P. Shanthan Rao

Synthesis of novel alkyltriazole tagged pyrido(2,3-d)pyrimidine derivatives and their anticancer activity

A series of novel alkyltriazole tagged pyrido[2,3-d]pyrimidine derivatives 5 and 6 was prepared starting from 2,3-active functional pyridine 1via cyclization, propargylation followed by reaction with alkyl or perfluoroalkyl azides under Sharpless conditions. All the compounds 5 and 6 were screened for anticancer activity against three cancer cell lines such as U(937), THP-1 and Colo205. The promising compounds 5b and 5e have been identified.

Design, synthesis, structure-activity relationship and antibacterial activity series of novel imidazo fused quinolone carboxamides.

A series of novel 7,8 and 1,8 imidazo fused quinolone carboxamides are synthesized and evaluated against antibacterial activity. 1,8 Imidazo fused quinolones exhibit moderate antibacterial activity. Molecular modeling studies were carried out to optimize the pharmacophore.

Synthesis of Novel 5‐Trifluoromethyl‐2,4,7‐Trisubstituted Pyrido[2,3‐d]Pyrimidines

Abstract Novel pyrido[2,3‐d]pyrimidines (2,4) were synthesized by reacting 2‐amino‐3‐cyano‐4‐trifluoromethyl‐6‐substituted pyridines (1) with Grignard reagent followed by condensation with anhydride/chloroacetylchloride/aromatic aldehyde. aIICT Communication No.: 040104.

Synthesis of novel 1,2,3-triazole/isoxazole functionalized 2H-Chromene derivatives and their cytotoxic activity.

A series of novel 2-(1,2,3-triazolylmethoxy) 5a-q and isoxazole tagged 6a-g 2H-Chromene derivatives were prepared starting from salicylaldehyde and ethyl-4,4,4-trifluoroacetoacetate via cyclization to form ethyl 2-hydroxy-2-(trifluoromethyl)-2H-Chromene-3-carboxylate 3. Compound 3 on reaction with propargyl bromide resulted compound 4 and was independently reacted with aryl/alkyl azides and aryl aldoximes obtained 2-(1,2,3-triazolylmethoxy) and isoxazole tagged 2H-Chromene derivatives 5a-q, 6a-i, respectively. Compounds 6 were further hydrolysed to acid derivatives 7a-g. All the products 5a-q, 6a-i, 7a-g were screened for cytotoxic activity against four human cancer cell lines and among all the compounds, 5f, 5g, 5l, 5q showed promising activity at <20 μM concentration.

A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

A simple and facile strategy for the synthesis of highly substituted imidazoles has been developed by multi-component condensation of 1,2-diketone, aldehyde, amine, and ammonium acetate in presence of tetrabutyl ammonium bromide as catalyst.

Synthesis of novel 2-alkyl triazole-3-alkyl substituted quinoline derivatives and their cytotoxic activity

The propargyl alcohol on reaction with alkylazides under Sharpless conditions through click chemistry concept gave exclusively 1,4-disubstituted triazoles 2. The compounds 2 were oxidized to aldehydes 3 followed by reaction with aniline resulted Schiffs bases 4. The compounds 4 was further reacted with various aldehydes having α-hydrogen using molecular iodine as a catalyst and obtained 2-alkyl triazole-3-alkyl substituted quinoline derivatives 5. All the final compounds were screened against four human cancer cell lines (THP-1, Colo205, U937 & HeLa) and promising compounds have been identified.

An Efficient Multi-component Synthesis of 6-Amino-3-methyl-4-Aryl-2,4- dihydropyrano[2,3-c]Pyrazole-5-carbonitriles

Multi-component reactions are effective in building complex molecules in a single step in a minimum amount of time and with facile isolation procedures; they have high economy1–7 and thus have become a powerful synthetic strategy in recent years.8–10 The multicomponent protocols are even more attractive when carried out in aqueous medium. Water offers several benefits, including control over exothermicity, and the isolation of products can be carried out by single phase separation technique. Pyranopyrazoles are a biologically important class of heterocyclic compounds and in particular dihydropyrano[2,3-c]pyrazoles play an essential role in promoting biological activity and represent an interesting template in medicinal chemistry. Heterocyclic compounds bearing the 4-H pyran unit have received much attention in recent years as they constitute important precursors for promising drugs.11–13 Pyrano[2,3-c]pyrazoles exhibit analgesic,14 anti-cancer,15 anti-microbial and anti-inflammatory16 activity. Furthermore dihydropyrano[2,3-c]pyrazoles show molluscidal activity17,18 and are used in a screening kit for Chk 1 kinase inhibitor activity.19,20 They also find applications as pharmaceutical ingredients and bio-degradable agrochemicals.21–29 Junek and Aigner30 first reported the synthesis of pyrano[2,3-c]pyrazole derivatives from 3-methyl-1-phenylpyrazolin-5-one and tetracyanoethylene in the presence of triethylamine. Subsequently, a number of synthetic approaches such as the use of triethylamine,31 piperazine,32 piperidine,33 N-methylmorpholine in ethanol,34 microwave irradiation,35,36 solvent-free conditions,37–39 cyclodextrins (CDs),40 different bases in water,41 γ -alumina,42 and l-proline43 have been reported for the synthesis of 6-amino-4-alkyl/aryl-3-methyl2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles. Recently, tetraethylammonium bromide (TEABr) has emerged as mild, water-tolerant, eco-friendly and inexpensive catalyst. To the best of our knowledge, quaternary ammonium salts, more specifically TEABr, have not

ZnBr2‐Catalyzed Efficient Oxidative Homo Coupling of Aryl Magnesium Bromides

Abstract Oxidative homo coupling of various arylmagnesium bromides in the presence of ZnBr2 gave the corresponding symmetrical biaryls in moderate to good yields at room temperature. An efficient method under mild conditions without the use of reoxidant is described. IICT Communication No. 050507

Design and synthesis of positional isomers of 1-alkyl-2-trifluoromethyl-5 or 6-substituted benzimidazoles and their antimicrobial activity

A series of novel positional isomers of 1-alkyl-2-trifluoromethyl benzimidazole derivatives 3a–j and 4a–j have been synthesized and screened for antibacterial activity against gram positive bacteria viz, Bacillus subtilis, Staphylococcus aureus and gram negative bacteria viz., Escherichia coli, Pseudomonas aeruginosa and antifungal activity against Candida albicans, Aspergillus niger, Rhizopus oryzae and Saccharomyces cerevisiae. Results indicate that compounds 3b, 4b were having promising antibacterial and antifungal activity.

Synthesis of novel optically pure α-amino acid functionalised-7-trifluoromethyl substituted quinolone derivatives and their antibacterial activity

Abstract7-Trifluoromethyl-4-hydroxy quinoline-3-carboxylic acid ethyl ester was prepared from 3-amino benzotrifluoride and EMME. The hydroxyquinoline was reacted with amino acids to furnish amino acid funtionalised quinolines (5, 6, 7). The compounds were alkylated by ethyl iodide followed by hydrolysis afforded the title compounds in good yields. They were screened for their antibacterial activity for in vitro against Gram +ve and Gram −ve bacterial strains and found 11e and 11b as promising compounds.