Acetate → Pregna-4,20-dien-3,6-dione

Participants

Reaction Steps

This synthesis is depicted in FIG. 153. 19-Nor-testosterone (XIX) is commercially available, e.g., from Chemical Dynamics Corp. It provides the starting material for 19-Nor-16-androstene derivatives. 19-Nor-testosterone (XIX) was converted into the acetate (Hartman, J. A. et al. J. Am. Chem. Soc. (1956) 78:5662) with acetanhydride and pyridine. (a) A solution of this acetate (4.8 g, 15.17 mmol) in toluene (10 ml) was pyrolyzed (b) at 540° (200 Torr, slow N2-stream) in a glass tube packed with quartz pieces. Chromatography of the crude pyrolysate (3.1 g) on silica gel (150 g) with CH2Cl2 gave 1.1 g (28%) of the homogenous oily ketone 9; +57.9° (C 1) ([27]: m.p. 71-73°). -IR. (CHCl3): 1660s, 1615m, 1585w, -1H-NMR. (90 MHz): 0.84 (s, 3 H); 5.82 (m, 2 H); 5.87 (br. s, 1 H).

Provenance & Evidence