A ring conformation of androstan-3-one
For solid-state structures of androstan-3-one derivatives presented in Cambridge structural database (CSD), the puckering parameters for the six-membered rings were calculated to investigate the ring conformation. It was found that for the A-ring, except for typical chair conformation, the boat conformation appears very often. This conformation is also possible for the rings B and C. There are a few compounds with boat conformation of A- and B- or A- and C-ring, but simultaneous boat conformation of B- and C-ring has not been found. The methyl substituents at 10 and 13 position of the androstane-3-one as well as carbonyl group at the 3-carbon atom play a significant role in the stabilisation of the structure of androstan-3-one.