Z. You, M. Khalil, D. Ko
May 8, 1995
Citations
0
Influential Citations
24
Citations
Journal
Tetrahedron Letters
Abstract
Abstract Prednisolone derivatives with a 16α-methyl carboxylate group were synthesized by a novel procedure of 1,3-dipole addition of fulminic acid to 21-acetyloxy-11β-hydroxy-3,20-dioxo-1,4,16-pregnatriene, followed by base-catalyzed ring opening of the resulting isoxazoline to yield a 16α-cyanoprednisolone derivative and treatment of the nitrile with methanolic HCl. Conversion of the cyanosteroids in the acid to the corresponding methyl carboxylates was achieved with or without the Mattox rearrangement by controlling reaction temperature and protective group for the 21-OH.