Molecular Structures of syn- and anti-20-carboethoxyhydrazone isomers of 3Β, 21-diacetoxypregna-5,16-dien-20-one
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science
The validity of syn- and anti-isomer assignments in the case of 3Β,21-diacetoxypregna-5, 16-dien-20-one 20-carboethoxyhydrazones has been established by x-ray structural analysis; the isomer designations had been made previously based on chemical and spectral data. The isomers differ sharply in the conjugative relationship between the hydrazone group and the C16=C17 double bond in the steroid skeleton: the syn-isomer is trans-conjugated (the degree of twisting about the C17-C20 bond is characterized by a torsional angleψ=-161.0‡), while the anti-isomer is not conjugated (ϕ=− 75.3‡); this explains the electronic spectral features of these isomers.
Lindeman, Sergey; Turuta, A. M.; Struchkov, Yuri T.; and Kamernitskii, A. V., "Molecular Structures of syn- and anti-20-carboethoxyhydrazone isomers of 3Β, 21-diacetoxypregna-5,16-dien-20-one" (1991). Chemistry Faculty Research and Publications. 720.