合成路线1

A short and efficient synthesis of xemilofiban has been achieved as follows: The reaction of ethyl chloroformate (I) with trimethylsilylacetylene (II) by means of butyllithium gives ethyl 3-(trimethylsilyl)propyonate (III), which is condensed with the lithium salt of ethyl acetate (IV) yielding ethyl 5-(trimethylsilyl)-3-oxo-4-pentynoate (V). The selective reduction of (V) with lyophilized baker's yeast (Saccharomyces cerevisiae, Sigma type II) affords ethyl 3(R)-hydroxy-5-(trimethylsilyl)-4-pentynoate (VI), which by reaction with ammonia (VII), diethyl azodicarboxylate (VIII) and triphenylphosphine, followed by hydrolysis with water gives 3(S)-amino-5-(trimethylsilyl)-4-pentynoate (IX). Finally, this compound is condensed with N-(4-amidinophenyl)succinamic acid (XI) by means of isobutyl chloroformate and N-methylmorpholine (NMM). The intermediate succinamic acid (XI) has been obtained by condensation of 4-aminobenzamidine (XII) with succinic anhydride (XIII) in DMF.