6-[(3-benzyloxy-5-formyl-2-methyl-pyridin-4-ylmethyl)-tert-butoxycarbonyl-amino]-hexanoic acid benzyl ester 、
4'-氨基-4-氰基联苯 以gave 6-({3-benzyloxy-5-[(4′-cyano-biphenyl-4-ylamino)-methyl]-2-methyl-pyridin-4-ylmethyl}-tert-butoxycarbonyl-amino)-hexanoic acid benzyl ester (44) (2.4 g, 83% yield)的产率得到6-({3-benzyloxy-5-[(4'-cyano-biphenyl-4-ylamino)-methyl]-2-methyl-pyridin-4-ylmethyl}-tert-butoxycarbonyl-amino)-hexanoic acid benzyl ester