cyclopregnol cyclopregnol cyclopregnol (inn), also known as neurosterone, as well as 6β-hydroxy-3:5-cyclopregnan-20-one, is a synthetic pregnane steroid which was developed in the 1950s as a "psychotropic agent" for the treatment of mental disorders but was never marketed. although an initial small clinical study found effectiveness, a subsequent, larger and more rigorous study found that cyclopregnol was no more effective than placebo and was clearly inferior to chlorpromazine. cyclopregnolclinical dataother namesneurosterone; 6β-hydroxy-3:5-cyclopregnan-20-oneidentifierscas number465-53-2pubchem cid12308830chemspider35517184uniiz06494074xchemical and physical dataformulac21h32o2molar mass316.485 g·mol−13d model (jsmol)interactive image smiles cc(=o)1cc21(cc32c(453(cc4c5)c)o)c inchi inchi=1s/c21h32o2/c1-12(22)15-4-5-16-14-10-18(23)21-11-13(21)6-9-20(21,3)17(14)7-8-19(15,16)2/h13-18,23h,4-11h2,1-3h3/t13-,14-,15+,16-,17-,18+,19+,20+,21+/m0/s1key:ugiarlnnaprcpf-huppadnksa-n