Synthesis, antibacterial, and antioxidant studies of 7-amino-3-(4-fluorobenzoyl)indolizine-1-carboxylate derivatives

In the present work, the quaternary salts of 4-aminopyridine, i.e., 4-amino-1-[2-(4-bromophenyl)-2-oxoethyl]pyridin-1-iumbromides were obtained by stirring 4-aminopyridine with phenacyl bromides in acetone at room temperature separately.These quaternary salts of 4-aminopyridine were treated with acetylenes (electron deficient), in the presence of anhydrouspossium carbonate in N,N-dimethylformamide solvent to get indolizine derivatives. The structures of newly synthesisedcompounds have been confirmed by spectroscopic techniques, such as liquid chromatography mass spectrometry,1H-NMR, and elemental analysis. Synthesized all compounds were screened for antibacterial and antioxidant activity.The compounds 2e, 2g, and 2j shows inhibition zone against bacteria and compounds 2a and 2f moderately active againstbacteria. All compounds 2a to 2j show 1,1-diphenyl-2-picrylhydrazide radical free radical scavenging activity, NitricOxide free radical scavenging activity, Reducing power scavenging activity, and Lipid peroxidation inhibition activity.

Synthesis and characterization of novel 1,6-dihydropyrimidine derivatives for their pharmacological properties

The present research work involves the use of commercially available thiophene-2-carbaldehyde as a starting materialto construct novel pyrimidine compounds. Synthesis of pyrimidine derivatives has been done by the trimolecularBiginelli condensation reaction, which involves the use of thiophene-2-carbaldehyde with cyano ethylacetate andthiourea to yield 4-oxo-6-(thiophen-2-yl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile (1). The intermediate 1was methylated using methyl iodide and K2CO3 in dimethylformamide (DMF) which afforded dimethylated derivative1-methyl-2-(methylthio)-6-oxo-4-(thiophen-2-yl)-1,6-dihydropyrimidine-5-carbonitrile (2). The intermediatecompound 2 when refluxed with hydrazine hydrate in ethanol as a solvent led to the formation of the parent compound2-hydrazineyl-1-methyl-6-oxo-4-(thiophen-2-yl)-1,6-dihydropyrimidine-5-carbonitrile (3), the parent compound 3was used for the synthesis of carboxamides of N′-(5-cyano-1-methyl-6-oxo-4-(thiophen-2-yl)-1,6-dihydropyrimidin2-yl)substituted benzohydrazide (4a–d) and Schiff bases of (E)-2-(2-substituted benzylidenehydrazineyl)-1-methyl6-oxo-4-(thiophen-2-yl)-1,6-dihydropyrimidine-5-carbonitrile (5a–g). Selected title compounds are screened forantibacterial, analgesic, and antifungal activities.