Continuous process for the preparation of optically pure decahydroisoquinolinecarboxamide

A method of preparing [3S-(3α,4aβ,8aβ)]-N-tert-butyl-decahydro-3-isoquinoline carboxamide from N-tert-butyl-1,2,3,4-tetrahydro-3(S)-isoquinolinecarboxamide with a high optical yield, comprising continuously reducing N-tert-butyl-1,2,3,4tetrahydro-3(S)-isoquinolinecarboxamide dissolved in an inorganic solvent to [3S-(3α,4aβ,8aβ)]-N-tert-butyl-decahydro-3-isoquinolinecarboxamide with hydrogen in a fixed bed reactor charging a noble metal catalyst supported on an inorganic oxide carrier with the range of the metal content between 0.5 and 10 wt %, at a temperature in the range of about 50 and 200° C., under the pressure in the range of about 300 and 2,500 psig and at the WHSV in the range of about 0.1 and 10 h−1, wherein the molecular ratio of hydrogen to N-tert-butyl-1,2,3,4tetrahydro-3(S)-isoquinolinecarboxamide is in the range of about 4 and 10, N-tert-butyl-1,2,3,4-tetrahydro-3(S)-isoquinolinecarboxamide content in an organic solvent is in the range of about 2 and 50 wt % and the inorganic oxide carrier has the BET surface area in the range of about 10 and 1,000 m2/g, the median pore diameter of the major pores of less than 200 Å and the total pore volume in the range of about 0.2 and 1.2 cc/g.