696
ROMANOVA et al.
NMR spectrum, , ppm (J, Hz): E isomer: 1.23 t (3H,
microwave oven for 10 min at a power of 175 W
(until carbon dioxide no longer evolved). The result-
ing mixture was subjected to chromatographic separa-
tion on a column charged with silica gel L 40/100 m;
a 2:1 benzene ethyl acetate mixture was used as
eluent. -Amino esters Ia and Ib are light yellow
viscous oily substances. Ethyl 4-phenyl-2-pentenoate
(II) and ethyl 4-phenyl-3-pentenoate (III) are color-
less liquids.
General procedure for thermally activated
reactions. A mixture of equimolar amounts of the
reactants (in the Michael reaction, 1.5 equiv of the
amine was taken) was heated for 3 h at 120 140 C,
and the products were separated by column chromato-
graphy as described above. N-benzyl-4-phenyl-3-
pentenamide (IV) is a colorless crystalline substance.
Ethyl 3-benzylamino-4-phenylpentanoate (Ia).
Rf 0.65. IR spectrum, , cm : 1745 (C O), 3350
(N H). H NMR spectrum, , ppm (J, Hz): major
pair of diastereoisomers: 1.25 t (3H, CH3CH2, J =
7.15), 1.32 d (3H, CH3CH, J = 6.91), 1.55 br.s (1H,
NH), 2.42 d (2H, CH2CO, J = 6.91), 3.01 q (1H,
CHCH3, J = 6.91), 3.22 q (1H, CHCH2, J = 6.91),
3
3
CH3CH2, J = 7.13), 1.38 d (3H, CH3CH, J = 6.93),
3
4
3.57 d.q (1H, CHCH3, J = 6.93, J = 1.49), 4.13 q
3
(2H, CH2CH3, J = 7.13), 5.79 d.d (1H, CH CHCO,
3J = 15.75, 4J = 1.49), 7.10 d.d (1H, CHCH CH, 3J =
3
6.93, J = 15.75), 7.15 7.35 m (5H, Ph). Z isomer:
1.26 t (3H, CH3CH2, J = 7.13), 1.44 d (3H, CH3CH,
3J = 9.81), 3.08 d.q (1H, CHCH3, J = 9.81, J =
3
3
4
3
1.09), 4.15 q (2H, CH2CH3, J = 7.13), 5.71 d.d
3
4
(1H, CH CHCO, J = 11.30, J = 1.09), 6.23 d.d
(1H, CHCH CH, J = 9.81, 3J = 11.30), 7.15 7.35 m
3
(5H, Ph).
Ethyl 4-phenyl-3-pentenoate (III). Rf 0.95. IR
1
1
spectrum, , cm : 1740 (C O). H NMR spectrum,
3
, ppm (J, Hz): E isomer: 1.27 t (3H, CH3CH2, J =
4
5
7.13), 2.05 d.t (3H, CH3CPh CH, J = 1.25, J =
1.07), 3.24 d.q (2H, CHCH2CO, 3J = 7.15, 5J = 1.07),
4.16 q (2H, CH2CH3, 3J = 7.13), 5.95 t.q (1H,
CH3CPh CHCH2, J 7.15, J = 1.25), 7.15 7.35 m
(5H, Ph); Z isomer: 1.26 t (3H, CH3CH2, J = 7.13),
1
1
3
4
3
3
3
4
5
2.08 d.t (3H, CH3CPh CH, J = 1.46, J = 1.38),
3
3
5
3.00 d.q (2H, CHCH2CO, J = 7.38, J = 1.38),
3
3
4.11 q (2H, CH2CH3, 3J = 7.13), 5.65 t.q (1H,
2
3
4
3.72 d (1H, CH2Ph, J = 13.00), 3.79 d (1H, CH2Ph,
CH3CPh CHCH2, J = 7.38, J = 1.46), 7.15 7.35 m
2J = 13.00), 4.12 q (2H, CH2CH3, J = 7.15), 7.10
3
(5H, Ph).
7.36 m (10H, Ph). Mass spectrum, m/z (Irel, %): 311
(<1%) M+, 224 (24%), 206 (98%), 105 (10%), 91
(100%), 77 (7%); minor pair of diastereoisomers:
1.24 t (3H, CH3CH2, J = 7.13), 1.38 d (3H, CH3CH,
3J = 7.12), 2.23 d.d (1H, CH2CO, J = 6.60), J =
15.11), 3.21 q (2H, CHCH3, J = 6.60), 4.04 q (2H,
CH2CH3, J = 7.15) (the other signals are overlapped
by those of the major diastereoisomers). Mass spec-
trum, m/z (Irel, %): 311 (<1%) M+, 224 (4%), 206
(36%), 105 (8%), 91 (100%), 77 (7%).
N-Benzyl-4-phenyl-3-pentenamide (IV).
1
mp 75 C. Rf 0.6. IR spectrum, , cm : 1645 (C O),
1
1610 (C C), 3290 (N H). H NMR spectrum,
,
3
ppm (J, Hz): E isomer: 1.96 d.t (3H, CH3CPh CH,
3
2
5
3
4J = 1.12, J = 0.97), 3.11 d.q (2H, CHCH2CO, J =
3
5
3
7.39, J = 0.97), 4.33 d (2H, NHCH2Ph, J = 5.94),
5.89 t.q (1H, CH3CPh CHCH2, 3J = 7.39, 4J = 1.12),
6.77 br.s (1H, NH), 7.08 7.35 m (10H, Ph); Z isomer:
3
4
5
2.01 d.t (3H, CH3CPh CH, J = 1.51, J = 1.00),
2.88 d.q (2H, CHCH2CO, J = 7.47, J = 1.00),
4.29 d (2H, NHCH2Ph, J = 5.99), 5.60 t.q (1H,
3
5
3
Ethyl 3-[(S)-1-phenylethylamino]-4-phenylpen-
tanoate (Ib). Rf 0.5. IR spectrum, , cm : 1735
1
3
4
CH3CPh CHCH2, J = 7.47, J = 1.51), 6.40 br.s
(C O); 3330 (N H). 13C NMR spectrum, C, ppm
(the signals are given for diastereoisomers in the order
of decreasing fraction): isomer 1: 14.18, 16.97, 24.59,
36.04, 41.04, 55.25, 57.01, 60.14, 144.57, 145.90,
172.73; isomer 2: 14.16, 17.22, 24.85, 36.15, 43.16,
55.14, 57.36, 60.60, 144.22, 145.93, 172.47; isomer 3:
14.06, 17.37, 24.45, 37.43, 40.26, 55.02, 57.54,
60.21, 143.56, 145.30, 172.54; isomer 4: 14.06,
17.37, 24.31, 36.42, 43.42, 55.27, 57.54, 60.21,
142.99, 145.08, 172.48; for all isomers, signals from
the aromatic carbon atoms appear in the region
(1H, NH), 7.08 7.35 m (10H, Ph).
REFERENCES
1. Caddick, S., Tetrahedron, 1995, vol. 51, p. 10403;
Tselinskii, I.V., Astrat’ev, A.A., and Brykov, A.S.,
Russ. J. Gen. Chem., 1996, vol. 66, p. 1656;
Loupy, A., Petit, A., Hamelin, J., Texier-Boullet, F.,
Jacquault, P., and Mathe, D., Synthesis, 1998, p. 1213;
Romanova, N.N., Kudan, P.V., Gravis, A.G., and
Bundel’, Yu.G., Khim. Geterotsikl. Soedin., 2000,
p. 1308; Lindstrom, P., Tierney, J., Wathley, B., and
Westman, J., Tetrahedron, 2001, vol. 57, p. 9225.
126.0 128.5 ppm.
C
Ethyl 4-phenyl-2-pentenoate (II). Rf 0.95. IR
spectrum, , cm : 1690 (C O), 1655 (C C). H
2. Perreux, L. and Loupy, A., Tetrahedron, 2001, vol. 57,
1
1
p. 9199.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 5 2003