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Synlett 2007(9): 1475-1476  
DOI: 10.1055/s-2007-980375
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

Ammonium Acetate

Madan Gopal Barthakur*
Medicinal Chemistry Division, Regional Research Laboratory (CSIR), Jorhat 785006, Assam, India
e-Mail: mgb_chem@rediffmail.com;
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Publication History

Publication Date:
23 May 2007 (online)

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Introduction

Ammonium acetate (NH4OAc) is an easily biodegradable chemical, which displays its versatility in almost all arrays of chemical science. It is a white crystalline solid with a melting range of 110-114 °C and is generally stored at low temperature under vacuum because it is hygroscopic and decomposes at elevated temperatures. Pure ammonium acetate can be prepared by saturating glacial acetic acid with dry ammonia. [1] Qualities like cheap and wide commercial availability, safe and easy handling, fair solubility in water and organic solvents and, above all, its non-toxic and eco-friendly nature make ammonium acetate a popular reagent and effective alternative to gaseous ­ammonia.

From the budding stage of chemistry it has been used in textile and rubber industries, agro and food technology, for analytical purposes as buffer, [2] and in many organic ­reactions (Knoevenagel condensation, [3a] Hantzsch pyridine synthesis, [3b] Krohnke pyridine synthesis, [3c] reactions involving NH4OAc/HOAc combination [3d] ).

In 1957, Hasselstrom et al. reported an amazing synthesis of amino acids by β-radiation of NH4OAc. [4] In some cases ammonium acetate shows excellent catalytic activity. [5] Literature reveals that it has been extensively used in the synthesis of N-heterocyclic compounds (pyridines, [6-8] ­pyridopyrimidines, [9] aziridines, [10] imidazoles, [11] benz­oxazines [12] ), many of which exhibit ­pharmacological activity or act as drug precursors. Moreover, it finds application in modern techniques of analytical chemistry [13a] and molecular biology (purification and ­precipitation of DNA, [13b] protein crystallization [13c] ). Recently, a valuable regioselective synthesis of synthetically important α-iodo acetates from alkenes, NH4OAc, and I2 was reported. [14a]

Ammonium acetate is an efficient reagent in low- and high-boiling organic solvents at room temperature [14b] as well as under reflux conditions. [6-9] Its high efficacy as ­reagent in water, [7a] ionic liquids, [7b] microwave-promoted solvent-less synthesis, [12] and supercritical water [15] gives it a unique position in the present scenario of green ­chemistry.