Katsuhito Miyamoto

Synthetic analogues of vitamin D3 with an oxygen atom in the side chain skeleton A trial of the development of vitamin D compounds which exhibit potent differentiation‐inducing activity without inducing hypercalcemia

Four analogues of vitamin D3 with an oxygen atom in the side chain skeleton were synthesized to determine whether their differentiation‐inducing activity could be separated structurally from their activity to induce hypercalcemia. The order of the in vitro potency to reduce nitroblue tetrazolium in human myeloid leukemia cells (HL‐60) was 22‐oxa‐1α25‐(OH)2D3 > 1α,25‐(OH)2D3 > 20‐oxa‐1α,25‐(OH)2D3≒22‐oxa‐1α‐(OH) D3 > 1α‐(OH)D3 > 20‐oxa‐1α‐(OH)D3. 22‐Oxa‐1α,25‐(OH)2D3, was also about 10‐times more potent than 1α,25‐(OH)2D3 in suppressing proliferation and inducing differentiation of mouse myelomonocytic leukemia cells (WEHI‐3), but the former was much weaker than the latter in inducing the release of 45Ca from prelabeled fetal mouse calvaria. These results suggest that the differentiation‐inducing activity of vitamin D compounds can be separated structurally from their activity to induce hypercalcemia.

Synthetic Studies on Vitamin D Analogues VI. A New Synthesis of 25-Hydroxycholesterol from Lithocholic Acid

Abstract The conversion of lithocholic acid (1) into 25-hydroxycholesterol (10) via methyl 3β-hydroxy-5-cholenate (6) is described.

Synthesis and immunoregulating activity of vitamin D analogues bearing pregnane side chains

Abstract The synthesis of Vitamin D analogues bearing pregnane side chains and their immunoregulating activity in mice are described.

Synthesis and differentiation-inducing activity of 1α-24-dihydroxy-22-oxa-vitamin D3 analogues

Abstract The synthesis of four vitamin D3 analogues, 1α,24(S)- and 1α,24(R)-dihydroxy-22-oxa-vitamin D3, (5) and (6), and their 26,27-diemethylated homologues, (7) and (8), and the preliminary evaluation of their differentiation-inducing activity in vitro are described.

Novel procedure for the preparation of 1α,3β-dihydroxy-2β-tritiated steroidal compounds

Abstract A novel procedure for the preparation of 1α,3β-dihydroxy-2β-tritiated steroidal compounds by the reduction of the α-epoxide with sodium horotritiide in diglyme at 80 C is described.