Synthesis of 2-imino-4-vinyl-2,5-dihydrofuran-3-carboxamides and some their chemical transformations

Article abstract of DOI:10.1134/S1070428009070082

2-Imino-2,5-dihydrofuran-3-carboxamides containing 2-phenyl- and 2-furylvinyl substituents in position 4 of the furan ring were synthesized by condensation of 2-imino-4-methyl-2,5-dihydrofuran-3-carboxamides with the corresponding aldehydes. Acid hydrolys

Full text of DOI:10.1134/S1070428009070082

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2009, Vol. 45, No. 7, pp. 1031–1035. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © A.A. Avetisyan, L.V. Karapetyan, M.D. Tadevosyan, 2009, published in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 7,
pp. 1044–1048.
Synthesis of 2-Imino-4-vinyl-2,5-dihydrofuran-3-carboxamides
and Some Their Chemical Transformations
A. A. Avetisyan, L. V. Karapetyan, and M. D. Tadevosyan
Erevan State University, ul. Aleka Manukyana 1, Erevan, 0025 Armenia
e-mail: lousine_karapetyan@yahoo.com
Received August 13, 2008
Abstract—2-Imino-2,5-dihydrofuran-3-carboxamides containing 2-phenyl- and 2-furylvinyl substituents in
position 4 of the furan ring were synthesized by condensation of 2-imino-4-methyl-2,5-dihydrofuran-3-carbox-
amides with the corresponding aldehydes. Acid hydrolysis of 4-(2-arylvinyl)-2-imino-2,5-dihydrofuran-3-car-
boxamides gave 4-(2-arylvinyl)-2-oxo-2,5-dihydrofuran-3-carboxamides, and their condensation with malono-
nitrile resulted in the formation of 2-dicyanomethylidene derivatives.
DOI: 10.1134/S1070428009070082
Unsaturated γ-lactones are widespread in nature.
They exhibit biological activity and are used in various
fields such as medicine, agriculture, perfumery, etc.
[1]. Biological activity of unsaturated γ-lactones origi-
nates from the presence of double carbon–carbon bond
or aromatic ring [2, 3]. Their derivatives having con-
jugated double bond and carbonyl group are known as
plant growth stimulators [4, 5].
4 h under reflux in the presence of a catalytic amount
of sodium hydroxide. 4-Vinyl-substituted 2-imino-2,5-
dihydrofuran-3-carboxamides IIa–IIf readily under-
went hydrolysis in acid medium (pH 4–5) at 85–90°C
(reaction time 2 h) to give the corresponding 4-sub-
stituted 2-oxo-2,5-dihydrofuran-3-carboxamides IIIa–
IIIf (Scheme 1). This reaction may be regarded as
a convenient method for the preparation of function-
ally substituted 2,5-dihydrofuran-2-ones.
Taking into account the above stated, as well as the
fact that activated methyl group in position 4 of 2,5-di-
hydrofuran-2-ones is capable of being involved in
condensation processes [5–7], in the present work we
synthesized 2-imino-2,5-dihydrofuran-3-carboxamides
IIa–IIf having 2-phenyl- or 2-furylvinyl substituent in
position 4 by reaction of the corresponding 2-imino-
4-methyl-2,5-dihydrofuran-3-carboxamides Ia–If with
benzaldehyde or 2-furaldehyde (Scheme 1). Study on
the effects of different factors on the reaction course
allowed us to determine optimal conditions for the
condensation. The best yields of compounds IIa–IIf
were obtained when a mixture of equimolar amounts
of the reactants in anhydrous ethanol was heated for
2-Imino-2,5-dihydrofurans IIa–IIf were converted
in quantitative yield to hydrochlorides IVa–IVf by
passing gaseous hydrogen chloride through their solu-
tions in benzene. Hydrochlorides IVa–IVf can be
titrated with 0.1 N aqueous sodium hydroxide, and
their treatment with a solution of potassium carbonate
regenerates free bases IIa–IIf. Acid hydrolysis of hy-
drochlorides IVa–IVf at 85–90°C (3 h) gives 2,5-di-
hydrofuran-2-ones IIIa–IIIf (Scheme 2).
2-Imino derivatives IIa–IIf were also brought into
condensation with malononitrile. The reaction oc-
curred on mixing equimolar amounts of the reactants at
room temperature and was accompanied by evolution
Scheme 1.
R4
R4
O
O
O
NHR1
NHR1
NHR1
Me
R4CHO, NaOH, EtOH
H2O, HCl, pH 4–5
R2
R3
R2
R3
R2
R3
NH
NH
O
O
O
O
Ia–If
IIa–IIf
IIIa–IIIf
R1 = H (a–d), Me (e, f); R2 = R3 = Me (a, c, e); R2R3 = (CH2)5 (b, d, f); R4 = 2-furyl (a, b), Ph (c–f).
1031

AVETISYAN et al.
1032
Scheme 2.
R4
O
NHR1
HCl
H2O
IIa–IIf
·HCl
IIIa–IIIf
R2
R3
K2CO3 or NaOH
NH
O
IVa–IVf
of ammonia. The products were the corresponding
2-dicyanomethylidene-2,5-dihydrofuran-3-carbox-
amides Va–Vf which were formed in quantitative yield
(Scheme 3).
trum, δ, ppm: 1.65 s (6H, CH3), 6.49 d and 6.51 d (1H,
4′-H, J = 17.4 Hz), 6.72 d (1H, 3′-H, J = 17.4 Hz),
7.0 d (1H, =CH, J = 17.4 Hz), 7.21 br.s (1H, NH2),
7.34 s (1H, =NH), 7.65 d (1H, 5′-H, J = 17.4 Hz),
8.25 d (1H, =CH, J = 17.4 Hz), 9.08 br.s (1H, NH2).
Found, %: C 63.49; H 5.84; N 11.44. C13H14N2O3. Cal-
culated, %: C 63.40; H 5.73; N 11.38.
Scheme 3.
R4
O
NHR1
4-[2-(2-Furyl)vinyl]-2-imino-5,5-pentamethylene-
2,5-dihydrofuran-3-carboxamide (IIb). Yield 73%,
mp 182–183°C. IR spectrum, ν, cm–1: 3412 (NH2),
3263 (NH), 1671 (C=O), 1645 (C=N), 1630 (C=C),
CH2(CN)2
IIa–IIf
CN
CN
–NH3
R2
R3
O
1
Va–Vf
1625 (C=C), 1588, 1540 (C=C, furan). H NMR spec-
trum, δ, ppm: 1.58–1.88 m (10H, CH2), 6.49 d and
6.51 d (1H, 4′-H, J = 17.4 Hz), 6.72 d (1H, 3′-H, J =
17.4 Hz), 7.0 d (1H, =CH, J = 17.4 Hz ), 7.21 br.s
(1H, NH2), 7.34 s (1H, =NH), 7.65 d (1H, 5′-H, J =
17.4 Hz), 8.25 d (1H, =CH, J = 17.4 Hz), 9.08 br.s
(1H, NH2). Found, %: C 67.24; H 6.38; N 9.84.
C16H18N2O3. Calculated, %: C 67.12; H 6.34; N 9.78.
The structure of the newly synthesized compounds
was confirmed by their IR and H NMR spectra and
elemental analyses.
1
EXPERIMENTAL
The IR spectra were recorded on a Specord 75IR
spectrometer from samples dispersed in mineral oil.
2-Imino-5,5-dimethyl-4-(2-phenylvinyl)-2,5-dihy-
drofuran-3-carboxamide (IIc). Yield 93%, mp 193–
194°C. IR spectrum, ν, cm–1: 3300 (NH2), 3140 (NH),
1680 (C=O), 1640 (C=N), 1630 (C=C), 1620 (C=C),
1
The H NMR spectra were measured on a Varian
Mercury-300 instrument (300 MHz) from solutions in
DMSO-d6–CCl4 (1:3) using tetramethylsilane as inter-
nal reference. The purity of the products was checked
by TLC on Silufol UV-254 plates using acetone–ben-
zene (1:2) as eluent; spots were visualized by treat-
ment with iodine vapor or under UV light.
1
1600–1500 (C=Carom). H NMR spectrum, δ, ppm:
1.70 s (6H, CH3), 7.13 d (1H, =CH, J = 17.4 Hz),
7.25–7.44 m (5H, Harom, =NH, NH2), 7.62 m (2H,
H
arom), 8.53 d (1H, =CH, J = 17.4 Hz), 9.16 br.s
(1H, NH2). Found, %: C 70.34; H 6.44; N 11.04.
C15H15N2O2. Calculated, %: C 70.29; H 6.29; N 10.93.
5,5-Dialkyl-4-(2-arylvinyl)-2-imino-2,5-dihydro-
furan-3-carboxamides IIa–IIf (general procedure).
Sodium hydroxide, 10 mg, was added to a solution of
5 mmol of compound Ia–If and 5 mmol of benzalde-
hyde or 2-furaldehyde in 20 ml of anhydrous ethanol.
The mixture was heated for 4 h under reflux, the sol-
vent was removed under reduced pressure, the residue
was treated with water, and the precipitate was filtered
off, washed with water, and recrystallized from aque-
ous ethanol.
2-Imino-5,5-pentamethylene-4-(2-phenylvinyl)-
2,5-dihydrofuran-3-carboxamide (IId). Yield 85%,
mp 155–157°C. IR spectrum, ν, cm–1: 3300 (NH2),
3140 (NH), 1680 (C=O), 1640 (C=N), 1630 (C=C),
1
1620 (C=C), 1600–1500 (C=Carom). H NMR spec-
trum, δ, ppm: 1.6–1.9 m (10H, CH2), 7.2 d (1H, =CH,
J = 17.4 Hz), 7.25–7.44 m (5H, Harom, =NH, NH2),
7.64 m (2H, Harom), 8.5 d (1H, =CH, J = 17.4 Hz),
9.16 br.s (1H, NH2). Found, %: C 72.99; H 6.89;
N 9.54. C18H20N2O2. Calculated, %: C 72.95; H 6.80;
N 9.45.
4-[2-(2-Furyl)vinyl]-2-imino-5,5-dimethyl-2,5-
dihydrofuran-3-carboxamide (IIa). Yield 82%,
mp 191–192°C. IR spectrum, ν, cm–1: 3300 (NH2),
3140 (NH), 1680 (C=O), 1640 (C=N), 1625 (C=C),
2-Imino-N,5,5-trimethyl-4-(2-phenylvinyl)-2,5-
dihydrofuran-3-carboxamide (IIe). Yield 88%,
1
1620 (C=C), 1588, 1540 (C=C, furan). H NMR spec-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

SYNTHESIS OF 2-IMINO-4-VINYL-2,5-DIHYDROFURAN-3-CARBOXAMIDES
1033
1
mp 128–130°C. IR spectrum, ν, cm–1: 3340 (NH),
152°C. H NMR spectrum, δ, ppm: 1.70 s (6H, CH3),
7.13 d (1H, =CH, J = 17.4 Hz), 7.25–7.44 m (5H,
3160 (NH), 1680 (C=O), 1640 (C=N), 1635 (C=C),
1
1620 (C=C), 1600–1500 (C=Carom). H NMR spec-
Harom, NH2), 7.62 m (2H, Harom), 8.53 d (1H, =CH, J =
trum, δ, ppm: 1.48 s (6H, CH3), 2.82 d (3H, NCH3, J =
4.9 Hz), 7.13 d (1H, =CH, J = 17.4 Hz), 7.25–7.4 m
(4H, Harom, =NH), 7.61 m (2H, Harom), 8.5 d (1H, =CH,
J = 17.4 Hz), 9.84 br.s (1H, NH). Found, %: C 71.26;
H 6.81; N 10.44. C16H18N2O2. Calculated, %: C 71.09;
H 6.71; N 10.36.
17.4 Hz), 9.16 br.s (1H, NH2). Found, %: C 70.05;
H 5.89; N 5.50. C15H15NO3. Calculated, %: C 70.02;
H 5.88; N 5.44.
2-Oxo-5,5-pentamethylene-4-(2-phenylvinyl)-
2,5-dihydrofuran-3-carboxamide (IIId). Yield 79%,
mp 218–220°C. 1H NMR spectrum, δ, ppm: 1.6–1.9 m
(10H, CH2), 7.2 d (1H, =CH, J = 17.4 Hz), 7.25–
7.44 m (5H, Harom, NH2), 7.64 m (2H, Harom), 8.5 d
(1H, =CH, J = 17.4 Hz), 9.16 br.s (1H, NH2). Found,
%: C 72.75; H 6.49; N 4.75. C18H19NO3. Calculated,
%: C 72.71; H 6.44; N 4.71.
2-Imino-N-methyl-5,5-pentamethylene-4-
(2-phenylvinyl)-2,5-dihydrofuran-3-carboxamide
(IIf). Yield 83%, mp 145–146°C. IR spectrum, ν, cm–1:
3335 (NH), 3150 (NH), 1680 (C=O), 1640 (C=N),
1635 (C=C), 1620 (C=C), 1600–1500 (C=Carom).
1H NMR spectrum, δ, ppm: 1.6–1.9 m (10H, CH2),
2.82 d (3H, NCH3, J = 4.9 Hz), 7.13 d (1H, =CH, J =
17.4 Hz), 7.25–7.40 m (4H, Harom, =NH), 7.61 m (2H,
N,5,5-Trimethyl-2-oxo-4-(2-phenylvinyl)-2,5-di-
hydrofuran-3-carboxamide (IIIe). Yield 81%,
1
mp 132–133°C. H NMR spectrum, δ, ppm: 1.48 s
Harom), 8.5 d (1H, =CH, J = 17.4 Hz), 9.84 br.s (1H,
(6H, CH3), 2.82 d (3H, NCH3, J = 4.9 Hz), 7.13 d (1H,
=CH, J = 17.4 Hz), 7.25–7.40 m (5H, Harom, NH2),
7.61 m (2H, Harom), 8.5 d (1H, =CH, J = 17.4 Hz),
9.84 br.s (1H, NH). Found, %: C 70.85; H 6.39;
N 5.19. C16H17NO3. Calculated, %: C 70.83; H 6.32;
N 5.16.
NH). Found, %: C 73.59; H 7.28; N 9.27. C19H22N2O2.
Calculated, %: C 73.52; H 7.14; N 9.03.
5,5-Dialkyl-4-(2-arylvinyl)-2-oxo-2,5-dihydro-
furan-3-carboxamides IIIa–IIIf (general procedure).
A mixture of 1 mmol of 2-imino-2,5-dihydrofuran IIa–
IIf and 5 ml of water acidified with hydrochloric acid
to pH 4–5 was heated for 3 h at 85–90°C. The mixture
was cooled and extracted with diethyl ether (3×5 ml),
the extract was dried over magnesium sulfate and
evaporated, and the residue was recrystallized from
petroleum ether.
N-Methyl-2-oxo-5,5-pentamethylene-4-(2-phenyl-
vinyl)-2,5-dihydrofuran-3-carboxamide (IIIf). Yield
80%, mp 126–130°C. 1H NMR spectrum, δ, ppm: 1.6–
1.9 m (10H, CH2), 2.82 d (3H, NCH3, J = 4.9 Hz),
7.13 d (1H, =CH, J = 17.4 Hz), 7.25–7.4 m (5H, Harom
,
NH2), 7.61 m (2H, Harom), 8.5 d (1H, =CH, J =
17.4 Hz), 9.84 br.s (1H, NH). Found, %: C 73.34;
H 6.89; N 4.52. C19H21NO3. Calculated, %: C 73.29;
H 6.80; N 4.50.
4-[2-(2-Furyl)vinyl]-5,5-dimethyl-2-oxo-2,5-di-
hydrofuran-3-carboxamide (IIIa). Yield 80%,
1
mp >270°C. H NMR spectrum, δ, ppm: 1.65 s (6H,
CH3), 6.49 d and 6.51 d (1H, 4′-H, J = 17.4 Hz), 6.72 d
(1H, 3′-H, J = 17.4 Hz), 7.0 d (1H, =CH, J = 17.4 Hz),
7.21 br.s (1H, NH2), 7.65 d (1H, 5′-H, J = 17.4 Hz),
8.25 d (1H, =CH, J = 17.4 Hz), 9.08 br.s (1H, NH2).
Found, %: C 63.25; H 5.38; N 5.67. C13H13NO4. Cal-
culated, %: C 63.15; H 5.30; N 5.66.
5,5-Dialkyl-4-(2-arylvinyl)-2-imino-2,5-dihydro-
furan-3-carboxamide hydrochlorides IVa–IVf (gen-
eral procedure). Compound IIa–IIf, 2 mmol, was dis-
solved in benzene, gaseous hydrogen chloride was
passed through the solution, and the precipitate was
filtered off and washed with diethyl ether.
4-[2-(2-Furyl)vinyl]-2-oxo-5,5-pentamethylene-
4-[2-(2-Furyl)vinyl]-2-imino-5,5-dimethyl-2,5-di-
hydrofuran-3-carboxamide hydrochloride (IVa).
Yield 96%, mp 178–184°C. H NMR spectrum, δ,
2,5-dihydrofuran-3-carboxamide (IIIb). Yield 78%,
1
1
mp 160–162°C. H NMR spectrum, δ, ppm: 1.58–
1.88 m (10H, CH2), 6.49 d and 6.51 d (1H, 4′-H, J =
17.4 Hz), 6.72 d (1H, 3′-H, J = 17.4 Hz), 7.0 d (1H,
=CH, J = 17.4 Hz), 7.21 br.s (1H, NH2), 7.65 d (1H,
5′-H, J = 17.4 Hz), 8.25 d (1H, =CH, J = 17.4 Hz),
9.08 br.s (1H, NH2). Found, %: C 66.95; H 5.98;
N 4.51. C16H17NO4. Calculated, %: C 66.89; H 5.96;
N 4.88.
ppm: 1.65 s (6H, CH3), 6.49 d and 6.51 d (1H, 4′-H,
J = 17.4 Hz), 6.72 d (1H, 3′-H, J = 17.4 Hz), 7.0 d (1H,
=CH, J = 17.4 Hz), 7.21 br.s (1H, NH2), 7.65 d (1H,
5′-H, J = 17.4 Hz), 8.25 d (1H, =CH, J = 17.4 Hz),
9.08 br.s (1H, NH2), 10.34 br.s (2H, =NH·HCl). Found,
%: C 55.57; H 5.59; N 10.04. C13H14N2O3·HCl. Calcu-
lated, %: C 55.23; H 5.35; N 9.91.
5,5-Dimethyl-2-oxo-4-(2-phenylvinyl)-2,5-dihy-
drofuran-3-carboxamide (IIIc). Yield 82%, mp 151–
4-[2-(2-Furyl)vinyl]-2-imino-5,5-pentamethylene-
2,5-dihydrofuran-3-carboxamide hydrochloride
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

AVETISYAN et al.
1034
(IVb). Yield 96%, mp 173–179°C. 1H NMR spectrum,
δ, ppm: 1.58–1.88 m (10H, CH2), 6.49 d and 6.51 d
(1H, 4′-H, J = 17.4 Hz), 6.72 d (1H, 3′-H, J =
17.4 Hz), 7.0 d (1H, =CH, J = 17.4 Hz), 7.21 br.s (1H,
NH2), 7.65 d (1H, 5′-H, J = 17.4 Hz), 8.25 d (1H,
=CH, J = 17.4 Hz), 9.08 br.s (1H, NH2), 10.2 br.s (2H,
=NH·HCl). Found, %: C 59.72; H 6.09; N 8.99.
C16H18N2O3 ·HCl. Calculated, %: C 59.54; H 5.93;
N 8.68.
until pH 7–8. The precipitate was filtered off and
washed with water. We thus isolated iminolactones
IIa–IIf which showed no depression of the melting
point on mixing with samples prepared as described
above by condensation of compounds Ia–If with the
corresponding aldehydes.
Hydrolysis of compounds IVa–IVf (general
procedure). A mixture of 0.5 mmol of hydrochloride
IVa–IVf and 5 ml of water was heated for 2 h at 85–
90°C. The mixture was cooled and extracted with
diethyl ether (3×5 ml), the extract was dried over
magnesium sulfate, the solvent was distilled off, and
the residue was recrystallized from petroleum ether.
The products were identical to compounds IIIa–IIIf in
melting points.
2-Imino-5,5-dimethyl-4-(2-phenylvinyl)-2,5-di-
hydrofuran-3-carboxamide hydrochloride (IVc).
1
Yield 98%, mp 178–186°C. H NMR spectrum, δ,
ppm: 1.70 s (6H, CH3), 7.13 d (1H, =CH, J = 17.4 Hz),
7.25–7.4 m (5H, Harom, NH2), 7.62 m (2H, Harom),
8.53 d (1H, =CH, J = 17.4 Hz), 9.16 br.s (1H, NH2),
10.2 br.s (2H, =NH·HCl). Found, %: C 61.99; H 5.89;
N 9.64. C15H16N2O2 ·HCl. Calculated, %: C 61.75;
H 5.53; N 9.60.
5,5-Dialkyl-4-(2-arylvinyl)-2-dicyanomethyli-
dene-2,5-dihydrofuran-3-carboxamides Va–Vf (gen-
eral procedure). A mixture of 2.5 mmol of compound
IIa–IIf, 0.17 g (2.5 mmol) of malononitrile and 5 ml
of anhydrous ethanol was stirred at room temperature
until ammonia no longer evolved. The solvent was
distilled off, the residue was treated with water, and the
precipitate was filtered off, washed with water, and re-
crystallized from ethanol–water (2:1).
2-Imino-5,5-pentamethylene-4-(2-phenylvinyl)-
2,5-dihydrofuran-3-carboxamide hydrochloride
(IVd). Yield 98%, mp 184–188°C. 1H NMR spectrum,
δ, ppm: 1.6–1.9 m (10H, CH2), 7.2 d (1H, =CH, J =
17.4 Hz), 7.25–7.44 m (5H, Harom, NH2), 7.64 m (2H,
Harom), 8.5 d (1H, =CH, J = 17.4 Hz), 9.16 br.s (1H,
NH2), 10.25 br.s (2H, =NH·HCl). Found, %: C 65.12;
H 6.56; N 8.64. C18H20N2O2 ·HCl. Calculated, %:
C 64.96; H 6.36; N 8.42.
2-Dicyanomethylidene-4-[2-(2-furyl)vinyl]-5,5-
dimethyl-2,5-dihydrofuran-3-carboxamide (Va).
Yield 96%, mp >290°C. H NMR spectrum, δ, ppm:
1
2-Imino-N,5,5-trimethyl-4-(2-phenylvinyl)-2,5-
1.65 s (6H, CH3), 6.49 d and 6.51 d (1H, 4′-H, J =
17.4 Hz), 6.72 d (1H, 3′-H, J = 17.4 Hz), 7.0 d (1H,
=CH, J = 17.4 Hz), 7.21 br.s (1H, NH2), 7.65 d (1H,
5′-H, J = 17.4 Hz), 8.25 d (1H, =CH, J = 17.4 Hz),
9.08 br.s (1H, NH2). Found, %: C 65.09; H 4.49;
N 14.26. C16H13N3O3. Calculated, %: C 65.08; H 4.44;
N 14.23.
dihydrofuran-3-carboxamide hydrochloride (IVe).
1
Yield 97%, mp 164–169°C. H NMR spectrum, δ,
ppm: 1.46 s (6H, CH3), 2.82 d (3H, NCH3, J = 4.9 Hz),
7.13 d (1H, =CH, J = 17.4 Hz), 7.25–7.4 m (5H, Harom
,
NH2), 7.61 m (2H, Harom), 8.5 d (1H, =CH, J =
17.4 Hz), 9.84 br.s (1H, NH), 10.4 br.s (2H, =NH·
HCl). Found, %: C 62.89; H 6.39; N 9.24. C16H18N2O2·
HCl. Calculated, %: C 62.64; H 6.24; N 9.13.
2-Dicyanomethylidene-4-[2-(2-furyl)vinyl]-5,5-
pentamethylene-2,5-dihydrofuran-3-carboxamide
1
2-Imino-N-methyl-5,5-pentamethylene-4-
(2-phenylvinyl)-2,5-dihydrofuran-3-carboxamide
hydrochloride (IVf). Yield 94%, mp 174–179°C.
1H NMR spectrum, δ, ppm: 1.6–1.88 m (10H, CH2),
2.82 d (3H, NCH3, J = 4.9 Hz), 7.13 d (1H, =CH, J =
17.4 Hz), 7.25–7.4 m (5H, Harom, NH2), 7.61 m (2H,
(Vb). Yield 88%, mp 273–275°C. H NMR spectrum,
δ, ppm: 1.58–1.88 m (10H, CH2), 6.49 d and 6.51 d
(1H, 4′-H, J = 17.4 Hz), 6.72 d (1H, 3′-H, J = 17.4 Hz),
7.0 d (1H, =CH, J = 17.4 Hz), 7.21 br.s (1H, NH2),
7.65 d (1H, 5′-H, J = 17.4 Hz), 8.25 d (1H, =CH, J =
17.4 Hz), 9.08 br.s (1H, NH2). Found, %: C 68.05;
H 5.17; N 12.56. C19H17N3O3. Calculated, %: C 68.05;
H 5.11; N 12.53.
H
arom), 8.5 d (1H, =CH, J = 17.4 Hz), 9.84 br.s (1H,
NH), 10.55 br.s (2H, =NH·HCl). Found, %: C 65.99;
H 6.99; N 8.16. C19H22N2O2 ·HCl. Calculated, %:
C 65.79; H 6.68; N 8.08.
2-Dicyanomethylidene-5,5-dimethyl-4-(2-phenyl-
vinyl)-2,5-dihydrofuran-3-carboxamide (Vc). Yield
1
Reaction of compounds IVa–IVf with potassium
carbonate (general procedure). A concentrated aque-
ous solution of potassium carbonate was added to a so-
lution of 1 mmol of hydrochloride IVa–IVf in water
95%, mp 240–242°C. H NMR spectrum, δ, ppm:
1.70 s (6H, CH3), 7.13 d (1H, =CH, J = 17.4 Hz),
7.25–7.44 m (4H, Harom, NH2), 7.62 m (2H, Harom),
8.53 d (1H, =CH, J = 17.4 Hz), 9.16 br.s (1H, NH2).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

SYNTHESIS OF 2-IMINO-4-VINYL-2,5-DIHYDROFURAN-3-CARBOXAMIDES
1035
Found, %: C 70.89; H 4.99; N 13.84. C18H15N3O2. Cal-
culated, %: C 70.81; H 4.95; N 13.76.
NCH3, J = 4.9 Hz), 7.13 d (1H, =CH, J = 17.4 Hz),
7.25–7.4 m (3H, Harom), 7.61 m (2H, Harom), 8.5 d (1H,
=CH, J = 17.4 Hz), 9.84 br.s (1H, NH). Found, %:
C 73.54; H 5.92; N 11.74. C22H21N3O2. Calculated, %:
C 73.52; H 5.89; N 11.69.
2-Dicyanomethylidene-5,5-pentamethylene-4-(2-
phenylvinyl)-2,5-dihydrofuran-3-carboxamide
1
(Vd). Yield 90%, mp 269–270°C. H NMR spectrum,
δ, ppm: 1.6–1.9 m (10H, CH2), 7.2 d (1H, =CH, J =
17.4 Hz), 7.25–7.44 m (4H, Harom, NH2), 7.64 m (2H,
REFERENCES
H
arom), 8.5 d (1H, =CH, J = 17.4 Hz), 9.16 br.s
1. Avetisyan, A.A. and Tokmadzhyan, G.G., Arm. Khim. Zh.,
1993, vol. 46, p. 219.
2. Hollingworth, G.J. and Sweeney, J.B., Tetrahedron Lett.,
1992, vol. 33, p. 7049.
3. Dal Pozzo, A., Dansi, A., Mariotti, V., and Meneghini, E.,
(1H, NH2). Found, %: C 73.14; H 5.59; N 12.21.
C21H19N3O2. Calculated, %: C 73.03; H 5.54; N 12.17.
2-Dicyanomethylidene-N,5,5-trimethyl-4-(2-phen-
ylvinyl)-2,5-dihydrofuran-3-carboxamide (Ve).
Yield 84%, mp 184–185°C. H NMR spectrum, δ,
1
Bull. Chim. Farm., 1972, vol. 111, p. 342.
ppm: 1.48 s (6H, CH3), 2.82 d (3H, NCH3, J = 4.9 Hz),
7.13 d (1H, =CH, J = 17.4 Hz), 7.25–7.4 m (3H,
Harom), 7.61 m (2H, Harom), 8.5 d (1H, =CH, J =
17.4 Hz), 9.84 br.s (1H, NH). Found, %: C 71.54;
H 5.42; N 13.21. C19H17N3O2. Calculated, %: C 71.46;
H 5.37; N 13.16.
4. Yansone, D., Leite, L., Fleisher, M., Popelis, Yu., Ma-
zheika, I., Lukevits, E., Melikyan, G., and Avetisyan, A.,
Khim. Geterotsikl. Soedin., 1998, p. 298.
5. Avetisyan, A.A., Akhnazaryan, A.A., and Melikyan, G.S.,
Arm. Khim. Zh., 1988, vol. 41, p. 756.
6. Perlessy, A., Avetisian, A.A., Aknazarian, A.A., and
Melikian, G.S., Collect. Czech. Chem. Commun., 1989,
vol. 54, p. 1666.
2-Dicyanomethylidene-N-methyl-5,5-pentameth-
ylene-4-(2-phenylvinyl)-2,5-dihydrofuran-3-carbox-
1
amide (Vf). Yield 84%, mp 154–155°C. H NMR
7. Avetisyan, A.A., Kagramanyan, A.A., and Melikyan, G.S.,
spectrum, δ, ppm: 1.6–1.9 m (10H, CH2), 2.82 d (3H,
Arm. Khim. Zh., 1989, vol. 42, p. 633.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009