Synthesis of steroidal thiadiazoles from steroidal ketones.
Syntheses of steroidal heterocycles containing a five-membered N,S- heterocycle attached at the 6,7 positions of the B ring are reported. 5Alpha-cholestane-6-one (1), its 3beta-acetoxy- (2) and 3beta-chloro- (3) analogues reacted with semicarbazide and aqueous sodium acetate in refluxing ethanol to yield 5alpha-cholestan-6-one-semicarbazone 1a and its 3-beta-acetoxy and 3beta-chloro derivatives 2a and 3a, respectively. The reactions of 1a, 2a and 3a with thionyl chloride in dichloromethane at low temperature afforded the cyclized thiadiazole 4 and its 3beta-acetoxy- and 3beta-chloro analogues 5 and 6 in good yields.
Mushfiq
M
M
Department of Chemistry, AMU,Aligarh 202002, India. mmushfiq@rediffmail.com
Alam
Mahboob
M
Akhtar
Mohd Shaheer
MS
D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D007659:Ketones / Q000138:chemical synthesis*; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D004364:Pharmaceutical Preparations / Q000138:chemical synthesis*; D012663:Semicarbazides / Q000138:chemical synthesis; D013256:Steroids / Q000138:chemical synthesis*; D013830:Thiadiazoles / Q000138:chemical synthesis*
D006571:Heterocyclic Compounds; D007659:Ketones; D004364:Pharmaceutical Preparations; D012663:Semicarbazides; D013256:Steroids; D013830:Thiadiazoles