文摘
A pilot-scale process has been developed for green and scalable synthesis of (卤)-尾-(3,4-dihydroxyphenyl) lactic acid ((卤)-DSS) and their two important derivatives, namely, (卤)-IDHP [(卤)-isopropyl 2-hydroxy-3-(3,4-dihydroxyphenyl)propanoate] and (卤)-DBZ [(卤)-bornyl 2-hydroxy-3-(3,4-dihydroxyphenyl)propanoate]. Subsequent hydrogenation has been carried out by employing Raney Ni as catalyst. The improved process results in higher yields of 47.5% for (卤)-DBZ and 49.2% for (卤)-IDHP compared to the initial process with a yield of 12% for (卤)-DBZ and 18% for (卤)-IDHP in our original medicinal chemistry route. Furthermore, kilograms of optical DBZ [(鈭?-S-DBZ and (+)-R-DBZ, >99% ee] and IDHP [(鈭?-S-IDHP and (+)-R-IDHP, >99% ee] have been produced by chiral high-performance liquid chromatography in good yield (>84%).