ONE-POT SYNTHESIS OF IMIDAZO[1,2-B]PYRAZOLE, IMIDAZO[1,2-B]-1,2,4-TRIAZOLE, IMIDAZO[1,2-A]PYRIDINE, IMIDAZO[1,2-A]PYRAMIDINE, IMIDAZO[1,2-A]BENZIMIDAZOLE, AND 1,2,4-TRIAZOLO[4,3-A]BENZIMIDAZOLE DERIVATIVES

Hydrazonoyl bromides 1a-c react with 5-amino-3-phenyl-1H-pyrazole, 5-a mino-1H-1,2,4-triazole, 2-aminopyridine, 2-aminopyrimidine, and 2-amin obenzimidazole to afford the corresponding imidazo[1, 2-b]pyrazoles 10 , imidazo[1, 2-b]-1,2,4-triazoles 11, imidazo[1,2-a]pyridines 16, imid azo[1, 2-a]pyrimidines 17, and imidazo[1,2-a]benzimidazoles 20, respec tively. Compounds 1a-c reacted also with 2-methylthiobenzimidazole to give 1,2,4-triazolo[4,3-a]benzimidazole derivatives 21. (C) 1997 John Wiley & Sons, Inc.