1987 Volume 35 Issue 3 Pages 1118-1127
The mechanism of the color reaction and the structures of the colored products of cortisone (1a) and deoxycorticosterone (2a) with pyrrole were elucidated. In the presence of cupric acetate, la and 2a were converted to the oxidation products (1b and 2b) which have a glyoxal side chain at C (17). For studying the chemical structures of the colored products derived from corticoids, phenylglyoxal (3a) was used as a model compound with a glyoxal side chain. By reacting 3a with pyrrole in hydrochloric acid, di (2-pyrrolyl) benzoylmethane (3b) was produced as an intermediate in the formation of the colored product. Compound 3b was changed to [5- (2-pyrrolyl) -2 (2H) - pyrrolylidene] (2-pyrrolyl) benzoylmethane (3d) by reaction with pyrrole in the presence of cupric acetate and hydrochloric acid. Compound 3d in dichloromethane gave the absorption maximum at 480 nm. Corticoids 1b and 2b were converted to the colored products, 21- [5- (2-pyrrolyl) -2 (2H) - pyrrolylidene] -21- (2-pyrrolyl) -4-pregnene-3, 11, 20-trione (1e) and 21- [5- (2-pyrrolyl) -2 (2H) -pyrrolylidene] -21- (2-pyrrolyl) -4-pregnene-3, 20-dione (2e), by reaction with pyrrole under the above conditions. Corticoids 1e and 2e in dichloromethane gave absorption maxima at 510 and 480 nm, respectively. Corticoid 1e showed fluorescence at 562 nm with excitation at 516 nm.
