反应详情

In Scheme 1 the compounds of the invention, 1, are prepared in 4 steps. Sulfonylation of valine methyl ester with 4-bromo-benzenesulfonyl chloride was carried out in the presence of Hunig base to give sulfonamide Intermediate 1. This 4-bromo-benzenesulfonamide was furthered coupled with boronate ester using Palladium catalyst under Suzuki coupling condition to provide biphenyl sulfonamide Intermediate 2. Biphenyl sulfonamide Intermediate 2 was then alkylated with various alkylating reagents to provide biphenyl sulfonamide ester (Intermediate 3). Hydrolysis of Intermediate 3 was carried out using bases such as NaOH, or LiOH to form the final product 1.