ChemicalBook CAS DataBase List 5α-Pregnane-3,20-dione

5α-Pregnane-3,20-dione synthesis

13synthesis methods

Product Name:5α-Pregnane-3,20-dione
CAS Number:566-65-4
Molecular formula:C21H32O2
Molecular Weight:316.48

516-55-2 Synthesis

516-55-2
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$20.00/250mg

566-65-4
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$50.00/1g

Yield:566-65-4 81%

Reaction Conditions:

with sodium hypochlorite;acetic acid;sodium bromide in tetrahydrofuran at 20 - 40; for 2 h;

Steps:

2 Synthesis of (8R,10S,13S,14S,17S)-17-acetyl-10,13-dimethyltetradecahydro-1H-cyclopenta[a]phenanthren-3(2H)-one

To a solution of the above product 1-((3S,8R,10S,13S,14S,17S)-3-hydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)ethenone, 3.2 g, 10 mmol) in 40 mL of THF and 10 mL of acetic acid was added NaBr (1.03 g, 0.1 eq.). It was cooled in an ice bath and was followed by the dropwise addition of NaOCl (82 mL, 10-15%, 18 eq.) at such a rate that the internal temperature was maintained <40 °C. After addition, it was stirred at room temperature for 2h. Thin layer chromatography (TLC) indicated it was complete. The mixture was diluted with dichloromethane and layers were separated. The organic layer was washed with Na2S203 (10% aq.), H20, NaHCCb (sat.) and NaCl (sat.). Drying over Na2S04 and concentration afforded 3.8 g of the crude product, which was recrystallized from CH2Cl2/Hex to give 2.57 g of the desired product (81%). NMR (400 MHz, CDC13): 2.51 (t, 1H), 2.2-2.4 (m, 3H), 2.1-2.2 (m, 1H), 2.10 (s, 3H), 1.98-2.01 (m, 2H), 1.6-1.7 (m, 4H), 1.55-1.6 (m, 1H), 1.3-1.4 (m, 7H), 1.1-1.2 (m, 2H), 0.99 (s, 3H), 0.95-0.98 (m, 1H), 0.75-0.78 (m, 1H), 0.62 (s, 3H).

References:

WO2019/209850,2019,A1 Location in patent:Paragraph 0103; 0105; 0107

57-83-0 Synthesis