NEW STEROID HAPTENS FOR RADIOIMMUNOASSAY - SYNTHESIS OF STEROIDS SUBSTITUTED WITH THIOETHER OR ESTER LINKAGES AT THE 2-ALPHA-POSITION

Abstract

Haptens with bridge at the 2-position have not yet been explored. Radioimmunoassays with antibodies directed against 2-alpha-alkyl bridged steroid haptens are expected to be highly specific due to greater topographical exposure and similarity in conformation to the native steroid. The 2-alpha-alkyl bridged haptens were synthesized by first adding a cyclopropane ring to 2-methylene-4-en-3-one. Selective opening of the three-membered ring with trimethyl silyl iodide and transformation of the iodo group gave a carbocyclic acid, the desired analog for conjugation with protein.