12,20-Dioxo-5α-pregnan-3β-yl acetate, obtained from hecogenin, was treated with NaH in DMSO to yield the bridged cyclopropano ketone, 3β-hydroxy-12α,21-cyclo-12β,21-methano-5α,17α-pregnan-20-one. In tert-BuOH the reaction leads to 3β-hydroxy-12,21-cyclo-5α-pregn-12,21-en-20-one. Experimental data prove that the new methylene group of the cyclopropane ring came from DMSO.
SlavikovaB, KasalA, ChodounskaH, KristofikovaZ. (2002) 3α-Fluoro analogues of “allopregnanolone” and their binding to GABAA receptors. Collection of Czechoslovak Chemical Communications, 67, 30–46.
2.
MatyasL, KasalA, RieraZB, SunolCE (2004) Effects of 3α-amino-5α-pregnan-20-one on GABAA receptor: synthesis, activity and cytotoxicity. Collection of Czechoslovak Chemical Communications, 69, 1506–1516.
SunolC, GarciaDA, BujonsJ, KristofikovaZ, MatyasL, BabotZ, KasalA (2006) Activity of B-nor analogues of neurosteroids on the GABAA receptor in primary neuronal cultures. Journal of Medicinal Chemistry, 49, 3225–3234.
