Steroids which have undergone contraction in ring size or reduction in side chains.
D004963
Estrenes
Unsaturated derivatives of the ESTRANES with methyl groups at carbon-13, with no carbon at carbon-10, and with no more than one carbon at carbon-17. They must contain one or more double bonds.
19-Norandrostenes,19 Norandrostenes
D001378
Azasteroids
Steroidal compounds in which one or more carbon atoms in the steroid ring system have been substituted with nitrogen atoms.