A two step facile synthesis of new steroidal linear and angular pyranones having anti-mycobacterial activity

Title compounds 2′,2′-dimethylcholesta-2,4-dien[3,2-b]-pyran-4′-one ( 3), 2′,2′-dimethyl-3 β-substituted cholesta-4,6-dien[7,6-b]-pyran-4′-one ( 6a, b) and ( 6c) were prepared by the cyclization of 2-acetylcholesta-2,4-dien-3-ol ( 2), 6-acetyl-3 β-substitutedcholesta-4,6-dien-7-ol ( 5a, b) and ( 5c) respectively, with pyrrolidine, dry benzene and dry acetone using Dean Stark separator through conventional heating. Furthermore, compounds were also found to be active against Mycobacterium tuberculosis.