Trifluoroacetic acid → HCID 10424224, compound

Participants

Reaction Conditions

Reaction Steps

A suspension made of sodiumborohydride (152 g) in dichloromethane (0.60 liters) was added to a mixture of trifluoroacetic acid (1.13 liters) in acetic acid (1.13 liters) under stirring at a temperature of 0° C. in about 2 hours. At the end of the addition of the suspension of sodiumborohydride, a solution made of 13-ethyl-11-hydroxy-gon-4en-3,17-dione (201.00 g; 0.66 moles; compound XVIa) in dichloromethane (660 ml) was added to the reaction mixture under stirring at the temperature of 0° C. The reaction mixture was kept under stirring at a temperature of 20° C. for 20′ then it was cooled at the temperature of 0° C. and 4 liters of an aqueous admixture of sodium hydroxide were added (this solution was prepared from 1 liter of water and 3 liters of 30% sodium hydroxide). The reaction was then extracted with dichloromethane (3×2.5 liters), the organic extracts dehydrated on sodium sulfate, filtered and concentrated under vacuum to give 210.20 g of raw 13-ethyl-11-hydroxy-gon-4-en-17-one (compound XIVa). Such a crude may be further purified by silica gel chromatography (1/5 p/p) by eluting under a gradient of polarity, by using an admixture of toluene and ethyl acetate as mobile phase: by eluting with 9/1 toluene/ethyl acetate 144.67 g (0.50 moles; yields 76%) of pure compound XIVa were obtained, with the following analytical characteristics:

Provenance & Evidence