Efficient Kg-Scale Synthesis of Thrombin Inhibitor CRC 220

Article abstract of DOI:10.1016/0040-4020(95)00765-Z

Potent thrombin inhibitor 2 is prepared in 10 steps with 20percent overall yield from commercial 4 on a kg-scale by the convergent approach depicted in Schemes 1 and 2.The (R)-configuration of the 4-amidinophenylalanine piperidide moiety is controlled by asymmetric hydrogenation.A novel method, the hydrogenolysis of amidoximes 11 and 21, is employed to attain a particularly clean transformation of the cyano into the amidinium functionality.Despite of the amorphous nature of target compound 2, the approach is devoid of any chromatographic purification.