methyl propionate

All kinds of ring A stereoisomers of 2-methyl-1 alpha, 25-dihydroxyvitamin D (3) (2) and 20-epi-2-methyl-1 alpha, 25-dihydroxyvitamin D (3) (3) were synthesized by palladium catalysis. Kernel coupling reaction A "building blocks enin 'with CD-ring sections, the building block A-ring were made rationally through a novel and practical way, from methyl (R) - (+) - and ( S) - (-) -. 3-hydroxy-2-methyl-propionate, good yield X-ray crystallographic analysis 2alpha-methyl-1 alpha, 25-dihydroxyvitamin D (3) (2b) and the analysis of conformation the ring A of the 2alpha-methyl- (2b) and two methyl-1 beta and alpha ;, 25-dihydroxyvitamin D (3) (2f) is performed, and the results are described All diastereoisomers A-ring (2 and 3) , were synthesized and biologically evaluated both in vitro and in vivo .. The biological activity was highly dependent on the stereochemistry of the substituents A-ring. In particular, 4 times 2b showed high levels of the vitamin D receptor [VDR ] binding activity as the natural hormone and its 20-epimer (3b) showed high activity 12 times more potent in binding VDR, 7 times in the mobilization of calcium and 590 times in inducing differentiation of human leukemia promyelocytic (HL-60) cell relative to the natural hormone. In addition, the 20-epi-2beta-Me-1beta, 3alpha (OH) (2) isomer (3g) have significant biological activity relative to the natural hormone, in spite 1beta-OH-configuration. The activities of the transcription promoter of human osteocalcin, including VDRE in transfected mammalian cells were also evaluated. Finally, there was a clear contrast between the group of 2-methyl effects on HL-60 cell differentiation and apoptosis inducing activity. 2 and 3