A practical and scalable synthesis of SR 142801, a tachykinin NK3 antagonist

Abstract A practical and scalable total synthesis of tachykinin NK3 receptor antagonist SR 142801, ( R )-N-[1-[3-[1-benzoyl-3-(3,4-dichlorophenyl)-3-piperidinyl]propyl]-4-phenyl-4-piperidinyl]-N-methyl acetamide 1 is described. The absolute configuration of the key intermediate 7 was determined by single crystal X-ray crystallography, on the basis of which, the absolute configuration of SR 142801 should be ( R )-(+), instead of the recently reported ( S )-(+). 1