Arylmethylidene derivatives of furan-2(3H)-ones in the synthesis of furopyridinecarbonitriles

Full text of DOI:10.1134/S1070428012120172

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 12, pp. 1578–1579. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © T.V. Anis’kova, A.Yu. Egorova, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 12, pp. 1607–1608.
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Arylmethylidene Derivatives of Furan-2(3H)-ones
in the Synthesis of Furopyridinecarbonitriles
T. V. Anis’kova and A. Yu. Egorova
Chernyshevskii Saratov State University, ul. Astrakhanskaya 83-1, Saratov, 410012 Russia
e-mail: aniskovatv@mail.ru
Received May 15, 2012
DOI: 10.1134/S1070428012120172
In recent time, the chemistry of functionally sub-
stituted pyridines extensively develops. This is related
to both theoretical interest in such organic compounds
and extremely broad spectrum of practical applications
of pyridine derivatives as potential therapeutic agents
for the treatment of cancer [1], diabetes [2], and other
genetic and metabolic disorders. In addition, pyridine
fragment is one of the most frequently occurring
heterocyclic systems in such natural compounds as
coenzymes and vitamins.
2,4-Diarylfuro[2,3-b]pyridine-5-carbonitriles IIa
and IIb (general procedure). A mixture of 0.01 mol of
furanone Ia or Ib, 0.01 mol of malononitrile, and
0.01 mol of triethylamine in 20 ml of anhydrous
ethanol was heated for 3 h. The precipitate was filtered
off, washed with an acidified solution of sodium
carbonate, and recrystallized from hexane.
Scheme 2.
Ar
H
NEt3
CN
N
With a view to obtain a fused pyridine system, we
used accessible 5-aryl-3-arylmethylidenefuran(pyr-
role)-2(3H)-ones. Heating of 5-aryl-3-arylmethylidene-
furan-2(3H)-ones Ia and Ib with malononitrile in an-
hydrous ethanol in the presence of triethylamine led to
the formation of 2,4-diarylfuro[2,3-b]pyridine-5-carbo-
nitriles IIa and IIb (Scheme 1). The number and
CN
CN
EtOH, Et3N
C
Ia, Ib
+
HOEt
R
O
O
Ar
Ar
CN
CN
·
NH
O
R
O
R
NH
1
positions of signals in the H and 13C NMR spectra of
O
O
IIa, IIb
compounds IIa and IIb were very consistent with the
–H2O
assumed structure.
4-(2-Chlorophenyl)-2-phenylfuro[2,3-b]pyridine-
5-carbonitrile (IIa). Yield 83%, mp 86–88°C.
1H NMR spectrum, δ, ppm: 5.60 s (1H, 3-H), 6.57–
7.48 m (9H, Harom), 9.03 s (1H, 6-H). 13C NMR spec-
trum, δC, ppm: 105.4, 112.1, 112.8, 114.3, 115.1, 117.3,
118.9, 120.2, 124.3, 125.5, 129.1, 131.1, 132.3, 134.3,
135.4, 137.3, 142.3, 166.4. Found, %: C 72.15; H 3.70;
N 8.97. C20H11ClN2O. Calculated, %: C 72.62; H 3.35;
N 8.47.
Scheme 1.
Ar
Ar
CN
EtOH, Et3N
CN
+
R
R
O
CN
O
O
N
Ia, Ib
IIa, IIb
Ar = 2-ClC6H4; R = Ph (a), 4-MeC6H4 (b).
4-(2-Chlorophenyl)-2-(4-methylphenyl)furo-
Malononitrile carbanion generated by the action of
[2,3-b]pyridine-5-carbonitrile (IIb). Yield 85%,
1
triethylamine adds across the exocyclic double C=C
bond of Ia or Ib to give the corresponding Michael
adduct. Activation of the latter by the base favors the
Thorpe–Ziegler reaction, and the subsequent hetero-
cyclization yields furopyridines II (Scheme 2).
mp 68–70°C. H NMR spectrum, δ, ppm: 2.37 s (3H,
CH3), 5.63 s (1H, 3-H), 6.53–7.38 m (8H, Harom),
9.02 s (1H, 6-H). 13C NMR spectrum, δC, ppm: 21.4,
105.3, 111.2, 113.3, 115.8, 120.9, 121.4, 122.8, 124.7,
126.3, 127.3, 129.8, 130.6, 132.5, 133.9, 138.5, 146.7,
1578

ARYLMETHYLIDENE DERIVATIVES OF FURAN-2(3H)-ONES
1579
153.8, 169.8. Found, %: C 72.71; H 4.33; N 8.78.
C21H13ClN2O. Calculated, %: C 73.15; H 3.80; N 8.12.
for state support of young Russian scientists, project
no. MK-2054.2011.3) and by the Russian Foundation
for Basic Research (project no. 10-03-00640-a).
1
The H NMR spectra were recorded at 20–25°C on
a Varian-400 spectrometer (400 MHz) from solutions
in CDCl3 using tetramethylsilane as internal reference.
Thin-layer chromatography was performed on Silufol
UV-254 plates using hexane–ethyl acetate–chloroform
(2:2:1) as eluent; spots were visualized by treatment
with iodine vapor.
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Patel, D.N., Gupta, A.A., Sharma, A., Tom, R., Bandyo-
padhya, D., Moodi, H., and Patel, P.K., Bioorg. Med.
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This study was performed under financial support
by the President of the Russian Federation (program
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 12 2012