SYNTHESIS OF NEW PEPTIDYL[1,2,4]TRIAZOLO[3,4-B][1,3]THIAZIN-5-ONES INVOLVING RING TRANSFORMATION OF 5-OXAZOLONE DERIVATIVES

Michael addition of sulphur nucleophiles, 3-mercapto-1,2,4-triazoles ( 2a, b) to 4-arylidene-5(4H)-oxazolones (1a, b) followed by ring transf ormation of the resultant Michael adducts (3a-d) yields 6-acetamido-3, 7-diaryl-6, 7-dihydro-5H-1, 2, 4-triazolo[3, 4-b] [1, 3]thiazin-5-one s (4a-d) in one pot. The compounds 4a-d on deacetylation furnish the c orresponding 6-amino analogues (5a-d) which have been converted into 6 -peptidyl (gly. gly and gly.L-phe)amino derivatives (7a-h). The compou nds 3-7 have been compared with a commercial fungicide, Dithane M-45, for their fungitoxicity against A. niger and F. oxysarpium.