SYNTHESIS AND ANTI-MICROBIAL ACTIVITIES OF SOME 3-(4-PHENYLTHIAZOLE-2-YL) / 3-(3-CARBETHOXY-4,5,6,7-TETRAHYDROBENZOTHIOPHENE-2YL) QUINAZOLIN-4(3H)-ONE

Authors: G.Saravanan*, V.Alagarsamy1, C.R.Prakash2, T.Panneer Selvam2, V.Karthick and P.Dinesh Kumar

*Medicinal Chemistry Research Lab, Bapatla College of Pharmacy, Bapatla(A.P), India; 1Medicinal Chemistry Research Lab, M.N.R. College of Pharmacy, Sangareddy (A.P), India; 2Department of Pharmaceutical Chemistry, D.C.R.M. Pharmacy College, Inkollu(A.P), India; E.-mail: sarachem1981@gmail.com

In the present study, a novel quinazolin-4-(3H)-ones were synthesized by condensation of 2-amino-4-phenylthiazole/2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzothiophene with 6,8-(un/mono/di)-bromo-2-(methyl/phenyl)-4H-benzo-[1,3]-oxazine-4-ones. The 2-amino-4-phenylthiazole and 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzothiophene was synthesized from acetophenone and cyclohexanone respectively. The 6,8-(un/mono/di)-bromo-2-(methyl/phenyl)-4H-benzo-[1,3]-oxazine-4-ones were synthesized from 3,5-(un/mono/di)-bromo anthranilic acid. The chemical structures of the synthesized compounds were confirmed by means of IR, ¹H-NMR, Mass spectral and Elemental analysis. These compounds were screened for anti-bacterial (Staphylococcus aureus ATCC 9144, Staphylococcus epidermidis ATCC 155, Micrococcus luteus ATCC 4698, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2853, and Klebsiella pneumoniae ATCC 11298) and anti-fungal (Aspergillus niger ATCC 9029 and Aspergillus fumigatus ATCC 46645) activities by paper disc diffusion technique. The minimum inhibitory concentrations (MIC) of the compounds were also determined by agar streak dilution method. Most of the synthesized compounds exhibited mild to moderate anti-bacterial and anti-fungal activities. Among the synthesized compounds, 6,8-Dibromo-2-methyl-3-(4-phenylthiazol-2-yl)-quinazolin-4(3H)-one (7c) was found to exhibit the highest anti-bacterial activity and 6,8-Dibromo-2-methyl-3-(3-carbethoxy-4,5,6,7-tetrahydrobenzothiophene-2-yl)-quinazolin-4(3H)-one (7f) exhibited  highest anti-fungal activity.

Keywords : Quinazolin-4-(3H)-one, Thiazole, Benzothiophene, Anti-bacterial and Anti-fungal.