Abstract Steroidal phosphonate esters having the dialkoxyphosphinyl group,(RO) 2 P (O)-, as a ring substituent have been synthesized via reaction of the appropriate α, β-unsaturated ketosteroid with trialkyl phosphite in alcohol. By this means a phosphorus substituent has been introduced into the 1-positions of testosterone, hydrocortisone, and cortisone, into the 7-position of testosterone and into the 16-positions of pregnenolone and progesterone. ...
