REACTION OF SCHIFF-BASE OF THIOHYDRAZIDES WITH P(NR2)(3)

Three pathways were observed in the reactions of Schiff bases of Thioh ydrazides with P(NR2)(3). (a) MeS-R2N exchange: MeS-C(=S)-NHN=CHPh (1) reacted with P(NR2)(3) led to new Schiff bases, R2N-C(=S)-NHN=CH=Ph ( 2). (b) Cleavage of C=S bond and the formation of P-S bond: H2N-C(=S)- NHN=CH=Ph (3) reacted with P (NR2)(3) gave rise to the thiophosphoric amide, (Et2N)(2)P(=S)-NH-CH=N-N=CH-Ph (4). (c) Formation of thiadiazol e and triazole: Schiff bases (2a) and H2N(MeS)C=N-N=CH-Ph (6) reacted with P(NR2)(3) respectively and produced -dimethylamino-2-phenyl-2,3-( 2H)-1,3,4-thiadiazole (5) and 5-methylthio-2-phenyl-2,3-(2H)-1,3,4-tri azole (7).