[GRAPHICS]Melanin-concentrating hormone (MCH) is implicated in the feeding behavior in mammals affording a potential target to control overeating in people. Compound 1 (AMG 076) has been identified as a potent MCHr1 antagonist for the treatment of obesity. A synthesis suitable for the large-scale preparation of this lead candidate was developed to support preclinical studies. A Robinson annulation of benzylpiperidone and resolution of the desired enone from a mixture of the diastereomers afforded key intermediate 6 after a stereoselective hydrogenation. Subsequent Fischer indole synthesis with hydrazine 5 then provided the advanced intermediate, indole 2. Two complementary reductive amination strategies employing either aldehyde 3 or lactol 4 led to the synthesis of title compound 1.
Hydrocyanation. Part IX. Synthesis of β-cyano-aldehydes by conjugate hydrocyanation of allylideneamines followed by hydrolysis
作者:W. Nagata、M. Yoshioka、T. Okumura、M. Murakami
DOI:10.1039/j39700002355
日期:——
Conjugate hydrocyanation of αβ-unsaturated aldehydes with diethylaluminium cyanide or with hydrogencyanide and an alkylaluminium was only successful with a substrate having a sterically hindered formyl group. Attempts to desulphurise β-cyano-thiocarboxylates to β-cyano-aldehydes failed. However, allylideneamines (I) carrying a bulky N-alkyl substituent reacted with hydrogen cyanide–alkylaluminium