A Practical Synthesis of 5-Lipoxygenase Inhibitor MK-0633
摘要:
Practical, chromatography-free syntheses of 5-lipoxygenase inhibitor MK-0633 p-toluenesullonate (1) are described. The first route used an asymmetric zincate addition to ethyl 2,2,2-trifluoropyruvate followed by 1,3,4-oxadiazole formation and reductive amination as key steps. An improved second route features an inexpensive diastereomeric salt resolution of vinyl hydroxy-acid 22 followed by a robust end-game featuring a through-process hydrazide acylation/1,3,4-oxadiazole ring closure/salt formation sequence to afford MK-0633 p-toluenesulfonate (1).
Several substrates containing both cyano and Weinreb amide functionalities have been synthesized to study the chemoselectivity of their reactions with organomagnesium bromides (ArMgBr and RMgBr). Excellent chemoselectivity towards the Weinreb amide was observed in most cases, even in the presence of excess Grignardreagent, affording cyano ketones in good-to-excellent yields.
A Practical Synthesis of 5-Lipoxygenase Inhibitor MK-0633
作者:Francis Gosselin、Robert A. Britton、Ian W. Davies、Sarah J. Dolman、Danny Gauvreau、R. Scott Hoerrner、Gregory Hughes、Jacob Janey、Stephen Lau、Carmela Molinaro、Christian Nadeau、Paul D. O’Shea、Michael Palucki、Rick Sidler
DOI:10.1021/jo100561u
日期:2010.6.18
Practical, chromatography-free syntheses of 5-lipoxygenase inhibitor MK-0633 p-toluenesullonate (1) are described. The first route used an asymmetric zincate addition to ethyl 2,2,2-trifluoropyruvate followed by 1,3,4-oxadiazole formation and reductive amination as key steps. An improved second route features an inexpensive diastereomeric salt resolution of vinyl hydroxy-acid 22 followed by a robust end-game featuring a through-process hydrazide acylation/1,3,4-oxadiazole ring closure/salt formation sequence to afford MK-0633 p-toluenesulfonate (1).