General Papers ARKIVOC 2015 (vii) 101-112
Page 101
©
ARKAT-USA, Inc
A mild alkaline hydrolysis of N- and N,N-substituted amides and
nitriles
Vassiliki Theodorou,*
a
Georgios Paraskevopoulos,
b
and Konstantinos Skobridis*
a
a
Department of Chemistry, University of Ioannina, GR-451 10 Ioannina, Greece
b
Department of Inorganic and Organic Chemistry, Charles University, Prague, Hradec Králové
50005, Czech Republic
E-mail: vtheodor@cc.uoi.gr
DOI: http://dx.doi.org/10.3998/ark.5550190.p009.205
Abstract
A mild protocol for the alkaline hydrolysis of secondary and tertiary amides in non-aqueous
conditions, by the use of NaOH in methanol/dichloromethane or methanol/dioxane (1:9) at room
temperature or under reflux, has been developed and a plausible reaction mechanism is
discussed. Primary amides are hydrolyzed much slower than with the classical procedure, while
nitriles are converted selectively to primary amides.
Keywords: Alkaline hydrolysis, amides, N-substituted amides, nitriles, imidates, anhydrous
conditions, protection
Introduction
Amide derivatives constitute important moieties in many pharmaceutical and biologically active
molecules. Hydrolysis of an amide, a nitrile or an ester functional group is a very common
transformation in organic synthesis with many applications and a common way to prepare
carboxylic acids. In general, nitriles and amides are exceptionally stable to acid and basic
hydrolysis and classically they are hydrolyzed under vigorous reaction conditions and long
reaction times
1-3
by heating in the presence of mineral acids or concentrated solutions of alkali
hydroxides (10-40%), which can sometimes cause undesirable side reactions and low yield.
Tertiary amides are very difficult to be cleaved and in most cases stronger conditions are
required than for primary and secondary amides. Nitriles are hydrolyzed first to amides and
further to carboxylic acids and ammonia with even more strong reaction conditions.
The hydrolysis of amides and nitriles is a well studied reaction and numerous methods have
been developed.
4-14
Among them, the use of sodium peroxide
4
and of phthalic anhydride
5
for the
amide hydrolysis have been described, while nitriles can also be converted to amides by
catalyzed hydration,
6-9
enzymatically
10
and on unactivated alumina.
11
Ames and Islip in their