H-1, C-13, AND F-19 NUCLEAR-MAGNETIC-RESONANCE ASSIGNMENTS OF 3,3-DIFLUORO-5-ALPHA-ANDROSTANE-17-BETA-OL ACETATE

The molecular structure of 3,3-difluoro-5alpha-androstane-17beta-ol acetate was analyzed by H-1, C-13, and F-19 nuclear magnetic resonance (NMR) techniques; two-dimensional NMR was used to assigned H-1 and C-13 resonances. The H-1 NMR spectrum in deuterated chloroform shows three sharp singlets (delta = 0.74, 0.79, and 2.00 ppm) integrating for three protons each, an isolated triplet at 4.55 ppm integrating for one proton, and overlapping multiplets between 0.72 and 2.12 ppm integrating for 31 protons. The C-13 spectrum shows 18 resonances between 10 and 55 ppm, and three additional resonances at 82.9, 124.0, and 171.5 ppm. The F-19[H-1] spectrum shows two sets of doublets (observed 2J = 150 Hz) at 5.00 and -4.80 ppm. Multiplets arising from F-19-C-13 J-coupling provide the starting assignment for all resonances by means of H-1 homonuclear correlation (COSY) and H-1-C-13 heteronuclear correlation spectroscopy.