Convergent and stereoselective synthesis of vitamin D3 via 3,5-cyclovitamins D3

A convergent and stereoselective synthesis of vitamin D₃ was achieved via 3,5-cyclovitamins D₃ (20) which were prepared from the chiral aldehyde (2) and the vinyl bromide (12) derived from Grundmann's ketone.     

Novel regioselective C-6 and C-19 alkylation of vitamin D3 via its sulfur-dioxide adducts

Vitamin D-sulfur dioxide adducts undergo regioselective methylation at C-6 with sodium hydride used as the base and at C-19 with lithium tetramethylpiperidide. The methylated adducts are converted to the corresponding vitamin D derivatives by extrusion of sulfur dioxide.     

Synthesis of new vitamin D3 analogues with a decalin-type CD-ring

Vitamin D analogues, characterized by a decalin CD-ring fragment are described.     

Total synthesis of prostaglandin D1 methyl ester and 9-epi-prostaglandin D1 methyl ester

Synthesis of the title compounds are described via the dithiane enone (VIII); cuprate addition to (VIII) proceeds with asymmetric induction.     

Synthesis of 23,23-difluoro-25-hydroxyvitamin D3

23,23-Difluoro-25-hydroxyvitamin D₃ was synthesized from 6β-methoxy-3α,5-cyclo-23,24-dinor-5α-cholan-22-ol.     

Synthesis of 24,24-difluoro-25-hydroxyvitamin D3

24,24-Difluoro-25-hydroxyvitamin D₃ ($\text{13}$) has been prepared from commercially available lithocholic acid derivative to study the role of 24-hydroxylation in the metabolism of vitamin D₃.     

Synthesis of prostaglandin D1 and D2 via the three-component coupling process

Facile, convergent entries to prostaglandin D₁ and D₂ are outlined.     

A stereocontrolled partial synthesis of 1α-hydroxy vitamin D3

A novel and efficient partial synthesis of 1α-hydroxy vitamin D₃ ($\text{6}$), starting from 7-dehydrocholesterol ($\text{1}$), is reported. The crucial step in the synthesis involves a selective Diels-Alder reaction of 4-phenyl-1,2,4-triazoline-3,5-dione with the 6,8-diene system of previtamin D₃ ($\text{3}$), generating an adduct $\text{7}$ suitable for the stereoselective introduction of the 1α-hydroxyl group. Cycloreversion of $\text{13}$ leads to the title compound.     

The convenient route to cd fragment for the synthesis of vitamin D3 relatives

The efficient degradation of $\text{1}$ to the α-methylene ketone $\text{4}$ is described. Compound $\text{4}$ was then converted to the allylic alcohol $\text{8a}$ - the precursor of vitamin D³ relatives.     

Synthesis of 2β-fluoro-1α-hydroxyvitamin D3

2β-Fluoro-1α-hydroxyvitamin D₃($\text{3}$) was prepared from 1,2α-epoxy-cholest-5-en-3β-yl tetrahydropyranyl ether($\text{1a}$ via 2β-fluorocholest-5-ene-1α, 3β-diol($\text{2}$).     

An efficient synthesis of 1α, 25-dihydroxy vitamin D3

An efficient synthesis of the title compound is reported based on C-1 functionalization of the triazoline Diels-Alder adduct of 25-OH provitamin D₃ ($\text{2C}$).     

Stereoselective synthesis of Certonardolsterol D3

The first stereoselective synthesis of Certonardolsterol D₃ was described. Ene reaction and improved allylic oxidation were employed as key steps for efficient construction of the desired 3β,6α,15β-triol steroidal framework. The chiral side chain in Certonardolsterol D₃ was finally introduced by Julia olefination.     

lα-hydroxy previtamin D3, and its selective formation from 1-keto previtamin D3

An efficient method for the preparation of crystalline α-hydroxy previtamin D₃ is described. Also the stereoselective reduction of 1-keto previtamin $\text{9}$ is discussed; it was observed that with aluminum hydride $\text{7}$ is the most abundant product. This stands in contrast with previously reported LiAlH₄ and NaBH₄ mediated reductions.     

Synthesis of 24,24-difluoro- and 24ξ-fluoro-25-hydroxyvitamin D3

From cholenic acid 24,24-difluoro-25-hydroxyvitamin D₃ and 24ξ-fluoro-25-hydroxyvitamin D₃ were prepared.     

熊果酸C-3,C-28位衍生物的合成及其抗肿瘤活性研究

以天然产物熊果酸为原料,经过氧化、酰化、酯化等反应合成了11个未见报道的熊果酸衍生物,其结构经过MS、1H NMR及元素分析确定。以氟尿嘧啶和吉非替尼为阳性对照药,经MTT法对A549和SGC-7901细胞进行初步体外抗肿瘤活性研究。结果表明,目标化合物对两种细胞株的抑制率均明显高于母体化合物,且化合物4b和5a的抑制效果高于阳性对照药,值得进一步研究。