合成路线1

Alternatively, the condensation of dimethyl malonate (VI) with benzaldehyde (VII) by means of piperidine in refluxing toluene gives dimethyl benzylidenemalonate (VIII), which is reduced with H2 over Pd/C in toluene to yield the corresponding benzyl derivative (IX). The hydrolysis of (IX) with NaOH in water affords the benzylmalonic acid (X). Alternatively, intermediate (X) can also be obtained starting from diethyl malonate (XI), which is condensed with with benzaldehyde (VII) by means of piperidine in refluxing toluene to give diethyl benzylidenemalonate (XII). Reduction of (XII) with H2 over Pd/C in toluene yields the corresponding benzyl derivative (XIII), which is then hydrolized with NaOH in water. The monodecarboxylation of (X) and its condensation with paraformaldehyde and diethylamine in refluxing ethyl acetate provides 2-benzylacrylic acid (XIV), which is condensed with thioacetic acid (V) by heating at 70 C to afford 2-(acetylsulfanylmethyl)-3-phenylpropionic acid (XV). Finally, this compound is condensed with N-tosylglycine benzyl ester (XVI) by means of HOBt, DCC and TEA in THF.