The reactions of triphenylphosphine alkylenes with 3(2-thienyl)acrylonitriles

Article abstract of DOI:10.1080/10426500307778

Ethyl 3-(2-thienyl)acrylocyanoacetate (1b) reacts with ester ylide phosphoranes 2a,b in toluene, containing triethylamine, affording the Michael addition products 7a,b and the cyclopropanes 6a,b and 8a,b. The reaction of 1b with keto ylide 2c in ethyl ace

Full text of DOI:10.1080/10426500307778

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The Reactions of Triphenylphosphine Alkylenes with
3(2-Thienyl)acrylonitriles
Wafaa M. Abdou a , Mounir A. I. Salem b & Reham F. Barghash a
a National Research Centre, Dokki, Cairo, Egypt
b Ain-Shams University, Cairo, Egypt
Version of record first published: 27 Oct 2010.
To cite this article: Wafaa M. Abdou , Mounir A. I. Salem & Reham F. Barghash (2003): The Reactions of Triphenylphosphine
Alkylenes with 3(2-Thienyl)acrylonitriles, Phosphorus, Sulfur, and Silicon and the Related Elements, 178:1, 125-135
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Phosphorus, Sulfur and Silicon, 2003, Vol. 178:125–135
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Copyright 2003 Taylor & Francis
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DOI: 10.1080/10426500390170264
THE REACTIONS OF TRIPHENYLPHOSPHINE
ALKYLENES WITH 3(2-THIENYL)ACRYLONITRILES
Wafaa M. Abdou,a Mounir A. I. Salem,b
and Reham F. Barghasha
National Research Centre, Dokki, Cairo, Egypt a
and Ain-Shams University, Cairo, Egyptb
(Received April 11, 2002; accepted June 14, 2002)
Ethyl 3-(2-thienyl)acrylocyanoacetate (1b) reacts with ester ylide phos-
phoranes 2a,b in toluene, containing triethylamine, affording the
Michael addition products 7a,b and the cyclopropanes 6a,b and 8a,b.
The reaction of 1b with keto ylide 2c in ethyl acetate containing benzoic
acid in addition to the ylide 7c the pyran 12 was obtained. On the other
hand, (cyanomethyl)triphenylphosphonium chloride (13) reacts, under
the phase-transfer catalysis conditions, with 1b to give the cyclopropane
derivative 15 whereas with 1a, the new ylide 16 along with the propene
derivative 17 were obtained.
Keywords: Acrylonitriles; alkylidenephosphoranes; Michael addition;
substitution reaction; Wittig reaction
INTRODUCTION
Recently,1 it has been shown that the phosphoryl carbanions [Horner-
Wittig reagents, (EtO)2P(O)CH2R] react with 3-(2-thienyl)acrylonitrile
(1a) and ethyl 3-(2-thienyl)acrylocyanoacetate (1b) to give different
phosphorylated cyclic and acyclic systems, depending on the nature of
the -substituent of the reagent and the basicity of the reaction medium
employed. The investigation also has indicated that 1b behaves differ-
ently from 1a toward the phosphoryl carbanions, whereupon the ester
function of the substituted acrylonitrile 1b was involved in some reac-
tions. In an earlier study,2 we reported that the reaction of the nitrile 1a
with the conventional Wittig reagents 2a–c resulted to mainly the corre-
sponding (1:1) phosphorus ylides 3 along with the ethylene derivatives
Address correspondence to Wafaa M. Abdou, Department of Pesticide Chemistry,
National Research Center, Dokki-12622, Dokki, Cairo, Egypt. E-mail: wabdou@intouch.
com
125

126
W. M. Abdou et al.
SCHEME 1
4 as a minor products (Scheme 1). Similar reactions also were studied3,4
and in all cases,1–4 an initial Michael addition occurred at the exocyclic
ethylene bond in this class of compounds, regardless of the type of the
phosphorus carbanion used.
In continuation of our interest in this area, we now report our
results on the reactions of stabilized ester-2a,b and keto-2c ylide phos-
phoranes with acrylonitrile 1b. The reactions between (cyanomethy-
lene)triphenylphosphorane (14) and 1a,b as well as some transforma-
tions of the products obtained are also reported.
RESULTS AND DISCUSSION
Acrylonitrile 1b on treatment with (methoxycarbonylmethylene)-
triphenylphosphorane (2a) (2 molar amounts) in boiling toluene, the
educts remained practically unchanged, even after 3 days. Conversely,
the reaction completed when it was carried out in the presence of tri-
ethylamine. Separation of the product mixture by column chromatog-
raphy yielded the new ylide 7a (18%) together with the cyclopropane
derivatives 6a (22%) and 8a (28%). Similarly treatment of 1b with
(ethoxycarbonylmethylene)triphenylphosphorane for 3 days at reflux,
ylide 7b (15%) along with the cyclopropane derivatives 6b (26%) and 8b
(29%) were obtained (Scheme 2). However, when 1b was treated with an
equimolar amount of 2a under the same reaction conditions, products
7a (20%), 6a (10%), and 8a (25%) were obtained along with unchanged
nitrile 1b (25%). Further reaction of ylides 7a,b with aromatic aldehyde
(O2N C6H4CHO-p) led to the formation of Wittig products 9a,b in good
yields ( 65%) (Scheme 3). Elemental analyses, molecular weight mea-
surements (MS), IR, and NMR spectroscopy elucidate the structures of
the new products.

Triphenylphosphine
127
SCHEME 2
Respective mechanism for the formation of the products 6–8 from
the reaction of 2a,b with 1b involves two routes. 1) Michael addition
reaction of the ylides 2a,b on the more electrophilic site of the exocyclic
ethylenic linkage in 1b yields the resonance hybrid 5.1 4 The intermedi-
ate 5 stabilizes itself through the migration of the proton- - to the pos-
itive phosphorus atom-to the electron rich carbanionic center, yielding
the ylide 7. In addition, the dipolar form 5 might undergo an elimination
reaction-ejection of triphenylphosphine-producing the cyclopropane 8.5
2) The ylide 2, concurrently, attacks both the activated carbon-carbon
double bond and the ester-carbonyl group, to give the product 6 with
concomitant loss of triphenylphosphine and triphenylphosphine oxide.
For similar reactions, cyclopropane derivatives have also been reported
in the literature,6 on treatment of oxobutenoate with alkylidene phos-
phoranes. Furthermore, the attack at the carbonyl ester rather than
the nitrile group in the cyanoacetate moiety is a documented process.7
In favor of Scheme 2, the product 8a (as a representative example) is re-
covered, practically unchanged, when heated with 2a in boiling toluene
containing TEA, even for 2 days. Nevertheless, heating the ylide 7a,b
in ethyl acetate for 24 h at the reflux temperature afforded the respec-
tive cyclopropane 8 and the olefin 10 (Scheme 3). Repeating the latter
reaction in the presence of one mole equivalent of 2 led to the same
result whereupon 8 and 10 were obtained.
An unexpected result was obtained in the case of applying (benzoyl-
methylene)triphenylphosphorane on 1b. In addition to the analogous
ylide 7c 3-cyano-2-ethoxy-6-phenyl-4H-4-(2-thienyl)pyran (12) was ob-
tained as the major product. Cyclopropane analog was not observed in
this reaction. The reaction did not proceed in toluene containing TEA,

128
W. M. Abdou et al.
SCHEME 3
as previously described for 2a,b whereas in ethyl acetate containing a
catalytic amount of benzoic acid the reaction was completed. Elemental
analysis and exact mass measurement of 12 showed the empirical for-
mula to be C18H15NO2S (309). The spectroscopic data are also in agree-
ment with the assigned structure. The formation of 12 is suggested to
start with the attack by the carbanion center in 2c to the active exo-
cyclic methide carbon in 1b giving rise to the intermediate 11. Further
elimination of triphenylphosphine oxide affords the pyran derivative
12 (Scheme 4). An analogous reaction is reported to proceed between
the same ylide and quinone methides, with concomitant formation of
triphenylphosphine oxide.7
SCHEME 4
Next, the reaction between (cyanomethylene)triphenylphosphorane
(14) and 1b as well as 1a was investigated. Treatment of the ylide 14,
prepared in situ from the corresponding phosphonium salt 13, with the
cyanoacetate 1b yielded the cyclopropane derivative 15 (48%), as the
sole reaction product (Scheme 5).

Triphenylphosphine
129
SCHEME 5
On the other hand, the malonitrile 1a reacted the phosphonium
salt 13, under the same prevailing conditions, giving the ylide 16
and the known1 propene derivative 17 (Scheme 6). Compound 17 was
found to be identical with the product previously1 isolated from the
reaction of the nitrile 1a with the Horner-Wittig reagent counterpart
[(EtO)2P(O)CH2CN]. Furthermore, the reaction and the products that
have been described in Scheme 6 parallel to Scheme 1, previously
reported.2
SCHEME 6
In summary, the results of the earlier1,2 and the present investiga-
tion allow interesting observations to be drawn. 1) Notwithstanding,
the initial step in the reactions of the , -unsaturated nitriles 1a,b
with -phosphoryl- and -phosphorane carbanions involves the Michael
addition of the synthon at the exocyclic methide carbon in 1a,b, the se-
quel of the initial step vary markedly, according to the nature of the
-substituent in the educts and the reaction conditions. 2) The results
also showed that the behavior of 1b with either the Wittig or the Wittig-
Horner reagents are in great disparity with that of the malonitrile ana-
log 1a. The latter result is, however, attributable to the involvement of
the ester function of the substituted acrylonitrile 1b in the reactions.
3) The unexpected behavior of 1b toward the keto ylide 2c leading to

130
W. M. Abdou et al.
the pyran 12 represents a facile and direct approach for incorporating
two heterocyclic moieties of anticipated biological activities in one and
the same molecule.
EXPERIMENTAL
All melting points are uncorrected. IR spectra were recorded on a
Perkin-Elmer spectrophotometer model 297 (Grating) using KBr disc.
The 1H and 13C NMR spectra were run on a Varian Gemini 200
(200 MHZ) instrument, using TMS as an internal reference. The
31P NMR spectra were recorded relative to external H3PO4 (85%) with a
Varian CFT-80 instrument. The mass spectra were performed at 70 eV
on an MS-50 Kratos (A.E.I.) spectrometer provided with data system.
The appropriate precautions in handling moisture-sensitive compounds
were observed. Light petroleum refers to the fraction 40–60 C.
I. Action of Phosphorus Ylides 2a and 2b
on Acrylonitrile 1b
No reaction was observed when 1b and 2 molar amounts of 2a (or 2b)
were refluxed in toluene even after 3 days whereupon 1b and 2a (or 2b)
were recovered, practically unchanged, in 90% yield.
General Procedure
A stirred solution of ethyl 3-(2-thienyl)acrylocyanoacetate (1b)8
(0.8 g, 3.88 mmol) and (methoxycarbonylmethylene)triphenylphospho-
rane (2a) (2.7 g, 7.76 mmol) in dry toluene (20 mL) containing triethy-
lamine (TEA, 0.5 ml) was boiled under reflux for 3 days. The product
mixture was evaporated on silica gel under reduced pressure, and ap-
plied to a silica gel column using hexane containing increasing amounts
of ethyl acetate as eluents whereby compounds 8a, 7a, and 6a were
eluted respectively.
Ethyl methyl 1-cyano-2-(2-thienyl)cyclopropane-1,3-dicarboxylate
(8a) was obtained (up to 7:3, v/v) as yellow crystals (300 mg, 28%),
m.p. 147–148 C (CH2Cl2); C13H13NO4S (279.32): calcd.: C 55.90, H 4.69,
N 5.01, S 11.48; found: C 55.98, H 4.77, N 4.93, S 11.37; NMR (CDCl3);
1.23 (t, 3H, JHH = 7.2 Hz, O.C.CH3), 3.61, 3.77 (2d, 2 1H, JHH
=
H
11.5 Hz, C-2-H & C-3-H), 3.89 (s, 3H, OCH3), 4.36 (q, 2H, JHH = 7.2 Hz,
O.CH2CH3), 7.16, 7.66, 7.87 (m, 3 1H, Het-H); 14.4 (O.C.CH3),
C
30.4, 32.3 (C-2 & C-3), 54.8 (OCH3), 62.5 (OCH2 CH3), 110.6 (CN),
122.3, 124.5, 126.2 (C-4, C-3, C-5, Het-C), 137.6 (C-2, thienyl), 160.5,
162.8 (2 C(O), esters) ppm; MS: m/z (%) = 279 (M+, 20), 264 (11), 252
(100), 249 (17), 222 (21), 194 (4), 179 (20), 166 (13), 96 (48); IR: = 2218
1
(CN), 1722, 1715 (2 C(O), esters) cm
.

Triphenylphosphine
131
Ethyl methyl [1-cyano-2-(2-thienyl)propanylid-3-ene]triphenylphos-
phorane-1,3-dicarboxylate (7a) was obtained (3:7, v/v) as yellow flakes
(376 mg, 18%); m.p. 172–174 C (CHCl3); C31H28NO4PS (541.62): calcd.:
C 68.34, H 5.21, N 2.59, P 5.72, S 5.92; found: C 68.84, H 5.28, N 2.49,
P 5.66, S 5.84; NMR (CDCl3):
1.22 (t, 3H, JHH = 7.3 Hz, O.C.CH3),
H
3.45 (dd, 1H, JHH = 10.3, JHP = 3.8 Hz, C-2-H), 3.86 (s, 3H, O.C.CH3),
4.03 (q, 2H, JHH = 7.3 Hz, OCH2CH3), 4.25 (dd, 1H, JHH = 10.3, JHP
=
2.2 Hz, C-1-H), 7.25–7.92 (m, 18 H, Ar-H & Het-H); P = 28.6 ppm; MS:
m/z (%) = 541 (M+, 12), 526 (9), 511 (4), 514 (28), 262 (10), 252 (100),
251 (12), 222 (14), 194 (8), 166 (16), 96 (35); IR: = 2220 (CN), 1720w
1
(2 C O, esters), 1675, 1445 (C PPh3) cm
.
1-Cyano-2-(2-thienyl)-1(methyl-1-ethoxyethylene-2-carboxylate)cyclo-
propane-3-carboxylic acid methyl ester (6a) was obtained (pure AcOEt)
as yellow crystals (285 mg, 22%), m.p. 188–190 C (CHCl3); C16H17NO5S
(335.39): calcd.: C 57.30, H 5.11, N 4.17, S 9.56; found: C 57.37, H 5.19, N
4.06, S 9.46; 1H NMR (CDCl3): = 1.07 (t, 3H, JHH = 6.8 Hz, CH2CH3),
3.58 (d, 1H, JHH = 8.8 Hz, C-3-H), 3.77–4.13 (m, 9H, C-1-H &
2
OCH3 & OCH2), 6.28 (s, 1H, C CH), 7.23–7.86 (m, 3H, Het-H)
ppm; MS: m/z (%) = 335 (M+, 13), 320 (26), 308 (100), 305 (7), 278 (41),
250 (11), 222 (3), 191 (24), 146 (13), 96 (29); IR: = 2195 (CN), 1725w
1
[2 C(O)], 1618 (C C) cm
.
Similarly, the reaction of (ethoxycarbonylmethylene)triphenylphos-
phorane (2b) with 1b was carried out under reflux in toluene contain-
ing TEA for 3 days thereby the procedure and the workup are the
same (with 2a) using the same amounts. The product residue was chro-
matographed with hexane/AcOEt to give 8b, 7b, and 6b respectively.
Diethyl 1-cyano-2-(2-thienyl)cyclopropane-1,3-dicarboxylate (8b) was
obtained (up to 6:4, v/v) as yellow crystals (328 mg, 29%), m.p. 141–
143 C (CHCl3); C14H15NO4S (293.35): calcd.: C 57.32, H 5.15, N 4.77,
S 10.93; found: C 57.41, H 5.21, N 4.72, S 10.86; NMR (CDCl3):
=
H
0.85, 1.16 (2t, 2
3H, JHH = 7.3 Hz, 2
O.C.CH3), 3.58, 3.75 (2d,
2
1H, JHH = 11.5 Hz, C-2-H & C-3-H); 3.87–4.12 (2q (m), 2 2H, 2
OCH2CH3), 7.14, 7.66, 7.88 (m, 3 1H, Het-H); C = 14.42, 16.7 (C.CH3,
esters), 31.6, 33.5 (C-2 & C-3), 62.5, 63.1 (2 OCH2, esters), 109.2 (CN),
122.6, 124.4, 126.8 (C-4, C-3, C-5, Het-C), 135.6 (C-2, thienyl), 159.7,
162.4 (2 C(O), esters) ppm; MS: m/z (%) = 293 (M+, 11), 278 (24), 266
(100), 263 (6), 236 (11), 208 (9), 180 (18), 193 (16), 96 (41); IR: = 2220
1
(CN), 1720, 1705 (2 C(O), ester) cm
.
Diethyl- [1- cyano- 2(2 - thienyl)propanylid-3-ene]triphenylphospho-
rane-1,3-dicarboxylate (7b) was obtained (3:7, v/v) as yellow flakes
(322 mg, 15%); m.p. 156–158 C (CHCl3); C32H30NO4PS (555.65): calcd.:
C 69.17, H 5.44, N 2.52, P 5.57, S 5.77; found: C 69.25, H 5.51, N 2.43,
P 5.51, S 5.66; NMR (CDCl3): H = 1.12, 1.27 (2t, 2 3H, JHH = 6.8 Hz,

132
W. M. Abdou et al.
2
O.C.CH3), 3.56 (dd, 1H, JHH = 11.3, JHP = 3.3 Hz, C-2-H),
3.95–4.08 (2q, 2
2H, JHH = 6.8 Hz, 2
OCH2CH3), 4.42 (d, 1H,
JHH = 11.3, JHP = 2.5 Hz, C-1-H), 7.25–7.83 (m, 18 H, Ar-H & Het-H);
= 30.3 ppm; MS: m/z (%) = 555 (M+, 12), 540 (7), 528 (21), 525 (6),
P
266 (100), 262 (21), 238 (13), 210 (10), 185 (8), 96 (30); IR: = 2198
1
(CN), 1720w (2 C O, esters), 1674, 1460 (C PPh3) cm
.
1-Cyano-2-(2-thienyl)-1-(ethyl 1-ethoxyethylene-2-carboxylate)cyclo-
propane-3-carboxylic acid ethyl ester (6b) was obtained (pure AcOEt) as
yellow crystals (364 mg, 26%), m.p. 180–182 C (CHCl3); C18H21NO5S
(363.44): calcd.: C 59.49, H 5.82, N 3.85, S 8.82; found: C 59.57, H 4.78,
1
N 3.77, S 8.73; H NMR (CDCl3): = 1.07–1.23 (m, 9H, 3
C.CH3),
OCH2 &
3.63 (d, 1H, JHH = 8.8 Hz, C-3-H), 3.96–4.21 (m, 7H, 3
C-2-H), 6.21 (s, 1H, C CH), 7.23–7.81 (m, 3H, Het-H) ppm; MS: m/z
(%) = 363 (M+, 18), 348 (29), 336 (100), 333 (5), 306 (43), 278 (9), 250
(5), 205 (19), 160 (9), 96 (31); IR: = 2183 (CN), 1731w [2 C(O)], 1622
1
(C C) cm
.
(B). The reaction between equimolar amounts of compounds 1b and
2a under the same reaction conditions described above gave unchanged
nitrile 1b (ca. 25%). Further elution afforded again compounds 8a
(25%), 7a (20%), and 6a (10%).
Wittig Reaction of Ylides 7a,b
To a stirred solution of 7a or 7b (0.5 g, 0.9 mmol) in ethyl acetate
(10 mL) p-nitrobenzaldehyde (150 mg, 1 mmol) was added, and the
reaction mixture was refluxed for 48 h. After the evaporation of the sol-
vent, the residue was chromatographed by hexane/AcOEt to give firstly
(6:4, v/v) triphenylphosphine oxide, followed by the second fraction (2:8,
v/v), which afforded the Wittig product 9a or 9b in 45% yield.
Olefin 9a, m.p. 225 C (ethyl alcohol); C20H18N2O6S (414.45) calcd.:
C 57.96, H 4.38, N 6.76, S 7.74; found: C 57.92, H 4.45, N 6.68, S 7.62;
1H NMR (CDCl3): = 1.23 (t, 3H, CH2CH3), 3.57, 3.71 (2d, 2
1H,
JHH = 10 Hz, C-1-H & C-2-H), 4.07 (m, 5H, OCH2 & OCH3), 6.73 (s,
1H, C CH), 7.25–7.89 (m, 7H, Ar-H & Het-H) ppm; MS: m/z (%) = 414
(M+, 24), 399 (9), 387 (33), 384 (17), 378 (7), 351 (100), 321 (35), 293
(7), 265 (21), 234 (23), 220 (13), 96 (37); IR: = 2190 (CN), 1720w, [2
1
C(O)], 1615 (C C, exocyclic) cm
.
Olefin 9b, m.p. 196–198 C (ethyl alcohol); C21H20N2O6S (428.47):
calcd.: C 58.87, H 4.71, N 6.54, S 7.48; found: C 58.93, H 4.77, N 6.44,
S 7.39; 1H NMR (CDCl3): = 1.22, 1.24 (2t, 2 3H, 2 O.C.CH3), 3.61,
3.75 (2d, 2 1H, JHH = 9.5 Hz, C-1-H & C-2-H), 4.13 (m, 2 2H, 2
OCH2); 6.68 (s, 1H, C CH), 7.25–7.89 (m, 7H, Ar-H & Het-H) ppm; MS:
m/z (%) = 428 (M+, 13), 413 (9), 401 (28), 398 (12), 392 (21), 365 (100),

Triphenylphosphine
133
335 (29), 307 (16), 279 (25), 234 (19), 220 (9), 96 (39); IR: = 2200 (CN),
1
1720w, [2 C(O)], 1618 (C C, exocyclic) cm
.
Action of Heat on the Ylides 7a,b: A solution of the ylide 7a or
7b (0.4 g) in toluene (10 mL) was heated under reflux for 24 h. After
the removal of the solvent, the residue was chromatographed by hex-
ane/AcOEt to give two fractions.
(A) with 7a: The first fraction (7:3, v/v) afforded yellow crystals of
the cyclopropane 8a (37 mg, 18%), m.p. 146–148 C (CH2Cl2), identical
with the material has previously obtained.
The second fraction (3:7, v/v) gave orange crystals of ethyl methyl
1-cyano-2-(2-thienyl)prop-1-ene-1,3-dicarboxylate (10a) (88 mg, 43%),
m.p. 155–156 C (MeCN); C13H13NO4S (279.32): calcd.: C 55.90, H 4.69,
N 5.01, S 11.48; found: C 55.96, H 4.78, N 5.10, S 11.35; 1H NMR
(CDCl3): = 1.12 (t, 3H, O.CH2CH3), 2.73 (s, 2H, 3-CH2), 3.88–3.98
(m, 5H, OCH2 & OCH3), 7.2, 7.58, 7.94 (m, 3H, Het-H) ppm; MS: m/z
(%) = 279 (M+, 30), 264 (13), 252 (100), 249 (13), 222 (20), 194 (5), 179
(22), 166 (13), 96 (49); IR: = 2222 (CN), 1731, 1718 [2 C(O], 1618
1
(C C, exocyclic) cm
.
(B) with 7b: The first fraction (6:4, v/v) afforded yellow crystals of 8b
(42 mg, 26%), m.p. 141–142 C (CHCl3), identical with the one obtained
before.
The second fraction (3:7, v/v) yielded orange crystals of diethyl 2-
(2-thienyl)prop-1-ene-1,3-dicarboxylate (10b) (59 mg, 28%), m.p. 147–
148 C (MeCN); C14H15NO4S (293.35): calcd.: C 57.32, H 5.51, N 4.77,
S 10.93; found: C 57.39, H 5.26, N 4.71, S 10.88; 1H NMR (CDCl3):
=
1.17–1.2 (m (2t), 6H, 2 C.CH3), 2.78 (s, 2H, CH2), 4.11 (m (2q), 4H, 2
O.CH2), 7.24–7.86 (m, 3H, Het-H) ppm; MS: m/z (%) = 293 (M+, 10),
278 (4), 266 (100), 263 (9), 208 (9), 180 (21), 193 (10), 96 (38); IR:
=
1
2195 (CN), 1730, 1715 (2 C O), 1610 (C C, exocyclic) cm
.
Repeating the above reaction in the presence of equimolar amount
of the ylide 2 led to the same result yielding 8 ( 15) and 10 ( 32%).
Action of the Ylide 2a on the product 8a: The reaction between
compound 8a (0.3 g) and one quiv. of the ylide 2a in boiling toluene
(10 mL), containing TEA, for 2 days was carried out and the product
mixture was worked up as usual to give yellow crystals ( 0.25 g, 90%)
and proved to be unchanged 8a (m.p., mixed m.p., and comparative
IR spectra). No identification (TLC) for 6a in the product mixture was
observed.
II. Action of Phosphorus Ylide 2c on Acrylonitrile 1b
A stirred solution of compound 1a (0.8 g, 3.88 mmol) and (benzoyl-
methylene)triphenylphosphorane (2c) (1.52 g, 4 mmol) in dry toluene

134
W. M. Abdou et al.
(30 mL) containing TEA (0.5 ml) was refluxed for 4 days whereupon
no reaction was occurred (TLC). Repeating the reaction in boiling ethyl
acetate containing benzoic acid (0.5 g) for 3 days afforded compounds
12 and 7c, respectively, after the usual workup.
3-Cyano-2-ethoxy-6-phenyl-4H-4-(2-thienyl)pyran (12) was obtained
(1:1, v/v, AcOEt/EtOH) as red crystals (490 mg, 41%), m.p. 238–240 C
(EtOH); C18H15NO2S (309.39): calcd.: C 69.88, H 4.88, N 4.53, S 10.36;
found: C 69.81, H 4.95, N 4.42, S 10.27; 1H NMR (d6-DMSO): = 0.99
(t, 3H, JHH = 6.8 Hz, O.C.CH3), 3.76 (q, 2H, O.CH2CH3), 4.66 (s, 1H,
C-4-H), 7.24–8.22 (m, 9H, Ph-H, Het-H & C-5-H); MS: m/z (%) = 309
(M+, 32), 294 (10), 282 (100), 281 (58), 236 (17), 189 (33), 96 (40); IR:
1
= 2195 (CN) cm
.
Ethyl [2-(2-thienyl)-3-benzoylpropanylidene]triphenylphosphorane-
1,1-cyanoacetate (7c) was obtained (2:8, v/v, AcOEt/EtOH) as reddish
brown crystals (400 mg, 18%), m.p. 181–183 C (EtOH); C36H30NO3PS
(587.69): calcd.: C 73.57, H 5.14, N 2.38, P 5.27, S 5.46; found: C 73.66,
H 5.04, N 2.24, P 5.22, S 5.39; NMR (d6-DMSO) H = 1.14 (t, 3H, JHH
=
6.6 Hz, O.C.CH3), 3.58 (dd, 1H, JHH = 10.5, JHP = 3.8 Hz, C-2-H), 4.04
(q, 2H, JHH = 6.6 Hz, OCH2), 4.45 (dd, 1H, JHH = 10.5, JHP = 2.3 Hz,
C-1-H), 7.24–8.01 (m, 23 H, Ph-H & Het-H); P= 22.53 ppm; MS: m/z
(%) = 587 (M+, 18), 572 (3), 560 (23), 298 (100), 270 (29), 262 (13), 207
(29), 96 (37); IR: = 2216 (CN), 1720 (C O, ester), 1682 (C O, benzoyl),
1
1672, 1443 (C PPh3) cm
.
III. Action of Phosphorus Ylide 14 on 1b and 1a
General Procedure
A solution of cyanomethylenephosphomium chloride (13) (7.76 mmol)
and the acrylonitriles 1b,a (3.88 mmol) in absolute ethanol (40 mL) was
stirred for 15 min. Freshly prepared aqueous lithium hydroxide (0.5 N,
10 mL) was added in one portion to the mixture, and the two-phase
system was stirred at room temperature until the consumption of the
starting acrylonitrile (for 72 h for 1b and for 24 h for 1a). The mixture
was then extracted with CHCl3 (2
50 mL). The combined extracts
were washed with water (25 mL), dried, and the solvent was removed
under reduced pressure. The residue was chromatographed on silica
gel by using hexane containing an increasing amounts of ethyl acetate.
A. The reaction with 1b (0.8 g, 3.88 mmol ) gave 1-(cyanomethyl-
vinylether)-1,3-dicyano-2-(2-thienyl)cyclopropane (15) (AcOEt, eluent)
as orange crystals (0.5 g, 48%), m.p. 142–144 C (CH2Cl2/light
petroleum); C14H11N3OS (269.33): calcd.: C 62.43, H 4.12, N 15.60,
S 11.90; found: C, 62.54; H, 4.07; N, 15.54; S, 11.82; 1H NMR (DMSO-d6):
= 1.14 (t, 3H, JHH = 7 Hz, C.CH3), 3.51 (d, 1H, JHH = 8.8 Hz, C-2-H),

Triphenylphosphine
135
3.95 (2H, q, OCH2), 4.42 (d, 1H, JHH = 8.8 Hz, C-3-H), 5.74 (s, 1H,
CHCN), 7.28–7.94 (m, 3H, Het-H); MS: m/z (%) = 269 (M+, 62), 254
(5), 272 (76), 260 (100), 245 (36), 233 (65), 188 (13), 96 (23); IR: = 1987,
1
1995–2005 (3 CN), 1618 (C C, exocyclic) cm
.
B. The reaction with 1a9 (0.8 g, 5 mmol) gave two fractions. The
first fraction (up to 4:1, v/v, hexane/AcOEt) afforded yellow sub-
stance, recrystalized from benzene, and identified as 1,1,3-tricyano-2-
(2-thienyl)prop-1-ene (17) (230 mg, 23%), m.p.: 118–120 C [lit.1, m.p.:
168–170 C]; MS: m/z (%) = 199 (M+, 55); requires 199.234.
The second fraction yielded a reddish brown substance, recrystallized
from chloroform to give 16 (855 mg, 37%); m.p. 179–182 C; C28H20N3PS
(462.38): calcd.: C 72.73, H 4.54, N 9.09, P 6.70, S 6.93; found: C 72.66,
H 4.46, N 9.04, P 6.77, S 6.82; NMR (d6-DMSO):
3.42 (d of d, 1H,
H
1 JHP = 10.5 Hz, C-2-H); 3.68 (d of d, 1H, JHH = 7.2 Hz, C-1-H); 7.23–
8.02 (m, 18 H, Ph-H, Het-H);
23), 435 (18), 381 (6) 370 (11), 262 (10), 161 (100), 96 (33); IR: = 2222w
= 24.8 ppm; MS: m/z (%) = 462 (M+,
P
1
(3 CN), 1645, 1535 (C P) cm
.
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