Girish Chandra

• Dr.
• Professor (Assistant) at Central University of South Bihar, Gaya, India

Wheat (Triticum aestivum) is a vital cereal crop and a staple food source worldwide. However, wheat grain productivity has significantly declined as a consequence of infestations by Phalaris minor. Traditional weed control methods have proven inadequate owing to the physiological similarities between P. minor and wheat during early growth stages. C...

Fluorine is the 13th abundant element in the earth’s crust, but it appears that Mother Nature is unable to efficiently explore fluorine to produce natural organofluorine compounds, and thus only a few are known to date. And due to that, a synthetic approach becomes essential to exploring their benefits. In the last two decades, we have been observi...

Azobenzene is a well-known dye that undergoes fast trans-cis photoisomerization and has been widely studied and used in the development of organic functional materials. Due to its selective isomeric distribution in the excited state, azobenzene has been used as a photoswitch in the storage of information on a molecular level, photo-controllable cat...

Hydroxy azo‐benzenes are very well known for their rapid trans⇆cis photoisomerization under polar solvents. In contrast, we synthesized two hydroxymethylated‐ hydroxyazobenzene derivatives and investigated their light‐triggered photoisomerization and stability under polar solvents. The result showed just opposite behavior and very slow trans⇆cis is...

Here we present the synthesis of a new fluorinated pyridyl‐azo dye and demonstrate an effective way to convert monomer fluorinated pyridyl‐azo dye to H‐aggregated form through UV‐light induced trans‐cis‐trans photoisomerization. And upto a 12 : 88 ratio between monomer : aggregation was achieved through a small pulse of UV irradiation. The H‐aggreg...

Here we report a comparative study of the interaction of different metal ions with fluorinated and non-fluorinated azobenzene-Schiff bases. Three new varieties of fluorinated Schiff bases were synthesized in high...

The isolation of two carbocyclic nucleosides, viz., neplanocin A and aristeromycin, from natural sources, triggered a revolution in the scientific community, leading to the development of more versatile and therapeutically useful compounds. For this purpose, many new methods for the synthesis of the carbocyclic framework of nucleosides have been de...

The use of FDA-approved drugs for the therapy of lung cancer through drug repurposing is a noteworthy approach. We retrieved all the FDA-approved triazole-based drugs from Drugbank and conducted docking-based virtual screening of the triazole-based FDA-approved drugs against the EGFR target. Deferasirox demonstrated hydrogen bonding interactions wi...

Here we reported the synthesis of hydroxymethylated diazo compounds through the reduction of corresponding diazo aldehydes and presented our exploration towards oxidation reaction with NaIO4 and PhI(OAc)2, where we were expecting oxidative dearomatization reaction, and the product should be the nature of spiroepoxy cyclohexadienone but surprisingly...

During the last twenty years, organic fluorination chemistry established itself as an important tool to get a biologically active compound. This belief can be supported by the fact that every year, we are getting fluorinated drugs in the market in extremely significant numbers. Last year, also ten fluorinated drugs have been approved by FDA and dur...

As technologies using RNA or DNA have been developed, various chemical modifications of nucleosides have been attempted to increase the stability of oligonucleotides. Since it is known that 2'-OMe-modification greatly contributes to increasing the stability of oligonucleotides, we added 2'-OMe to our previously developed 4'-selenonucleoside and 5'-...

Vancomycin and daptomycin are commonly used glycopeptide antibiotics to cure Gram-positive staphylococcal infections. The clinical isolates of mutant Staphylococcus aureus strains, Methicillin-Resistant (MRSA) and Vancomycin-Resistant (VRSA), have developed resistance against these antibiotics. A recently discovered Serine/threonine phosphatase (St...

Over the last twenty years, fluorination on nucleoside has established itself as the most promising tool to use to get biologically active compounds that could sustain the clinical trial by affecting the pharmacodynamics and pharmacokinetic properties. Due to fluorine's inherent unique properties and its judicious introduction into the molecule, ma...

Parasite Plasmodium falciparum is continuously giving a challenge to human beings by changing itself against most of the antimalarial drugs and its consequences can be seen in the form of a huge number of deaths each year especially in the poor and developing country. Due to its drug resistance ability, new drugs are regularly needed to kill the or...

Synthesis of complex organic molecules from simple, cheap, and readily available starting materials is one of the most challenging and desirable factors in organic synthesis. In the last two decades, various methods have been developed for the de‐aromatization reaction of planar aromatics compounds which lead to reactive intermediates like 2,5‐cycl...

Based on the potent anticancer activity of 6'-fluorocyclopentenyl-cytosine 2b in phase IIa clinical trials for the treatment of gemcitabine-resistant pancreatic cancer, we carried out a systematic structure-activity relationship study of 6'-fluorocyclopentenyl-pyrimidines 3a-i and -purines 3j-o to discover novel anticancer agents. We also synthesiz...

Stereo- and regio-selective synthesis of 3′-C-substituted-(N)-methanocarba adenosines 3a-c as potential anticancer agents was achieved by employing stereoselective cyclopropanation, stereoselective nucleophilic addition, regioselective isopropylidene cleavage and regioselective base condensation of cyclic sulfate as key steps.

Based on the potent inhibitory activity of neplanocin A (1) against S-adenosylhomocysteine (AdoHcy) hydrolase, we analyzed the comprehensive structure-activity relationships by modifying the adenine and carbasugar moiety of 1 to find the pharmacophore in the active site of the enzyme. The introduction of 7-deazaadenine instead of adenine eliminated...

Truncated N6-substituted-(N)-methanocarba-adenosine derivatives with 2-hexynyl substitution were synthesized to examine parallels with corresponding 4'-thioadenosines. Hydrophobic N6 and/or C2 substituents were tolerated in A3AR binding, but only an unsubstituted 6-amino group with a C2-hexynyl group promoted high hA2AAR affinity. A small hydrophob...

4′-thionucleosides have attracted attention due to their potent biological activity and unique metabolic stability. When incorporated into RNA strands, certain 4′-thionucleosides led to enhanced thermal stability of the resulting modified RNA duplex. Intense efforts toward the successful synthesis of these nucleoside analogues have been the subject...

On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implan...

Fluoro-homoneplanocin A (4) was synthesized from d-ribose, via the enyne ring-closing metathesis of 9, the stereoselective opening of epoxide 23a with fluoride, and a simultaneous oxidation-elimination reaction. The key intermediate 8 is expected to serve as a versatile intermediate for the synthesis of carbanucleosides.

An improved synthesis of DNA-dependent protein kinase inhibitor, IC86621 is described. This developed method provides an easy access to this simple molecule by using amination, acetylation and Fries rearrangement reactions.

Conformationally restricted 2′-C-azido-, hydroxy- and fluoromethyl-carbanucleosides 4b–f were efficiently synthesized via the stereoselective conversion of ketone 7 to epoxide 14, followed by the stereoselective opening of the epoxide with nucleophiles (OAc, N3, and F), while the corresponding 2′-C-methyl-carbanucleoside 4a was synthesized via the...

Truncated N(6)-substituted-4'-oxo- and 4'-thioadenosine derivatives with C2 or C8 substitution were studied as dual acting A(2A) and A(3) adenosine receptor (AR) ligands. The lithiation-mediated stannyl transfer and palladium-catalyzed cross-coupling reactions were utilized for functionalization of the C2 position of 6-chloropurine nucleosides. An...

The stereoselective synthesis of truncated 3'-aminocarbanucleosides 4a-d via a stereo- and regioselective conversion of a diol 9 to bromoacetate 11a and their binding affinity towards the human A(3) adenosine receptor are described.

The first synthesis of 4'-selenothymidine (1), a novel DNA building block, and 4'-seleno-AZT (2) was accomplished from 2-deoxy-d-ribose via stereoselective formation of 2-deoxy-4-seleno-d-furanose 17 and a Pummerer-type base condensation as key steps. 4'-Selenothymidine (1) was discovered to adopt the same 2'-endo/3'-exo conformation as thymidine,...

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Stereoselective cycloaddn. of 6-hydroxy-2,6-dimethylcyclohexa-2,4-dienones with Et vinyl ether, Bu vinyl ether, vinyl acetate and vinyl Ph sulfone gave bicyclo[2.2.2]octanes I [R = EtO, BuO, AcO, PhS(O)2] having quaternary Me group. A novel thermal 1,2-Me migration has also been described. [on SciFinder(R)]

n t h e s i s o f T e t r a m e t h y l b i c y c l o [ 3 . 3 . 0 ] o c t a n e F r a m e w o r k o f P t y c h a n o l i d Abstract: An expeditious route to methyl-7-oxo-1,4,5,8-tetra-methylbicyclo[3.3.0]octane-3-carboxylate from a simple aromatic precursor is described. Oxidative dearomatization of 2-hydroxy-methyl-3,4,6-trimethylphenol into spir...

The cycloaddn. of in-situ generated cyclohexa-2,4-dienones with vinyl ethers, vinyl acetate, and Ph vinyl sulfone leading to variously functionalized bicyclo[2.2.2]octanes was examd. Functional group manipulation in the resulting adducts gave bicyclo[2.2.2]octanes endowed with a β,γ-enone chromophore. Triplet-sensitized irradn. of bicyclooctenones...

A new stereoselective synthesis of a linearly fused triquinane intermediate (I) from a simple arom. precursor is described. Cycloaddn. of cyclohexa-2,4-dienone and photochem. oxa-di-π-methane rearrangement in a functionalized tricycloundecenone are the key features of this methodol. [on SciFinder(R)]

spirocyclopropanetricyclo[6.3.0.0 2,6 ]undec-10-one: A Potential Intermediate for Synthesis of Ceratopicanol R o u t e t o 1 , 8 -D i m e t h y l -5 -s p i r o c y c l o p r o p a n e t r i c y c l o [ 6 . 3 . 0 . 0 2 , 6 ] u n d e c -1 0 -o n e Abstract: A new stereoselective synthesis of linearly fused triquinane intermediate from a simple aromat...