合成路线1

Tetralone (I) was reduced with NaBH4 and the resulting alcohol (II) was dehydrated with p-TsOH in refluxing toluene to yield the dihydronaphthalene (III). Oxidation of (III) with N-methylmorpholine N-oxide and OsO4 produced diol (IV), which was converted to the 2-tetralone (V) by acid-catalyzed rearrangement. The unstable tetralone (V) was condensed with the sodium salt of tert-butyl diethyl phosphonoacetate (VI) providing a mixture of olefin isomers (VII). Catalytic hydrogenation of the olefin (VIIa-c) with simultaneous removal of the carbobenzoxy group furnished the aminotetralin (VIII). This was coupled with 4-cyanobenzoic acid (IX) using EDC to give amide (X). Addition of H2S to the nitrile group of (X), followed by S-methylation provided (XI). Then, displacement of the methylthio group of (XI) by ammonium acetate and further treatment with di-tert-butyl dicarbonate yielded the Boc-protected benzamidine (XII). Deprotection with trifluoroacetic acid produced the amidino acid (XIII), which was finally esterified with EtOH and HCl.