Synthesis and antimicrobial activity of new substituted dihydropyrimidine derivatives

A new series of ethyl 6-methyl-4-[substituted]phenyl-2-[substituted]-phenacyl-thio-1, 4- dihydropyrimidine-5-carboxylate [2a-x] was prepared by reaction of ethyl 1, 2, 3, 4-tetrahydro-6-methyl-4-[substituted]phenyl-2-thioxopyrimidine-5-carboxy-late J [a-d] with phenacyl bromides. Compounds 1[a-d] were synthesized using the principle of Bignelli condensation by one pot reaction of the appropriate araldehyde. ethyl acetoacetate and thiourea in acidic medium. Confirmation of the chemical structure of the synthesized compounds [2a-x] was substintiated by different spectral data IR. [1]H-NMR. MS in addition to their microanalyses. The newly synthesized compounds were evaluated for their antimicrobial activities. The antibacterial and antifungal testing identified compounds 2b, 2e, 2k, 21, 2m, 2n, 20, 2p, 2q, 2, and 2x as the most effective agents in comparison to Chloramphenicol and Clotrimazole as reference antibacterial and antifungal drugs respectively

Synthesis and antimicrobial activity of some 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazine-2-thione derivatives

Twelve new 3-[isobutyl]-5-substituted-tetrahydro-2H-1,3,5-thiadiaz- ine-2-thiones were synthesized by the reaction of isobutylamine with carbon disulfide and potassium hydroxide, followed by formaldehyde and appropriate alkyl, cycloalkyl aralkyl amines, amino acid, and INH. Their structures have been elucidated by spectral data and elemental analysis. The title compounds were tested for antimicrobial activity in vitro against gram-positive bacteria [Staphylococcus aureus,and Micrococcus leuteus], gram-negative bacteria [Serratia marcescens and Escherichia coli] and some fungi [Candida albicans, Scopulariopsis brevicalus, Geotrichum candidum, Macrophomina phaseolina, Fusarium oxysporum and Trichoderma harzianum] using agar cup diffusion method. The antimicrobial activity was found to be greatly affected by the bulkiness of the side chain and the presence of polar carboxylic group. Highest activity was obtained with compounds 4a and 4k [R= CH3, CH2-COOH]

Synthesis of some quinoline thiosemicarbazone derivatives of potential antimicrobial activity

5-Acetyl [or 5-benzoyl]-8-hydroxyquinoline-4-substituted thiosemi- carbazones [IIa-m, IIIa-m respectively] have been prepared via the condensation of 5-acetyl [or 5-benzoyl]-8-hydroxyquinoline with the appropriate 4-substituted-3-thiosemicabazides [Ia-l]. The thiosemicarbazones [IIa-l, IIIa-f] were subjected to cyclization into the corresponding thiazolidinones [IVa-l, Va-f] by the reaction with ethyl bromoacetate in the presence of anhydrous sodium acetate. The structures of the thiosemicarbazones as well as the corresponding thiazolidinones were assigned based on both elemental and spectroscopic evidences. The prepared compounds were also evaluated for antibacterial and antifungal activities