反应详情

(2S,4S)-2-(4'-Methoxyphenyl)-4-methyl-N-phenoxyacetyl-1,3-oxazolidin-5-one (18) was prepared from sodium N-(para-methoxybenzylidene)-(L)-alaninate (2.29 g, 10.0 mM) and phenoxyacetyl chloride (1.37 mL, 10.0 mM) following general procedure D and obtained as a colourless oil after purification by flash column chromatography, using 20% ethyl acetate/petroleum ether as eluant (1.87 g, 55%, mixture of two diastereomers in a ratio of 4:1 by 1H-NMR). Upon trituration with diethyl ether 18 was obtained as very fine white needles and as a single diastereomer by 1H NMR: [α] D20 +224 (c 1.0, CHCl3); mp 95-97° C.; IR (KBr): 1795, 1715, 1670 cm-1 ; 1H NMR (500 MHz, d8 -toluene, 90° C.): δ 6.45-7.09 (m, 9H), 6.44 (s, 1H), 4.50 (q, J=7 Hz, 1H), 4.06 (d, J=14 Hz, 1H), 3.81 (d, J=14 Hz, 1H), 3.31 (s, 3H), 1.41 (d, J=7 Hz, 3H); 13C NMR (50.3 MHz, CDCl3): δ 172.1, 167.3, 161.4, 156.7, 129.0, 128.5, 128.1, 122.1, 114.6, 114.0, 89.6, 67.8, 55.4, 52.7, 16.1; LRMS (NH3): 342 (MH+). Anal. Calcd for C19H19NO5 : C, 66.86; H, 5.57; N, 4.10; found: C, 66.69; H, 5.59; N, 4.01.

1. customobtained as a colourless oil
2. customafter purification by flash column chromatography
3. addition1.87 g, 55%, mixture of two diastereomers in a ratio of 4:1 by 1H-NMR)