... Journal of Medicinal ... figure Scheme 3 a. a (i) N-Methyl-4-piperidone, NaOMe, MeOH, 48 h, reflux; (ii) H 2 , Pd/C, EtOH; (iii) R 1 SO 2 Cl, pyridine. ... The piperidine derivatives were treated with the appropriate sulfonyl chlorides to afford the final compounds 23a−j. figure Scheme 4 a. ...