Synthesis of potential pregnenolone and progesterone spin probes for biomembranes and immunoassays

The synthesis and characterization of four new steroidal spin labels, viz., 3'-[[(pregn-5-en-3 beta-ol-20S-yl)methyl]oate]- 2',2',5',5'-tetramethylpyr rolidine-1'-oxyl,3'-[[(pregn-4-en-3- one-20S-yl)methyl]oate]-2',2',5'.5'-te tra methyl pyrrolidine-1'-oxyl, 3 "[(3 beta-acetoxypregn-5-en-20-one-16 alp ha-yl)prop-2'xi-ol-3'xi-oate]-2 ",2 ",5 ",5 "-tetramethyl pyrrolidine-1 "-o xyl and 3 "-[(pregn-5-en-3,20-dione-16 alpha-yl)prop-2'xi-ol-3'xi-oate]-2', 2',5',5'-tetramethylpyrrolidine-1'-oxyl has been described which involves f unctionalization of the parent hormone at C-20 and C-16. The key step to al l the products was the condensation of 3-carboxyproxyl with the derivatized synthons. (C) 1999 Elsevier Science Ltd. All rights reserved.