Urea → Acetate

Participants

Reaction Steps

A solution of 2-(tetrahydropyran-2-yloxy)-1-diazoethane (prepared from 69.1 g of N-]2-(tetrahydropyran-2-yloxy)ethyl]urea by the procedure described in (a) - (e) above) in 600 ml of 3:1 ether-pentane is stirred with 200 ml each of ether and methanol at 0°C. Fourteen g of 11β,16α,17,21-tetrahydroxypregna-1,4-diene-3,20-dione, 16,17-cycloborate is added in portions. After nitrogen evolution ceases the solvents are removed in vacuo and the residue is dissolved in chloroform and chromatographed on a 150 g-silica gel column. Elution with chloroform and then 1:1 chloroformethyl acetate gives 4.0 g of TLC pure 16α-[2-(tetrahydropyran-2-yloxy)ethoxy]-11β,17,21-trihydroxypregna-1,4-diene-3,20-dione.

Provenance & Evidence