合成路线1

A new synthesis of Sch-56592 has been described: The reaction of (S)-ethyl lactate (I) with pyrrolidine (II) gives 1-[(S)-lactoyl]pyrrolidine (III), which is benzylated as usual with benzyl chloride yielding the benzyl ether (IV). The reaction of (IV) with ethylmagnesium bromide in THF affords 2(S)-benzyloxy-3-pentanone (V), which is reduced with LiBH4 in dimethoxyethane giving 2(S)-benzyloxy-3(RS)-pentanol (VI). The reaction of (VI) with 4-chlorobenzenesulfonyl chloride (VII) yields the corresponding sulfonate (VIII), which is treated with hydrazine in ethanol to afford a diastereomeric mixture of hydrazines that is resolved with L-dibenzoyltartaric acid giving the (S,S)-enantiomer (IX). The formylation of (IX) with refluxing ethyl formate yields the chiral formyl hydrazide (X), which is cyclized with N-[4-[4-[4-(trimethylsilyloxy)phenyl]piperazin-1-yl]phenyl]carbamic acid phenyl ester (XI) affording the triazolone (XII). Finally, this compound is condensed with the chiral tetrahydrofuran derivative (XIII) by means of NaOH in DMSO, and debenzylated by hydrogenation with H2 over Pd/C in formic acid