Cycloadducts of ergosterol with azo-type dienophiles, and their chemical reactivities
Abstract
The 1,4-cycloadduct of ergosteryl acetate with pyridazine-3,6-dione was made and used in a synthesis of 3β-acetoxycholesta-5,7,22-triene. The Cycloadducts of ergosteryl acetate with 4,5-dihydropyridazine-3,6-dione, phthalazine-1,4-dione, and 4-phenyl-1,2,4-triazoline-3,5-dione were also prepared. Selective hydrogenation of the 22,23-double bond was not achieved in any of these Cycloadducts.