Etlioxalglatiun of 16a, lT~-isopropylidenedioxy-4, 9 ( 1 l)-pregnadiene-3, 23-dione (XI), which was prepared from 16a, 17aepoxy-1 lor-hydroxyprogesterone (11), in the presence of a molar equivalent of sodiurn methoxitie gave exclusively the 2-ethoxalyl derivative XVIII, which was converted by a six-step procedure into 9~-fluoro-ll, 8, 16or, l7a-trihydrosy-1, 4- pregna-diene-3, 20-dione (XXL'II). Bis-ethoxalylation of XI led to the preparation of the 2a, ...
