(CDCl3) d 7.65 (d, J = 8.0 Hz, 2 H), 7.21 (d, J = 8.0 Hz, 2 H), 4.98 (d, J = 8.4 Hz, 1 H), 3.69 (d, J = 8.4 Hz, 1 H), 3.39 (s, 3 H), 2.38 (s, 3 H), 2.02-1.93 (m, 1 H), 0.94 (d, J = 6.7 Hz, 3 H), 0.87 (d, J = 6.7 Hz, 3 H); 13C NMR (CDCl3) d 171.0, 142.9, 136.8, 129.8, 126.1, 61.2, 52.1, 32.1, 21.8, 19.4, 18,6. Anal. Calcd for C13H19NO4S: C, 54.72; H, 6.71; N, 4.91. Found: C, 54.69; H, 6.88; N, 4.89%.
(S)-(+)-Methyl-3,3-dimethyl-2-(p-toluenesulfonyl)-amino-butyrate 12d. Flash chromatography EtOAc/hexane (4:6) gave 40% of a white solid, mp 108-110 oC; [a]20D +42.1 (c, 0.7, CHCl3); IR (KBr) 3250, 1732, 1449, 1088 cm-1; 1H NMR (CDCl3) d 7.69 (d, J = 8.0 Hz, 2 H), 7.23 (d, J = 8.0 Hz, 2 H), 5.08 (d, J = 12 Hz, 1 H), 3.57 (d, J = 12 Hz, 1 H), 3.33 (s, 3 H), 2.41 (s, 3 H), 0.94 (m, 9 H); 13C NMR (CDCl3) d 171.1, 144.1, 136.8, 129.9, 127.8, 64.6, 52.1, 34.9, 26.6, 21.9. Anal. Calcd for C14H21NO4S: C, 56.16; H, 7.07; N, 4.68. Found: C, 56.14; H, 7.12; N, 4.71%.
Acknowledgements
This work was supported by NIGMS (GM 51982 and 57870) and Boehringer Ingelheim Pharmaceuticals, Inc.
References
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