Convenient preparation of A-ring fused pyridines from steroidal enamides

• Published in: Steroids Vol. 73; no. 11; pp. 1137 - 1142
• Main Authors: Barthakur, Madan G., Borthakur, Moyurima, Boruah, Romesh C.
• Format: Journal Article
• Language: English
• Published: NEW YORK Elsevier Inc 01.10.2008; Elsevier; Elsevier Science
• Subjects: Anaerobiosis; Biochemistry & Molecular Biology; Biological and medical sciences; Chemistry, Organic - methods; Chloromethyleneiminium salt; Crystallography, X-Ray; Endocrinology & Metabolism; Formylation; Fundamental and applied biological sciences. Psychology; Hot Temperature; Life Sciences & Biomedicine; Molecular Conformation; Pyridines - chemical synthesis; Pyridines - chemistry; Pyridosteroid; Science & Technology; Steroidal enamide; Steroids - chemical synthesis; Steroids - chemistry; Vertebrates: endocrinology; Vilsmeier reaction; Pyridosteroid; Vilsmeier reaction; Chloromethyleneiminium salt; Steroidal enamide; Formylation; pyridosteroid; PYRAZOLES; HETEROCYCLES; formylation; ONE-POT SYNTHESIS; steroidal enamide; chloromethyleneiminium salt; Steroidal enamide;Formylation;Vilsmeier reaction;Pyridosteroid;Chloromethyleneiminium salt
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2008.04.016

A facile strategy for the preparation of A-ring fused pyridosteroids has been accomplished in high yields by the reaction of Vilsmeier reagent (chloromethyleneiminium salt) with steroidal A-ring enamides (2- and 3-ene) under thermal conditions. The structure of 6′-chloro-5α-cholest [3,2- b]pyridine was determined by X-ray analysis.