General procedure for the synthesis of 1-N-tert-butoxycarbonylpiperidine-4-boronic acid pinacol ester from 1,2,3,6-tetrahydro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine: method 4: general conditions for the reduction of tetrahydropyridines to piperidines in the presence of boronic acid ester: the boronic acid ester was dissolved in a mixed solvent of ethyl acetate and methanol (1:1 v/v) , with a final borate concentration of 0.4 M) in a mixture of ethyl acetate and methanol, followed by the addition of palladium hydroxide (0.35 equiv). The reaction mixture was stirred under hydrogen atmosphere for 14 hours. Upon completion of the reaction, the reaction mixture was filtered and concentrated in vacuum to give the target piperidine product in quantitative yield. Example 8: Piperidine 8 was prepared from compound 1 in a two-step reaction using Method 4, followed by deprotection of pinacol esters using Method 2. [M-H]? = 228.2 m/z. activity: b
