1718
B. P. Bandgar et al.
LETTER
Table 3 NBS Catalyzed Transesterification of -Keto Esters with Different Nucleophiles
Entry
Ester
Alcohol
Product
Reaction time (h) Yielda,b (%)
1
6
4
75
80
2
3
4
4
4
89
79
5
4
80
a Yields of pure isolated products.
b Products are characterized by their spectral analysis.
(4) Banetti, S.; Ramagnoli, R.; De Risi, C.; Spalluto, G.;
Zanirato, V. Chem. Rev. 1995, 95, 1065.
(5) Witzeman J. S., Nottingham W. D.; J. Org. Chem.; 1991, 56:
1713.
(6) (a) Otera, J.; Yano, T.; Kawabata, A.; Hitoshi, N.
Tetrahedron Lett. 1986, 27, 2383. (b) Otera, J.; Danoh, N.;
Nozaki, H. J. Org. Chem. 1991, 56, 5307.
cation of -keto esters under essentially neutral conditions
with a simple work-up. The effectiveness of this protocol
is manifested in its selectivity towards -keto esters
whereas other esters are found to be unreactive under
these reaction conditions.
(7) Habi, A.; Gravel, D. Tetrahedron Lett. 1994, 35, 4315.
(8) (a) Paquette, I. A. Encyclopedia of Reagents for Organic
Synthesis; John Wiley and Sons Inc.: New York, 1997, 768–
772. (b) Karimi, B.; Seradj, H.; Ebrahimian, G. R. Synlett
1999, 9, 1456. (c) Karimi, B.; Seradj, H.; Ebrahimian, G. R.
Synlett 2000, 5, 623. (d) Karimi, B.; Ebrahimian, G. R. Org.
Lett. 1999, 11), 1737.
Acknowledgement
VSS thanks CSIR, New Delhi for a Junior Research Fellowship.
References and Notes
(1) (a) Fujoita, T.; Tanak, M.; Norimine, Y.; Suemunc, H. J.
Org. Chem. 1997, 62, 3824. (b) Shapiro, G.; Marli, M. J.
Org. Chem. 1997, 62, 7096.
(9) Satish Goud, B.; Desiraju, G. R. J. Chem. Res. (Suppl.) 1995,
244.
(10) Typical procedure: Ethyl acetoacetate (5 mmol), 2-amino-
2-methyl-propanol (5 mmol), NBS (1 mmol)in toluene (20
mL) was heated to 90–100 °C in a round bottom flask with
distillation condenser to remove ethanol. After completion
(TLC) the reaction mixture was cooled, filtered and the
filtrate was concentrated and chromatographed on SiO2
(hexane–ethyl acetate, 9:1) to afford -keto ester in pure
form as a colourless liquid; IR (cm–1, Neat): 1045, 1452,
1550, 1650, 1710, 3305, 3350; 1H NMR (CDCl3 ) : 1.32 ( s,
6 H ), 2.24 ( s, 3 H ), 3.35 (s, 2 H), 3.60 (s, 2 H), 4.5 ( br s,
1 H), 7.10 ( br s, 1 H ); MS m/z (%): [M+] 173 (2.3), 143
(100), 135 (2.6) 100 (8.25), 85 (15.01), 74 (6.01), 58 (41.2);
Anal. Calcd for C8H15O3N (173.211): C, 55.47; H, 8.73; N,
8.09. Found: C, 55.23; H, 8.85; N, 7.98.
(11) Chavan S. P., Zubaidha P. K., Dantale S. W., Keshavraja A.,
Ramaswami A. V., Ravindranathan T.; Tetrahedron Lett.;
1996, 37: 233.
(12) (a) Hamelin, O.; Depres, J.-P.; Green, A. E.; Tinant, B.;
Declerq, J. P. J. Am. Chem. Soc. 1996, 118, 9992.
(b) Hamelin, O.; Depres, J.-P.; Heidenhain, S.; Green, A. E.
Nat. Prod. Lett. 1997, 10, 99.
(2) (a) Rehberg, C. E.; Fisher, C. H. J. Am. Chem. Soc. 1944, 66,
1203. (b) Rehberg, C. E.; Faucette, W. A.; Fisher, C. H. J.
Am. Chem. Soc. 1944, 66, 1723. (c) Rehberg, C. E. Organic
Synthesis,Coll. Vol. III; Wiley: New York, 1955, 146.
(d) Haken, J. K. J. Appl. Chem. 1963, 13, 168. (e) Yazaka,
H.; Tanaka, K.; Kariyone, K. Tetrahedron Lett. 1974, 3995.
(f) Blossey, E. C.; Turner, L. M.; Neckers, D. C.
Tetrahedron Lett. 1923, 1823. (g) Taber, D. F.; Amedio, J.
C. Jr.,Patel, Y. K. J. Org. Chem. 1985, 50, 3618. (h) Taft,
R. W. Jr.; Newman, M. S.; Verhoek, F. H. J. Am. Chem. Soc.
1950, 72, 4511. (i) Billman J. H., Smith W. T. Jr., Rendall J.
L.; J. Am. Chem. Soc.; 1947, 69: 2058. (j) Osipow, L.;
Shell, F. D.; Finchler, A. J. Am. Oil Chem., Soc. 1957, 34,
185. (k) Komori, S.; Okahara, M.; Okamoto, K. J. Am. Oil
Chem. Soc. 1960, 37, 468.
(3) (a) Kumar, P.; Pande, R. K. Synlett 2000, 2, 251. (b) Balaji,
B. S.; Sasidharam, M.; Kumar, R.; Chanda, B. Chem.
Commun. 1996, 707. (c) Balaji, B. S.; Chanda, B. M.
Tetrahedron 1998, 54, 13227. (d) Ranu, B. C.; Dutta, P.;
Sarkar, A. J. Org. Chem. 1998, 63, 6027. (e) Reddy, B. M.;
Reddy, V. R.; Manohar, B. Synth. Commun. 1999, 29, 1235.
(f) Krasik, P. Tetrahedron Lett. 1998, 39, 4223.
(13) Gilbert, J. C.; Kelly, T. A. J. Org. Chem. 1988, 53, 449.
(g) Fukuzawa, S.; Hango, Y. Tetrahedron Lett. 1998, 39,
352. (h) Mottek, C.; Hamelin, O.; Garavel, G.; Depres, J. P.;
Greene, A. E. J. Org. Chem. 1999, 64, 13. (i) Mottek, C.;
Hamelin, O.; Garavel, G.; Depres, J. P.; Greene, A. E. J.
Org. Chem. 1999, 64, 90.
Synlett 2001, No. 11, 1715–1718 ISSN 0936-5214 © Thieme Stuttgart · New York