PREPARATION OF AB-DINOR STEROIDS

AB-Dinorcholestenone (4) and AB-dinortestosterone (21) have been synthesized to determine the chemical and biological consequences of contracting both the A and B rings of the steroid nucleus. The AB-dinor analogs were prepared from the corresponding B-nor steroids by formylation of B-norenone 1, ozonization of 2-hydroxymethylene ketone 2, and cyclization of the resulting diacid 3. Catalytic or chemical reduction of enone 4 gave exclusively the 5β-saturated ketone 7. Hydride reduction of cis ketone 7 gave predominantly 2a alcohol 12, whereas lithium-ammonia reduction of 7 gave mostly the more stable 2β alcohol 13. © 1969, American Chemical Society. All rights reserved.