1 alpha,24(R)-Dihydroxy-25-nitrovitamin D-3 1 and 1 alpha,24(S)-dihydroxy-2
5-nitrovitamin D-3 2 were synthesized using the palladium-catalyzed; alkyla
tive enyne cyclization reaction. Their biological properties were studied b
ased on VDR binding affinity and HL-60 cell differentiation activity. (C) 1
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