1419 J. Indian Chem. Soc., Vol. 96, November 2019, pp. 1419-1427 Ammonium acetate in acetic acid: A versatile chemical mixture in organic synthesis Md. Firoj Hossain Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling-734 013, West Bengal, India E- mail: firoj01982@gmail.com Manuscript received online 16 September 2019, accepted 22 September 2019 Ammonium acetate in acetic acid is an alternative source of ammonia gas. The beauty of this chemical mixture is it is inex- pensive, fairly soluble in water, commercially available, very safe and can handle easily. Moreover the mixture is nontoxic and eco-friendly in nature. This chemical mixture is easily biodegradable. It is widely used mixture as buffer for analytical purpose. Literature reveals that many organic reactions involve this NH 4 OAc/HOAc combination. The mixture has been ex- tensively used for the synthesis of heterocycles (pyridine, triazole, oxazole, thiazole, acridine derivatives, isoindole deriva- tives, phenazine derivatives, dihydrofuran, pyrimidine), N-acetylation of anilines and secondary amine. Also this mixture cata- lyzed the highly regio- and stereoselective ring enlargement reaction of cyclopropane derivatives to 2,3-dihydrofuran deriva- tives. NH 4 OAc/HOAc mixture is used as additives for the epoxidation of alkene. Keywords: NH 4 OAc/HOAc, ammoniating agent, heterocycles, pyridine, triazole, oxazole, N-acetylation. Introduction Mohammed Hilmy Elnagdi and coworkers were interested to synthesize the densely functionalized, biologically active heteroaromatic compounds 1 using readily available and cheap starting materials. They reported the synthesis of 7- benzyl-4-methyl-8-phenyl pyrido[2  ,3  :2,3] thieno[4,5- d]pyrimidine (2) and 6-benzyl-2-methyl-5-phenylnicotinic acid ethyl ester (4) from N,N-dimethyl-formamidine derivative (1) and the enaminone intermediate (3) respectively using the ammonium acetate in acetic acid which shown in the Scheme 1. Also they reported the synthesis of 3,5-diphenyl-pyran- 4-one (6a), 3,5-diphenyl-1H-pyridin-4-one (6b) and 1,3,5- trisubstituted pyridin-4-ones ( 7a,b) from the intermediate compound dienaminone (5) shown in the Scheme 2. G. W. V. Cave and C. L. Raston, reported 2 the synthesis of bipyridine, a supramolecular building block, in chiral and achiral form in a solvent-free condition involving Michael addition followed by treatment with ammonium acetate in acetic acid of the appropriate starting material with better yield. Literature revealed that bipyridine known to complexed with various metal ions. Specially pinene and camphor con- Scheme 1