Potassium thiocyanate-promoted one-pot synthesis of (1,3-diaryl-2,5- dioxoimidazolidin-4-ylidene)acetates from aryl isocyanates and alkyl propiolates short communication

Article abstract of DOI:10.1002/hlca.200900444

The reaction of aryl isocyanates and alkyl propiolates (=alkyl prop-2-ynoates) in the presence of potassium thiocyanate (KSCN) led to geometric isomers of alkyl 2-(1,3-diaryl-2,5-dioxoimidazolidin-4-ylidene)acetates in moderate-to-good yields.

Full text of DOI:10.1002/hlca.200900444

Helvetica Chimica Acta – Vol. 93 (2010)
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Potassium Thiocyanate-Promoted One-Pot Synthesis of (1,3-Diaryl-2,5-
dioxoimidazolidin-4-ylidene)acetates from Aryl Isocyanates and Alkyl
Propiolates
Short Communication
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 aryl isocyanates and alkyl propiolates (¼alkyl prop-2-ynoates) in the presence of
potassium thiocyanate (KSCN) led to geometric isomers of alkyl 2-(1,3-diaryl-2,5-dioxoimidazolidin-4-
ylidene)acetates in moderate-to-good yields.
Introduction. – Hydantoins, a class of cyclic imides, have been shown to possess a
wide range of pharmacological properties [1 – 3]. C(5)-Unsaturated hydantoins are
important as biological and pharmaceutical intermediates and as precursors to C(5)-
substituted hydantoins and their subsequent a-amino acids [4 – 6]. Classic methods for
preparing these compounds are i) base- or acid-catalyzed condensations of 5-
unsubstituted hydantoins with aldehydes, and unhindered or activated ketones [4][5]
and ii) reactions of aldehydes, certain ketones, and a-dicarbonyl compounds with
diethyl hydantoinyl-5-phosphonate in the presence of a base [6]. Recently, three-
component synthesis of 1-alkyl-3-(arylsulfonyl)-5-methylidenehydantoins has been
reported [7][8]. 1,3-Diaryl-5-arylidenehydantoins have been obtained by the reaction
of terminal alkynes with isocyanates in the presence of a catalytic amount of a
manganese complex, MnBr(CO)5, rhenium complex, Re2(CO)10, or an iron complex,
Fe(CO)5 [9][10].
As part of our current studies on the development of new routes to heterocyclic
systems [11 – 13], we now report a straightforward synthesis of alkyl 2-(2,5-dioxo-1,3-
diarylimidazolidin-4-ylidene)acetates (3) from aryl isocyanates and alkyl propiolates in
the presence of KSCN in good-to-moderate yields (Scheme 1).
Results and Discussion. – The reaction of 1 and 2 in the presence of 10 mol-%
KSCN in MeCN at reflux temperature led to a mixture of geometric isomers of alkyl 2-
(1,3-diaryl-2,5-dioxoimidazolidin-4-ylidene)acetates (3) in 55 – 73% yields.
1
The structures of compounds 3a – 3g were deduced from their IR, and H- and
13C-NMR spectra. For example, the 1H-NMR spectrum of (Z)-3a exhibited two singlets
(d(H) 3.22 and 6.22) for the MeO and olefinic groups, along with multiplets (d(H)
7.34 – 7.54) for the Ph groups. The MeO and olefinic groups of (E)-3a also showed two
singlets (d(H) 3.83 and 5.66). The 1H-decoupled 13C-NMR spectra of (Z)-3a and (E)-
3a exhibited, in each case, 14 distinct resonances that confirm the proposed structures.
The 1H- and 13C-NMR spectra of 3b – 3g were similar to those of 3a except for the aryl
ꢀ 2010 Verlag Helvetica Chimica Acta AG, Zꢁrich

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Helvetica Chimica Acta – Vol. 93 (2010)
Scheme 1
and alkoxy residues, which showed characteristic resonances in appropriate regions of
the spectrum.
Assignment of the (Z)- and (E)-configuration to the C¼C bond in (Z)-3a and (E)-
3a is based on the chemical shift of the olefinic H-atoms [14]. The IR spectra of these
compounds are in agreement with the proposed structure. The mass spectra of these
compounds displayed molecular-ion peaks at the appropriate m/z values and were
fairly identical in each pair of geometric isomers.
A tentative mechanism for the formation of 3 is proposed in Scheme 2. It is
conceivable that the reaction involves the initial formation of anionic intermediate 5
from KSCN and 2 [15], which reacts with 1 to produce 6. Intermediate 6 reacts with
another molecule of aryl isothiocyanate 1 to produce 7. Cyclization of this intermediate,
followed by [1, 2] shift of the ester group and subsequently loss of KSCN, leads to
geometric isomers of 3 through intermediates 8 and 9 (Scheme 2).
Scheme 2
In conclusion, we have described the use of KSCN in a synthesis of geometrical
isomers of alkyl 2-(2,5-dioxo-1,3-diphenylimidazolidin-4-ylidene)acetates (3) from aryl
isocyanates and alkyl propiolates. Simple mixing of the starting materials, use of KSCN
as a recoverable and inexpensive catalyst, and potential diversity of this type of reaction
are the advantages of this procedure.

Helvetica Chimica Acta – Vol. 93 (2010)
1853
Experimental Part
General. Compounds 1, 2, and KSCN were obtained from Merck and used without further
purification. Column chromatography (CC): silica gel (SiO2; 230 – 400 mesh; Merck). M.p.: Electro-
.
thermal-9100 apparatus. IR Spectra: Shimadzu IR-460 spectrometer; ˜n in cmꢀ1 1H- 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: General Procedure. To a stirred soln. of 1 (4.2 mmol) and 2 (2 mmol) in MeCN (7 ml)
was added KSCN (0.02 g, 0.2 mmol) at r.t. The mixture was refluxed for ca. 2 h (as indicated by TLC),
and then the solvent was evaporated, and the brown residue, dissolved in CH2Cl2 (5 ml), was purified by
CC and KSCN was filtered. Separation of the products was achieved by CC (SiO2; hexane/AcOEt 4 :1).
Methyl (Z)-(2,5-Dioxo-1,3-diphenylimidazolidin-4-ylidene)acetate ((Z)-3a). Yield: 0.30 g (47%).
Pale yellow crystals. M.p. 173 – 1758. IR (KBr): 1787, 1739, 1704 (COꢀNRꢀCO, COO), 1654 (C¼C),
1592, 1492, 1452, 1396, 1259, 1206, 1170, 1120, 960, 874, 827, 768. 1H-NMR: 3.22 (s, MeO); 6.22 (s, CH);
7.34 – 7.36 (m, 2 CH); 7.41 – 7.44 (m, 2 CH); 7.48 – 7.54 (m, 6 CH). 13C-NMR: 51.7 (MeO); 100.6 (CH);
125.8 (2 CH); 126.6 (2 CH); 128.5 (CH); 128.6 (CH); 129.2 (2 CH); 129.3 (2 CH); 131.6 (C); 134.6 (C);
135.0 (C); 152.9 (C¼O); 161.5 (C¼O); 163.8 (C¼O). EI-MS: 323 (8, [M þ 1]þ), 322 (5, Mþ), 321 (20),
263 (18), 175 (52), 144 (100), 119 (70), 77 (22), 51 (19). Anal. calc. for C18H14N2O4 (322.32): C 67.07, H
4.38, N 8.69; found: C 67.11, H 4.39, N 8.72.
Methyl (E)-2-(2,5-Dioxo-1,3-diphenylimidazolidin-4-ylidene)acetate ((E)-3a). Yield: 0.13 g (20%).
Pale yellow crystals. M.p. 199 – 2018. IR (KBr): 1777, 1730, 1703 (COꢀNꢀCO, COO), 1661 (C¼C),
1589, 1490, 1450, 1406, 1295, 1257, 1214, 1179, 1148, 934, 882, 855, 811, 768. 1H-NMR: 3.83 (s, MeO); 5.66
(s, CH); 7.39 – 7.44 (m, 3 CH); 7.49 – 7.51 (m, 5 CH); 7.55 – 7.58 (m, 2 CH). 13C-NMR: 52.5 (MeO); 103.7
(CH); 126.0 (2 CH); 127.6 (2 CH); 128.5 (CH); 129.1 (2 CH); 129.5 (CH); 130.1 (2 CH); 132.1 (C); 135.1
(C); 136.3 (C); 151.7 (C¼O); 158.7 (C¼O); 164.7 (C¼O). EI-MS: 323 (8, [M þ 1]þ), 322 (5, Mþ), 321
(20), 263 (18), 175 (52), 144 (100), 119 (70), 77 (22), 51 (19). Anal. calc. for C18H14N2O4 (322.32): C 67.07,
H 4.38, N 8.69; found: C 67.10, H 4.39, N 8.71.
Ethyl (Z)-2-(2,5-Dioxo-1,3-diphenylimidazolidin-4-ylidene)acetate ((Z)-3b). Yield: 0.30 g (45%).
Pale yellow crystals. M.p. 115 – 1178. IR (KBr): 1783, 1737, 1708 (COꢀNꢀCO, COO), 1665 (C¼C),
1592, 1490, 1455, 1393, 1249, 1208, 1170, 1106, 1029, 963, 857, 822, 769, 691. 1H-NMR: 1.00 (t, 3J ¼ 7.2, Me);
3.69 (q, 3J ¼ 7.2, CH2O); 6.24 (s, CH); 7.35 – 7.37 (m, 2 CH); 7.42 – 7.44 (m, 2 CH); 7.47 – 7.51 (m, 6 CH).
13C-NMR: 13.8 (Me); 61.1 (CH2O); 101.2 (CH); 125.9 (2 CH); 126.4 (2 CH); 128.5 (CH); 128.6 (CH);
129.2 (2 CH); 129.3 (2 CH); 131.0 (C); 134.6 (C); 134.7 (C); 152.9 (C¼O); 161.6 (C¼O); 163.5 (C¼O).
EI-MS: 337 (8, [M þ 1]þ), 336 (4, Mþ), 335 (15), 263 (20), 189 (35), 144 (100), 119 (75), 77 (27), 51 (25).
Anal. calc. for C19H16N2O4 (336.34): C 67.85, H 4.79, N 8.33; found: C 67.79, H 4.75, N 8.30.
Ethyl (E)-2-(2,5-Dioxo-1,3-diphenylimidazolidin-4-ylidene)acetate ((E)-3b). Yield: 0.12 g (18%).
Pale yellow crystals. M.p. 117 – 1198. IR (KBr): 1779, 1735, 1707 (COꢀNꢀCO, COO), 1663 (C¼C),
1590, 1491, 1450, 1402, 1297, 1253, 1211, 1158, 1113, 1033, 975, 926, 862, 810, 769, 710. 1H-NMR: 1.33 (t,
3J ¼ 7.2, Me); 4.30 (q, 3J ¼ 7.2, CH2O); 5.67 (s, CH); 7.40 – 7.43 (m, 2 CH); 7.48 – 7.51 (m, 5 CH); 7.55 – 7.58
(m, 3 CH). 13C-NMR: 14.0 (Me); 61.8 (CH2O); 104.3 (CH); 126.1 (2 CH); 127.6 (2 CH); 128.6 (CH);
129.2 (2 CH); 129.4 (CH); 130.1 (2 CH); 131.4 (C); 131.9 (C); 136.0 (C); 151.7 (C¼O); 158.7 (C¼O);
164.3 (C¼O). EI-MS: 337 (8, [M þ 1]þ), 336 (4, Mþ), 335 (15), 263 (20), 189 (35), 144 (100), 119 (75), 77
(27), 51 (25). Anal. calc. for C19H16N2O4 (336.34): C 67.85, H 4.79, N 8.33; found: C 67.79, H 4.80, N 8.35.
Methyl (Z)-2-[1,3-Bis(3-chloro-4-methylphenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((Z)-3c).
Yield: 0.34 g (40%). Pale yellow crystals. M.p. 156 – 1588. IR (KBr): 1785, 1733, 1701 (COꢀNꢀCO,
COO), 1670 (C¼C), 1494, 1433, 1390, 1309, 1268, 1229, 1207, 1162, 1119, 1049, 867, 815. 1H-NMR: 2.42 (s,
Me); 2.43 (s, Me); 3.36 (s, MeO); 6.23 (s, CH); 7.15 (dd, 3J ¼ 8.1, 4J ¼ 2.2, CH); 7.30 – 7.37 (m, 4 CH); 7.53
4
(d, J ¼ 2.0, CH). 13C-NMR: 19.8 (Me); 19.9 (Me); 51.9 (MeO); 101.0 (CH); 123.9 (CH); 124.8 (CH);
126.3 (CH); 127.2 (CH); 129.4 (C); 131.2 (CH); 131.3 (CH); 132.9 (C); 134.6 (C); 134.7 (C); 134.8 (C);
136.9 (C); 137.0 (C); 152.5 (C¼O); 161.1 (C¼O); 163.6 (C¼O). EI-MS: 422 (4, [M þ 3]þ) 421 (6, [M þ
2]þ), 420 (10, [M þ 1]þ), 419 (6, Mþ), 418 (19), 360 (15), 223 (48), 192 (100), 165 (75), 132 (65), 89 (50).
Anal. calc. for C20H16Cl2N2O4 (419.26): C 57.30, H 3.85, N 6.68; found: C 57.41, H 3.79, N 6.72.

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Methyl (E)-2-[1,3-Bis(3-chloro-4-methylphenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((E)-3c).
Yield: 0.21 g (25%). Pale yellow crystals. M.p. 222 – 2248. IR (KBr): 1779, 1732, 1707 (COꢀNꢀCO,
COO), 1655 (C¼C), 1571, 1492, 1411, 1397, 1296, 1262, 1207, 1180, 1098, 1051, 813, 753. 1H-NMR: 2.42 (s,
2 Me); 3.84 (s, MeO); 5.66 (s, CH); 7.18 – 7.20 (m, 2 CH); 7.26 – 7.36 (m, 3 CH); 7.39 – 7.42 (m, CH).
13C-NMR: 19.9 (2 Me); 52.6 (MeO); 104.3 (CH); 124.1 (CH); 125.7 (CH); 126.5 (CH); 126.6 (CH);
128.2 (C); 129.0 (CH); 131.2 (C); 131.4 (CH); 131.8 (C); 132.2 (C); 134.9 (C); 137.9 (C); 148.2 (C); 151.2
(C¼O); 158.3 (C¼O); 164.4 (C¼O). EI-MS: 422 (4, [M þ 3]þ) 421 (7, [M þ 2]þ), 420 (10, [M þ 1]þ), 419
(6, Mþ), 418 (19), 360 (15), 223 (48), 192 (100), 165 (75), 132 (65), 89 (50). Anal. calc. for C20H16Cl2N2O4
(419.26): C 57.30, H 3.85, N 6.68; found: C 57.35, H 3.81, N 6.74.
Ethyl (Z)-2-[1,3-Bis(3-chloro-4-methylphenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((Z)-3d).
Yield: 0.33 g (38%). Pale yellow crystals. M.p. 168 – 1708. IR (KBr): 1786, 1734, 1702 (COꢀNꢀCO,
COO), 1671 (C¼C), 1493, 1457, 1392, 1310, 1287, 1224, 1204, 1162, 1119, 1093, 1070, 869, 817. 1H-NMR:
3
1.01 (t, J ¼ 7.1, Me); 2.42 (s, Me); 2.43 (s, Me); 3.81 (q, 3J ¼ 7.1, CH2O); 6.24 (s, CH); 7.16 (dd, 3J ¼ 8.1,
4J ¼ 2.0, CH); 7.30 – 7.37 (m, 4 CH); 7.52 (d, 4J ¼ 1.9, CH). 13C-NMR: 13.8 (Me); 19.8 (2 Me); 61.4
(CH2O); 101.6 (CH); 123.9 (CH); 124.8 (CH); 126.3 (CH); 127.0 (CH); 129.4 (C); 131.2 (CH); 131.3
(CH); 132.9 (C); 134.2 (C); 134.6 (C); 134.8 (C); 136.9 (C); 137.0 (C); 152.5 (C¼O); 161.1 (C¼O); 163.2
(C¼O). EI-MS: 436 (3, [M þ 3]þ), 435 (4, [M þ 2]þ), 434 (12, [M þ 1]þ), 433 (7, Mþ), 432 (20), 360 (12),
237 (41), 192 (100), 165 (82), 132 (51), 89 (49). Anal. calc. for C21H18Cl2N2O4 (433.28): C 58.21, H 4.19, N
6.47; found: C 58.08, H 4.25, N 6.43.
Ethyl (E)-2-[1,3-Bis(3-chloro-4-methylphenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((E)-3d).
Yield: 0.22 g (25%). Pale yellow crystals. M.p. 141 – 1438. IR (KBr): 1782, 1734, 1708 (COꢀNꢀCO,
COO), 1666 (C¼C), 1496, 1409, 1303, 1268, 1198, 1179, 1144, 1097, 1049, 1025, 809, 764, 693. 1H-NMR:
1.32 (t, 3J ¼ 7.2, Me); 2.41 (s, Me); 2.45 (s, Me); 4.30 (q, 3J ¼ 7.2, CH2O); 5.66 (s, CH); 7.20 (dd, 3J ¼ 8.1,
4J ¼ 2.1, CH); 7.30 (dd, 3J ¼ 8.2, 4J ¼ 2.0, CH); 7.34 – 7.42 (m, 3 CH); 7.52 (d, 4J ¼ 1.9, CH). 13C-NMR: 14.0
(Me); 19.8 (Me); 19.9 (Me); 61.9 (CH2O); 100.0 (CH); 124.1 (CH); 125.8 (CH); 126.6 (CH); 128.2
(CH); 129.3 (C); 130.3 (C); 131.2 (CH); 132.1 (CH); 134.7 (C); 135.6 (C); 135.7 (C); 136.9 (C); 138.1
(C); 153.7 (C¼O); 158.3 (C¼O); 164.0 (C¼O). EI-MS: 436 (3, [M þ 3]þ), 435 (4, [M þ 2]þ), 434 (12,
[M þ 1]þ), 433 (7, Mþ), 432 (20), 360 (12), 237 (41), 192 (100), 165 (82), 132 (51), 89 (49). Anal. calc. for
C21H18Cl2N2O4 (433.28): C 58.21, H 4.19, N 6.47; found: C 58.14, H 4.26, N 6.45.
Methyl (Z)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((Z)-3e). Yield: 0.39 g
(50%). Pale yellow crystals. M.p. 182 – 1848. IR (KBr): 1784, 1730, 1710 (COꢀNꢀCO, COO), 1671
(C¼C), 1491, 1435, 1407, 1306, 1271, 1220, 1200, 1158, 1119, 1112, 1087, 962, 824, 803. 1H-NMR: 3.35 (s,
MeO); 6.25 (s, CH); 7.27 – 7.29 (m, 2 CH); 7.44 – 7.52 (m, 6 CH). 13C-NMR: 51.9 (MeO); 101.1 (CH);
126.9 (2 CH); 127.9 (2 CH); 129.3 (C); 129.4 (2 CH); 129.5 (2 CH); 132.9 (C); 134.5 (C); 134.6 (C); 134.7
(C); 152.4 (C¼O); 161.1 (C¼O); 163.5 (C¼O). EI-MS: 394 (3, [M þ 3]þ), 393 (5, [M þ 2]þ), 392 (15,
[M þ 1]þ), 391 (6, Mþ), 390 (28), 332 (18), 209 (62), 178 (100), 153 (72), 125 (26), 90 (15). Anal. calc. for
C18H12Cl2N2O4 (391.21): C 55.26, H 3.09, N 7.16; found: C 55.32, H 3.10, N 7.15.
Methyl (E)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((E)-3e). Yield: 0.17 g
(22%). Pale yellow crystals. M.p. 184 – 1868. IR (KBr): 1781, 1737, 1711 (COꢀNꢀCO, COO), 1657
(C¼C), 1490, 1413, 1402, 1340, 1312, 1272, 1247, 1191, 1157, 1137, 1088, 1014, 942, 898, 851, 845, 818.
3
3
1H-NMR: 3.83 (s, MeO); 5.64 (s, CH); 7.32 (d, J ¼ 8.3, 2 CH); 7.44 – 7.47 (m, 4 CH); 7.53 (d, J ¼ 8.3,
2 CH). 13C-NMR: 52.7 (MeO); 104.3 (CH); 127.1 (2 CH); 128.9 (2 CH); 129.3 (C); 129.4 (2 CH); 130.2
(C); 130.5 (2 CH); 134.5 (C); 135.6 (C); 135.7 (C); 151.2 (C¼O); 158.2 (C¼O); 164.3 (C¼O). EI-MS:
394 (3, [M þ 3]þ), 393 (4, [M þ 2]þ), 392 (14, [M þ 1]þ), 391 (6, Mþ), 390 (28), 332 (18), 209 (62), 178
(100), 153 (72), 125 (26), 90 (15). Anal. calc. for C18H12Cl2N2O4 (391.21): C 55.26, H 3.09, N 7.16; found:
C 55.30, H 3.09, N 7.15.
Ethyl (Z)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((Z)-3f). Yield: 0.39 g
(48%). Pale yellow crystals. M.p. 164 – 1668. IR (KBr): 1793, 1735, 1706 (COꢀNꢀCO, COO), 1667
(C¼C), 1490, 1456, 1428, 1394, 1365, 1305, 1217, 1155, 1121, 1088, 1025, 976, 941, 828, 803. 1H-NMR: 1.07
(t, 3J ¼ 7.2, Me); 3.81 (q, 3J ¼ 7.2, CH2O); 6.26 (s, CH); 7.27 – 7.30 (m, 2 CH); 7.44 – 7.50 (m, 6 CH).
13C-NMR: 13.8 (Me); 61.3 (CH2O); 101.7 (CH); 126.9 (2 CH); 127.8 (2 CH); 128.9 (C); 129.4 (2 CH);
129.5 (2 CH); 132.9 (C); 134.3 (C); 134.6 (C); 134.7 (C); 152.4 (C¼O); 161.1 (C¼O); 163.5 (C¼O). EI-
MS: 408 (2, [M þ 3]þ), 407 (3, [M þ 2]þ), 406 (10, [M þ 1]þ), 405 (5, Mþ), 404 (18), 332 (22), 223 (55),

Helvetica Chimica Acta – Vol. 93 (2010)
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178 (100), 153 (65), 125 (20), 90 (10). Anal. calc. for C19H14Cl2N2O4 (405.24): C 56.32, H 3.48, N 6.91;
found: C 56.41, H 3.50, N 7.01.
Ethyl (E)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((E)-3f). Yield: 0.20 g
(25%). Pale yellow crystals. M.p. 203 – 2058. IR (KBr): 1782, 1737, 1708 (COꢀNꢀCO, COO), 1662
(C¼C), 1490, 1468, 1396, 1366, 1310, 1301, 1266, 1221, 1185, 1146, 1087, 1015, 918, 869, 832, 802, 765.
1H-NMR: 1.32 (t, 3J ¼ 7.1, Me); 4.30 (q, 3J ¼ 7.1, CH2O); 5.66 (s, CH); 7.34 (d, 3J ¼ 8.5, 2 CH); 7.44 – 7.50
(m, 4 CH); 7.53 (d, 3J ¼ 8.5, 2 CH). 13C-NMR: 14.0 (Me); 61.9 (CH2O); 104.9 (CH); 127.1 (2 CH); 128.9
(2 CH); 129.3 (C); 129.4 (2 CH); 130.3 (C); 130.4 (2 CH); 134.5 (C); 135.4 (C); 135.6 (C); 151.2 (C¼O);
158.2 (C¼O); 163.8 (C¼O). EI-MS: 408 (4, [M þ 3]þ), 407 (5, [M þ 2]þ), 406 (12, [M þ 1]þ), 405 (7,
Mþ), 404 (18), 332 (24), 223 (56), 178 (100), 153 (65), 125 (20), 90 (11). Anal. calc. for C19H14Cl2N2O4
(405.24): C 56.32, H 3.48, N 6.91; found: C 56.40, H 3.50, N 6.95.
tert-Butyl (Z)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((Z)-3g). Yield:
0.26 g (30%). Pale yellow crystals. M.p. 186 – 1888. IR (KBr): 1762, 1736, 1705 (COꢀNꢀCO, COO),
1681 (C¼C), 1490, 1451, 1401, 1365, 1316, 1290, 1237, 1195, 1148, 1089, 1013, 961, 830, 807. 1H-NMR: 1.25
(s, tBu); 6.22 (s, CH); 7.27 – 7.31 (m, 2 CH); 7.42 – 7.47 (m, 6 CH). 13C-NMR: 27.8 (Me3C); 82.5 (Me3C);
103.8 (CH); 126.9 (2 CH); 127.8 (2 CH); 129.3 (C); 129.5 (2 CH); 129.6 (2 CH); 131.9 (C); 133.4 (C);
134.4 (C); 134.5 (C); 152.5 (C¼O); 161.3 (C¼O); 164.7 (C¼O). EI-MS: 436 (2, [M þ 3]þ), 435 (5, [M þ
2]þ), 434 (8, [M þ 1]þ), 433 (6, Mþ), 432 (15), 332 (15), 251 (32), 178 (81), 153 (27), 125 (11), 90 (5), 57
(100). Anal. calc. for C21H18Cl2N2O4 (433.29): C 58.21, H 4.19, N 6.47; found: C 58.30, H 4.16, N 6.50.
tert-Butyl (E)-[1,3-Bis(4-chlorophenyl)-2,5-dioxoimidazolidin-4-ylidene]acetate ((E)-3g). Yield:
0.22 g (25%). Pale yellow crystals. M.p. 177 – 1798. IR (KBr): 1780, 1734, 1707 (COꢀNꢀCO, COO),
1666 (C¼C), 1454, 1400, 1365, 1314, 1291, 1268, 1220, 1156, 1090, 1014, 983, 915, 868, 819, 759. 1H-NMR:
t
1.54 (s, Bu); 5.64 (s, CH); 7.35 (d, 3J ¼ 8.5, 2 CH); 7.44 – 7.50 (m, 4 CH); 7.52 (d, 3J ¼ 8.5, 2 CH).
13C-NMR: 27.9 (Me3C); 82.6 (Me3C); 106.6 (CH); 127.2 (2 CH); 128.9 (2 CH); 129.4 (2 CH); 129.5 (C);
130.4 (2 CH); 130.5 (C); 134.2 (C); 134.4 (C); 135.4 (C); 152.5 (C¼O); 158.4 (C¼O); 163.0 (C¼O). EI-
MS: 436 (3, [M þ 3]þ), 435 (5, [M þ 2]þ), 434 (8, [M þ 1]þ), 433 (6, Mþ), 432 (15), 332 (15), 251 (32), 178
(80), 153 (27), 125 (14), 90 (5), 57 (100). Anal. calc. for C21H18Cl2N2O4 (433.29): C 58.21, H 4.19, N 6.47;
found: C 58.27, H 4.15, N 6.52.
REFERENCES
´
[1] S. Hanessian, J.-Y. Sanceau, P. Chemla, Tetrahedron 1995, 51, 6669.
´
[2] J. C. Menendez, M. P. Dꢂaz, C. Bellver, M. M. Sçllhuber, Eur. J. Med. Chem. 1992, 27, 61.
[3] F. Balavoine, P. Malabre, T. Alleaume, A. Rey, V. Cherfils, O. Jeanneton, S. Seigneurin-Venin, F.
Revah, Bioorg. Med. Chem. Lett. 2007, 17, 3754.
[4] G. Guella, I. Mancini, H. Zibrowius, F. Pietra, Helv. Chim. Acta 1988, 71, 773.
[5] N. A. Meanwell, H. R. Roth, E. C. R. Smith, D. L. Wedding, J. J. K. Wright, J. Org. Chem. 1991, 56, 6897.
[6] N. C. Mathur, S. K. Wong, H. Shechter, Tetrahedron Lett. 2003, 44, 5141.
[7] A. Alizadeh, E. Sheikhi, Tetrahedron Lett. 2007, 48, 4887.
[8] A. Alizadeh, E. Sheikhi, Synthesis 2008, 1061.
[9] Y. Ohshiro, K. Kinugasa, T. Minami, T. Agawa, J. Org. Chem. 1970, 35, 2136.
[10] Y. Kuninobu, K. Kikuchi, K. Takai, Chem. Lett. 2008, 37, 740.
[11] I. Yavari, Z. Hossaini, S. Seyfi, F. Shirgahi-Talari, Helv. Chim. Acta. 2008, 91, 1177.
[12] I. Yavari, M. Sabbaghan, Z. Hossaini, M. Ghazanfarpour-Darjani, Helv. Chim. Acta 2008, 91, 1144.
[13] I. Yavari, M. J. Bayat, S. Souri, M. Sirouspour, Helv. Chim. Acta. 2009, 92, 1903.
[14] E. L. Eliel, S. H. Wilen, ꢃStereochemistry of Organic Compoundsꢄ, Wiley-Interscience, New York,
2001, p. 358.
[15] M. Giffard, J. Cousseau, L. Gouin, M.-R. Crahe, Tetrahedron 1985, 41, 801.
Received December 10, 2009