Raveendra K. Hunnur

One-pot synthesis of pyrazoline derivatised carbazoles as antitubercular, anticancer agents, their DNA cleavage and antioxidant activities.

Novel tricyclic carbazoles 4a-k were synthesized in one-pot employing sydnone derivatives 3a-k as masked hydrazines by the ring transformation in presence of conc. HCl and cyclohexanone. The title compounds were screened for anti-tubercular, anti cancer, DNA cleavage, antioxidant activity. MIC, GI50, LC50, TGI were evaluated. The title compounds have exhibited significant antitubercular, DNA cleavage and antioxidant activities and partial anticancer activity.

Synthesis, characterization and in vitro anticancer evaluation of novel 1,2,4-triazolin-3-one derivatives

A series of novel 2-(4-chlorophenyl)-5-methyl-4-(2-amine/oxy-ethyl)-2,4-dihydro-[1,2,4]triazol-3-one (5a-t) were synthesized and in vitro anticancerous action of the resulting compounds was studied against NCI-60 Human Tumor Cell Line at a single high dose (10(-5) M) concentration for primary cytotoxicity assay. Among the tested compounds (5a-e, 5g-h, 5k, 5p), the compound 5g (NSC: 761736/1) was further evaluated for five dose criteria at five different minimal concentrations against the full panel of 60 human tumor cell lines which exhibited activity against Leukemia (GI50: 1.10 μM), Non-Small Cell Lung Cancer (GI50: 1.00 μM), Renal Cancer (GI50: 1.00 μM), Colon Cancer (GI50: 1.66 μM), CNS Cancer (GI50: 1.36 μM), Melanoma (GI50: 1.82 μM), Ovarian Cancer (GI50: 1.64 μM) and Breast Cancer (GI50: 1.69 μM).

1,3-Dipolar cycloaddition reactions in heterocyclic synthesis. Synthesis of [1-[4-(thiazolyl/imidazothiazolyl/triazolyl)phenyl]-1H-pyrazole-3,4-dicarboxylate esters from 3-(4-acetylphenyl)sydnone

Cycloaddition of 3-(4-acetylphenyl)sydnone (1) with DMAD gave dimethyl 1-(4-acetylphenyl)-1H-pyrazole-3,4-dicarboxylate (2), which on bromination yielded the corresponding monobromoacetyl (3) and dibromoacetyl (4) derivatives. Both compounds 3 and 4 on reaction with thiourea and thioacetamide afforded the 2-amino- (5) and the 2-methyl- (6) thiazole derivatives respectively, while compound 3 on reaction with 2-aminothiazole gave the imidazothiazole 7. Compound 3 was converted into its azide (8), which on 1,3-dipolar cycloaddition with DMAD afforded the 1,2,3-triazole-4,5-dicarboxylate (9).

An expeditious synthesis of 1,2,4-triazolinones appended to 1,3-thiazoles using zinc triflate as catalyst

A convenient and high yielding method was developed for the ring transformation of 1,3,4-oxadiazolinones (2a-e) from 3-arylsydnones (1a-e) to 1,2,4-triazolinones (3a-e) using zinc triflate as catalyst and then appended to 1,3-thiazoles via an imino bridge in one-pot reaction with excellent yields. The novel compounds were further scored for c logP values, drug likeliness, drug score and toxicity rates using molecular OSIRIS property explorer. Selective compounds were also screened for antimicrobial studies.