Synthesis of ortho-modified mercapto- and piperazino-methyl-phenylboronic acid derivatives

The synthesis of 2-mercapto- and 2-piperazino- (methyl-phenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolanes and , respectively, is described and their inhibitory activity against serine proteases including thrombin was measured. Some of these compounds were studied in both the solid state and in solution, displaying no S–B coordination and only weak N–B coordination.