A four step synthesis of 4(S)-oxazolidineacetic acid, 2-oxo benzyl ester (D-Oxac-OBn) from L-Asp-OH in 45% overall yield is reported. The formation of by-products is completely avoided, by microwave irradiation and by the use of caesium carbonate as base. Moreover the synthesis and IR and 1H NMR conformational analysis of the tetramers Boc-L-Val-D-Oxac-L-Ala-OBn and Boc-L-Val-D-Oxac-Aib-L-Ala-OBn in solution is reported.
本研究以 L-Asp-OH 为原料,分四步合成了 4(S)-
恶唑烷
乙酸 2-氧代苄基酯(D-Oxac-OBn),总收率为 45%。通过微波辐照和使用
碳酸铯作为碱,完全避免了副产物的生成。此外,还报道了四聚体 Boc-L-Val-D-Oxac-L-Ala-OBn 和 Boc-L-Val-D-Oxac-Aib-L-Ala-OBn 在溶液中的合成、红外和 1H NMR 构象分析。