Cyanoacetylene and its derivatives: XXXII. Addition of ammonia and methylamine to 4-hydroxy-4,4-diphenyl-2-butynenitrile

Article abstract of DOI:10.1007/s11178-005-0121-2

Nucleophilic addition of ammonia (25% aqueous solution) and methylamine to 4-hydroxy-4,4-diphenyl-2-butynenitrile occurs under mild conditions to afford 4-amino(or methylamino)-2,5-dihydro-5,5-diphenyl-2-iminofurans. 4-Hydroxy-4,4-diphenyl-2-butynenitrile

Full text of DOI:10.1007/s11178-005-0121-2

Russian Journal of Organic Chemistry, Vol. 41, No. 1, 2005, pp. 61 -66. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005,
pp. 64-69.
Original Russian Text Copyright Ó 2005 by Mal'kina, Sokolyanskaya, Kudyakova, Sinegovskaya, Albanov, Shemyakina, Trofimov.
Cyanoacetylene and Its Derivatives:
XXXII.*Addition ofAmmonia and Methylamine
to 4-Hydroxy-4,4-diphenyl-2-butynenitrile
A. G. Mal’kina, L. V. Sokolyanskaya, R. N. Kudyakova, L. M. Sinegovskaya, A. I. Albanov,
O.A. Shemyakina, and B. A. Trofimov
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
Received February 11, 2004
Abstract—Nucleophilic addition of ammonia (25% aqueous solution) and methylamine to 4-hydroxy-4,4-diphenyl-
2-butynenitrile occurs under mild conditions to afford 4-amino(or methylamino)-2,5-dihydro-5,5-diphenyl-2-
iminofurans. 4-Hydroxy-4,4-diphenyl-2-butynenitrile in anhydrous liquid ammonia gives rise to 3-amino-4-hydroxy-
4,4-diphenyl-2-butenenitrile which is quantitatively converted into the corresponding iminodihydrofuran or
iminodihydrofuran hydrochloride in the presence of 10 wt % of KOH or gaseous hydrogen chloride. 4-Amino- and
4-methylamino-2-iminofurans react with 4-hydroxy-4-methyl-2-pentynenitrile to give 3-(4-amino- and 4-methylamino-
5,5-diphenyl-2,5-dihydrofuran-2-ylideneamino)-4-hydroxy-4-methyl-2-pentenenitriles.
The reactivity of a,b-acetylenic g-hydroxy carbo-
nitriles [R1R2C(OH)CºC–CN, R1 = R2 = Me; R1 = Me,
R2 = Et; R1R2 = (CH2)5] toward N-centered nucleophiles
has been the subject of review articles [2, 3] and original
papers [4–7]. These studies have shown that acetylenic
hydroxy nitriles in anhydrous liquid ammonia give rise to
(Z)-3-amino-4-hydroxy-2-alkenenitriles which undergo
intramolecular cyclization in the presence of water with
formation of 4-amino-5,5-dialkyl-2,5-dihydro-2-
iminofurans [4]. Primary amines (aqueous solutions) and
amino alcohols react with acetylenic hydroxy nitriles un-
der mild conditions, following the addition–cyclization pat-
tern; as a result, the corresponding 4-amino-2,5-dihydro-
2-iminofurans are formed [5, 6]. We previously devel-
oped a general synthetic approach to polyconjugated het-
erocyclic systems consisting of 2,5-dihydro-2-iminofuran
units on the basis of the reaction of methylamine and
4-hydroxy-4-methyl-2-pentynenitrile [7]. The addition of
secondary amines occurs in a regio- and stereoselective
fashion, yielding (Z)-3-dialkylamino-2-alkenenitriles
which undergo quantitative cyclization to the correspond-
ing 2,5-dihydro-2-iminofuran hydrochlorides by the action
of hydrogen chloride [8]. On the other hand, there are no
published data on reactions of amines with acetylenic hy-
droxy nitriles containing aromatic substituents, though the
synthesis of new iminodihydrofuran derivatives is an im-
portant problem: The 2-imino-2,5-dihydrofuran system is
related to the 2,5-dihydrofuran-2-one fragment which
constitutes a part of a number of natural compounds, e.g.,
ascorbic, penicillic, and tetronic acids. Moreover, the pres-
ence of aromatic substituents in the iminodihydrofuran
molecule could make it possible to use the resulting com-
pounds as materials for optoelectronics.
Taking the above stated into account, the goal of the
present work was to elucidate specific features and gen-
eral relations holding in the addition of amines to acety-
lenic hydroxy nitriles and to obtain new unsaturated com-
pounds of the 2,5-dihydro-2-iminofuran series. For this
purpose, we extended the series of acetylenic hydroxy
nitriles by inclusion of 4-hydroxy-4,4-diphenyl-2-butyne-
nitrile (I) and examined its reactions with ammonia and
methylamine.
Cyanoacetylene I reacted with anhydrous liquid am-
monia under mild conditions (–33°C, 3 h) to give (Z)-3-
amino-4-hydroxy-4,4-diphenyl-2-butenenitrile (II) in 70%
yield with high stereoselectivity. The reaction of I with
25% aqueous ammonia afforded 4-amino-5,5-diphenyl-
2-imino-2,5-dihydrofuran (III) (Scheme 1). Substituted
aminoacrylonitrile II was isolated as a colorless powder
which is soluble in chloroform, acetonitrile, ethanol, and
dimethyl sulfoxide and insoluble in diethyl ether and hex-
* For communication XXXI, see [1].
1070-4280/05/4101-0061Ó2005 Pleiades Publishing, Inc.

MAL’KINAet al.
62
Scheme 1.
the spectrum. The cyano group gives rise to only one
absorption band with its frequency at 2197 cm , indicat-
–1
+ 1
3K
ing formation of an acrylonitrile fragment (unconjugated
cyano group is characterized by absorption in the region
2260–2240 cm [9]). These data suggest that compound
II exists mainly as acrylonitrile tautomer A. In the
1H NMR spectrum of II in CDCl3, the olefinic proton
signal appeared at d 3.83 ppm; also, signals at d 2.77
(OH), 5.14 (NH2), and 7.39–7.28 ppm (aromatic protons)
were present. The 13C NMR data also confirm configu-
rational homogeneity of compound II.
3K
1+ ꢀ+ 2
1+
3K
&1
–1
2
3K
2+
,
,,,
1+
ꢁDQK\GURXVꢂ
+ 1
3K
&1
2+
3K
,,
Scheme 2.
Unlike 3-amino-4-hydroxy-2-alkenenitriles obtained
previously [4], aminoacrylonitrile II undergoes only par-
tial intramolecular cyclization to iminodihydrofuran III on
storage at room temperature. After storage for a month,
the 1H NMR spectrum contained a signal at d 3.83 ppm
due to Z isomer II and a signal at d 5.18 ppm, which
belongs to iminodihydrofuran III. In the presence of po-
tassium hydroxide (10 wt %), compound II in ethanol is
quantitatively converted into iminodihydrofuran III in 2 h
at 20–25°C. Presumably, KOH favors transformation of
unsaturated nitrile II into the E isomer which is capable
of undergoing intramolecular cyclization. In addition, the
basic medium promotes ionization of the hydroxy group.
Analogous intramolecular cyclization involving the hydroxy
and cyano groups was effected by passing gaseous hy-
drogen chloride through a solution of aminoacrylonitrile
II in dioxane (20–25°C, 3 h). In this case, the product
was iminodihydrofuran hydrochloride IV (yield 96%,
Scheme 3). Obviously, the cyclization begins with proto-
+ 1
3K
+1
3K
&1
&1
2+
2+
%
3K
3K
$
ane. Aminoacrylonitrile II can exist as E and Z isomers
and tautomers A and B (Scheme 2). The tautomeric trans-
formation A gB should facilitate Z,E-isomerization. The
3600–3000-cm region of the IR spectrum of a solution
of aminoacrylonitrile II in carbon tetrachloride (c ~
0.01 M; d = 0.5, 2, and 5 cm) contained absorption bands
from both associated and unassociated hydroxy and amino
groups, n, cm : 3608, 3276 (OH); 3508, 3480, 3400, 3375
(NH2). The associates decompose in going to more di-
f
–1
~
–1
lute solutions (c ~ 0.001 M, d = 5 cm), and absorption
bands belonging to only unassociated OH (3608 cm )
and NH2 groups (3508 and 3400 cm ) are observed in
~
–1
–1
Scheme 3.
+ 1
.2+
(WKDQRO
+&O
'LR[DQH
,,,
,,
3K
3K
1+ &O
2
,9
1+
+ 1
3K
&
+ 1
3K
1+
+&O
,,
2+
2+
3K
3K
&
'
1+
+ 1
3K
+ 1
3K
+ 1
3K
,9
1+ꢃꢃ&O
2
&O
3K
2+
2
+
3K
3K
1+
(
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 1 2005

CYANOACETYLENE AND ITS DERIVATIVES: XXXII.
63
Scheme 4.
0H
+1
0H
+1
3K
3K
3K
0H1+ ꢀꢀ+&O
(WKDQRO
0H1+
'LR[DQH
,
1+ ꢀꢀ&O
1+
3K
2
2
9,
9
.2+ꢁ(WKDQRO
Scheme 5.
51+
0H
0H
3K
3K
1
&1
&1
,,,ꢀꢁ9ꢁꢁꢂ
2
0H
2+
2+
0H
9,,,DꢀꢁE
9,,
R = H (a), Me (b).
nation of the cyano group to give mesomeric cation C n
D n E in which rotation about the C2–C3 bond is not
restricted and no steric constraint (Z configuration of the
initial nitrile) on intramolecular addition of the hydroxy
group to cyano exists (azaallene system).
amino)-4-hydroxy-4-methyl-2-pentenenitriles VIIIa and
VIIIb (Scheme 5). Compounds VIIIa and VIIIb were
isolated as crystalline substances, which showed in the
–1
IR spectra CºN absorption band at 2213 cm . Stretch-
ing vibrations of the amino group gave rise to two ab-
–1
sorption bands at 3405 and 3502 cm (compound VIIIa
Nucleophilic addition of methylamine to
cyanoacetylene I also occurs under mild conditions (di-
oxane, 20–25°C, 1 h) to afford 2-imino-4-methylamino-
5,5-diphenyl-2,5-dihydrofuran (V) in 84% yield. The re-
action of Iwith methylamine hydrochloride (ethanol, 50°C,
3 h) gave iminodihydrofuran hydrochloride VI which can
be converted into free base V by treatment with an
equimolar amount of potassium hydroxide (ethanol, 20–
25°C, 2 h; Scheme 4).
–1
in CHCl3) or one band at 3435 cm (VIIIb in CCl4). No
–1
absorption was present at 3306 cm , i.e., at a frequency
corresponding to stretching vibrations of the =N–H group
in iminodihydrofuran III. These data suggest that the ad-
dition of iminodihydrofurans III and V to nitrile VII in-
volves the imino group in the former, despite the pres-
ence of two nucleophilic centers (=NH and NH2 or NH)
1
in their molecules. The H NMR spectra of VIIIa and
VIIIb contained two olefinic proton signals at d, ppm:
5.28 and 5.07 (VIIIa); 4.24 and 3.52 (VIIIb).
Iminodihydrofurans III and V are crystalline sub-
stances. The IR spectrum of III in CHCl3 (c = 0.01–
0.02 M; d = 0.5, 1, and 2 cm) contained three absorption
Thus nucleophilic addition of ammonia and methyl-
amine to cyanoacetylene I led to formation of polycon-
jugated heterocyclic systems, iminodihydrofurans having
aromatic substituents. These compounds can be used as
synthons in fine organic synthesis, biologically active sub-
stances, and intermediate products for the preparation of
new materials for optoelectronics [10].
–1
bands in the region 3000–3600 cm : 3306 (=NH); 3405,
–1
3499 cm (NH2). Iminodihydrofuran V displayed two
absorption bands in the same region: 3305 (=NH) and
–1
3441 cm (NH). The IR spectra of both compounds
lacked absorption bands assignable to cyano and hydroxy
1
groups. In the H NMR spectra of iminodihydrofurans
III and V in CDCl3 we observed only one olefinic proton
signal at d 5.18 and 4.94 ppm, respectively. The electron
absorption spectra of compounds III and V are charac-
terized by two maxima at l 266 (log e = 4.13) and
261 nm (log e = 4.12) (III) and 268 (log e = 4.36) and
261 nm (log e = 4.32) (V).
Iminodihydrofurans III and V reacted with 4-hydroxy-
4-methyl-2-pentynenitrile (VII) under mild conditions
(acetonitrile, 20–50°C, 0.5–3 h) to give 3-(4-amino- and
4-methylamino-5,5-diphenyl-2,5-dihydrofuran-2-ylidene-
EXPERIMENTAL
The IR spectra were recorded on Specord 75-IR and
Bruker IFS-25 spectrometers from samples prepared as
KBr pellets (or thin films) or solutions in CCl4 and CHCl3
(c ~ 0.01 M, d = 0.5–5 cm). The 1H and 13C NMR spec-
~
tra were obtained on a Bruker DPX-400 instrument
(400 MHz for 1H) from solutions in CDCl3 or DMSO-d6
(compounds II, VIIIa, and VIIIb) using HMDS as in-
ternal reference. The electron absorption spectra were
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 1 2005

MAL’KINAet al.
64
measured on a Specord UV-Vis spectrophotometer from
solutions in alcohol. The mass spectra were obtained on
an LKB-2091 instrument with direct sample admission
into the ion source (ion source temperature 240°C). The
progress of reactions was monitored by thin-layer chro-
matography on Al2O3 using chloroform–benzene–etha-
nol (20 : 4 : 1) as eluent.
H 5.77; N 10.79. C16H14N2O. Calculated, %: C 76.78;
H 5.64; N 11.19.
4-Amino-2-imino-5,5-diphenyl-2,5-dihydrofuran
(III). a. Cyanoacetylene I, 0.23 g (1 mmol), was added
to 30 ml of 25% aqueous ammonia, and the mixture was
kept for 6 h at room temperature. The precipitate was
filtered off and washed with diethyl ether. Yield 0.20 g
(80%), mp 162–164°C (decomp.). IR spectrum (KBr),
Liquid ammonia, 25% aqueous ammonia, methylamine,
and methylamine hydrochloride were commercial prod-
ucts. 4-Hydroxy-4-methyl-2-pentynenitrile (VII) was
synthesized by the procedure described in [11]; its physi-
cal constants coincided with published data.
–1
n, cm : 3297 s, 3058 s, 1633 s, 1616 s, 1492 m, 1447 m,
1403 m, 1338 s, 1230 m, 1187 m, 1111 s, 1081 m, 1035 w,
1010 w, 973 s, 940 s, 911 m, 849 v.w, 799 m, 773 s, 732 m,
697 s, 672 s, 637 w, 596 w, 571 w, 513 v.w, 486 w.
1H NMR spectrum, d, ppm: 5.18 s (1H, =CH), 4.89 br.s
(3H, NH2, =NH), 7.34–7.35 m (10H, Harom). 13C NMR
spectrum, dC, ppm: 92.23 (Ph2C), 127.54 and 128.66 (Co,
Cm), 128.84 (Cp), 139.65 (Ci), 89.44 (=CH), 163.90
(C=CH), 171.64 (C=NH). Mass spectrum, m/z (Irel, %):
250 (42.2), 221 (14.1), 206 (7.0), 183 (7.0), 105 (100.0),
77 (74.2), 51 (23.4), 41 (7.8). Found, %: C 76.49; H 5.89;
N 10.95. C16H14N2O. Calculated, %: C 76.78; H 5.64;
N 11.19.
4-Hydroxy-4,4-diphenyl-2-butynenitrile (I).
A solution of 37 g (129 mmol) of 3-bromo-1,1-diphenyl-
2-propyn-1-ol in 20 ml of DMF was added dropwise at
20°C to a mixture of 64 g (715 mmol) of CuCN and 80 ml
of anhydrous DMF. The mixture warmed up to 35°C and
was stirred for 5 h at 75°C. The hot dark brown thick
material was slowly poured into 500 ml of cold water,
and the mixture was stirred until a solid precipitate was
formed. The precipitate was filtered off and washed with
diethyl ether (5 ´ 30 ml), and the aqueous filtrate was
extracted with diethyl ether (5 ´ 50 ml). The extracts were
combined, washed with cold water, dried over magne-
sium sulfate, and evaporated to obtain 15 g (50%) of
cyanoacetylene I as a viscous oily liquid. IR spectrum
b.Amixture of 0.08 g (0.3 mmol) of aminoacrylonitrile
II and 0.008 g of potassium hydroxide in 4 ml of ethanol
was stirred for 2 h at 20–25°C. The mixture was then
passed through a 3–4-cm layer of Al2O3, the sorbent was
washed with ethanol, the solvent was removed under re-
duced pressure, and the solid residue was washed with
anhydrous diethyl ether. Yield of iminodihydrofuran III
0.08 g (100%).
–1
(film), n, cm : 3450–3350, 3080, 3060, 3030, 2290 (2260
sh), 1960, 1900, 1600, 1580, 1495, 1450, 1390, 1320, 1280,
1170, 1160, 1140, 1070, 1030, 1000, 940, 920, 895, 805,
770, 700, 650. Found, %: C 82.70; H 4.43; N 5.67.
C16H11NO. Calculated, %: C 82.38; H 4.75; N 6.00.
4-Amino-2-imino-5,5-diphenyl-2,5-dihydrofuran
hydrochloride (IV). Gaseous hydrogen chloride was
passed over a period of 3 h through a solution of 0.10 g
(0.4 mmol) of compound II in 2 ml of anhydrous dioxane.
The solvent was removed under reduced pressure to ob-
tain 0.11 g (96%) of hydrochloride IV, mp 177–178°C
(Z)-3-Amino-4-hydroxy-4,4-diphenyl-2-butene-
nitrile (II). Compound I, 1 g (4.3 mmol), was added to
30 ml of anhydrous liquid ammonia, the mixture was kept
for 3 h at –33°C, and removal of ammonia left 0.75 g
(70%) of compound II with mp 130–132°C (decomp.).
–1
(decomp.). IR spectrum (KBr), n, cm : 3414–2861 s, br,
–1
1646 s, 1562 s, 1493 w, 1448 m, 1288 v.w, 1254 v.w,
1230 v.w, 1191 v.w, 1118 w, 1071 w, 1036 v.w, 1012 m,
985 m, 934 w, 913 v.w, 889 v.w, 870 w, 805 w, 764 m,
735 w, 698 m, 615 v.w, 589 v.w, 477 w. 1H NMR spec-
trum, d, ppm: 5.35 s (1H, =CH), 3.34 s (3H, NH2, =NH),
7.49–7.47 m (5H, Harom), 7.39–7.36 m (5H, Harom).
13C NMR spectrum, dC, ppm: 98.56 (Ph2C), 128.82 and
130.34 (Co, Cm), 138.17 (Ci), 81.03 (=CH), 178.79
(NC=CH), 178.56 (C=NH). Found, %: C 66.72; H 5.61;
Cl 12.77; N 9.36. C16H15ClN2O. Calculated, %: C 67.02;
H 5.27; Cl 12.36; N 9.77.
IR spectrum (KBr), n, cm : 3471 s, 3376 s, 3282 s, br,
3107 w, 3088 w, 3055 w, 3030 w, 2197 s, 1950 w, 1890 w,
1805 w, 1635 s, 1613 s, 1574 s, 1489 m, 1445 m, 1376 m,
1311 w, 1280 w, 1208 w, 1184 v.w, 1159 v.w, 1091 w,
1050 m, 1031 w, 1000 w, 970 w, 923 w, 847 w, 770 m,
744 m, 698 s, 675 m, 659 m, 615 v.w, 584 w, 503 w,
1
473 w. H NMR spectrum, d, ppm: 3.83 s (1H, =CH),
2.77 s (1H, OH), 5.14 s (2H, NH2), 7.39–7.28 m (10H,
Harom). 13C NMR spectrum, dC, ppm: 92.67 (Ph2C),
119.28 (CN), 127.03 (Cp), 127.18 (Co), 127.22 (Cm),
139.09 (Ci), 79.71 (=CH), 168.25 (C=CH). Mass spec-
trum, m/z (Irel, %): 250 (100.0), 182 (14.8), 173 (10.9),
105 (82.0), 77 (64.5), 32 (12.5). Found, %: C 76.61;
2-Imino-4-methylamino-5,5-diphenyl-2,5-di-
hydrofuran (V). Cyanoacetylene I, 0.23 g (1 mmol), was
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 1 2005

CYANOACETYLENE AND ITS DERIVATIVES: XXXII.
65
slowly added to a solution of 0.6 g (19.4 mmol) of methy-
lamine in 5 ml of dioxane, cooled to 0°C. The mixture
was kept for 1 h at that temperature, allowed to warm up
to room temperature, and stirred for 1 h. The solvent was
removed under reduced pressure to obtain 0.22 g (83%)
of compound V with mp 193–195°C. IR spectrum (KBr),
3-(4-Amino-5,5-diphenyl-2,5-dihydrofuran-2-
ylideneamino)-4-hydroxy-4-methyl-2-pentenenitrile
(VIIIa). A solution of 0.18 g (1.65 mmol) of cyanoacet-
ylene VII in 0.5 ml of acetonitrile was added to a solution
of 0.40 g (1.6 mmol) of iminodihydrofuran III in 4 ml of
acetonitrile. The mixture was stirred for 0.5 h at 40°C
and evaporated under reduced pressure to obtain 0.57 g
(100%) of compound VIIIa with mp 168–170°C. IR spec-
–1
n, cm : 3426 w, br, 3302 m, 3209 w, 3182 w, 3114 w,
3059 w, 2993 m, 2936 w, 2882 w, 2814 v.w, 1669 s,
1615 s, 1529 m, 1493 m, 1448 m, 1418 m, 1345 s, 1257 w,
1230 w, 1195 w, 1143 m, 1105 m, 1069 w, 1035 w, 1002 s,
973 m, 933 s, 911 w, 848 w, 806 w, 774 m, 742 m, 699 m,
681 w, 595 v.w, 583 v.w, 512 v.w, 483 w. 1H NMR spec-
trum, d, ppm: 4.94 s (1H, =CH), 2.82 s (3H, NMe), 4.06–
3.98 (NH), 7.31–7.34 m (10H, Harom). 13C NMR spec-
trum, dC, ppm: 31.99 (NMe), 127.51–128.51 (Co, Cm),
128.53 (Cp), 145.44 (Ci), 85.85 (=CH), 165.63 (C=CH),
177.21 (C=NH). Mass spectrum: m/z 264. Found, %:
C 77.09; H 6.10; N 10.64. C17H16N2O. Calculated, %:
C 77.25; H 6.10; N 10.60.
–1
trum (KBr), n, cm : 3431 s, 3310–3212 br.m, 3074 w,
2990 w, 2978 w, 2935 v.w, 2209 m, 1635 s, 1588 s,
1490 w, 1449 m, 1405 m, 1337 w, 1278 m, 1217 m,
1186 m, 1140 w, 1095 m, 1036 w, 983 m, 956 w, 936 m,
886 w, 819 m, 785 w, 764 w, 754 w, 706 w, 695 m, 668 w,
1
604 w, 581 w, 529 w, 501 w, 458 w, 432 w. H NMR
spectrum, d, ppm: 1.15 (6H, CH3), 4.85 s (1H, =CH),
5.08 s (1H, =CH), 5.12 (1H, OH), 7.02 (2H, NH2), 7.36–
7.48 m (10H, Harom). 13C NMR spectrum, dC, ppm: 28.79
(CH3), 81.85 and 75.66 (=CH), 91.25 (Ph2C), 119.48
(CN), 127.83–128.67 (Co, Cm), 128.89 (Cp), 136.98 (Ci),
165.15 (=N–C=), 168.00 (H2N–C=), 178.62 (C=N).
Found, %: C 73.26; H 6.32; N 11.79. C22H21N3O2. Cal-
culated, %: C 73.52; H 5.89; N 11.69.
2-Imino-4-methylamino-5,5-diphenyl-2,5-di-
hydrofuran hydrochloride (VI). Cyanoacetylene I,
0.21 g (0.9 mmol), was added at 20–25°C to a solution of
0.25 g (3.7 mmol) of methylamine hydrochloride in 20 ml
of ethanol. The mixture was stirred for 1 h, 0.22 g of
potassium hydroxide was added, and the mixture was
stirred for 3 h at 50°C. The precipitate (KCl) was filtered
off, the filtrate was diluted with an equal volume of di-
ethyl ether, and the precipitate was filtered off and washed
with diethyl ether. Yield 0.20 g (74%), mp 258–260°C
4-Hydroxy-4-methyl-3-(4-methylamino-5,5-
diphenyl-2,5-dihydrofuran-2-ylideneamino)-2-
pentenenitrile (VIIIb).Asolution of 0.06 g (0.55 mmol)
of cyanoacetylene VII in 0.5 ml of acetonitrile and
1.5 ml of triethylamine were added to a solution of 0.14 g
(0.5 mmol) of iminodihydrofuran V in 2 ml of acetonitrile.
The mixture was stirred for 1 h at 20°C and for 2 h at
50°C and evaporated under reduced pressure to obtain
0.11 g (58%) of compound VIIIb, mp 115–117°C. IR
–1
(decomp.). IR spectrum (KBr), n, cm : 3364 s, br, 3230–
2855 s, br, 1690 s, 1624 s, 1557 w, 1527 w, 1493 w,
1447 w, 1417 s, 1373 s, 1301 v.w, 1249 m, 1193 m,
1143 m, 1085 v.w, 1072 v.w, 1057 m, 1035 v.w, 993 m,
960 m, 944 v.w, 933 v.w, 914 v.w, 785 w, 772 w, 747 w,
–1
spectrum (KBr), n, cm : 3433–3349 br.s, 3115 v.w,
3085 v.w, 3058 w, 3027 v.w, 2985 w, 2932 w, 2870 w,
2806 w, 2189 s, 1662 m, 1623 s, 1494 w, 1445 m, 1411 m,
1384 v.w, 1666 v.w, 1344 m, 1264 m, 1237 v.w, 1195 w,
1170 m, 1068 w, 1037 m, 1009 s, 975 s, 933 w, 917 w,
1
709 m, 697 m, 664 w, 589 w, 569 w, 470 w. H NMR
spectrum, d, ppm: 5.44 s (1H, =CH), 2.81 s (3H, NMe),
7.30 m (10H, Harom). 13C NMR spectrum, dC, ppm: 31.96
(NMe), 127.26–128.64 (Co, Cm), 129.53 (Cp), 136.63 (Ci),
78.62 (=CH), 172.03 (C=CH), 173.87 (C=NH), 96.68
(Ph2C). Found, %: C 67.44; H 5.51; Cl 10.98; N 9.71.
C17H17ClN2O. Calculated, %: C 67.88; H 5.70; Cl 11.79;
N 9.31.
1
869 w, 817 w, 767 m, 704 m, 660 m, 531 w. H NMR
spectrum, d, ppm: 4.32 s (1H, =CH), 3.59 s (1H, =CH),
2.82 s (3H, NMe), 1.84 and 1.76 (6H, CH3), 7.32 m (10H,
H
arom). 13C NMR spectrum, dC, ppm: 27.21 and 26.54
(CH3), 32.16 (NMe), 83.40 and 86.37 (=CH), 91.04
(Ph2C), 120.64 (CN), 127.21–128.22 (Co, Cm), 128.36
(Cp), 142.38 (Ci), 146.00 (=C–N=), 156.97 (=N–C=),
167.56 (C=N). Found, %: C 73.54; H 6.98; N 11.74.
C23H23N3O2. Calculated, %: C 73.99; H 6.17; N 11.26.
A mixture of 0.04 g (0.13 mmol) of hydrochloride VI
and 0.004 g of potassium hydroxide in 3 ml of ethanol
was stirred for 2 h at 20–25°C. The mixture was passed
through a 3–4-cm layer ofAl2O3, the sorbent was washed
with ethanol, the solvent was removed under reduced
pressure, and the solid residue was washed with anhy-
drous diethyl ether. Yield of iminodihydrofuran V 0.03 g
(86%).
This study was performed under financial support by
the Russian Foundation for Basic Research (project
no. 02-03-32 400 a).
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 1 2005

MAL’KINAet al.
6. Skvortsov, Yu.M., Mal’kina, A.G., Sokolyanskaya, L.V.,
66
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