Design and synthesis of new 1,2,4-triazole derivatives containing morpholine moiety as antimicrobial agents

2-Morpholine-4ylethyl-3H -1,2,4-triazole-3-ones (2a, 2b) were obtained from the condensation between the corresponding ethoxycarbonylhydrazones and 2-morpholinoethanamine. 2a was converted to acetohydrazide (4) via the formation of an ester derivative (3). Treatment of 2a and 2b with several aryl sulfonyl chlorides afforded the corresponding 2-arylsulfonyl-1,2,4-triazole-3-ones (5a-c and 6). The reaction of hydrazide (4) with benzyl iso- and benzyl isothiocyanate produced the corresponding carboxamide (8a) and carbothioamide (8b). The basic treatment of 8b yielded 5-mercapto-4H-1,2,4-triazol-3-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-one (10). The synthesis of 1,3-thiazol-2(3H)-ylidene-1,2,4-triazol-1-ylacetohydrazide (11) and 1,3-oxazole-2(3H)-ylidene-1,2,4-triazole-1-yl)acetohydrazide (9) derivatives was performed from the reaction of 8a and 8b with substituted phenacyl bromides.