SHORT PAPER
Synthesis of Highly Substituted But-2-enoic Acid Esters
31
13C NMR: d = 194.3, 193.1, 164.1, 135.8, 135.2, 133.7, 133.4,
132.5, 129.9, 129.4, 129.1, 128.7, 128.6, 128.2, 52.6.
3f
Colorless solid; mp 102–104 °C.
Anal. Calcd for C24H18O4: C, 77.82; H, 4.90. Found: C, 77.66; H,
4.71.
IR (KBr): 3091, 2941, 1718, 1646, 1518, 1461, 1231, 1145, 1063
cm–1.
1H NMR: d = 7.69 (d, J = 5.0 Hz, 2 H), 7.64–7.56 (m, 7 H), 7.19–
3b
7.15 (m, 2 H), 3.83 (s, 3 H).
Colorless solid; mp 148–150 °C.
IR (KBr): 2941, 1720, 1688, 1587, 1463, 1411, 1229, 1144 cm–1.
1H NMR: d = 7.91 (d, J = 8.01 Hz, 4 H), 8.06 (d, J = 8.20 Hz, 4 H),
7.58–7.51 (m, 5 H), 3.81 (s, 3 H).
13C NMR: d = 197.2, 196.6, 163.9, 138.7, 136.8, 136.7, 136.5,
134.3, 133.9, 133.1, 128.6, 127.6, 53.2.
HRMS (EI): m/z calcd for C20H14S2O4: 382.4548; found: 382.4556.
13C NMR: d = 191.7, 190.6, 163.9, 137.1, 135.5, 134.4, 133.1,
132.8, 130.6, 129.7, 129.3, 128.8, 126.7, 53.6.
Acknowledgment
HRMS (EI): m/z calcd for C24H16Br2O4: 528.1894; found:
528.1881.
Financial assistance from the Council of Scientific and Industrial
Research (CSIR), and the Department of Science and Technology
(DST), New Delhi is acknowledged. The authors thank Ms. Soumi-
ni Mathew for recording NMR data and Ms. S.Viji for mass data.
We also thank Dr. Rajeev S. Menon for valuable discussions.
3c
Colorless solid; mp 143–145 °C.
IR (KBr): 2957, 1718, 1674, 1569, 1443, 1404, 1221, 1152 cm–1.
1H NMR: d = 8.32 (d, J = 7.13 Hz, 4 H), 8.08 (d, J = 7.26 Hz, 4 H),
7.56–7.46 (m, 5 H), 3.82 (s, 3 H).
References
(1) (a) Diels, O.; Alder, K. Justus Liebigs Ann. Chem. 1932,
498, 16. (b) Winterfeldt, E. Angew. Chem., Int. Ed. Engl.
1969, 6, 423. (c) Winterfeldt, E. In Chemistry of Acetylenes;
Viehe, H. G., Ed.; Dekker: New York, 1969, 267.
13C NMR: d = 190.1, 189.8, 164.5, 138.1, 137.6, 136.1, 135.4,
134.3, 133.7, 132.4, 129.4, 128.5, 126.6, 52.1.
HRMS (EI): m/z calcd for C26H16F6O4: 506.3933; found: 506.3912.
(d) Dickstein, J. I.; Miller, S. I. In The Chemistry of
Functional Groups. The Chemistry of the Carbon–Carbon
Triple Bond, Part 2; Patai, S., Ed.; Wiley: Chichester, 1978,
Chap. 19, 813. (e) Acheson, R. M.; Elmore, N. F. Adv.
Heterocycl. Chem. 1978, 23, 263.
3d
Colorless solid; mp 145–147 °C.
IR (KBr): 2941, 1726, 1670, 1515, 1478, 1409, 1356, 1238, 1144
cm–1.
1H NMR: d = 8.01 (s, 2 H), 7.73 (d, J = 7.40 Hz, 4 H), 7.60–7.51 (m,
5 H), 7.45 (t, J = 7.60 Hz, 2 H), 3.76 (s, 3 H).
13C NMR: d = 191.3, 190.8, 162.6, 138.9, 135.7, 134.8, 134.3,
132.4, 132.1, 129.5, 128.1, 127.7, 53.9.
(2) (a) Nair, V.; Rajesh, C.; Vinod, A. U.; Bindu, S.; Sreekanth,
A. R.; Mathen, J. S.; Balagopal, L. Acc. Chem. Res. 2003, 36,
899. (b) Nair, V.; Menon, R. S.; Sreekanth, A. R.; Abhilash,
N.; Biju, A. T. Acc. Chem. Res. 2006, 39, 520.
(3) (a) Nair, V.; Vinod, A. U.; Abhilash, N.; Menon, R. S.;
Santhi, V.; Varma, R. L.; Viji, S.; Mathew, S.; Srinivas, R.
Tetrahedron 2003, 59, 10279; and references citied therein.
(b) Nair, V.; Sreekanth, A. R.; Abhilash, N.; Bhadbhade, M.
M.; Gonnade, R. C. Org. Lett. 2002, 4, 3575. (c) Nair, V.;
Pillai, A. N.; Menon, R. S.; Suresh, E. Org. Lett. 2005, 7,
1189. (d) Nair, V.; Pillai, A. N.; Beneesh, P. B.; Suresh, E.
Org. Lett. 2005, 7, 4625. (e) Pillai, A. N.; Devi, B. R.;
Suresh, E.; Nair, V. Tetrahedron Lett. 2007, 48, 4391.
(4) Crystal data for 3a: Empirical formula: C24H18O4; Unit cell
parameters: a = 8.332(9) Å, b = 8.609(10) Å, c = 14.263(16)
Å, a = 76.913(18)°, b = 86.448(17)°, g = 72.752(17)°; Space
group P–1. CCDC 653243 contains the supplementary
crystallographic data for compound 3a. These data can be
obtained free of charge from The Cambridge Crystallog-
cif.
HRMS (EI): m/z calcd for C24H16Cl2O4: 439.2868; found:
439.2860.
3e
Colorless solid; mp 153–155 °C.
IR (KBr): 2939, 1723, 1676, 1517, 1501, 1463, 1262, 1175 cm–1.
1H NMR: d = 8.13 (d, J = 8.36 Hz, 4 H), 7.46 (d, J = 8.29 Hz, 4 H),
7.59–7.54 (m, 5 H), 3.84 (s, 3 H), 3.71 (s, 6 H).
13C NMR: d = 190.8, 190.1, 163.1, 159.2, 136.4, 135.2, 134.8,
134.3, 133.1, 132.7, 128.5, 126.8, 121.4, 53.5.
HRMS (EI): m/z calcd for C26H22O6: 430.4493; found: 430.4491.
Synthesis 2008, No. 1, 29–31 © Thieme Stuttgart · New York