Synthesis and theoretical studies on energetics of novel N- and O- perfluoroalkyl triazole tagged thienopyrimidines--their potential as adenosine receptor ligands.

A series of novel N- and O- perfluoroalkyl triazole tagged thienopyrimidines 6a-c and 7a-d was synthesized in two steps from thienopyrimidin-4-ones 2 through O- and N-propargylated regioisomers 3a-i and 4a-i respectively. Compound 2 was reacted with propargyl bromide to form O- and N-propargylated regioisomers 3 and 4 in definite proportions. Each regioisomer was separated and independently subjected to [3+2] cycloaddition using perfluoroalkyl azides through Click reaction under Sharpless conditions and obtained exclusively anti product in each case. The formation of two regioisomers in the first step and single anti addition product in the next step could be explained based on computational studies carried out at B3LYP/6-31G(d) level of theory. Results of Fukui function indices at the reactive centers are in accordance with the observations. On evaluation of the synthesized molecules for their binding affinities towards adenosine receptors, 4d and 4f were found to be selective to A1 over A2A receptors.

Click chemistry: studies on the synthesis of novel fluorous tagged triazol-4-yl substituted quinazoline derivatives and their biological evaluation--theoretical and experimental validation.

The formation of N- and O-propargylated quinazoline derivatives 2, 3 from quinazol-4-ones 1 was theoretically predicted by optimizations at B3LYP/6-31G* level, analysed kinetically and thermodynamically. Theoretical predictions are validated by experiment to observe the trends and found deviation. Thus, compound 1 was propargylated in basic media to obtain compound 2 and 3 in definite proportions. Each compound was further subjected to [3+2] cycloaddition using perfluoroalkyl azides through Click reaction under Sharpless conditions, and obtained a series of novel perfluoroalkyl-1H,1,2,3-triazol-4-yl substituted quinazolines 4, 5, and 6. All the compounds were screened for antimicrobial activity and identified potential compounds.

Synthesis of novel 4,6-disubstituted quinazoline derivatives, their anti-inflammatory and anti-cancer activity (cytotoxic) against U937 leukemia cell lines.

In view of the link between use of NSAIDs and altered cancer incidence and a growing evidence of COX-II implication in angiogenesis, a novel series of 4,6-disubstituted quinazoline derivatives have been synthesized starting from anthranilic acid derivatives 1 through conventional methods. Initially acylation followed by cyclisation to obtain benz-oxazinones 2 which on further treatment with ammonia yielded the crucial intermediate, 2-substituted benzamide (3). The products were subsequently cyclised to obtain quinazolones 4, chlorinated 5, then hooked to various optically pure alpha-amino acids to have 4,6-disubstituted quinazoline derivatives 6. All the derivatives 6 are screened for anti-inflammatory and anti-cancer activity against U937 leukemia cell lines. Some of the compounds exhibited promising anti-cancer activity with reference to standard drug Etoposide.

GdCl(3) catalysed Grieco condensation: a facile approach for the synthesis of novel pyrimidine and annulated pyrimidine fused indazole derivatives in single pot under mild conditions and their anti-microbial activity.

Indazole regioisomers such as 3-amino-4-(trifluoromethyl)-6-phenyl-1H-indazole-7-carbonitrile 1 and 3-amino-6-(trifluoromethyl)-4-phenyl-1H-indazole-7-carbonitrile 2 were independently reacted with formaldehyde followed by unsymmetrical, symmetrical and cyclic electron rich olefins in presence of GdCl(3) as catalyst and obtained pyrimidine fused indazole derivatives 3 and 4, respectively. The reaction is found to be concerted and an exclusive product is formed. Representative examples of compounds 3 and 4 were screened against Gram-positive, Gram-negative bacteria and fungal species such as yeast and filamentous fungi in vitro. Compound 3f showed significant activity against all species of Gram-positive and Gram-negative bacteria, whereas compounds 3h and 4a showed the least activity with reference to penicillin as well as streptomycin. Similarly compound 3c showed promising activity against yeast and filamentous fungi whereas compound 3f is inactive at the maximum concentration of 150 microg/mL.

Synthesis and structure-activity relationships of novel pyrimido[1,2-b]indazoles as potential anticancer agents against A-549 cell lines.

A series of novel pyrimido[1,2-b]indazoles 5, 7 have been prepared from 3-trifluoromethyl-5-phenyl-2,6-dicyano anilines 1 via novel indazole regioisomers 3 and 4 through a facile strategy. Specific examples were evaluated for anticancer activity in vitro and found to exhibit promising activity against A-549 cell lines and are more effective than Etoposide. QSAR models were developed and validated by cross-validation method. The results of the best QSAR model were further compared with the crystal structure of tubulin protein. The binding energies estimated were found to have a good correlation with the experimental inhibitory potencies.