Synthesis and Properties of 1-Methyl-2-phenyl-5-(2-furyl)-
E. V. Vlasova, A. A. Aleksandrov, and M. M. El’chaninov
South-Russian State Technical University (Novocherkassk Polytechnic Institute), Novocherkassk, Rostov oblast, Russia
Received June 23, 2009
Abstract—2-Phenyl-5-(2-furyl)- and 2-phenyl-5-(2-thienyl)imidazoles were synthesized by condensation of 2-
furoylmethyl and 2-thenoylmethyl acetates with benzaldehyde under the conditions of Weidenhagen reaction.
The products were converted to N-methyl derivatives in the KOH–acetone system. The electrophilic
substitution reactions of the products (acylation, bromination, nitration, sulfonation, hydroxymethylation) were
ORGANIC SYNTHESIS AND INDUSTRIAL
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 6, pp. 1027–1031. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © E.V. Vlasova, A.A. Aleksandrov, M.M. El’chaninov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 6, pp. 974–
Polycyclic fluorophores are widely used today in
designing fluorescent dyes. For example, derivatives of
naphthoylbenzimidazole , oxazole , and oxadi-
azole  find growing application. The electronic
structure and spectral properties of fused 2-hetaryl-
imidazoles were studied previously .
This paper deals with the synthesis of 2-phenyl-
4(5)-(2'-furyl)imidazole VII and 2-phenyl-4(5)-(2'-thi-
enyl)imidazole VIII and with electrophilic substitution
reactions of these compounds, performed to prepare
4(5)-(2'-furyl)imidazole was prepared previously
from furoyl chloride, diazomethane, and potassium
acetate, with the subsequent condensation of the
resulting 2-furoylmethyl acetate with formalin under
the conditions of Weidenhagen reaction . We were
able to synthesize compounds VII and VIII by the
similar reaction but without using dangerously
OH, 25% PhCHO
I, II III, IV V, VI VII, VIII
X = O (VII, IX, XI), S (VIII, X, XII).
We were able to methylate 2-phenyl-4(5)-(2'-hetaryl)
imidazoles VII and VIII in almost quantitative yield
with an equivalent amount of methyl iodide in the
KOH–acetone system , which, in contrast to the
reaction in alcoholic alkaline solutions, considerably
accelerates the reaction and virtually fully excludes
quaternization. Because of the asymmetric structure of
the imidazole anions, two isomers (4- and 5-) were
obtained in each case IX–XII.
According to the
H NMR spectrum, the isomer
ratio in the mixture is 1 : 2, with isomers XI and XII pre-
X = O (I, III, V, VII), S (II, IV, VI, VIII).
VII, VIII IX, X