Thermal and photochemical reactions of steroidal α-azido ketones

Abstract

Photolysis of 9α-azido-3β,20β-diacetoxy-5α-pregnan-11-one in methanol gave the N-acyl imine 11-aza-3β,20β-diacetoxy-C-homo-5α-pregn-9,11-en-12-one 4 and the aminoketone 9a-aza-3β,20β-diacetoxy-9-methoxy-B-homo-5α-pregnan-11-one 7. In dichloromethane containing triethylamine the irradiation of this azide gave the N-acyl imine 4 and the α,β-unsaturated amino ketone 9a-aza-3β,20β-diacetoxy-B-homo-5α-pregn-8-en-11-one 8. Thermolysis or photolysis of 12α-azido-3α,20β-diacetoxy-5β-pregnan-11-one gave the N-acyl imine 12-aza-3α,20β-diacetoxy-C-homo-5β-pregn-12-en-11-one 10 as major product. Photolysis of 20β-acetoxy-12α-azido-3α-hydroxy-5β-pregnan-11-one gave the 3-hydroxy analogue of 10. Transformation products of the N-acyl imines are described.