合成路线1

Esterification of p-hydroxyphenylacetic acid (I) with NaHSO4 in refluxing butanol provides butyl acetate derivative (II), which is then subjected to reaction with epichlorohydrin (III) in pyridine to furnish a mixture of epoxypropane (IV) and chloro derivative (V). Treatment of the mixture (IV)/(V) with HCl affords derivative (VI), which is then selectively acylated by means of Lipase Amano PS (LAPS) and vinyl acetate or acetic anhydride/diisopropyl ether to yield compound (S)-(VII). Treatment of the mixture (IV)/(V) with acetyl chloride gives derivative (VIII), which is selectively deacylated using LAPS in butanol/diisopropyl ether to afford derivative (S)-(IX). Coupling of derivative (S)-(VII) with isopropylamine (X) in H2O, followed by removal of the acetyl group with NaOH furnishes derivative (XI) (alternatively, (XI) can also be synthesized by coupling of (S)-(IX) with amine (X)). Finally, conversion of (XI) into the desired product is achieved by treatment with ammonium hydroxide in MeOH.