3,5‐dimethylphenylcarbamate) as chiral selector with neat methanol was identified as the most promising system. In order to improve resolution, an orthogonal experimental design was employed, altering the concentration of 2‐propanol, column temperature, and flow rate in a multivariate manner. Using the optimized method (85/15 v/v methanol/2‐propanol, 40°C, flow rate: 0.7 mL/min) we were not only able to separate the four isomers but also detect 0.1% S‐enantiomer as chiral impurity in R‐tofisopam. This is important since the latter is under development as a single enantiomeric agent. Thermodynamic investigation revealed an unusual entropy and enthalpy‐entropy co‐driven controlled enantioseparation on Chiralcel OJ and on Chiralpak AD column, respectively. Our newly developed HPLC method was validated according to the ICH guidelines and its application was tested on a pharmaceutical formulation containing the racemic mixture of the drug. As a further novelty, a separate circular dichroism method was applied for the investigation of the interconversion kinetics of tofisopam conformers, which proved to be crucial for sample preparation and method validation.
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A C–H activation-based strategy has been developed for the synthesis of N-amino azaheterocycles. Rh(III)-catalyzed coupling of N-Boc hydrazones/N-Boc hydrazines with diazodiesters/diazoketoesters provides convenient access to synthetically and medicinally important compounds, N-amino isoquinolin-3-ones and N-amino indoles, by harnessing N-tert-butyloxycarbonyl (N-Boc) cleavage as an adaptable reactivity pattern in distinct synthetic scenarios.
An efficient Rh(III)-catalyzed C–H activation protocol has been developed for the synthesis of 2,3-benzodiazepines with use of N-Boc hydrazones and diazoketoesters as substrates. The reaction features retention of the C═N and N–N bonds and selective cleavage of the N-Boc moiety.
In this work, we designed and synthesized novel N-3-bromoisoxazolin-5-yl substituted 2,3-benzodiazepines as noncompetitive AMPAR antagonists, with the aim that this heterocycle could establish favourable interactions with a putative binding pocket of the receptor, like the thiadiazole nucleus of GYKI 47409 does. Within this investigation, we identified some active molecules and, among these 2,3-benzodiazepines, 4c showed a much improved inhibitory potency as compared with unsubstituted 2,3-benzodiazepines.
New derivatives of 11,12-dihydroquinazolino[3,2-c][2,3]benzodiazepin-14(6H)-one have been synthesized. 11-(2-Thienyl)- and 11-(5-R-2-furyl)-substituted compounds were prepared by the Pictet–Spengler reaction of 3-amino-2-(3,4-dimethoxybenzyl)quinazolin-4(3H)-one with heterocyclic aldehydes in aprotic media. Their chemical structures were confirmed by ¹H and ¹³C NMR spectroscopy and mass spectrometry. We observed the opening of diazepine ring in 8,9-dimethoxy-11-(5-chloro-2-furyl)-11,12-dihydroquinazolino[3,2-c][2,3]benzodiazepin-14(6H)-one when treated with trifluoroacetic acid, and the structure of the product was determined by NMR (¹H, ¹³C, HSQC, HMBC experiments) and mass spectrometry data. The crystal structure of 3-amino-2-[4,5-dimethoxy-2-[(5-oxofuran-2(5H)-yliden)methyl]benzyl]quinazolin-4(3H)-one was confirmed by single-crystal X-ray analysis.
Representatives of new tricyclic ring systems based upon the pyrrolotriazepine core, have been synthesized at our laboratory using cycloaddition reactions of 1-aryl-pyrrolotriazepinones or 1,4-diarylpyrrolotriazepines in a dichloromethane solution at room temperature, with nitrile oxides generated in situ from N-hydroxyarylcarboximidoyl chlorides with triethylamine. The reaction between 1-aryl-3. H-pyrrolo[2,1-d][1,2,5]triazepin-4(5. H)-ones and the corresponding nitrile oxides led to 3,11b-diaryl-5. H,11b. H-[1,2,4]oxadiazolo[4,5-b]pyrrolo[2,1-d][1,2,5]triazepin-6(7. H)-one derivatives. Cycloaddition reactions of 1,4-diaryl-5. H-pyrrolo[2,1-d][1,2,5]triazepines under similar conditions gave two products, depending on which double bond was involved in the cycloaddition: 3,6,11b-triaryl-7. H,11b. H-[1,2,4]oxadiazolo[4,5-b]pyrrolo[2,1-d][1,2,5]triazepines and 3,6,11a-triaryl-11,11a-dihydro[1,2,4]oxadiazolo[4,5-b]pyrrolo[1,2-e][1,2,5]triazepines. The structures of the new compounds were also justified by 2D NMR and single-crystal X-ray measurements.
A preparative procedure has been developed for the synthesis of 4-oxo-7-phenyl-5,8-dihydro-4H-pyrazolo[ 5,1-d][1,2,5]triazepine-2-carbohydrazide, the first representative of a new heterocyclic system, by recyclization of methyl 4-oxo-6-phenyl-4H-pyrazolo[5,1-c][1,4]oxazine-2-carboxylate with hydrazine hydrate.
A preparative procedure has been developed for the synthesis of substituted 5,7-dihydropyrrolo-[3,4-d][1,2]diazepines by recyclization of 6-phenylpyrano[3,4-c]pyrrol-4(2H)-one with hydrazine hydrate. The stability of the seven-membered ring in the products under acidic conditions, alkylation, and heteroring fusion to the diazepine ring have been studied.
Representatives of a new compound family, 9-aryl-5H-imidazo[2,1-d][1,2,5]triazepin-6(7H)-ones have been synthesized. As structural analogues of biologically active 1-aryl-2,3-benzodiazepine-4-ones, these compounds are potential drug candidates in the diseases of the central nervous system. An efficient five-step synthesis starting from imidazole is described here for the preparation of the target compounds. Shorter routes have also been studied, however, these attempts failed.
In a previous paper, we have disclosed a practical synthesis of 1-aryl-3H-pyrrolo[2,1-d][1,2,5]triazepin-4(5H)-ones. Now, these compounds have been used as the starting materials for the synthesis of three new ring systems, pyrrolotriazepines condensed with an imidazole, a triazole, or a tetrazole ring. The newly synthesized compounds are structurally closely related to tricyclic derivatives known from the literature as strong anticonvulsant agents.
The classical, widely-used synthesis of the anxiolytic drug tofisopam applies chromium(VI) oxide reagent for the synthesis of the diketone key intermediate. The chromium salts formed in the course of the reaction are strongly toxic compounds. In order to reduce the reagents contributing to the pollution of the environment, an alternative manufacturing process has been elaborated at our laboratory. Starting compound (3,4-dimethoxyphenyl)acetone was transformed to the ethylene ketal of (2-bromo-4,5-dimethoxyphenyl)acetone. Bromine-lithium exchange and introduction of a 3,4-dimethoxybenzoyl moiety resulted in the new key intermediate. Removal of the ketal protecting group and ring closure with hydrazine was carried out in one pot affording drug substance tofisopam.
Through a cell-based biological screening, the benzocinnolinone derivative (±)-2c was identified as a promising STAT3 inhibitor. Since SAR studies on a series of compounds structurally related to (±)-2c (1c, 2a-p, 3c, 4c, 6) showed that the latter had the most significant inhibitory activity, we investigated in depth its essential structural features. In particular, enantiomeric separation was performed, and the absolute configuration of the stereoisomers was assigned by theoretical and crystallographic studies. The biological evaluation highlighted that (S)-(−)-2c is twice as potent as (R)-(+)-2c.
Signal Transducer and Activator of Transcription 3 (STAT3) is a cytoplasmic factor that mediates intracellular signaling commonly generated at cell surface receptors and transmits it to the nucleus. In previous research studies we synthesized several molecules inhibiting STAT3 and among them oxadiazole MD77 and pyridazinone I showed an interesting activity. For the first one, a direct inhibition mechanism was determined, while I interfered within the STAT3 pathway at a different level. In order to discover novel compounds possibly endowed with an improved activity, we decided to merge their scaffolds on the basis of their calculated conformational properties. Therefore we designed and synthesized the chimera diastereomers 3-oxo-N-(4-(trifluoromethyl)phenyl)-2,3,4,4a,5,6-hexahydrobenzo[h]cinnoline-6-carboxamide (1, 2) and 3-oxo-N-(4-(trifluoromethyl)phenyl)-2,3,5,6-tetrahydrobenzo[h]cinnoline-6-carboxamide (3) as racemate and their enantiomeric separation was performed. Modeling studies and theoretical prediction of [α]D values were carried out beside NMR studies which allowed us to assign 1 and 2 relative configurations.
Concise cascade reactions of pyruvates with aldehydes that generate functionalized dihydropyran derivatives in one pot have been developed. The product, dihydropyrans were further concisely transformed to various molecules.
Representatives of a new family, 1-aryl-3H-pyrrolo[2,1-d][1,2,5]triazepin-4(5H)-ones have been synthesized at our laboratory as bioisosters of biologically active 1-aryl-2,3-benzodiazepine-4-ones. The efficient synthetic route described applies the synthesis of 2-(2-aroylpyrrol-1-yl)acyl hydrazides followed by ring closure under acidic conditions. The N(3)-unsubstituted title compounds thus obtained can optionally be N-alkylated rendering the preparation of variously substituted derivatives possible. Scope and limitations of the new protocol and some interesting side reactions are also discussed in detail.
Novel 3-alkyl-4,1-benzoxazepine-2,5-diones were synthesized in good ee exploiting the chiral pool methodology, an economical way of asymmetric synthesis. Various anthranilic acids are coupled with different α-haloacids to afford N-acylated anthranilic acid intermediates which undergo cyclization to (3R)-3-alkyl-4,1-benzoxazepines-2,5-diones. Chirality 00:000-000, 2013. © 2013 Wiley Periodicals, Inc.
An efficient method for preparing 2-alkylsulfanyl-3H-4,5-dihydro- 1,3-benzodiazepin-4-ones and 2-alkylsulfanyl-3H-4,5-dihydro- 1,3-benzodiazepine-4-thiones under mild conditions has been developed. Thus, 2-(2-isocyanophenyl)acetamides and 2-(2-isocyanophenyl)thioacetamides, easily available from respective 1-isocyano-2-methylbenzenes, were converted into the corresponding isothiocyanates on treatment with sulfur in the presence of a catalytic amount of selenium, which were then reacted with an equimolar amount to sodium hydride to give 2-(sodiosulfanyl)-3H-4,5-dihydro-1,3-benzodiazepin-4-one and 2-(sodiosulfanyl)-3H-4,5-dihydro- 1,3-benzodiazepine-4-thione intermediates, respectively. These intermediates were allowed to react with various alkyl halides to afford the desired benzodiazepinone or benzodiazepinethione derivatives in a one-pot reaction.
A series of 1-aryl-6,7-disubstituted-2H-isoquinolin-3-ones (2-10) was synthesized and evaluated for their inhibition against Plasmodium falciparum cysteine protease falcipain-2, as well as against cultured P. falciparum strain FCBR parasites. All compounds displayed inhibitory activity against recombinant falcipain-2 and against in vitro cultured intraerythrocytic P. falciparum, with the exception of 9. The new compounds exhibited no selectivity against human cysteine proteases such as cathepsins B and L. The inhibitory activity of the synthesized compounds was also evaluated against another protozoal cysteine protease, namely rhodesain of Trypanosoma brucei rhodesiense.
Efficient synthesis of 3,4-diazabenzo[b]tropone was first achieved utilizing 4pi-8pi sequential electrocyclic reactions of functionalized benzocyclobutenone derivatives. These compounds are highly electron deficient and readily form amine adducts at ambient temperature. Furthermore, gentle heating resulted in quantitative nitrogen extrusion to produce indenone derivatives. These diazabenzotropones were found to exhibit potent apoptosis-inducing activity against human lymphoma cells. Thus, novel amine-catalyzed nitrogen extrusion reactions and interesting bioactivities were found to be characteristic of these novel diazabenzotropone compounds.
2,3‐Benzodiazepine derivatives : 1‐(4‐Aminophenyl)‐3,5‐dihydro‐3‐ N ‐ethylcarbamoyl‐5‐methyl‐7,8‐methylenedioxy‐4 H ‐2,3‐benzodiazepin‐4‐one was synthesized, and its enantiomers were separated by chiral HPLC. Pharmacological evaluation of each enantiomer showed that ( S )‐(−)‐ 5 appears to be more potent than its optical antipode ( R )‐(+)‐ 5 in an AMPA receptor binding assay. magnified image
The resolution of 1‐(4‐aminophenyl)‐3,5‐dihydro‐3‐N‐ethylcarbamoyl‐5‐methyl‐7,8‐methylenedioxy‐4 H ‐2,3‐benzodiazepin‐4‐one ( R,S )‐(±)‐ 5 by chiral HPLC and assignment of the absolute configuration of the two enantiomers was carried out. Compound ( R,S )‐(±)‐ 5 and its enantiomers were tested in a binding assay to evaluate their affinity for AMPA receptors. Enantiomer ( S )‐(−)‐ 5 appears to be more potent than its optical antipode ( R )‐(+)‐ 5 . In a primary culture of rat cerebellar granule cells, which express AMPA receptors, ( R,S )‐(±)‐ 5 and ( S )‐(−)‐ 5 inhibited kainate‐ induced [Ca ²⁺ ] i increase, thus confirming the antagonism at the AMPA receptor.
1-(3,4-Dimethoxyphenyl)-4-methyl-5-ethyl-7,8-dimethoxy-5H-2,3-benzodiazepine (tofisopam) contains one chiral center, so two enantiomeric forms exist. The ring system of tofisopam possesses two sterically stable boat structures, leading to two distinct conformers for each enantiomer. A method was developed for the separation of these enantiomers and conformers in the drug substances and drug products. Separation was achieved with a separation factor of at least 3.9 for any adjacent peaks. Validation of the method challenged linearity, limit of detection, limit of quantification, specificity, accuracy, repeatability, intermediate precision, robustness, and stability of standard and sample solutions, and all validation results met the acceptance criteria. A study of accuracy at 80%, 100%, and 120% levels gave recoveries of 100 +/- 1%. The RSD of six sample injections for repeatability was less than 0.5%. The detection limit of tofisopam enantiomer was as low as 0.12 microg/mL. The kinetics and thermodynamics of the interconversion of tofisopam conformers were also investigated, and the kinetic and equilibrium constants of the interconversion process were determined at 15 degrees C, 25 degrees C, and 35 degrees C.
Efficient transformations of benzocyclobutenones into 2,3-benzodiazepines by a formal insertion of diazomethylene compounds are described. This sequential process includes nucleophilic addition of diazomethylene anion, oxy-anion accelerated o-quinodimethane formation by an electrocyclic ring-opening reaction, and 8pi-electrocyclization in one-pot under remarkably mild conditions. Intermediary oxy-anion plays an important role for the efficient transformations.
Small ring systems are important topics in both organic and inorganic chemistry, and draw considerable attention from both theoretical and preparative perspectives. This review intends to summarize the studies, focusing on the preparative aspects, that have been carried out in our laboratory. Namely, synthesis of (+)- and (-)-alpha-cuparenone, (+)-ipomeamarone, (+)-epiipomeamarone, (-)-ngaione, (-)-alpha-bisabolol, (-)-aplysin, (-)-debromoaplysin, (-)-mesembrine, (-)-filiformin, (-)-debromofiliformin, and (-)-4-deoxyverrucarol via successive asymmetric epoxidation and enantiospecific ring expansion of cyclopropylidenes, (+)-equilenin via successive ring expansion-insertion reaction, estrone, estradiol, chenodeoxycholic acid, 19-norspironolactone, 19-nordeoxycorticosterone, cortisone, adrenosterone, 11-oxoprogesterone, and 1alpha,25-dihydroxyvitamin D3 via intramolecular cycloaddition reaction of o-quinodimethanes. Medicinal chemistry aiming at developing a new type of anti-influenza agent, novel reaction mode of electrocyclic reaction, and substituent effect on that reaction are also discussed.
AMPA receptors are fast ligand-gated members of glutamate receptors in neuronal and many types of non-neuronal cells. The heterotetramer complexes are assembled from four subunits (GluR1-4) in region-, development- and function-selective patterns. Each subunit contains three extracellular domains (a large amino terminal domain, an agonist-binding domain and a transducer domain), and three transmembrane segments with a loop (pore forming domain), as well as the intracellular carboxy terminal tail (traffic and conductance regulatory domain). The binding of the agonist (excitatory amino acids and their derivatives) initiates conformational realignments, which transmit to the transducer domain and membrane spanning segments to gate the channel permeable to Na+, K+ and more or less to Ca2+. Several 2,3-benzodiazepines act as non-competitive antagonists of the AMPA receptor (termed also negative allosteric modulators), which are thought to bind to the transducer domains and inhibit channel gating. Analysing their effects in vitro, it has been possible to recognize a structure-activity relationship, and to describe the critical parts of the molecules involved in their action at AMPA receptors. Blockade of AMPA receptors can protect the brain from apoptotic and necrotic cell death by preventing neuronal excitotoxicity during pathophysiological activation of glutamatergic neurons. Animal experiments provided evidence for the potential usefulness of non-competitive AMPA antagonists in the treatment of human ischemic and neurodegenerative disorders including stroke, multiple sclerosis, Parkinson's disease, periventricular leukomalacia and motoneuron disease. 2,3-benzodiazepine AMPA antagonists can protect against seizures, decrease levodopa-induced dyskinesia in animal models of Parkinson's disease demonstrating their utility for the treatment of a variety of CNS disorders.
In the search for AMPA receptor (AMPAR) antagonists, 2,3-benzodiazepines represent a family of specific noncompetitive antagonists with anticonvulsant and neuroprotective properties. We have previously shown that 2,3-benzodiazepin-4-ones possess marked anticonvulsant properties and high affinity for the noncompetitive binding site of the AMPAR complex. In this paper, we report the synthesis and pharmacological characterization of a full set of 2,3-benzodiazepin-4-ones in order to better define the structure-activity relationship (SAR) of this class of compounds. Binding assays and functional tests were performed to evaluate the antagonistic activity at the AMPARs. Through these results we have identified a potent AMPAR antagonist, 1-(4-amino-3-methylphenyl)-3,5-dihydro-7,8-ethylenedioxy-4H-2,3-benzodiazepin-4-one (5c). This compound noncompetitively inhibited AMPAR-mediated toxicity in primary mouse hippocampal cultures with an IC(50) of 1.6muM and blocked kainate-induced calcium influx in rat cerebellar granule cells with an IC(50) of 6.4muM. Thus, 5c has the in vitro potential as therapeutic drug in the treatment of various neurological disorders.
The absolute configuration of the (+)-1,1-dimethyl-2-phenylethyl phenyl sulfoxide is determined to be (R), using three different chiroptical spectroscopic methods, namely vibrational circular dichroism (VCD), electronic circular dichroism (ECD) and specific rotation. Four solution conformations are identified for 1,1-dimethyl-2-phenylethyl phenyl sulfoxide. In each of the methods used, experimental data for the enantiomers of 1,1-dimethyl-2-phenylethyl phenyl sulfoxide were measured in the solution phase and concomitant quantum mechanical calculations of corresponding properties were carried out using density functional theory with B3LYP functional and 6-31G* and 6-31+G basis sets. Additional VCD and ECD calculations were also undertaken with 6-311G(2d,2p) basis set. A comparison of theoretically predicted data with the corresponding experimental data has allowed us to elucidate the absolute configuration and predominant conformations of (+)-1,1-dimethyl-2-phenylethyl phenyl sulfoxide.
A new theory of solvent effects on the optical rotations of chiral molecules is presented. The frequency-dependent electric dipole-magnetic dipole polarizability, beta(alphabeta)(nu), is calculated using density functional theory (DFT). Solvent effects are included using the polarizable continuum model (PCM). DFT/PCM calculations of sodium D line specific rotations, [alpha](D), have been carried out for seven conformationally rigid chiral organic molecules (fenchone, camphor, alpha-pinene, beta-pinene, camphorquinone, verbenone, and methyloxirane) for a diverse set of seven solvents (cyclohexane, carbon tetrachloride, benzene, chloroform, acetone, methanol, and acetonitrile). The predicted variation in [alpha](D) for the solvents cyclohexane, acetone, methanol, and acetonitrile are in excellent agreement with experiment for all seven molecules. For the solvents carbon tetrachloride, benzene, and chloroform, agreement is much poorer. Since only electrostatic solute-solvent interactions are included in the PCM, our results lead to the conclusion that, for the seven molecules studied, in cyclohexane, acetone, methanol, and acetonitrile electrostatic effects are dominant while in carbon tetrachloride, benzene, and chloroform other nonelectrostatic effects are more important. The observed variations in [alpha](D) with solvent are inconsistent, both qualitatively and quantitatively, with the variations predicted by the equation [alpha](D)(solvent) = {[alpha](D)(gas)}(n(D)(2) + 2)/3.
Detailed SAR examination and DIStance COmparison (DISCO) computation were used for identification and superposition of common structural features of 2,3-benzodiazepines with high affinity to an allosteric AMPA binding site. Two similar 4-point models were identified; both contained 2 donor sites, a donor atom and a hydrophobic centre. At one of the donor sites a characteristic difference between the two models was observed.
Previous attempts to combine Hartree–Fock theory with local density‐functional theory have been unsuccessful in applications to molecular bonding. We derive a new coupling of these two theories that maintains their simplicity and computational efficiency, and yet greatly improves their predictive power. Very encouraging results of tests on atomization energies, ionization potentials, and proton affinities are reported, and the potential for future development is discussed.
The enzymatic hydrolysis of a series of carboxylic esters by carboxylesterase NP has been investigated in order to determine the scope and limitations of this enzyme. 2-Substituted propionates were hydrolyzed with high enantioselectivity when an aromatic moiety was part of the 2-substituent. Enantioselective hydrolysis could be accomplished with several 2-arylpropionates, 2-(aryloxy)propionates and N-arylalanine esters. The propionate esters yielded propionic acids as (S) enantiomers, whereas the alanine esters yielded the (R) enantiomers. Without a 2-aryl substituent, the enzymatic hydrolysis of the propionates occurred at a lower rate without acceptable enantioselectivity. In addition to 2-substituted propionates, only a few other esters were hydrolyzed with high enantioselectivity by carboxylesterase NP, such as some prochiral disubstituted malonates. 1-Phenylethyl acetate was the only substrate with chirality in the alcohol part of the ester that was found to be hydrolyzed enantioselectively.
Carboxylesterase NP proved to be a powerful enzyme for kinetic resolution of propionate esters with an aromatic ring containing a 2-substituent.
A new method for obtaining optimized parameters for semiempirical methods has been developed and applied to the modified neglect of diatomic overlap (MNDO) method. The method uses derivatives of calculated values for properties with respect to adjustable parameters to obtain the optimized values of parameters. The large increase in speed is a result of using a simple series expression for calculated values of properties rather than employing full semiempirical calculations. With this optimization procedure, the rate-determining step for parameterizing elements changes from the mechanics of parameterization to the assembling of experimental reference data.
Microcrystalline triacetylcellulose (dp = 10–20 μm) was used for analytical liquid chromatography at pressures around 50 bar. 1,3,5-Tri-tert.-butylbenzene is proposed as a compound which is not retained on this sorbent. Thus, reliable information about porosity, linear flow-rates, u, and relative retentions become available for the first time. An attempt was made to obtain the plate height, H, dependence upon u in ethanol. For three racemates, comparable data with four eluents were obtained and discussed with a view to future separtions of enantiomers. A general increase of H values of the enantiomers with increasing k′ is found for triacetylcellulose as a sorbent.
A method is presented which utilizes the calculation of the molecular electrostatic potential or the electric field at a discrete number of preselected points to evaluate the environmental effects of a solvent on the properties of a molecular system. No limitations are imposed on the composition and dimension of the solute, on the goodness of the corresponding wavefunction, or on the shape of the cavity in the dielectric. Several levels of approximation, which evidence the effect of self-polarization of the system of surface charges, the influence of the tails of the solute charge distribution going beyond the limits of the cavity, and the effect of the polarization of the solute, are examined and discussed.
Despite the remarkable thermochemical accuracy of Kohn–Sham density-functional theories with gradient corrections for exchange-correlation [see, for example, A. D. Becke, J. Chem. Phys. 96, 2155 (1992)], we believe that further improvements are unlikely unless exact-exchange information is considered. Arguments to support this view are presented, and a semiempirical exchange-correlation functional containing local-spin-density, gradient, and exact-exchange terms is tested on 56 atomization energies, 42 ionization potentials, 8 proton affinities, and 10 total atomic energies of first- and second-row systems. This functional performs significantly better than previous functionals with gradient corrections only, and fits experimental atomization energies with an impressively small average absolute deviation of 2.4 kcal/mol.
The concentration of intracellular free Ca2+ ([Ca2+]i) was measured in rat cerebellar granule cells using the fluorescent indicator fura-2. Culturing the cells as monolayers on plastic squares which could be placed into cuvettes allowed measurements of [Ca2+]i to be performed on large and homogeneous populations of CNS neurons. Granule cells so cultured maintained low levels of [Ca2+]i (around 90 nM) which increased promptly upon the addition of various excitatory amino acids including N-methyl-D-aspartate (NMDA). Increases in [Ca2+]i elicited by NMDA were inhibited by Mg2+ (1 mM) and often potentiated by glycine (1 microM). The addition of TTX or strychnine (5 microM each) did not alter responses to NMDA or NMDA plus glycine. Cytosolic Ca2+ responses to NMDA/glycine were dependent on the presence of extracellular Ca2+ and were unaffected by concentrations of nifedipine or verapamil that blocked increases in [Ca2+]i elicited by K+ depolarization. Responses elicited by NMDA/glycine were inhibited competitively by 2-amino-5-phosphonovalerate or 3-((+-)-2-carboxypiperazin-4-yl)-propyl-1- phosphonic acid and non-competitively by MK-801 or Mg2+. HA-966 and 7-chlorokynurenate inhibited responses to NMDA alone and blocked competitively the potentiating effects of glycine. The results demonstrate NMDA-mediated increases in [Ca2+]i in cerebellar granule cells that arise solely from influx of extracellular Ca2+ through dihydropyridine-insensitive channels. The strict dependence of the NMDA-evoked response on extracellular Ca2+ provides little evidence for a coupling of NMDA receptors to inositol phosphate metabolism and mobilization of intracellular Ca2+. The effect of various agents on NMDA/glycine-induced increases in [Ca2+]i parallels their effects on ligand binding to or current flow through the NMDA receptor-channel complex. The measurement of cytosolic Ca2+ in this preparation of neuronal cells thus appears especially well suited for assessing, on a functional level, the regulation of NMDA receptors in the CNS.
Strychnine-insensitive [3H]glycine binding was detected in brain synaptic membranes treated with Triton X-100 using a filtration assay method. The binding was a time-dependent, inversely temperature-dependent, and reversible process with a relatively high affinity for the neuroactive amino acid. Scatchard analysis revealed that Triton treatment doubled both the affinity and density of the binding sites, which consisted of a single component. The binding was not only displaced by structurally-related amino acid such as D-serine and D-alanine, but also inhibited by some peptides containing glycine, including glycine methylester and N-methylglycine. These ligands invariably potentiated the binding of [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]- cyclohepten-5,10-imine ([3H]MK-801), a noncompetitive antagonist for the N-methyl-D-aspartate-sensitive subclass of the central excitatory amino acid receptors, in a concentration-dependent manner. Among various endogenous tryptophan metabolites, kynurenic acid significantly inhibited the strychnine-insensitive [3H]glycine binding. The Triton treatment did not affect the pharmacological profile of [3H]MK-801 binding sites. These results suggest that brain synaptic membranes treated with Triton X-100 are useful in evaluating the strychnine-insensitive and kynurenate-sensitive binding sites of glycine, which are functionally linked to N-methyl-D-aspartate- sensitive receptor channels.
Convulsive dose 50s (CD 50 s) for various convulsive drugs and minimal and maximal electroshock seizure thresholds were determined in DBA and C57 mice. DBA mice had lower maximal electroshock seizure thresholds (MESTs, 15%) and CD 50 s for homocysteine thiolactone (HTL, 23%) and bicuculline (69%), and a higher CD 50 for pentylenetetrazol (PTZ) at 3 weeks of age, the age of maximal audiogenic seizure (AGS) susceptibility. At 8 weeks, when DBA mice are not susceptible to AGSs, significant differences were a lower minimal electroshock seizure threshold (mEST, 37%) and maximal EST (MEST) (19%), lower CD so s for N‐methyl‐D‐aspartate (NMDA) (39%), kainic acid (KA, 50%), HTL (32%), strychnine (37%), and a higher CD 50 for nicotine (55%) in DBA mice. Based on these data it is suggested that pathways involving NMDA and KA receptors are responsible for increased susceptibility to seizure initiation (mEST), and are opposed by glycine pathways, and that opposing GABA and cholinergic systems at higher CNS levels are involved in seizure spread (AGSs and MEST) in these mice. Latency patterns indicate that nicotine, strychnine, PTZ and bicuculline have high blood‐brain barrier (BBB) penetrability. Picrotoxin and the excitatory amino acid receptor agonists had longer latencies, suggesting low BBB penetrability. Age‐related changes in latency, however, give evidence that difficulty in drug penetration of the BBB is not responsible for differences observed in CD 50 s between strains.
RÉSUMÉ
La dose convulsivante 50 (DC 50 ) de différents médicaments convulsivants, et le seuil critique minimal et maximal à l'éiec‐trochoc ont éteéétudiés ches les souris DBA et C57. Les souris DBA avaient des seuils convulsivants maximaux a l'eiectrochoc (SCME) plus bas (15%) et des DC 50 plus basses pour homocysteine thiolactone (HTL, 23%) et la bicuculline (69%), mais une DC 50 plus élevée pour le pentylenetetrazol (PTZ) à l'âge de 3 semaines, qui est l'âge de la susceptibilityé maximale aux crises audiogéniques (CAG). A 8 semaines, lorsque les souris DBA ne sont pas susceptibles aux CAG, les différences significatives sont représentées par un abaissement du seuil critique minimal a l'éiectrochoc (SCmE, 37%) et du SCME (19%), des DC 50 abais‐sées pour le N‐methyl‐D‐aspartate (NMDA, 39%), l'acide kai‐nique (AK, 50%), l'HTL (32%), la strychnine (37%), et une DC 50 dlevee pour la nicotine (55%) chez les souris DBA. Ces résultats suggerent que les circuits impliquant les récepteurs au NMDA et à l'AK sont responsables d'une susceptibilityé accrue à la provocation des crises (SCmE), et sont contrés par les circuits impliquant la glycine; les systèmes opposes GABAergiques et cholinergiques, à un niveau supérieur du SNC, seraient quant à eux impliqués dans l'extension des crises (susceptibilityé aux CAG et SCME) chez ces souris. Les latences relevées indiquent que la nicotine, la strychnine, le PZT et la bicuculline présentent une pénétration éievée a travers la barrière hémato‐encéphalique. La picrotoxine et les agonistes des récepteurs aux acides aminés excitateurs présentaient des latences plus longues, ce qui suggère que leur pénétration est plus difficile. Les modifications de pénétrabilité de la barrière hematoencephalique liees à l'âge montrent cependant que la difficulté pour un produit à passer la barrière hémato‐encéphalique n'est pas responsable des différences observées dans les DC 50 entre ces souches.
RESUMEN
En ratones DBA y C57 se han determinado las dosis convul‐sivas (CD 50 s) de varias medicaciones convulsiveógenas y los umbrales de ataques de electroshock minimo y maximo. Losra‐tones DBA mostraron un umbral reducido para ataques de electroshock máximo (MESTs, 15%) y un CD 50 s para homo‐cistein‐tiolactona (HTL, 23%) y bicuculina (69%), y un mayor CD 50 para pentilentetrazol (PTZ) a las 3 semanas de edad, que constituye la edad de máxima susceptibilidad para ataques audiogénics (AGS). A las 8 semanas, cuando los ratones DBA no son susceptibles a los AGSs, las diferencias significativas fueron: un umbral para ataques de electroshock mínimo más reducido (mEST, 37%) y MEST (19%), un CD 50 s más bajo para el N‐metil‐D‐aspartato (NMDA) (29%), el ácido caínico (KA, 50%), el HTL (32%), y la estricnina (37%), y un CD 50 más elevado para la nicotina (55%). Según esta informatión se sugiere que la vía de los receptores NMDA y KA es responsable del incremento de la susceptibilidad para la initiateón de los ataques (mEST) y está en oposición a las vías de la glicina. Los opuestos sistemas, GABAérgico y colinérgico, que actúan a niveles más elevados en el Sistema Nervioso Central parecen intervenir en la propagateón de los ataques (AGSs y MEST) en estos ratones. Los pa‐trones de latencia indican que la nicotina, estricnina, PTZ y bicuculina tienen una penetración más elevada a través de la barrera hémato‐encefálica (BBB). La picrotoxina y el aminoácido exci‐tador de los receptores agonístas poseen latencias más prolongadas lo que sugiere una penetración más reducida a traves de la BBB. Los cambios en las latencias relacionadas con la edad, sin embargo, ofrecen evidencia para deducir que la dificultad en la penetrateón de la droga a través de la BBB no es responsable de las diferencias observadas en los CD 50 s entre los diversos tipos de animates.
ZUSAMMENFASSUNG
Die anfallserzeugende CD 50 ‐Dosis für verschiedene Konvul‐siva sowie minimale und maximale Elektroschock‐ Anfalls‐schwellen wurden bei DBA‐ und C57 Mäusen bestimmt. DBA‐Mäuse hatten eine niedrigere maximale Elektroschockan‐fallsschwelle (MEST 15%) und eine niedrigere CD 50 fur Homozystein‐Thiolacton (HTL, 23%) und Bicucullin (69%) sowie eine hohere CD 50 für Pentylentetrazol (PTZ) im Alter von 3 Wochen, dem Alter großerer Empfindlichkeikt für audiogene Anfälle. Mit 8 Wochen, wenn DBA Mäuse nicht mehr für audio‐gene Anfälle empfänglich sind, lagen signifikante Unterschiede in einer niedrigeren minimalen Elektroschockanfallsschwelle (mEST 37%) und maximalen Elektroschockschwelle (MEST 19%), einer niedrigeren CD 50 für N‐Methyl‐D‐Aspartat (N‐MDA 39%), für Kainic Acid (KA 50%), für HTL (32%), Strychnin (37%) sowie eine hohere CD 50 für Nikotin (55%) bei DBA Mausen vor. Aufgrund dieser Daten wird vermutet, daß Lei‐tungsbahnen, die NMDA‐ und KA‐ Rezeptoren einschließen, für eine erhöhte mEST‐ Empfindlichkeit verantwortlich sind. Ihnen wirken Glycin‐Leitungsbahnen entgegen. Gegensätzliche GABA‐ und cholinerge Systeme sind auf höherem CNS‐ Niveau bei der Anfallsausbreitung (AGS und MEST) bei diesen Mausen beteiligt. Das Latenzmuster zeigt eine hohe Bluthirnschranke an für Nikotin, Strychnin, PTZ und Bicucullin. Picrotoxin und ex‐zitatorische Aminosäuren Rezeptor‐Agonisten haben längere Latenzzeiten als Hinweis auf eine niedrige Durchlassigkeit der Bluthirnschranke. Altersabhangige Veränderungen der Latenz zeigen, daß die Schwierigkeit der medicamentösen Durchlassigkeit der Bluthirnschranke nicht für die beobachteten CD 50 ‐Unterschiede zwischen den verschiedenen Stämmen verantwortlich ist.
The anticonvulsant actions of DS 103-282 [5-chloro-4-(2-imidazolin-2-yl-amino)-2,1,3- benzothiadazole , tizanidine], have been evaluated after intraperitoneal administration in DBA/2 mice (seizures induced by sound), in Swiss S mice (seizures induced by N-methyl-D,L-aspartate; NMDLA ) and following intravenous or oral administration in Papio papio (seizure responses to intermittent photic stimulation). Protection against sound-induced seizures occurred after intraperitoneal administration of DS 103-282 (0.66-3.33 mg/kg). The ED50 doses for suppression of the tonic, clonic and wild-running phases of sound-induced seizures were 0.53, 0.79 and 1.3 mg/kg respectively. This protective effect of DS 103-282 (1.5 mg/kg, i.p.) was maximal after 30 min and was maintained for 60-120 min. Seizures induced by NMDLA were not suppressed by DS 103-282 (3.3-10 mg/kg, i.p.). In the baboons, a transient protection against photomyoclonic responses was observed 1 hr after intravenous administration of DS 103-282 (2-4 mg/kg). A similar profile of action was seen after oral administration of larger doses of DS 103-282 (16-32 mg/kg). Unwanted effects of DS 103-282 included transient piloerection, slight disturbance of gait and a fall in rectal temperature in mice, and muscular hypotonia and signs of sedation in baboons. These studies demonstrate an anticonvulsant action of DS 103-282, in both rodent and primate models of epilepsy, but do not support a postsynaptic blockade in excitatory neurotransmission as the mechanism of this action.
The syndrome of sound-induced seizures in DBA/2 mice is described. Protection against seizure responses is provided by intraperitoneal administration of conventional anticonvulsant drugs with benzodiazepines being the most potent, and valproate, ethosuximide and trimethadione the least potent. Protection is also provided by intracerebroventricular administration of anticonvulsant drugs. GABAergic agents, antagonists of excitation due to dicarboxylic amino acids, alpha 2-noradrenergic agonists, and dopamine agonists all provide protection against the seizure responses. There is, however, no conclusive biochemical evidence that the syndrome is attributable to a defect in one or more of these neurotransmitter systems.
We have screened a new enzyme for the resolution ofR, S-naproxen enantiomers. The enzyme is free of lipase activity, and possesses a very high stereo-specificity on S-naproxen [2-(6-methoxy-2-naphthyl)-propionic acid] esters and esters of related drugs. The primary structure of the enzyme, determined from the nucleotide sequence, shows limited homology with the catalytic site of lipases. The gene coding for the stereo-selective carboxylesterase has been cloned and expressed inBacillus subtilis. Using a multicopy vector and an additional strong promoter an efficient production process was developed.
The enzyme was shown to be sensitive to very high concentrations of the products formed during the reaction it catalyses. To increase the resistance of the enzyme, lysine residues thought to be responsible for this phenomenon were replaced through site-directed mutagenesis. Enzymes with improved stability were obtained. An explanation is given in terms of a model in which a reaction of the acid moiety of naproxen with free lysine NH2 groups is a major cause of inactivation.
The synthesis and glycine-NMDA binding activity of a series of quinazoline-2-carboxylic acids 1 and quinazoline-2,4-diones 2, containing all the essential and optional pharmacophoric descriptors required by a putative glycine antagonist model, are reported. The binding results show that only three of the title compounds displayed micromolar receptor affinity, demonstrating how disappointing the synthesis of receptor ligands based only on interaction models can be.
The synthesis and anticonvulsant activity of novel 7,8-methylenedioxy-4H-2,3-benzodiazepin-4-ones 3a-e, structurally-related to GYKI 52466 1, a well-known noncompetitive AMPA-receptor antagonist, are reported. The new compounds possess marked anticonvulsant properties and, in analogy to 1, antagonize seizures induced by AMPA. In addition, when compared to the model compound 1, compounds 3 show a longer-lasting anticonvulsant activity and a lower toxicity.
Novel 1-aryl-3,5-dihydro-7,8-methylenedioxy-4H-2,3-benzodiazepine-4-ones (12a-j) were prepared and their anticonvulsant effects were evaluated by using various models of experimental epilepsy. The seizures were evoked both by means of auditory stimulation in DBA/2 mice and by pentylenetetrazole or maximal electroshock in Swiss mice. Some of these compounds possess marked anticonvulsant properties in all tests employed. Compounds 12 antagonise seizures induced by AMPA in analogy to the structurally-related 1-(4'-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3- benzodiazepine (1) (GYKI 52466), a well-known non-competitive AMPA-receptor antagonist. On the other hand, these novel 2,3-benzodiazepines exhibit anticonvulsant properties that are not affected by flumazenil, but are reversed by aniracetam. In addition, when compared to model compound 1, compounds 12 show a longer-lasting anticonvulsant activity and a lower toxicity. A structure-activity relationship study carried out on compounds 12 as well as analogous 7,8-dimethoxy derivatives 2 offers an approach for designing more potent agents.
The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor is an ionotropic glutamate receptor that mediates fast excitatory synaptic transmission throughout the central nervous system. In addition to the glutamate binding site, allosteric modulatory sites on the receptor are inferred from the ability of synthetic compounds to affect channel function without interaction with the glutamate binding site. We have identified a novel class of potent, noncompetitive AMPA receptor antagonists typified by CP-465, 022 and CP-526,427. The latter compound was radiolabeled and used to elucidate the pharmacology of one allosteric modulatory site. [(3)H]CP-526,427 labels a single binding site in rat forebrain membranes with a K(d) value of 3.3 nM and a B(max) of 7.0 pmol/mg of protein. The [(3)H]CP-526,427 binding site does not seem to interact directly with the glutamate binding site but overlaps with that for another class of AMPA receptor antagonists, the 2,3-benzodiazepines. This binding site is distinct from that for the antagonist Evans blue and for several classes of compounds that modulate AMPA receptor desensitization. These results indicate the existence of at least two physically distinct allosteric sites on the AMPA receptor through which channel activity or desensitization is modulated.
GYKI 52466 [1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine], a non-competitive AMPA [alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate] and kainate receptor antagonist and its two analogues, GYKI 53405 [1-(4-aminophenyl)-3-acetyl-4-methyl-3,4-dihydro-7,8-methylenedioxy-5H-2,3-benzodiazepine] and GYKI 53655 [1-(4-aminophenyl)-3-methylcarbamyl-4-methyl-3,4-dihydro-7,8-methylenedioxy-5H-2,3-benzodiazepine] were investigated in two seizure models and in MgCl2 induced global cerebral ischaemia, as an acute neuroprotective model. The ED(50) values of GYKI 52466 for suppression of the tonic and clonic phases of sound-induced seizures were 3.6 and 4.3 mg/kg, respectively. The corresponding data for GYKI 53405 were 1.1 and 3.1 mg/kg, while ED(50) values of GYKI 53655 were 1.3 and 2.0 mg/kg, respectively. The inhibition of seizure evoked by maximal electroshock was also found to be remarkable: the ED(50) values of GYKI 52466 and its two analogues were 6.9, 2.6, and 2.2 mg/kg, respectively. All compounds prolonged the survival times in MgCl2 induced global cerebral ischaemia test in a dose-dependent fashion, with PD(50) (dose of 50% prolongation) values of 24.1, 8.3, and 8.2 mg/kg intraperitoneal, respectively. In audiogenic seizure model the duration of anticonvulsant action of 10 mg/kg GYKI 52466 and 5 mg/kg GYKI 53405, GYKI 53655 were examined, too. The effect of GYKI 52466 decreased to 50% after 2 h, while the analogues showed more than 80% seizure suppression 3 h after treatment. After 6 h the effect of GYKI 53655 decreased to zero, while the effect of GYKI 52466, remained on the 50% level.
The discovery of the selective AMPA antagonist character of 2,3-benzodiazepine derivative GYKI 52466 (5) in the late eighties and the recognition of the non-competitive nature of its mode of action some years later set off the world-wide search for novel class of drugs. Notably the quest to develop new antiepileptic and neuroprotective medicines, which allosterically inhibit the AMPA sensitive glutamate operated channels. This review summarises our present knowledge about the allosteric site, dubbed "GYKI site" where the 2,3-benzodiazepines are supposed to bind to. The structure-activity relationships among AMPA antagonist 2,3-benzodiazepines and their structural analogues with similar biological profile are reviewed in a possibly comprehensive fashion. The chemical synthesis of 2,3-benzodiazepines is shortly described. The in vitro and in vivo experimental methods used for pharmacological characterisation of the biologically active compounds are briefly explained. Finally the therapeutic potential of 2,3-benzodiazepines i.e. the main fields of their clinical utility are outlined with special regard to talampanel (20) in the light of the ongoing clinical trials with this new drug candidate.
The authors report a double-blind, placebo-controlled, crossover study of talampanel in 49 patients with refractory partial seizures. Three doses of talampanel were investigated based on differences in patients' concomitant antiepileptic drug usage. Talampanel showed efficacy in reducing seizure frequency (p = 0.001) with a median seizure reduction of 21%. Eighty percent of patients had fewer seizures on talampanel than on placebo. Dizziness (52%) and ataxia (26%) were the only significant adverse events.
There is increasing evidence of the potential therapeutic utility of glutamate receptor antagonists in the treatment of several neurodegenerative disorders, including stroke and epilepsy. In the last few years noncompetitive AMPA receptor antagonists have received considerable attention due to their therapeutic potentiality. The discovery of GYKI 52466, the prototype of noncompetitive AMPA receptor antagonists endowed with anticonvulsant and neuroprotective properties, induced growing interest on 2,3-benzodiazepine derivatives. This review covers the chemistry and pharmacology of this important class of AMPA receptor antagonists.
[structure: see text] We report the first determinations of the absolute configurations (ACs) of chiral molecules using discrete frequency, transparent spectral region optical rotations calculated using density functional theory (DFT). The ACs of 2H-naphtho[1,8-bc]thiophene 1-oxide (3), naphtho[1,8-cd]-1,2-dithiole 1-oxide (4), and 9-phenanthryl methyl sulfoxide (5) are determined by comparison of their specific rotations to values calculated via the time-dependent DFT/gauge-invariant atomic orbital (TDDFT/GIAO) methodology using the B3LYP functional and the aug-cc-pVDZ basis set.
A selected set of 1-aryl-7,8-methylenedioxy-2,3-benzodiazepin-4-ones and their analogues were evaluated for their ability to bind the competitive and noncompetitive sites of the AMPA receptors complex as well as to the glycine site of the NMDA receptors. The results put in evidence that most of the test compounds, despite a close structural similarity with GYKI 52466, possess a significantly different pharmacological profile.
Ab initio calculations of the optical rotatory power of the natural cytokine modulator cytoxazone 1 and its trans-diastereomer 2, as well as the structural isomers cis-3 and trans-4 isocytoxazones, have been performed at four different wavelengths (589, 546, 435, and 405 nm) by Density Functional Theory. The calculation of ORD curves provides a reliable method for the assignment of absolute configuration of these conformationally flexible molecules. The absolute configurations of isocytoxazones has been established as (+)-(4R,5S)-cis-3 and (+)-(4S,5S)-trans-4.
Advanced pharmacophore model of non-competitive AMPA antagonist 2,3-benzodiazepines Development of a new Bacillus carboxyl esterase for use in the resolution of chiral drugs
- B Rezessy
- S Só
- J W H Smeets
- A Kieboom
- W J Quax
- C P Broekhuizen
Rezessy, B.; Só, S. Advanced pharmacophore model of non-competitive AMPA antagonist 2,3-benzodiazepines. Lett. Drug Des. DiscoVery 2004, 1, 217-223. (10) (a) Smeets, J. W. H.; Kieboom, A. P. G. Enzymic enantioselective ester hydrolysis by carboxylesterase NP. Recl. TraV. Chim. Pays-Bas 1992, 111, 490-495. (b) Quax, W. J.; Broekhuizen, C. P. Development of a new Bacillus carboxyl esterase for use in the resolution of chiral drugs. Appl. Microbiol. Biotechnol. 1994, 41, 425-431.
Chromatographic enantioseparation: methods and applications, 2nd ed.; Ellis Horwood: Chichester, 1991; p 82. (21) This approach is similar to that previously reported: Xia, H
- S Allenmark
Allenmark, S. Chromatographic enantioseparation: methods and applications, 2nd ed.; Ellis Horwood: Chichester, 1991; p 82. (21) This approach is similar to that previously reported: Xia, H.; Cai, S. X.;
Audiogenic Seizures In Experimental Models of Epilepsy
- R L Collins
- P Purpura
- J K Penry
- D Tower
- D M Woodbury
- R Walter
Collins, R. L. Audiogenic Seizures. In Experimental Models of Epilepsy; Purpura, P., Penry, J. K., Tower, D., Woodbury, D. M., Walter, R., Eds.; Raven Press: New York, 1972; pp 347-372.
Substituted 2,3-benzodiazepin-4-ones and the use thereof. US 5891871, 1999. (22) (a) Optimisation of parameters for semiempirical methods I. Method Optimisation of parameters for semiempirical methods II. Applications
- G Field
- N C Lan
- Y Wang
- J J P Stewart
- J J Stewart
Field, G.; Lan, N. C.; Wang, Y. Substituted 2,3-benzodiazepin-4-ones and the use thereof. US 5891871, 1999. (22) (a) Stewart, J. J. P. Optimisation of parameters for semiempirical methods I. Method. J. Comput. Chem. 1989, 10, 209-220. (b) Stewart, J. J. P. Optimisation of parameters for semiempirical methods II. Applications. J. Comput. Chem. 1989, 10, 221-264.
Comparison of anticonvulsive and acute neuroprotective activity of 580
- T Szabados
- G Gigler
- I Gacsalyi
- I Gyertan
- G Levay
Szabados, T.; Gigler, G.; Gacsalyi, I.; Gyertan, I.; Levay, G. Comparison of anticonvulsive and acute neuroprotective activity of 580 Journal of Medicinal Chemistry, 2006, Vol. 49, No. 2 Zappalà et al. three 2,3-benzodiazepine compounds, GYKI 52466, GYKI 53405, and GYKI 53655. Brain Res. Bull. 2001, 55, 387-391.
Anticonvulsant actions of DS 103-282: pharmacological studies in rodents and the baboon papio papio F MODULATION OF N-methyl-D-aspartate receptor-mediated increases in cytosolic calcium in cultured rat cerebellar granule cells
- De Sarro
- G B Croucher
- M J Meldrum
- B S 25 ) Parks
- T N Artman
- L D Alasti
- N Nemeth
De Sarro, G. B.; Croucher, M. J.; Meldrum, B. S. Anticonvulsant actions of DS 103-282: pharmacological studies in rodents and the baboon papio papio. Neuropharmacology 1984, 23, 526-530. (25) PARKS, T. N.; ARTMAN, L. D.; ALASTI, N.; NEMETH, E. F MODULATION OF N-methyl-D-aspartate receptor-mediated increases in cytosolic calcium in cultured rat cerebellar granule cells. Brain Res. 1991, 552, 13-22.
Anal. (C 18 H 15 NO 7 ) C, H, N. Synthesis of 3,5-Dihydro-5-methyl-7,8-methylenedioxy-1-(4-nitrophenyl)-4H-2,3-benzodiazepin-4-one (10) and 2-Amino-4-References (1)
- U Madsen
R f ) 0.35 (diethyl ether/light petroleum 40/60). Anal. (C 18 H 15 NO 7 ) C, H, N. Synthesis of 3,5-Dihydro-5-methyl-7,8-methylenedioxy-1-(4-nitrophenyl)-4H-2,3-benzodiazepin-4-one (10) and 2-Amino-4-References (1) Brä-Osborne, H.; Egebjerg, J.; Nielsen, E. Ø.; Madsen, U.;
A new mixing of Hartree-Fock and local-densityfunctional theories
- M J Frisch
- G W Trucks
- H B Schlegel
- G E Scuseria
- M A Robb
- J R Cheeseman
- J A Montgomery
- Jr
- T Vreven
- K N Kudin
- J C Burant
- J M Millam
- S S Iyengar
- J Tomasi
- V Barone
- B Mennucci
- M Cossi
- G Scalmani
- N Rega
- G A Petersson
- H Nakatsuji
- M Hada
- M Ehara
- K Toyota
- R Fukuda
- J Hasegawa
- M Ishida
- T Nakajima
- Y Honda
- O Kitao
- H Nakai
- M Klene
- X Li
- J E Knox
- H P Hratchian
- J B Cross
- V Bakken
- C Adamo
- J Jaramillo
- R Gomperts
- R E Stratmann
- O Yazyev
- A J Austin
- R Cammi
- C Pomelli
- J W Ochterski
- P Y Ayala
- K Morokuma
- G A Voth
- P Salvador
- J J Dannenberg
- V G Zakrzewski
- S Dapprich
- A D Daniels
- M C Strain
- O Farkas
- D K Malick
- A D Rabuck
- K Raghavachari
- J B Foresman
- J V Ortiz
- Q Cui
- A G Baboul
- S Clifford
- J Cioslowski
- B B Stefanov
- G Liu
- A Liashenko
- P Piskorz
- I Komaromi
- R L Martin
- D J Fox
- T Keith
- M A Al-Laham
- C Y Peng
- A Nanayakkara
- M Challacombe
- P M W Gill
- B Johnson
- W Chen
- M W Wong
- C Gonzalez
- J A Pople
- A D Becke
Gaussian 03, Revision C.02, Frisch, M. J.; Trucks, G. W.; Schlegel,
H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery,
J. A., Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.;
Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.;
Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.;
Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.;
Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.;
Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.;
Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin,
A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.;
Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.;
Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.;
Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.;
Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.;
Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M.
A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.;
Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A.;
Gaussian, Inc., Wallingford, CT, 2004.
(14) (a) Becke, A. D. A new mixing of Hartree-Fock and local-densityfunctional theories. J. Chem. Phys. 1993, 98, 1372-1377. (b) Becke,
A. D. Density-functional thermochemistry. III. The role of exact
exchange. J. Chem. Phys. 1993, 98, 5648-5652.
Glycine modulated [ 3 H]-MK-801 binding to the NMDA receptor in rat brain
- E H F Wong
- A R Knight
- R Ranson
Wong, E. H. F.; Knight, A. R.; Ranson, R. Glycine modulated [ 3 H]-MK-801 binding to the NMDA receptor in rat brain. Eur. J.
Pharmacol. 1987, 142, 487-488.
Substituted 2,3-benzodiazepin4-ones and the use thereof. US 5891871, 1999. (22) (a) Stewart
- S Allenmark
- H Xia
- S X Cai
- G Field
- N C Lan
- Y Wang
Allenmark, S. Chromatographic enantioseparation: methods and
applications, 2nd ed.; Ellis Horwood: Chichester, 1991; p 82.
(21) This approach is similar to that previously reported: Xia, H.; Cai,
S. X.; Field, G.; Lan, N. C.; Wang, Y. Substituted 2,3-benzodiazepin4-ones and the use thereof. US 5891871, 1999.
(22) (a) Stewart, J. J. P. Optimisation of parameters for semiempirical
methods I. Method. J. Comput. Chem. 1989, 10, 209-220. (b)
Synthesis of a 2,3-Benzodiazepine DeriVatiVe
Synthesis of a 2,3-Benzodiazepine DeriVatiVe
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