Patent ID: 8742111

Claim:
A method of making methyl 4-(phenylamino)-1-(phenylalkyl)-4-piperidinecarboxylate, by converting in sequence: a) 1-phenylalkyl-4-piperidinone to 4-(phenylamino)-1-(phenylalkyl)-4-piperidinenitrile; b) said 4-(phenylamino)-1-(phenylalkyl)-4-piperidinenitrile, to 4-(phenylamino)-1-(phenylalkyl)-4-piperidinecarboxamide; c) said 4-(phenylamino)-1-(phenylalkyl)-4-piperidinecarboxamide, to 1-(phenylalkyl)-4,4-(2-phenyl-2,4-diaza-4-oxo-cyclopentane)piperidine; and d) said 1-(phenylalkyl)-4,4-(2-phenyl-2,4-diaza-4-oxo cyclopentane)piperidine, to methyl 4-(phenylamino)-1-(phenylalkyl)-4-piperidinecarboxylate, wherein said phenylalkyl is phenylmethyl or phenylethyl.