S. Yoshida, K. Marumo, K. Takeguchi
Nov 3, 2014
Citations
0
Influential Citations
8
Citations
Journal
Organic Process Research & Development
Abstract
A novel, practical, and efficient synthesis of (−)-N-{2-[(R)-3-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-2-carbonyl)piperidino]ethyl}-4-fluorobenzamide monophosphate (YM758 monophosphate, (R)-1·H3PO4 (Figure 1) is described. The target molecule (R)-1 has a potent If current channel inhibitor. Medicinal chemistry synthetic routes were very long and suffered from extensive use of chlorinated solvents and silica-gel column chromatography. A number of steps in the medicinal chemistry route were also unattractive for large-scale synthesis due to some reasons for example the use of unstable intermediates. An important objective of a new synthetic route was avoidance of such a use of unstable intermediate, and it was achieved by the discovery of an important 4,5-dihydrooxazole intermediate 19 and ring-opening N-alkylation of chiral amine with 19 under acidic condition. The new procedure does not require any purification by column chromatography for all steps. The overall yield was significantly improved from...