Potassium sodium tartarate → HCID 12851151, compound

Participants

Reaction Steps

In a 2.5 l 4-neck flask equipped with a stirrer, 500 ml dropping funnel with pressure equilizer, thermometer and argon inlet, 800 ml of tetrahydrofuran (product from freshly-opened bottle was stored for 16 hr. over molecular sieves) at room temperature was added in one portion with stirring to 10.84 g (0.28 mol) of lithium aluminum hydride. The suspension was cooled to -20°, and, during cooling and stirring for 30 min., a solution of 26.5 g crude (20S)-1α,3β-diacetyloxy-20-methyl-21-p-toluenesulfonyloxypregn-5-ene in 450 ml tetrahydrofuran under an argon atmosphere was dripped into the flask in such a way that the temperature did not surpass -18°. After stirring for 1.5 hr. under argon at -20°, 1.2 l of tetrahydrofuran--ethyl acetate (1:1) was added to the suspension over a period of 30 min. in such a way that the temperature did not surpass -18°. The cold reaction mixture was poured into a stirred solution, precooled to 0°, of 0.8 l of 2 M potassium sodium tartrate solution. The organic solvent was removed under vacuum at 40°, and the aqueous residue was extracted first with 500 ml and then twice with 300 ml (total of 1.1 l) of ether. The ether extracts were washed successively 2 times with 250 ml of water and 2 times with 250 ml of sat. NaCl solution, combined and dried over sodium sulfate. After removal of the solvent under reduced pressure at 40°, the residue amounted to 24.1 g of crude (20S)-1α,3β-dihydroxy-20-methyl-21-p-toluenesulfonyloxypregn-5-ene (the crude product still contained some unreacted triol because of incomplete tosylation).

Provenance & Evidence