Antiproliferative, low-calcemic, fluorinated sulfone analogs of 1α,25-dihydroxyvitamin D₃: Chemical synthesis and biological evaluation

Novel fluorinated sulfone analogs of the hormone 1α,25-dihydroxyvitamin D₃ have been designed and synthesized in order to study the biological effects of fluorine incorporation at the terminus of the C,D-ring side chain. Although biologically active 26,27-hexafluorinated 1α,25-dihydroxyvitamin D₃ analogs have been synthesized previously, this investigation reports the first successful fluorinated series in which trifluoromethyl sulfone analogs present a favorable biological profile. This study shows that two new analogs featuring incorporation of a synthetically simple single trifluoromethyl sulfone group have significantly increased antiproliferative activity while causing desirably low in vivo calciuria relative to that of calcitriol. Incorporation of additional fluorines, as in a perfluorobutyl analog, results in a loss of antiproliferative activity.