5a-pregnane-3,20 dione

Deuteration at C-3 by Lithium Aluminum Deuteride Reduction of 5a.-Pregnane-3,20-dione 3-Tosylhydrazone 20-Ethylene keta ... 

Cyano-3 -hydroxy-5a-pregnan-20-one A suspension of 5a-pregnane-3, 20-dione (2 g) in ethanol (90 ml) is treated with acetone cyanohydrin (4 ml) and three drops of triethylamine and stirred at room temperature until complete dissolution. After 3 hr, the solution is diluted with 200 ml of water, acidified with acetic acid and the crystalline precipitate is thoroughly washed with water and dried under vacuum to give 2.1 g (97%) of product mp 172-178° (dec). A sample recrystallized from ethyl acetate melts at 176-179° (dec) [a]p 86° (ethyl acetate). 

Deuteration at C-3 by lithium aluminum deuteride reduction of 5a-pregnane-3, 20-dione 3-tosylhydrazone 20-ethylene ketal, 177... 

Several routes to 2,3-diketones have been reported. The most practical and general method is that of Ruzicka, Plattner and Furrer as adapted by Nace and Nelander for synthesis of the diosphenol corresponding to 5a-pregnane-2,3,20-trione (44) starting from 5a-pregnane-3,20-dione (40). The overall yield of diosphenol (44) by this route is 62% based on... 

The rDI3(3-HSD was also able to catalyse the reduction of 3-ketosteroids when NADH was used as a co-substrate. Pregnane-3,20-diones without A -or A -double bond like 5(3-pregnane-3,20-dione and 5a-pregnane-3,20-dione were accepted. 4-Androstene-3,17-dione was also accepted as a substrate ... 

No attempt as yet has been made to study the biogenesis of Buxus alkaloids. Indirect evidence gave rise to the presumption that in the biogenetic scheme lanosterol is followed by cycloartenol (or similar triterpene type). Goutarel (205) tentatively proposed a possible pathway via lanosterol, cycloartenol, 9j8,19-cyclo-4,4, 14a-trimethyI-5a-pregnan-3(8 - ol - 20 - one, 9, 19 - cyclo - 4,4, 14a - trimethyl - 5a - pregnan - 3,20 - dione, mono-, and diaminosteroids. 

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