Condensed heterocyclic systems containing bridgehead nitrogen atom:synthesis and antimicrobial activity of s-triazolo[3,4-b][1,3,4]thiadiazines,thiazolo[3,2-b]-s-triazoles and isomeric thiazolo[2,3-c]-s-triazoles

摘要

The synthesis of 2-#rho#-fluorophenyl-5-#rho#pbromophenylthiazolo[3,2-b]-s-triazole 5 has been achieved startingfrom 3-#rho#-fluorophenyl-5-mercapto-s-triazole 3.Compound 3 on condensation with #rho#-bromophenacyl bromide gave theketone 4 which on cyclization with PPA affords thiazolo[3,2-b]-s-triazole 5 and not the isomeric thiazolo[2,3-c]-s-triazole 7.This has been established by an unequivocal synthesis of 7 through POCl_3 cyclization of 2-#rho#-fluorophenyl-s-triazole 8 with #rho#-chlorophenacyl bromide furnishes 7H-6-#rho#-chlorophenyl-3-#rho#-fluorophenyl-s-triazolo[3,4-b][1,3,4]thiadiazine 9 in one step only.The diuretic,antibacterial and antifungal activities of these compounds have also been evaluated.