Support catalyst and microwave irradiation in eco-friendly organic synthesis
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Date
2005
Authors
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Publisher
CCSHAU
Abstract
The present study reports an eco-friendly organic synthesis for the preparation of
organic compound using support catalyst and microwave irradiation. This method
has been found to be cheaper, cleaner, faster, and gave higher yields of the
products. Substituted arylidene benzoyl hydrazine were prepared by using
benzaldehyde, 4-hydroxybenzaldehyde, 2-nitrobenzaldehyde, 4-
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methoxybenzaldehyde, and 4-N,N-dimethoxybenzaldehyde with benzoyl
hydrazine and arylidene 4-chlorobenzoyl hydrazines were prepared by using
aldehydes with 4-chlorobenzoyl hydrazine by microwave irradiation and adsorbed
on alumina. The product obtained have yield 90-95 % which is better than
conventional method. Oximes of carbonyl compounds has been prepared by the
microwave assisted reaction of ketones and hydroxylamine hydrochloride
adsorbed on silica supported Na2Co3 in 4-6 minutes with 91-94 % yield.
Alumna supported KMnO4 has been found as a very efficient and clean
reagent for the oxidation of primary alcohols to aldehydes. 2,6-diformyl-4-
methyl/chlorophenol was prepared by the oxidation of 2,6-dimethylol-4-
methyl/chlorophenol using KMnO4 doped alumina. Bridgehead nitrogen
heterocycles namely 2-phenyl/(4-chlorophenyl)thiazolo[3,2-b]-s-triazol-5-(6H)-
one, 2-phenyl-5,6-dihydrothiazolo[3,2-b]-s-triazole and 2-phenyl-5,6,7-
trihydrothiazino[3,2-b]-s-triazole were prepared by the microwave irradiation of 3-
phenyl/(4-chlorophenyl)-s-triazolyl-5-thione and chloroacetic acid, 1,2-
dichloroethane and 1,3-dibromopropane, respectively. The reactants were
adsorbed on acidic alumina/silica. Cyclohexanone has been condensed
with various substituent aromatic aldehydes in presence of acidic alumina and
microwave irradiation to afford α,α`-diarylidene cyclohexanone in 90-96% yields.
The structures of all compounds have been proposed on the basis of their
comparison with the known structures.