SYNTHESIS AND BIOLOGICAL-ACTIVITIES OF FU SED PHOSPHORUS HETEROCYCLIC-COMPOUNDS

The alkyl phosphorchloridisocyanatidate (2) is a kind of bifunctional compound which has a high reactivity. We have reported a new efficient method to prepare a new kind of fused phosphorus heterocyclic compoun ds using the reaction of the bifunctional compound - alkyl phosphorchl oridisocyanatidate (2) with 5-amino-3-benzylthio-1,2,4-triazole and it s analogues (1). In this paper, the cyclization reaction of aryl phosp honochloridisocyanatidate (2) with 5-amino-3-benzylthio-1,2,4-triazole and its analogues 1 was described. Twelve o-4,5,6,7-tetrahydro-1,2,4- triazolo[1,5a]triazines were synthesized. The structures were assigned on the basis of H-1 NMR, P-31 NMR, IR supported by satisfactory eleme ntal analysis. The H-1 NMR spectrum of ,6,7-tetrahydro-1,2,4-triazolo[ 1,5a]triazine(3(c)) shows doublet at delta 8.72 with the coupling cons tant (2)J(rcH) = 8.9 Hz, single peak at delta 10.84 for NH adjacent to the heterocyclic moiety. In P-31 NMR of 3(c), one singlet at delta 4. 2, appearing in the lower field than in that of 6,7-tetrahydro-1,2,4-t riazolo[1,5a]triazines(3(a), 3(b), 3(c), 3(t), 3(i), 3(j)) which could be attributed to the deshielding effect of the phenyl substituent, in dicated one isomer. Tile strong (C = O) stretching absorption band at 1 681 cm(-1) indicated that 3(c) existed in the keto form instead of e nolic form. The most probable mechanism of the cyclization reaction wa s proposed. Initially nucleophilic addition of NH2 group to the isocya nate group of 2 gives an intermediate 4, which undergoes cyclization b y nucleophilic attack of 1-NH group on P with the cleavage of P-CI bon d. The cyclization yield of aryl phosphonochloridisocyanatidate is low er than that of alkyl phosphorchloridisocyanatidate which might be due to the steric influence of the aryl group. On the basis of H-1 NMR, P -31 NMR, IR spectra, Z-configuration could be proposed. The preliminar y biological tests show that some compounds have-herbicidal activities .