TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 43 (2002) 1555–1556
A mild and efficient method for cleavage of CꢀN using
Mg(HSO4)2 in the presence of wet SiO2
F. Shirini,a,* M. A. Zolfigol,b B. Mallakpour,a S. E. Mallakpour,c A. R. Hajipourc and
I. M. Baltorkd
aDepartment of Chemistry, Faculty of Science, Guilan University, Rasht, Iran
bDepartment of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan, Iran
cOrganic Polymer Chemistry Research Laboratory, College of Chemistry, Isfahan University of Technology, Isfahan, Iran
dDepartment of Chemistry, Isfahan University, Isfahan, Iran
Received 2 November 2001; revised 13 December 2001; accepted 21 December 2001
Abstract—Mg(HSO4)2 in the presence of wet SiO2 was reacted with oximes, hydrazones and semicarbazones and converts them
to the corresponding carbonyl compounds in good to high yields under mild and heterogeneous conditions. © 2002 Elsevier
Science Ltd. All rights reserved.
Oximes, hydrazones and semicarbazones are used not
only for isolation, purification and characterization
but also for protection of carbonyl compounds.1,2
Since oximes can be prepared from non-carbonyl
compounds,3–8 the regeneration of carbonyl com-
pounds from oximes provides an alternative method
for the preparation of aldehydes and ketones. Some
hydrazones and semicarbazones using Mg(HSO4)2 in
the presence of wet SiO2.
The results of the conversions of various oximes,
hydrazones and semicarbazones to their correspond-
ing carbonyl compounds are presented in Table 1.
The products of the reaction with Mg(HSO4)2 in the
presence of wet SiO2 were isolated simply by filtering
the mixture and evaporating the solvent from the
filtrate. The method has advantages in terms of yield,
heterogeneous nature, cheapness and availability of
the reagents, short reaction times and easy work-up.
of the methods of generating carbonyl compounds
9–11
from oximes
involve reagents that are often haz-
ardous or very toxic, expensive, or not readily avail-
able, they need to be freshly prepared or the
reactions require drastic conditions, long reaction
times and tedious work-up. Thus, a milder, selective,
non-hazardous and inexpensive reagent is still in
demand. Little attention has been paid to the cleav-
age of the carbonꢁnitrogen double bonds of hydra-
zones and semicarbazones, and only a few reports are
available dealing with the conversion of these deriva-
tives into their corresponding carbonyl com-
pounds.12,13
The oximes, hydrazones and semicarbazones were
prepared by standard procedures.14,15 The purity of
the compounds was checked by TLC. A mixture of
the substrate (1 mmol), n-hexane (5 mL),
16
Mg(HSO4)2 (3 mmol) and wet SiO2 [(SiO2/H2O:
50% w/w), 0.1 g] was stirred at room temperature for
the specified time (Table 1). The reaction was moni-
tored by TLC. After completion of the reaction, the
mixture was filtered and the solid residue was washed
with n-hexane (9 mL). Evaporation of the solvent,
followed by column chromatography on silica gel,
gave the corresponding carbonyl compounds in good
to high yields.
We now report a convenient method for the cleavage
of the carbonꢁnitrogen double bonds of oximes,
* Corresponding author. Fax: +98 131 3220066; e-mail: shirini@
cd.gu.ac.ir
0040-4039/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(02)00007-2
Shirini
