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Synthesis and antibacterial activities of chloro-substituted-1, 3-thiazines
Abstract
The synthesis, spectral analysis and biological activities of some 4-phenyl-2-hydroxy-chlorosubstituted-2-imino-1, 3-thiazene with phenyl thiourea and diphenyl thiourea have been carried out in two series. In series I we got 4-(2-hydroxy-3,5-dichlorophenyl-6-(ethyl)-2-iminophenyl-1,3-thiazene and 4-(2-hydroxy-3,5-dichlorophenyl-6-(ethyl)-2-iminophenyl-3-phenyl-1,3-thiazene(3a-6a) from 2-hydroxy-3,5-dichloroacetophenone from phenyl thiourea and in series II 4-(2-hydroxy-3,5-dichlorophenyl)-6-(hexyl)-2-iminophenyl-1,3-thiazene and 4-(2-hydroxy-3,5-dichlorophenyl)-6-(hexyl)-2-iminophenyl-3-phenyl-1,3-thiazene(3b-6b) were synthesized from diphenyl thiourea. All these compounds have been analyzed by UV, IR and NMR for structure assignment. The Antibacterial activities of these compounds were studied.
... 1,2 Here in this context, we focused on thiazine and its derivatives owing to its therapeutic profile. 3 Thiazine heterocyclic rings consist of nitrogen and sulfur atoms which exist at various positions in the ring, 1, 2thiazine, 1, 3-thiazine, and 1,4-thiazine. 4 Thio analogue of morpholine which is called thiomorpholine is the reduced form of thiazine. ...
... 36 Reddy et al., 37 synthesized new series of synthetic compounds having compounds from 6a-r and tested against C. elegans for nematicidal activity. Among these, the most potent compounds (bis-[4-methoxy-3-[3-(4-fluorophenyl)-6-(4-methylphenyl)-2-benzyl3, 3a,5,6-tetrahydro-2H-pyrazolo- [3,4-d] [1,3] ...
... (4-chlorophenyl)-2-benzyl3,3a,5,6-tetrahydro-2H-pyrazolo- [3,4-d] [1,3]thiazol-5-yl]phenyl]methane (6j), etc.) showed LD 50 between 160 and 210 μg/mL compared with standard oxamyl (LD 50 at 180 μg/mL). 37 In the reference of above studies, we confirmed that thiazine derivatives 1−15 showed good nematicidal potential having LD 50 values at lower concentrations than standard fosthiazate and oxamyl (72.52 and 180 μg/mL) and at higher concentrations than levamisole (20.35 μg/mL). ...
In humans, animals, and agriculture, parasitic nematode infection is a very serious issue. Many drugs are being used to control nematode infections. Owing to toxicity and nematodes' resistance to the available drugs, special attention is required to synthesize new drugs that are environmentally friendly with high-level efficacy. In the present study, various substituted thiazine derivatives (1 to 15) were synthesized, and the structures were confirmed by infrared, proton (1H), and 13C NMR spectroscopies. The nematicidal potential of the synthesized derivatives was characterized using Caenorhabditis elegans (C. elegans) as a model organism. Among all synthesized compounds, 13 (LD50 = 38.95 μg/mL) and 15 (LD50 = 38.21 μg/mL) were considered the most potent compounds. Most compounds showed excellent anti-egg-hatching activity. Fluorescence microscopy confirmed that compounds 4, 8, 9, 13, and 15 displayed a high apoptotic effect. The expressions of gst-4, hsp-4, hsp16.2, and gpdh-1 genes were high in affected (treated with thiazine derivatives) C. elegans in comparison with normal C. elegans. The present research revealed that modified compounds are highly effective as they showed the gene level changes in the selected nematode. Due to structural modification in thiazine analogues, the compounds showed various modes of action. The most effective thiazine derivatives could be excellent candidates for novel broad-scale nematicidal drugs.
... Compounds with heterocyclic nuclei remain the topic of discussion when it comes to therapy and have received more attention in the drug development process [1]. In the context of heterocyclic compounds, thiazine and its substituted derivatives have been the talking point due to their varied therapeutic profile [2]. Thiazines are organic compounds with molecular formula C 4 H 5 NS and molar mass 99.15 g/mol containing a heterocyclic ring with nitrogen and sulfur atoms. ...
... Radhod et al. synthesized a few 2-imino-1,3-thiazine derivatives via phenyl thiourea and diphenyl thiourea; among all, compound 35 (MIC = >100 μg/mL) and compound 36 (MIC = >100 μg/mL) were found to have good antibacterial activity. SAR study showed that the presence of a phenyl ring at 4-position of the thiazine ring increased antimicrobial activity [2]. ...
... It has been acknowledged so far in various studies and reports that the modifications to the thiazine moiety display a variety of impressive biological activities, which furthermore need to be investigated through structureactivity relationship approaches for the designing of therapeutic molecules with extortionate potential for various diseases and multi-resistant microorganisms [7]. Thiazines and their analogues have been evidenced to exhibit the diversified extent of bioactivities such as anti-fungal [13,14], antiinflammatory [15], antibacterial [16,17], antitumor [18], analgesic [19], anticonvulsant, antioxidant [20], anticancer [21], antidepressant, antimicrobial [22], antimycobacterial [23][24][25]. The biological activities represented by thiazines encompass a wide range of molecular mechanistic pathways. ...
Thiazines are a sizable class of organic heterocycles that are notable for their skeletal versatility and relative chemical simplicity, making them among the most flexible sources of biologically active compounds. The term "green synthesis" refers to implementing energy-efficient procedures for the nature-friendly production of materials and chemicals using green solvents, catalysts, and suitable reaction conditions.Considering the importance of green chemistry and the outstanding therapeutic profile of thiazines, the present work was designed to review the recent advances in green chemistry-based synthetic strategies of thiazine and its derivatives. The green synthetic approaches, including microwave-assisted, ultrasound-assisted, and various other synthetic methods for thiazine and its derivatives, were discussed and generalized. In addition, applications of thiazine and its derivatives in pharmaceutical sciences were explained with examples of marketed drugs.The discussed sustainable synthetic methods for thiazines and their derivatives could be useful in developing other medicinally important lead molecules. They could also aid in developing new synthetic schemes and apparatuses that may simplify chemical manufacturing processes and enable novel reactions with minimal by-products while questing for optimal, green solvents. This review can help anyone interested in this fascinating class of heterocycles to make decisions about selecting targets and tasks for future research.
... Organic compounds with heterocyclic frameworks encompass a major part of modern drug discovery due to their dynamic therapeutic profile. 1 In recent years, considerable attention has been paid to the development of highly potent heterocyclic compounds against multi-drug resistant microorganisms and other diseases. 2 Heterocycles with nitrogen and sulfur atoms play a significant role in the field of medicinal and pharmaceutical chemistry. ...
... Thiazine are another useful units in the fields of medicinal and exhibit a variety of biological activities such as antidyslipidemic [9], antibacterial [10], antifungal [11], and antiinflammatory [12]. The aim of the present study is to evaluate the effect of some derivatives of thiadiazole and thiazine in vivo on CK and HMGR activities. ...
Hyperlipidemia is one of the most important factors leading to atherosclerosis and heart disease, therefore, this study conducted to examine the effect of two newly synthesized compounds[3-(5-(ethylthio)-1,3,4-thiadiazol-2-yl)-2,3-dihydro-2-(3-nitrophenyl)benzo[1-3-e] thiazin-4-one (I) and 5(4-dimethyl amino) benzylidene amino)-1,3,4-thiadiazole-2-thiol(II)] on the activities of creatine kinase(CK) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) in male Wister mice. Also to determine the type of inhibition of these compounds on the above enzymes .The study was carried out on sixty male Wister mice aged seven to eight weeks their weight ranged(180-200 g). The mice were grouped as: group(1): control group (12 mice).Group(2):consisted of 48 mice in which the mice were daily administered cholesterol (25mg/kg/day) in coconut oil 6% and creamy cheese for 28 days. Lipid profile was measured for 12 of mice chosen randomely from G2 to assure hyperlipidemia. Then group2 is subdivided into three groups as:group (2.A): (12 mice) positive control group in which the mice were daily administered simvastatin (40mg /day) as standard drug for hyperlipidemia for 20 days.Group(2.B):(12 mice) in which the mice were daily treated with (10-4)M of compound (I)via drinking water for 20 days. Group(2.C):(12 mice) in which the mice were daily treated with (10-5)M of compound II via drinking water for 20 days.Lipid profile(Tch, TG, HDL-c, LDL-c and VLDL-c) were determined in all groups.The activities of CK and HMGR were determined in all groups. Lineweaver-Burk plot was used for determination of Vmax, Km and type of inhibition for treated and untreated groups with compounds I and II. The results showed significant elevation in levels of Tch, TG, LDL and VLDL, while there are significant reduction in HDL-c levels in G2 comparing to control group(G1), after administration of fat rich diet. Simvastatin, compound I with concentration (10-4 M) and compound I The results revealed that the levels of Tch, TG, LDL and VLDL were reduced while the levels of HDL-c was elevated after administration of simvastatin, compound I and II in G2A, G2B and G2C respectively. The results showed that the activities of CK reduced for group G2B and G2C while it is increased for G2A. The results also showed that the activities of HMGR were reduced in the three groups. The effect of compound I on CK activity was found to be noncompetitive inhibitor with Vmax values values(1000and 166.6) U/L respectively for the uninhibited and inhibited reactions and Km value (0.6)mmol/L for compound I and with Vmax values (1000 and 250)U/L and Km value(0.84)mmol/L respectively for the uninhibited and inhibited reactions for compound II. Compounds I and II were found to be noncompetitive inhibitors on HMGR with Vmax values (0.83 and 0.16)U and Km value (0.34)mmol/L respectively for the uninhibited and inhibited reactions for compound I and Vmax values (0.83 and 0.35) U and Km value(0.28)mmol/L respectively for the uninhibited and inhibited reactions for compound II. In conclusion the new compounds(I and II) showed different inhibitory effect on CK and HMGR activities that could be used in treatment of hyperlipidemia and related disease in future.
... Literature review reveals that chalcones exhibited various biological and pharmacological activities such as antimicrobial [7], antifungal [8], analgesic [9], anti-platelet [10], insecticidal [8], anti-malarial [11], antiviral [7] activities. The reaction of thiourea and phenyl thiourea with α, β-unsaturated ketones results in 1, 3 thiazine derivatives [12]. Different chalcone derivatives are used as the starting material for the synthesis of 1, 3 thiazine derivatives. ...
... It is commonly reported that heterocyclic thiazine derivatives with nitrogen and sulphur are important because they are biological constituent of many biomolecules and drugs [1]. Thiazines and it's derivatives have been reported to exhibit a variety of biological activities like Antibacterial [2], Antifungal [3], Antitubercular [4], Anti-inflammatory [5], Analgesic- [6], Sedative-hypnotic [7], Immunosuppressive agents [8], Herbicidal [9] , Antihistamin-ic [10], Anti-HIV activities [11], Antiproliferative [12]. These are also known as anti-radiation agents and used as radiation-sickness drugs [13]. ...
... Radhod et al. synthesized few 2imino-1,3-thiazine derivatives via phenyl thiourea and diphenyl thiourea, out of all, compound 5 (MIC = >100µg/ml) and compound 6 (MIC=>100µg/ml) were found to have good antibacterial activity. SAR study showed that the presence of phenyl ring at 4 th position of thiazine ring increased antimicrobial activity [56]. ...
Nitrogen and sulphur based heterocyclic molecules have gained significant attention owing to their broad spectrum pharmacological profiles. Thiazine is one of such promising scaffolds which has been widely utilized in the synthesis of compounds that possess interesting biological profile including anti-proliferative, anti-bacterial, antipsychotic, analgesic, anti-inflammatory, antifungal and antiviral activities. The current review focus on the chemistry of thiazine and its derivatives along with potential pharmacological activities reported for them in scientific literature. Multifaceted pharmacological profile of thiazine derivatives provide new aspects for the design of superior medicinally active agents.
... Thiazine derivatives are also used in the preparation of peptide resin inhibitors and good colour photographic materials [19][20] . Literature survey reveals that number of synthetic methods are available for the synthesis of thiazine compounds and screening of their biological studies [21][22][23] . Recently Sambhaji P. Vartale et al 2013 has reported the synthesis of substituted pyrimido [2,1-b] [1,3] thiazines 24 . ...
... Furthermore, 2,3-diphenylcyclopropenone (1) acts as a starting material for several synthetic heterocyclic compounds such as 1,2,4-triazolo [4,3-b]pyridazinethiones [15], pyrrolo [2,1-b] [1,3,4]oxodiazoles [16] and (E)-2,5-disubstituted-1,3,4-thiadiazolyl-2,3-diphenyl-propenones [17]. In addition, compounds containing 1,3-thiazine rings have been reported to exhibit antifungal [18], antibacterial [19], anti-inflammatory [20] and anti-tubercular [21] biological activities. In addition, pyrazoles have high biological and medicinal reactivity [22,23]. ...
New classes of 3N-substituted-2-[(3-methyl-1H-pyrazole-5-yl)-imino]-5,6-diphenyl-2H-1,3-thiazin-4(3H)-ones have been synthesized, via one pot reactions between pyrazolylthioureas, 2,3-diphenylcyclopropenone and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The structures of the products have been confirmed by different spectroscopic analyses. A rationale for the formation of the products is presented.
... Thiazine derivatives are an important class of heterocyclic compounds reported to possess a wide spectrum of biological properties such as anticonvulsant [2], antimicrobial [10][11][12][13][14][15], anti-inflammatory [16][17][18][19], anticancer [20,21], antidiabetic [22], analgesic [23], immunotropic [24], antitubercular [25], antianxiety [26], insecticidal, anesthetic, ulcerogenic, etc. Thiazines exerted anticonvulsant activity in models of generalized seizure which are well documented in the literature. These observations have prompted us to synthesize more number of new derivatives having thiazine nucleus. ...
ABSTRACT
Purpose: Our previous studies (Bairam et al., 2017) have been demonstrated the effectiveness of the synthesized series of novel 4-aryl-8arylidene-2-imino-5,6-dihydro-4H, 7H-6-methyl-(3,1)benzothiazine derivatives as potent anticonvulsants and antimicrobial agents. In this work, the effect of substitution of electron withdrawing groups at the phenyl-1,3-thiazine moiety was investigated. Approach: In the present study, a new series of 2-amino-4-phenyl-6H-1, 3-thiazine indolin-2-one derivatives were synthesized from 1,3-thiazine derivatives. In the beginning acetophenone which underwent Claisen-Schmidt condensation to afford chalcones (1a-j). Further these various chalcones were subjected to cyclocondensation with thiourea,
to afford 1, 3-thiazine (2a-j) derivatives. Now these 1,3-thiazine derivatives were refluxed with substituted isatin catalyzed by glacial acetic acid inethanol to afford 2-amino-4-phenyl-6H-1,3-thiazine indolin-2-one derivatives (3a-j). Finding: The structures of the newly synthesized compounds have been characterized by their IR, 1H NMR, 13C NMR, Mass spectral data and elemental analysis. These newly synthesized compounds were screened for their antimicrobial activity; against S. Aureus, B. Subtilis were the Gram-positive bacteria, K. pneumoniae, E. aerogenes, Gram- negative and the fungal
strains used were A. flavus, A. niger, C. neoformans, C. albicans. Ciprofloxacin and Ketaconazole are used as the standards. The in vitro antimicrobial activity has been carried out by cup plate method. Conclusion: The presence of electron withdrawing groups at 1,3-thiazine derivatives moiety is an effective approach for improving the strength 2-amino-4-phenyl-6H-1,3-thiazine indolin-2-one scaffold.
KEY WORDS: Claisen-Schmidt; Schiff Base; Thiazine Derivatives; Antimicrobial Activity.
... Antibacterial activity was determined using gram positive and gram-negative pathogens. Among the two series of compounds, good activity was obtained for the derivatives possessing n-hexyl side chain than the other derivatives [37]. Among the synthesized compounds, unsubstituted derivative and methoxy containing derivatives exhibited better antifungal activity than the standard amphotericin-B. ...
1, 3-Thiazine based compounds continue to yield promising antimycobacterial, antibacterial, antipyretic, anti-inflammatory, analgesic, antitumor, and antioxidant agents. The success of these compounds has been based on simple and cost effective synthetic routes and the presence of N-C-S linkage in its scaffold. A number of studies have been reported in the recent years to investigate different biological activities of 1, 3-thiazines. There are different classes of 1, 3-thiazines in the literature which can be divided in to natural and synthetic 1, 3-thiazines. There are several structural classes of synthetic 1, 3-thiazines such as 1, 3-thiazines as dihydro-1, 3-thiazine derivatives, 1, 3-thiazine spiro-derivatives and thioethers; 1, 3-thiazines with heterocyclic rings such as pyrimidine, pyrazole, thiazolidin-4-one and 1, 3, 5-triazine moiety; 1, 3-thiazine-2-amine, amide and hydrazides; 1, 3-thiazines with Schiff's bases. Herein natural and synthetic 1, 3-thiazine possessing molecules and their therapeutic actions are discussed.
... They exhibit sundry of pharmacological activities including antimicrobial [4][5][6][7][8][9][10][11], anti-inflammatory [12][13][14][15], anticancer [16,17], antidiabetic [18], analgesic [19], immunotropic [20], antitubercular [21], anticonvulsant, and antianxiety [22]. Chalcones, on the other hand, are α, β-unsaturated enones with a broad range of biological activities and also acts as key synthon in the chemical synthesis of heterocyclic compounds [23]. ...
Objective: Chalcones and their heterocyclic analogs represent an important class of small molecules having anticonvulsant activities. Therefore, in this study, the synthesis and anticonvulsant activity of some new chalcones and 1,3-thiazines were described. Methods: The reaction of 1-acetylnaphthalene with substituted aromatic aldehydes in the presence of aq. NaOH afforded corresponding chalcones which upon further cyclization with thiourea resulted in 1,3-thiazine derivatives. The newly synthesized compounds were tested for anticonvulsant activity by pentylenetetrazole-induced seizures method using diazepam as standard. Results: Most of the compounds showed good anticonvulsant activity but is less than diazepam. 1,3-thiazines were more potent than chalcones and among them, compound P4 containing 4-fluorophenyl substituents on the thiazine moiety was more potent as it has prolonged the onset of convulsions by 155.2 seconds. Conclusion: We described the synthesis and anticonvulsant activity of novel chalcones and 1,3-thiazine derivatives. 1,3-thiazines are more active anticonvulsant agents than chalcones and in particular compounds with electron withdrawing substituents. © 2016, Innovare Academics Sciences Pvt. Ltd. All rights reserved.
1,3-thiazines were synthesised using Schiff base and 3-mercaptopropanoic acid and characterised. Using the Gaussian 09W program, the current investigation utilised the Hartree-Fock approximation (HF) to compute diverse molecular characteristics, comprising optimisation, hardness, EHOMO, ELUMO, and energy gap, for a collection of synthesised molecules.
Heterocyclic compounds are currently of great interest in pharmaceutical research. Many natural products, including vitamins, hormones, and antibiotics, contain heterocyclic compounds, and these substances have grown in importance. Heterocyclic thiazine derivatives have numerous pharmacological actions, including anticancer, antimicrobial, antipsychotic, anti-mycobacterial, anti-fungal, antiviral, antimycobacterial, antioxidant, analgesic, antipyretic, anti-inflammatory activities, which is present in numerous substances. The N-CS linkage in its scaffold and the ease and economy of its synthesis methods have been key factors in the development of these molecules. Recently, numerous studies considering the various biological actions of thiazines have been published. Thiazine, a six-membered heterocyclic compound with nitrogen and sulfur in its ring system, has a wide range of chemical possibilities, which has encouraged insistent research into their various synthesis processes. The current review focuses on thiazine derivatives with potential biological activities.
In the present era the use of fused heterocyclic compounds has been showing a considerable value in the development and designing of new drugs. Article flow through the synthetic strategies highlight on the application of metal-free, visible light mediated catalysis for the fusion of six-membered heterocyclic scaffolds containing nitrogen and sulfur heteroatoms. The power stratagem for the synthesis of diverse fused heterocyclic compounds is the sequencing of multicomponent reactions and subsequent cyclization reactions. The heterocyclic compounds containing Nitrogen and Sulphur atoms exhibit unique properties and are used as potential reactive materials in pharmacokinetic systems. These compounds can also be synthesized considering the high yield, low waste and green synthesis. The main aim of this review is to give an outlook about the synthetic feasibility of fused heterocyclic system and to development an innovative heterocyclic synthetic scheme that allow for different bond forming strategies which are having a significant impact in the pharmaceutical industry, especially the pyrimido-thiazine derivatives in the future synthetic heterocyclic chemistry. The future of Heterocyclic chemistry is development of robust synthetic routes which can generate bulk quantity of desired products and accelerate the drug development process.
1,3 – Thiazines have been applied as useful starting materials in the stereo selective synthesis of compounds of pharmacological interest and they have served as chiral ligants and auxiliaries in enantioselective transformation. The thiazines are of great importance because they act as precursor for the synthesis of Cephalosporins (3,6-dihydro-2H-,1,3-thiazine) and then converted to the thiazine derivatives (an heterocyclic compounds). Therefore, it was thought to combine chalcones moiety to thiazine derivative together in a molecular frame work to see the biological activities, additive effort of these rings towards biological activities like Anti- bacterial and Anti- fungal activities.
In recent days, heterocycles and their derivatives have become strong reflection in medicinal research and pharmaceutical fields because of theirpractical pharmacological and biological activities. Organic compounds; mainly heterocyclic compounds are wealthy in natural world and containextra value because their structural subunits are established in many natural products such as enzymes, vitamins, antibiotics, acids, and hormones.Thiazine nucleuses found in compounds have variety of pharmacological activities such as antitumor, antimicrobial, antibacterial, antifungal, antiviral,and anti-inflammatory. This review spotlight on the substituted thiazines with possible antimicrobial activities that are at the present in development.Keywords: Antibacterial, Substituted thiazines, Antimicrobial agents.
The synthesis, spectral analysis and biological activities of some 4-phenyl-2-hydroxychlorosubstituted- 2-imino-1, 3-thiazine with thiourea, phenyl thiourea and diphenyl thiourea have been carried out in three series. In series I we got 4-(2-hydroxy-3,5-dichlorophenyl)-6-(4-chlorophenyl)-2-imino-3,6- dihydro-1,3-thiazine (4a), 4-(2-hydroxy-3,5-dichlorophenyl)-6-(4-chlorophenyl)-2-imino phenyl -3,6-dihydro- 1,3-thiazine (5a) and 4-(2-hydroxy-3,5-dichlorophenyl)-6-(4-chlorophenyl)-2-iminophenyl-6-hydro-3-phenyl- 1,3-thiazine (6a) from 2-hydroxy-3,5-dichlorolphenyl-4-(4-chlorophenyl)-chalcone (3a) by the action of thiourea, phenylthiourea, diphenylthiourea. Initially the compound (3a) was synthesis from 2-hydroxy-3,5- dichloroacetophenone (2a) by the action of p-chlorobenzaldehyde in ethanol and 40% NaOH. Similarly (4b), (4c), (5b), (5c), (6b), and (6c) compounds were synthesized from the compounds (3b), and (3c) respectively. The compounds (3b) and (3c) were synthesized by the action of p-nitrobenzaldehyde and valeraldehyde respectively. All these compounds have been analyzed by UV, IR and NMR for structure assignment. The titled compounds were evaluated for their growth promoting activity on some flowering plants viz. Papaver rhoeas, Dianthus chinensis, Candy tuft, Calendula officinalise, Gladiola tristis, Gaillardia.
1, 3-thiazines are prepared by refluxing the mixture of 2-Hydroxy-3-bromo/nitro -5-chlorochalcone and phenylthiourea in alcohol and aq.KOH medium. The newly synthesized 1,3-thiazenes were characterized on the basis of elemental analysis and spectroscopic data of IR,NMR. The melting points were taken in an open capillary tube. All compounds have been evaluated for their in vitro growth of inhibitory activity againstEscherichia coli, Staphylococcus aureaus, Bacillus subtilis and Phaseolusargenosa.
Heterocyclization reaction of 1-phenylpyrazolidine-3,5-dione with some active nitriles and acrylonitriles is described. These cyclization reactions afforded novel heterocyclic derivatives such as pyrano[2,3-c]pyrazoles, pyrazolyl-thiazole, pyrazolyl-1,3-thiazines, and pyrazolyl-1,3-oxathiino[6,5-c] pyrazoles. Heating 1-phenylpyrazolidine-3,5-dione alone under phase transfer catalysis conditions afforded the tricyclic dipyrazolofurandione. The structure of the new products has been characterized by IR, NMR, mass spectra, and their elemental analyses.
An environmentally benign and economic synthesis of 6H-2-amino-4,6-diaryl- 1,3-thiazines (4a-g) is described from readily accessible substituted chalcones (1a-g) and thiourea (2) in presence of base and ethanol as energy transfer medium by exposure to microwaves. The reaction time has been brought down from hours to seconds with improved yield as compared to conventional heating. All the synthesized compounds were tested for their antibacterial, herbicidal, fungicidal, insecticidal and animal health activity.
An environmentally desirable, solventless, rapid high yielding technique for the synthesis of substituted chalcones involving Claisen-Schmidt condensation reaction using solid basic alumina under microwave irradiation (MWI) is described. All the compounds were screened for their antibacterial activity.
Some chalcones are known to be phototransformed in a solution from trans into cis isomers. 3-Hydroxy-3'-methylchalcone (3'Me-3-C) has been found to be isomerized from trans into cis by irradiation of daylight in the methanolic solution. The presence of a hydroxyl in the 2'- or 4-position in the trans-chalcone structure prevents phototransformation into cis isomers. The feasibility of phototransformation of chalcones was discussed using UV-spectral analysis. The phototransformed cis-3'Me-3-C showed more potent antitumorigenic activity than the original trans form. The generally recognized parallelism between antitumorigenic and antiinflammatory activities was not observed in trans and cis 3'-Me- and 4'-Me-3C, which are antitumorigenic but inactive in 12-O-tetradecanoylphorbol 13-acetate (TPA)- and arachidonic acid (AA)-induced mouse ear edema. However, inhibitory activity against ornithine decarboxylase (ODC) was commonly observed in both naturally occurring and synthetic antitumorigenic chalcones.
(Z)-3-[2H1]-Phenylprop-2-enone is isomerised by hydroperoxide to an equimolar mixture of the (Z)- and (E)-isomers prior to epoxidation. Poly-(L)-leucine (10 mole %) accelerates the addition of hydroperoxide by an order of magnitude and sequesters hydroperoxide from THF.