合成路线1

Coupling Method 1. Treatment of L-Arginine (XIII) with K2CO3 and assembling to intermediate (VII) affords derivative (XIV). After protection of the piperidine derivative (XV) as its tert-butyl ether (XVI) by means of isobutylene (B) in acidic media, (XVI) is condensed with (XIV) in the presence of Et3N to yield (XVII). Finally, elimination of the protecting groups with TFA, HBr gas or HCl in AcOH affords the desired product. 2. Alternatively, the coupling can be performed by reaction of nitro-protected L-arginine (XVIII) with isobutyl chloroformate in DMF in the presence of NMM, followed by reaction with protected piperidine derivative (XVI) to yield (XIX). Removal of the Boc group with HCl in AcOH or in dichloromethane/AcOH (2:1) and assembling to sulfonyl chloride intermediate (VII) with DIEA in DMF yields protected derivative (XX). Reductive cleavage of the nitro protecting group of (XX) with Pd/C, H2 in MeOH/AcOH/H2O (15:0.1:1), followed by elimination of the t-Bu protecting group in the conditions described above, yields the desired product.