6375
Gaset, A. Synth. Comm. 1994, 24, 2091±2096. (d) Abribat, B.; Le Bigot, Y. Tetrahedron 1997, 53, 2119±2124. For
an example involving a PEG 6000, see: Neumann, R.; Sasson, Y. Tetrahedron 1983, 39, 3437±3440.
7. For an example of PEG supported synthesis using microwave with water as solvent see: Blettner, C. G.; Konig, W. A.;
Stenzel, W.; Schotten, T. J. Org. Chem. 1999, 64, 3885±3890.
8. For an example of microwave mediated esteri®cation on a soluble poly(styrene-co-allylalcohol)polymer: Vanden
Eynde, J.-J.; Rutot, D. Tetrahedron 1999, 55, 2687±2694.
9. Microwave activated alkylation of a benzaldehyde Schi base glycine has been described: Jiang, Y.; Wang, Y.;
Deng, R.; Mi, A. In Phase Transfer Catalysis, Mechanisms and Syntheses; Halpern, M. E., Ed.; ACS Symposium
Series 659:Washington DC, 1996; p. 203.
10. Microwave-assisted reactions were performed in an open pyrex glass vessel (beaker, 2 cm diameter, 2 mm thick
glass) with a Brandt MS 1100 Domestic Microwave oven at a frequency of 2450 Hz and a power of 850 W.
Caution: the inorganic base must be well distributed by previous mixing with the organic compounds in order to
avoid the destruction of the reaction vessel. A representation procedure for the synthesis of 4e is as follows:
Cinnamyl bromide (11.8 mg, 0.06 mmol) was added to poly(ethylene glycol) 3400 N-(diphenylmethylene) glycinate
(80 mg, 0.02 mmol) and Cs2CO3 (39 mg, 0.12 mmol). The mixture was heated under microwave for 45 min. After
cooling, the product was dissolved in CH2Cl2, then ®ltered. The ®ltrate was concentrated, dissolved in CH2Cl2,
®ltered, and then precipitated in Et2O. The product was ®ltered and dried in vacuo to yield 80 mg (98%) of the
title compound: IR (KBr) 2865 (m), 1736 (s), 1655 (s), 1459 (s), 1100 (m), 954 (m) cm^1; 1H NMR (CDCl3, Me4Si)
ꢀ 2.70±2.90 (m, 2H), 3.50±3.80 (s large, 310H), 4.05±4.15 (m, 1H), 4.20±4.30 (m, 2H), 5.90±6.15 (m, 1H), 6.30±6.45
(d, J=15.5 Hz, 1H), 7.10±7.40 (m, 13H), 7.55±7.70 (m, 2H); 13C NMR (CDCl3, Me4Si) ꢀ 37.48, 64.44, 65.78,
69.36, 126.40, 127.49, 128.27, 128.40, 128.83, 128.86, 129.03, 129.18, 130.73, 133.08, 136.72, 137.68, 139.85, 171.17,
171.99.
1
11. All new compounds have been characterized by IR, H NMR, 13C NMR and ESI mass spectrometry.
12. Blettner, C. G.; Konig, W. A.; Stenzel, W.; Schotten, T. Synlett 1998, 295±297.
13. Conventional alkylation of Schi base protected glycine in the solid-phase has been described: (a) O'Donnell, M. J.;
Zhou, C.; Scott, W. L. J. Am. Chem. Soc. 1996, 118, 6070±6071. (b) O'Donnell, M. J.; Lugar, C. W.; Pottorf, R. S.;
Zhou, C. Tetrahedron Lett. 1997, 38, 7163±7166. (c) Domõnguez, E.; O'Donnell, M. J.; Scott, W. L. Tetrahedron
Lett. 1998, 39, 2167±2170. (d) O'Donnell, M. J.; Delgado, F.; Pottorf, R. S. Tetrahedron 1999, 55, 6347±6362.
14. (a) Larhed, M.; Lindeberg, G.; Hallberg, A. Tetrahedron Lett. 1996, 37, 8219±8222. (b) Chen, S. T.; Tseng, P. H.;
Yu, H. M.; Wu, C. Y.; Hsiao, K. F.; Wu, S. H.; Wang, K. T. J. Chin. Chem. Soc. 1997, 44, 169±182. (c) Hsieh, H. P.;
Chen, S. T.; Wang, K. T. J. Chin. Chem. Soc. 1997, 44, 597±600. (d) Yu, A. M.; Zhang, Z. P.; Yang, H. Z.; Zhang, C. X.;
Liu, Z. Synth. Commun. 1999, 29, 1595±1599. (e) Hoel, A. M. L.; Nielsen, J. Tetrahedron Lett. 1999, 40, 3941±
3944. (f) Chandrasekhar, S.; Padmaja, M. B.; Raza, A. Synlett 1999, 1597±1599.