Argatroban was synthesized in seven steps from 4-methylpiperidine. The condensation of (+/-)-trans-benzyl 4-methyl-pipecolic acid ester with N-alpha-Boc-N-omega-nitro-L-arginine led to two diastereomers that were separated. One of them is the precursor of argatroban. (C) 2001 Elsevier Science Ltd. All rights reserved.