New N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides
13, 20, and 21were synthesized using sodium bicarbonate and benzyl amine with 2-thioxo-substituted-1,3-benzoxazines 6, 10a, b, 11c, and 12a–n. The 2-thioxo-substituted-1,3-oxazines 6, 10a-b, 11d 12a–n, and 26were converted to the corresponding 2-methylthio-substituted-1,3-oxazines 14a–land 24which were then converted to 2-benzyl amino-substituted-benzoxazines 15a–iby refluxing with benzylamine. Products 15a, b, e, f, and gwere also synthesized by boiling the corresponding N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides 13a, b, f, l, and min acetic acid. 2-Oxo-substituted-1,3-benzoxazines 22and 25were prepared by treating the corresponding 2-methylthio-substituted-1,3-oxazines 14and 24with dilute HCl. The N-(benzyl carbamoyl)-2-hydroxy substituted benzamide 23was synthesized from the reaction of 2-oxo-substituted-1,3-benzoxazine 22with benzylamine. The new products were characterized using IR,1H, and13C NMR in addition to microanalysis. Selected compounds were tested in vitro for antibacterial and antifungi activity and the most active compounds were found to be the 4-(substituted-benzylamino)-2-hydroxy benzoic acids 9aand d( M. chlorophenolicum, MIC 50 and 25 µgm L−1, resp.), N1, N3-bis (benzyl carbamothioyl)-4,6-dihydroxy-substituted phthalamides 20aand 20c( B. subtilisMIC 12.5, 50 µgm L−1, resp.) and 21( M. chlorophenolicum, MIC 50 µgm L−1).