Bismuth(III) salt-catalyzed Westphalen and "backbone" rearrangements of 5 beta,6 beta-epoxysteroids synthesis and structural elucidation of new olefinic 19-nor and 18,19-dinorsteroids.
A new process using the "ecofriendly" bismuth(III) salts as catalysts for the Westphalen and "backbone" rearrangements of 5 beta,6 beta-epoxysteroids is reported. This method is particularly sensitive to changes on solvent, temperature, stereochemistry of starting epoxysteroid, and its substituent at C17. Depending on the reaction conditions, either Westphalen-type or "backbone" rearranged products were obtained, all being 3 beta-acetoxy-6 beta-hydroxy-substituted. Several new olefinic 19-nor and 18,19-dinorsteroids were obtained and their structural elucidation was fully accomplished using 2D NMR and X-ray crystallography techniques.
Pinto
Rui M A
RM
Laboratório de Química Farmacêutica, Faculdade de Farmácia, Universidade de Coimbra, 3000-295 Coimbra, Portugal.
Salvador
Jorge A R
JA
Le Roux
Christophe
C
Carvalho
Rui A
RA
Silva
Manuela Ramos
MR
Beja
Ana Matos
AM
Paixão
José A
JA
D001729:Bismuth / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003516:Cycloparaffins / Q000737:chemistry*; D008968:Molecular Conformation; D009654:Norsteroids / Q000138:chemical synthesis* / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D013696:Temperature
D003516:Cycloparaffins; D009654:Norsteroids; D012492:Salts; D001729:Bismuth