A three-component one-pot synthesis of functionalized 5,5- dicyanocyclopenta-1,3-dienes from arylidenemalononitriles, activated acetylenes, and KCN or KSCN

Article abstract of DOI:10.1002/hlca.201000082

The reaction of dialkyl acetylenedicarboxylates with arylidenemalononitriles in the presence of KSCN in MeCN led to a mixture of dialkyl (3E)-4-aryl-3-(arylideneamino)-5,5-dicyanocyclopenta-1,3-diene-1,2- dicarboxylates and dialkyl 4-aryl-5-cyanothiophene

Full text of DOI:10.1002/hlca.201000082

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A Three-Component One-Pot Synthesis of Functionalized 5,5-Dicyano-
cyclopenta-1,3-dienes from Arylidenemalononitriles, Activated Acetylenes,
and KCN or KSCN
by Issa Yavari*, Mehdi Sirouspour, and Sanaz Souri
Chemistry Department, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran
(phone: þ 98-21-82883465; fax: þ 98-21-82883455; e-mail: yavarisa@modares.ac.ir)
The reaction of dialkyl acetylenedicarboxylates with arylidenemalononitriles in the presence of
KSCN in MeCN led to a mixture of dialkyl (3E)-4-aryl-3-(arylideneamino)-5,5-dicyanocyclopenta-1,3-
diene-1,2-dicarboxylates and dialkyl 4-aryl-5-cyanothiophene-2,3-dicarboxylates. When these reactions
were performed in the presence of KCN, only the functionalized 5,5-dicyanocyclopenta-1,3-dienes were
obtained.
Introduction. – In view of our general interest in reactions involving zwitterionic
species [1 – 4], we report on two three-component reactions involving KSCN or KCN,
arylidenemalononitriles (1), and dialkyl acetylenedicarboxylates (2).
Results and Discussion. – The reaction of 1 and 2 in the presence of KSCN led to
dialkyl 4-aryl-5-cyanothiophene-2,3-dicarboxylates (3) in 16 – 30% yields, together
with minor amounts (10 – 15%) of dialkyl 4-aryl-3-[(E)-arylideneamino]-5,5-dicyano-
cyclopenta-1,3-diene-1,2-dicarboxylates (4; Scheme 1).
Scheme 1
ꢀ 2010 Verlag Helvetica Chimica Acta AG, Zꢁrich

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The structures of compounds 3 were established by spectroscopic methods. For
1
example, the H-NMR spectrum of 3c exhibited three singlets (at 2.40, 3.81, and
3.93 ppm) for the H-atoms of the Me and MeO groups, together with two characteristic
doublets (at 7.26 and 7.37 ppm) for the aromatic H-atoms. The 13C-NMR spectrum of 3c
exhibited 14 signals in agreement with the proposed structure.
1
The structures of compounds 4a – 4h were deduced from their IR, and H- and
1
13C-NMR spectra, and, in case of 4a, single-crystal X-ray analysis. The H-NMR
spectrum of 4a exhibited five singlets of the H-atoms of the MeO (at 3.79, 3.86, 3.87, and
3.95 ppm) and the H-atom of the imino group (at 8.35 ppm), together with four
1
characteristic doublets of the H-atoms of the two aromatic rings. The H-decoupled
13C-NMR spectrum of 4a showed 21 distinct resonances which further confirmed the
proposed structure. The 1H- and 13C-NMR spectra of 4b – 4h were similar to those for
4a except for the ester moieties, which exhibited characteristic resonances in the
appropriate regions of the spectra.
Unambiguous evidence for the structure of 4a was obtained from a single-crystal X-
ray analysis. An ORTEP [5] diagram of 4a is displayed in the Figure. There are four
molecules of 4a in the unit cell. The structure deduced from the crystallographic
experiment, by analogy, can be applied to the other products 4b – 4h on account of their
NMR-spectroscopic similarities.
Figure. X-Ray Crystal Structure of 4a (ORTEP-III plot [5], arbitrary atom numbering)
A plausible mechanism for the formation of compound 3 is proposed in Scheme 2. It
is conceivable that the reaction involves the initial formation of anionic intermediate 5

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Scheme 2
from SCNꢀ and 2, which reacts with 1 to produce 6. Cyclization of this intermediate,
followed by loss of CNꢀ and HCN, leads to 3.
The appearance of two geminal CN groups in 4 encouraged us to assume that the
formation of 4 involves the addition of a CNꢀ ion, released during the final steps of the
formation of compound 3. Thus, we repeated the reaction of 1 and 2 in the presence of
KCN and obtained, indeed, only compounds 4 (Scheme 3) and as expected in yields
higher than those achieved with KSCN.
Scheme 3
Although the mechanistic details of the formation of compounds 4 are not known, a
plausible rationalization is proposed in Scheme 4. It is conceivable that the reaction
starts with the formation of intermediate 8, followed by addition of 2, to generate 9.
Cyclization of this intermediate leads to 10, which reacts with another molecule of 1 to
form 11. Intermediate 11 may undergo an intramolecular H-atom transfer, followed by
elimination of dicyanomethanide, to give 4.
In conclusion, we have described the use of KSCN and KCN as anionic nucleophiles
in a reaction involving arylidenemalononitriles and acetylenedicarboxylates to produce
dialkyl 4-aryl-5-cyanothiophene-2,3-dicarboxylates and dialkyl 4-aryl-3-[(E)-arylide-
neamino]-5,5-dicyanocyclopenta-1,3-diene-1,2-dicarboxylates. When the reaction was
performed in the presence of KCN alone, only the latter products were obtained.

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Scheme 4
Simple mixing of the starting materials and the potential diversity of the reaction are
the advantages of this procedure.
Experimental Part
General. Dialkyl acetylenedicarboxylates, aldehydes, malononitrile, KSCN, and KCN were obtained
from Merck and were used without further purification. Arylidenemalononitriles were prepared
according to [6]. M.p.: Electrothermal-9100 apparatus. IR Spectra (KBr, cmꢀ1): Shimadzu IR-460
1
spectrometer. H- and 13C-NMR spectra: Bruker DRX-500 Avance instrument; in CDCl3; at 500.1 and
125.7 MHz, resp.; d in ppm, J in Hz. MS: Finnigan-MAT-8430 mass spectrometer; at 70 eV; in m/z (rel.
%). Elemental analyses (C, H, N): Heraeus CHN-O-Rapid analyzer.
Compounds 3 and 4: General Procedure. To a stirred soln. of 1 (5 mmol) and 2 (2 mmol) in 10 ml of
MeCN was added KSCN or KCN (2 mmol) at r.t. After completion of the reaction (2 h), as indicated by
TLC (hexane/AcOEt, 5 :1), the solvent was removed under reduced pressure, and the light brown
residue was separated by column chromatography (SiO2, 230 – 400 mesh, Merck; hexane/AcOEt) to
afford the pure products.
Dimethyl 5-Cyano-4-(4-methylphenyl)thiophene-2,3-dicarboxylate (3c). Yield: 0.19 g (30%). Color-
less crystals. M.p. 140 – 1428. IR: 1725, 1716, 1580, 1531, 1512, 1432, 1311, 1283, 1243, 1193, 1165, 1078,
991, 831. 1H-NMR: 2.40 (s, Me); 3.81 (s, MeO); 3.93 (s, MeO); 7.26 (d, J ¼ 7.9, 2 arom. H); 7.37 (d, J ¼ 7.9,
2 arom. H). 13C-NMR: 21.3 (Me); 53.2 (MeO); 53.3 (MeO); 110.7 (C); 112.9 (C); 128.2 (C); 128.3
(2 CH); 129.8 (2 CH); 135.4 (C); 138.9 (C); 140.2 (C); 150.5 (C); 159.8 (C¼O); 164.3 (C¼O). EI-MS:
317 (4, [M þ 2]þ), 315 (100, Mþ), 284 (90), 252 (85), 224 (50), 91 (5), 59 (40), 39 (36). Anal. calc. for
C16H13NO4S (315.34): C 60.94, H 4.16, N 4.44; found: C 61.23, H 4.24, N 4.30.
Diethyl 5-Cyano-4-(4-methylphenyl)thiophene-2,3-dicarboxylate (3d). Yield: 0.16 g (24%.). Color-
less crystals. M.p. 145 – 1478. IR: 1727, 1718, 1585, 1532, 1432, 1314, 1281, 1240, 1196, 1166, 1077, 995, 829.
1H-NMR: 1.40 (t, J ¼ 7.2, Me); 1.49 (t, J ¼ 7.2, Me); 2.40 (s, Me); 4.38 (q, J ¼ 7.2, CH2O); 4.44 (q, J ¼ 7.2,
CH2O); 7.30 (d, J ¼ 7.7, 2 arom. H); 7.52 (d, J ¼ 7.7, 2 arom. H). 13C-NMR: 13.9 (Me); 14.1 (Me); 21.3
(Me); 62.6 (CH2O); 63.1 (CH2O); 109.5 (C); 111.1 (C); 127.2 (C); 127.4 (2 CH); 130.4 (2 CH); 135.4 (C);
138.8 (C); 140.6 (C); 150.4 (C); 158.5 (C¼O); 162.3 (C¼O). EI-MS: 345 (3, [M þ 2]þ), 343 (100, Mþ),
298 (95), 197 (50), 196 (65), 91 (10), 59 (52), 39 (45). Anal. calc. for C18H17NO4S (343.39): C 62.96, H
4.99, N 4.08; found: C 63.19, H 5.11, N 4.19.
Dimethyl 5-Cyano-4-phenylthiophene-2,3-dicarboxylate (3e). Yield: 0.13 g (21%). Colorless crystals.
M.p. 134 – 1368. IR: 1725, 1715, 1590, 1545, 1430, 1315, 1247, 1199, 1171, 1080, 997, 824, 768. 1H-NMR: 3.79

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(s, MeO); 3.92 (s, MeO); 7.45 – 7.49 (m, 5 arom. H). 13C-NMR: 53.0 (MeO); 53.3 (MeO); 111.0 (C); 112.7
(C); 128.4 (2 CH); 128.9 (2 CH); 129.6 (CH); 129.8 (C); 130.6 (C); 138.9 (C); 150.3 (C); 159.8 (C¼O);
164.2 (C¼O). EI-MS: 303 (5), 301 (100, Mþ), 272 (85), 185 (40), 184 (60), 77 (60), 80 (10), 39 (55).
Anal. calc. for C15H11NO4S (301.31): C 59.79, H 3.68, N 4.65; found: C 59.45, H 3.60, N 4.76.
Diethyl 5-Cyano-4-phenylthiophene-2,3-dicarboxylate (3f). Yield: 0.17 g (26%). Colorless crystals.
M.p. 139 – 1408. IR: 1727, 1716, 1591, 1549, 1430, 1315, 1241, 1203, 1179, 1080, 995, 741. 1H-NMR: 1.35 (t,
J ¼ 7.0, Me); 1.40 (t, J ¼ 7.1, Me); 4.37 (q, J ¼ 7.0, CH2O); 4.41 (q, J ¼ 7.1, CH2O); 7.43 – 7.47 (m, 5 arom.
H). 13C-NMR: 13.9 (Me); 14.0 (Me); 62.5 (CH2O); 62.9 (CH2O); 111.1 (C); 112.8 (C); 128.0 (2 CH);
128.6 (2 CH); 129.7 (CH); 129.8 (C); 130.8 (C); 138.7 (C); 150.2 (C); 159.8 (C¼O); 164.2 (C¼O). EI-
MS: 331 (7, [M þ 2]þ), 329 (100, Mþ), 284 (85), 199 (40), 77 (64), 39 (50). Anal. calc. for C17H15NO4S
(329.42): C 61.99, H 4.59, N 4.25; found: C 59.95, H 4.61, N 4.66.
Dimethyl 4-(4-Chlorophenyl)-5-cyanothiophene-2,3-dicarboxylate (3g). Yield: 0.15 g (22%). Color-
less crystals. M.p. 144 – 1468. IR: 1729, 1717, 1590, 1521, 1437, 1284, 1249, 1194, 1165, 1007, 993, 960, 899,
848, 816. 1H-NMR: 3.80 (s, MeO); 3.93 (s, MeO); 7.41 (d, J ¼ 7.5, 2 arom. H); 7.45 (d, J ¼ 7.5, 2 arom. H).
13C-NMR: 53.3 (MeO); 53.4 (MeO); 111.3 (C); 112.5 (C); 129.4 (C); 129.5 (2 CH); 129.8 (2 CH); 135.8
(C); 136.3 (C); 138.7 (C); 148.9 (C); 159.6 (C¼O); 163.9 (C¼O). EI-MS: 338 (6, [M þ 2]þ), 336 (100,
Mþ), 304 (90), 217 (40), 216 (60), 111 (10), 80 (5), 77 (50), 59 (35), 39 (38). Anal. calc. for
C15H10ClNO4S (335.76): C 53.66, H 3.00, N 4.17; found: C 53.50, H 2.95, N 4.16.
Diethyl 4-(4-Chlorophenyl)-5-cyanothiophene-2,3-dicarboxylate (3h). Yield: 0.18 g (25%). Colorless
crystals. M.p. 151 – 1538. IR: 1728, 1718, 1592, 1519, 1440, 1280, 1248, 1194, 1163, 1005, 990, 962, 893, 845,
811. 1H-NMR: 1.37 (t, J ¼ 7.2, Me); 1.43 (t, J ¼ 7.2, Me); 4.40 (q, J ¼ 7.2, CH2O); 4.44 (q, J ¼ 7.2, CH2O);
7.47 (d, J ¼ 7.6, 2 arom. H); 7.57 (d, J ¼ 7.6, 2 arom. H). 13C-NMR: 13.8 (Me); 13.9 (Me); 62.7 (CH2O);
63.2 (CH2O); 110.9 (C); 111.4 (C); 129.4 (C); 129.5 (2 CH); 129.9 (2 CH); 134.7 (C); 142.3 (C); 143.9
(C); 152.1 (C); 158.4 (C¼O); 162.0 (C¼O). EI-MS: 366 (4, [M þ 2]þ), 364 (100, Mþ), 318 (95), 217 (55),
216 (65), 112 (5), 80 (10), 77 (55), 39 (48). Anal. calc. for C17H14ClNO4S (363.81): C 56.12, H 3.88, N
3.85; found: C 56.15, H 3.85, N 3.80.
Dimethyl 5-Cyano-4-(4-nitrophenyl)thiophene-2,3-dicarboxylate (3i). Yield: 0.11 g (16%). Pale
yellow crystals. M.p. 161 – 1638. IR: 1735, 1724, 1593, 1521, 1434, 1346, 1283, 1246, 1200, 1170, 1105, 1107,
1005, 990, 866, 835, 744. 1H-NMR: 3.80 (s, MeO); 3.94 (s, MeO); 7.65 (d, J ¼ 7.7, 2 arom. H); 8.31 (d, J ¼
7.7, 2 arom. H). 13C-NMR: 53.4 (MeO); 53.5 (MeO); 112.0 (C); 112.3 (C); 124.1 (2 CH); 127.2 (C); 129.7
(2 CH); 136.5 (C); 137.0 (C); 147.5 (C); 148.6 (C); 159.3 (C¼O); 163.5 (C¼O). EI-MS: 348 (4, [M þ
2]þ), 346 (100, Mþ), 315 (61), 287 (40), 77 (20), 39 (10). Anal. calc. for C15H10N2O6S (346.31): C
54.02, H 2.91, N 8.09; found: C 54.50, H 3.00, N 8.22.
Diethyl 5-Cyano-4-(4-nitrophenyl)thiophene-2,3-dicarboxylate (3j). Yield: 0.12 g (16%). Pale yellow
crystals. M.p. 154 – 1568. IR: 1735, 1724, 1593, 1521, 1434, 1346, 1283, 1246, 1200, 1170, 1105, 1107, 1005,
990, 866, 835, 744. 1H-NMR: 1.40 (t, J ¼ 7.0, Me); 1.45 (t, J ¼ 7.1, Me); 4.42 (q, J ¼ 7.0, CH2O); 4.46 (q, J ¼
7.1, CH2O); 7.64 (d, J ¼ 7.7, 2 arom. H); 8.30 (d, J ¼ 7.7, 2 arom. H). 13C-NMR: 14.2 (Me); 14.6 (Me); 63.0
(CH2O); 63.3 (CH2O); 112.1 (C); 112.2 (C); 124.1 (2 CH); 127.0 (C); 129.6 (2 CH); 136.6 (C); 136.8 (C);
147.2 (C); 148.2 (C); 159.4 (C¼O); 163.6 (C¼O). EI-MS: 376 (6, [M þ 2]þ), 374 (100, Mþ), 329 (61), 301
(40), 77 (24), 39 (15). Anal. calc. for C17H14N2O6S (374.43): C 54.54, H 3.77, N 7.48; found: C 54.40, H
3.67, N 7.52.
Dimethyl 5,5-Dicyano-4-(4-methoxyphenyl)-3-{[(E)-(4-methoxyphenyl)methylidene]amino}cyclo-
penta-1,3-diene-1,2-dicarboxylate (4a). Yield: 0.23 g (24%). Orange crystals. M.p. 180 – 1828. IR (KBr):
1735, 1728, 1593, 1564, 1525, 1501, 1427, 1323, 1297, 1254, 1232, 1181, 1024, 950, 828, 788, 729, 694.
1H-NMR: 3.79 (s, MeO); 3.86 (s, MeO); 3.87 (s, MeO); 3.95 (s, MeO); 6.93 (d, J ¼ 8.4, 2 arom. H); 6.98
(d, J ¼ 8.3, 2 arom. H); 7.78 (d, J ¼ 8.4, 2 arom. H); 7.81 (d, 3J ¼ 8.3, 2 arom. H); 8.35 (s, CH). 13C-NMR:
29.6 (C); 53.1 (MeO); 53.2 (MeO); 55.3 (MeO); 55.5 (MeO); 110.8 (CN); 114.6 (2 CH); 114.8 (2 CH);
121.9 (C); 124.9 (C); 127.6 (C); 127.8 (C); 129.8 (2 CH); 131.4 (2 CH); 147.9 (C); 150.8 (C); 159.1 (C);
160.6 (C); 162.6 (C¼N); 163.9 (C¼O); 165.2 (C¼O). EI-MS: 471 (82, Mþ), 456 (21), 440 (15), 412 (18),
205 (7), 107 (100), 77 (64), 39 (55). Anal. calc. for C26H21N3O6 (471.47): C 66.24, H 4.49, N 8.91; found: C
66.30, H 4.50, N 8.80.
X-Ray Crystal-Structure of 4a. Structure-determination and refinement data: C26H21N3O6, Mr 471.46,
crystal size, 0.30 ꢁ 0.20 ꢁ 0.20 mm3, monoclinic, a ¼ 14.5839(7) ꢂ, b ¼ 8.9554(4) ꢂ, c ¼ 19.7705(10) ꢂ;

Helvetica Chimica Acta – Vol. 93 (2010)
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a ¼ 908, b ¼ 111.1520(10)8, g ¼ 908; space group P21/n; Z ¼ 4, V¼ 2381.3(2) ꢂ3, Dcalc. ¼ 1.315 g cmꢀ3; R ¼
0.0456 (for 6555 reflections); Rw ¼ 0.0676; ꢀ 21 ꢂ h ꢂ 22; ꢀ 13 ꢂ k ꢂ 13; ꢀ 29 ꢂ l ꢂ 298; MoKa radiation
(l ¼ 0.71073 ꢂ); T¼ 100(2) K1).
Diethyl 5,5-Dicyano-4-(4-methoxyphenyl)-3-{[(E)-(4-methoxyphenyl)methylidene]amino}cyclopen-
ta-1,3-diene-1,2-dicarboxylate (4b). Yield: 0.25 g (25%). Orange crystals. M.p. 184 – 1868. IR (KBr): 1735,
1
1725, 1593, 1560, 1533, 1501, 1428, 1320, 1291, 1254, 1233, 1184, 1020, 950, 827, 785, 730, 697. H-NMR:
1.28 (t, J ¼ 7.1, Me); 1.40 (t, J ¼ 7.1, Me); 3.81 (s, MeO); 3.85 (s, MeO); 4.32 (q, J ¼ 7.1, CH2O); 4.38 (q, J ¼
7.1, CH2O); 6.92 (d, J ¼ 8.5, 2 arom. H); 6.97 (d, J ¼ 8.5, 2 arom. H); 7.75 (d, J ¼ 8.5, 2 arom. H); 7.87 (d,
J ¼ 8.5, 2 arom. H); 8.37 (s, CH). 13C-NMR: 14.0 (Me); 14.1 (Me); 29.5 (C); 55.4 (MeO); 55.6 (MeO);
62.3 (CH2O); 62.5 (CH2O); 110.7 (CN); 114.6 (2 CH); 114.9 (2 CH); 121.8 (C); 124.9 (C); 127.7 (C);
127.9 (C); 129.9 (2 CH); 131.5 (2 CH); 147.7 (C); 150.6 (C); 159.2 (C); 160.6 (C); 162.5 (C¼N); 163.8
(C¼O); 165.3 (C¼O). EI-MS: 500 (75, Mþ), 471 (19), 430 (14), 402 (26), 393 (45), 107 (100), 77 (59), 39
(51). Anal. calc. for C28H25N3O6 (499.52): C 67.33, H 5.04, N 8.41; found: C 67.50, H 5.16, N 8.30.
Dimethyl 5,5-Dicyano-4-(4-methylphenyl)-3-{[(E)-(4-methylphenyl)methylidene]amino}cyclopen-
ta-1,3-diene-1,2-dicarboxylate (4c). Yield: 0.21 g (24%). Yellow crystals. M.p. 175 – 1778. IR (KBr):
1742, 1735, 1623, 1617, 1561, 1493, 1430, 1324, 1294, 1231, 1175, 1054, 1014, 950, 811, 774, 729, 698.
1H-NMR: 2.32 (s, Me); 2.42 (s, Me); 3.87 (s, MeO); 3.97 (s, MeO); 7.21 (d, J ¼ 8.2, 2 arom. H); 7.29 (d, J ¼
8.0, 2 arom. H); 7.69 (d, J ¼ 8.2, 2 arom. H); 7.72 (d, J ¼ 8.0, 2 arom. H); 8.37 (s, CH). 13C-NMR: 21.3
(Me); 21.7 (Me); 29.7 (C); 53.1 (MeO); 53.2 (MeO); 110.6 (CN); 125.7 (C); 126.3 (C); 128.1 (2 CH);
129.0 (C); 129.5 (2 CH); 129.8 (2 CH); 129.9 (2 CH); 132.0 (C); 140.1 (C); 144.3 (C); 149.1 (C); 150.6
(C); 159.0 (C¼N); 162.4 (C¼O); 166.2 (C¼O). EI-MS: 439 (85, Mþ), 392 (25), 364 (14), 348 (55), 321
(30), 146 (100), 91 (90), 59 (74). Anal. calc. for C26H21N3O4 (439.47): C 71.06, H 4.82, N 9.56; found: C
71.01, H 4.94, N 9.65.
Diethyl 5,5-Dicyano-4-(4-methylphenyl)-3-{[(E)-(4-methylphenyl)methylidene]amino}cyclopenta-
1,3-diene-1,2-dicarboxylate (4d). Yield: 0.23 g (25%). Yellow crystals. M.p. 172 – 1748. IR (KBr): 1737,
1730, 1620, 1612, 1555, 1492, 1435, 1322, 1290, 1225, 1165, 1050, 1014, 956, 810, 777, 730, 700. 1H-NMR:
1.29 (t, J ¼ 7.1, Me); 1.43 (t, J ¼ 7.1, Me); 2.36 (s, Me); 2.45 (s, Me); 4.36 (q, J ¼ 7.1, CH2O); 4.45 (q, J ¼ 7.1,
CH2O); 7.23 (d, J ¼ 8.1, 2 arom. H); 7.31 (d, J ¼ 8.1, 2 arom. H); 7.70 (d, J ¼ 8.1, 2 arom. H); 7.73 (d, J ¼ 8.1,
2 arom. H); 8.41 (s, CH). 13C-NMR: 13.9 (Me); 14.0 (Me); 21.2 (Me); 21.7 (Me); 29.6 (C); 62.5 (CH2O);
62.7 (CH2O); 110.8 (CN); 125.6 (C); 126.4 (C); 128.1 (2 CH); 128.8 (C); 129.3 (2 CH); 129.8 (2 CH);
129.9 (2 CH); 132.1 (C); 140.0 (C); 144.2 (C); 149.2 (C); 150.5 (C); 158.5 (C¼N); 162.0 (C¼O); 166.1
(C¼O). EI-MS: 468 (75, Mþ), 439 (20), 398 (25), 370 (31), 146 (100), 91 (85), 59 (70). Anal. calc. for
C28H25N3O4 (467.52): C 71.93, H 5.39, N 8.99; found: C 71.45, H 5.44, N 8.88.
Dimethyl 5,5-Dicyano-4-phenyl-3-{[(E)-phenylmethylidene]amino}cyclopenta-1,3-diene-1,2-dicarb-
oxylate (4e). Yield: 0.23 g (28%). Bright yellow crystals. M.p. 165 – 1678. IR (KBr): 1725, 1717, 1611,
1564, 1523, 1425, 1317, 1265, 1210, 1154, 1040, 763, 678. 1H-NMR: 3.89 (s, MeO); 3.99 (s, MeO); 7.37 (t,
J ¼ 7.2, CH); 7.42 (t, J ¼ 7.1, 2 arom. H); 7.49 (t, J ¼ 7.7, 2 arom. H); 7.58 (t, J ¼ 7.5, CH); 7.80 (d, J ¼ 7.6, 2
arom. H); 7.83 (d, J ¼ 7.1, 2 arom. H); 8.43 (s, CH). 13C-NMR: 33.0 (C); 53.2 (MeO); 53.3 (MeO); 110.4
(CN); 125.9 (C); 126.3 (C); 128.2 (CH); 129.0 (C); 129.1 (CH); 129.2 (2 CH); 129.5 (2 CH); 129.7
(2 CH); 133.3 (2 CH); 134.4 (C); 149.7 (C); 150.3 (C); 158.9 (C¼N); 162.2 (C¼O); 166.7 (C¼O). EI-
MS: 411 (68, Mþ), 396 (25), 365 (22), 337 (30), 334 (46), 77 (100), 39 (57). Anal. calc. for C24H17N3O4
(411.41): C 70.07, H 4.16, N 10.21; found: C 70.12, H 4.23, N 10.27.
Diethyl 5,5-Dicyano-4-phenyl-3-{[(E)-phenylmethylidene]amino}cyclopenta-1,3-diene-1,2-dicarboxy-
late (4f). Yield: 0.22 g (25%). Bright yellow crystals. M.p. 173 – 1758. IR (KBr): 1729, 1721, 1614,
1560, 1522, 1425, 1321, 1265, 1205, 1150, 1040, 764, 678. 1H-NMR: 1.25 (t, J ¼ 7.1, Me); 1.40 (t, J ¼ 7.1, Me ) ;
4.34 (q, J ¼ 7.1, CH2O); 4.42 (q, J ¼ 7.1, CH2O); 7.36 (t, J ¼ 7.5, CH); 7.42 (t, J ¼ 7.1, 2 arom. H); 7.49 (t, J ¼
7.6, 2 arom. H); 7.59 (t, J ¼ 7.5, CH); 7.80 (d, J ¼ 7.6, 2 arom. H); 7.85 (d, J ¼ 7.1, 2 arom. H); 8.42 (s, CH).
13C-NMR: 13.9 (Me); 14.0 (Me); 32.8 (C); 62.8 (CH2O); 62.9 (CH2O); 110.5 (CN); 126.2 (C); 126.3 (C);
1
)
The crystallographic data of 4a have been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication No. CCDC-753003. Copies of the data can be obtained, free of
charge, via the internet (http://www.ccdc.cam.ac.uk/data_request/cif), e-mail (data_request@ccdc.
cam.ac.uk), or fax (þ44-1223-336033).

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Helvetica Chimica Acta – Vol. 93 (2010)
128.0 (CH); 129.1 (C); 129.3 (CH); 129.4 (2 CH); 129.5 (2 CH); 129.8 (2 CH); 133.3 (2 CH); 134.4 (C);
149.8 (C); 150.1 (C); 159.7 (C¼N); 162.3 (C¼O); 166.6 (C¼O). EI-MS: 439 (80, Mþ), 410 (19), 369
(24), 362 (54), 341 (45), 77 (100), 39 (62). Anal. calc. for C26H21N3O4 (439.47): C 71.06, H 4.82, N 9.56;
found: C 70.94, H 4.90, N 9.70.
Dimethyl 4-(4-Chlorophenyl)-3-{[(E)-(4-chlorophenyl)methylidene]amino}-5,5-dicyanocyclopenta-
1,3-diene-1,2-dicarboxylate (4g). Yield: 0.36 g (38%). Yellow crystals. M.p. 169 – 1718. IR (KBr): 1720,
1713, 1609, 1583, 1556, 1521, 1478, 1427, 1322, 1288, 1261, 1209, 1164, 1084, 1054, 1005, 820, 771. 1H-NMR:
3.89 (s, MeO); 3.99 (s, MeO); 7.40 (d, J ¼ 8.7, 2 arom. H); 7.48 (d, J ¼ 8.4, 2 arom. H); 7.71 (d, J ¼ 8.7, 2
arom. H); 7.77 (d, J ¼ 8.4, 2 arom. H); 8.39 (s, CH). 13C-NMR: 29.7 (C); 53.3 (MeO); 53.4 (MeO); 110.1
(CN); 126.7 (C); 127.4 (C); 129.4 (2 CH); 129.6 (2 CH); 129.7 (2 CH); 130.6 (2 CH); 130.8 (C); 132.7
(C); 136.2 (C); 140.1 (C); 149.6 (C); 149.7 (C); 158.8 (C¼N); 162.1 (C¼O); 165.5 (C¼O). EI-MS: 482
(5, [M þ 2]þ), 480 (78, Mþ), 465 (19), 434 (24), 406 (50), 370 (65), 77 (100), 39 (65). Anal. calc. for
C24H15Cl2N3O4 (480.30): C 60.02, H 3.15, N 8.75; found: C 60.11, H 3.13, N 8.72.
Diethyl 4-(4-Chlorophenyl)-3-{[(E)-(4-chlorophenyl)methylidene]amino}-5,5-dicyanocyclopenta-
1,3-diene-1,2-dicarboxylate (4h). Yield: 0.33 g (32%). Bright yellow crystals. M.p. 178 – 1808. IR
(KBr): 1725, 1715, 1602, 1581, 1550, 1520, 1471, 1425, 1321, 1289, 1265, 1205, 1160, 1085, 1050, 1003, 824,
770. 1H-NMR: 1.26 (t, J ¼ 7.0, Me); 1.43 (t, J ¼ 7.1, Me); 4.37 (q, J ¼ 7.0, CH2O); 4.45 (q, J ¼ 7.1, CH2O);
7.42 (d, J ¼ 8.4, 2 arom. H); 7.50 (d, J ¼ 8.1, 2 arom. H); 7.74 (d, J ¼ 8.4, 2 arom. H); 7.79 (d, J ¼ 8.1, 2 arom.
H); 8.42 (s, CH). 13C-NMR: 14.0 (Me); 14.1 (Me); 29.7 (C); 62.8 (CH2O); 62.9 (CH2O); 110.3 (CN);
126.7 (C); 127.5 (C); 129.4 (2 CH); 129.6 (2 CH); 129.7 (2 CH); 130.6 (2 CH); 131.1 (C); 132.7 (C); 136.1
(C); 139.8 (C); 149.5 (C); 149.7 (C); 158.3 (C¼N); 161.7 (C¼O); 165.3 (C¼O). EI-MS: 510 (4, [M þ
2]þ), 508 (70, Mþ), 479 (21), 438 (25), 410 (32), 397 (40), 77 (100), 39 (61). Anal. calc. for
C26H19Cl2N3O4 (508.36): C 61.43, H 3.77, N 8.27; found: C 61.45, H 3.72, N 8.32.
REFERENCES
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[3] I. Yavari, M. Sabbaghan, Z. Hossaini, M. Ghazanfarpour-Darjani, Helv. Chim. Acta 2008, 91, 1144.
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Received February 28, 2010