Reduction of aromatic steroidal A rings by lithium in ethyl amine.
The reduction of 3-methoxy-estra-1,3,5(10)-trien-17beta-ol (6) and 13-ethyl-3-ethoxy-gona-1,3,5(10)-triene-11alpha,17beta-diol (2) by lithium in ethyl amine in the absence of a proton source is described. Both reductions, contrary to the reports of previous investigators, which indicated the 4-ene to be the main reaction product, gave a complex mixture of products. In the case of the reduction of 2, which is an intermediate in the synthesis of the progestagen desogestrel (1), we obtained the expected known 13-ethyl-gona-4-ene-11alpha,17beta-diol (4) in small amounts and three new steroidal monoenes, 13-ethyl-gona-5(10)-ene-11alpha,17beta-diol (11), 13-ethyl-gona-5(6)-ene-11alpha,17beta-diol (12), and 13-ethyl-gona-1(10)-ene-11alpha,17beta-diol (13). These compounds were characterized as the 11,17-diacetates with the 5(10)-ene 11 being the major compound.
Modica
Emilia
E
Dipartimento di Chimica e Biochimica Medica, Università di Milano, Via Saldini 50, 20133 Milano, Italy.
Colombo
Diego
D
Compostella
Federica
F
Scala
Antonio
A
Ronchetti
Fiamma
F
D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D017135:Desogestrel / Q000138:chemical synthesis* / Q000737:chemistry; D005021:Ethylamines / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008094:Lithium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D013256:Steroids / Q000737:chemistry*
D005021:Ethylamines; D011084:Polycyclic Aromatic Hydrocarbons; D013256:Steroids; D017135:Desogestrel; D008094:Lithium