Synthese von 3-desoxy-3-amino-vitamin D3 und 3-desoxy-3-epiamino-vitamin D3 und D2

Vitamin D₂ and D₃ are transformed with triphenylphosphane-diethylazodicarboxylate-HN₃ into the epimeric azidoderivatives 1 and 3 with inversion of the configuration at C-3. Reduction with LiAlH₄ yields 3-desoxy-3-epiamino-vitamin D₂ and D₃2 and 4, which are characterized as their acetamides 2a and 4a. Furthermore epivitamin D₃-p-nitrobenzoate 5 is produced by reaction of vitamin D₃ with triphenyl- phosphanediethylazodicarboxylate-p-nitrobenzoic acid, which yields epivitamin D₃5a after saponification. Utilizing the same method as above leads with epivitamin D₃ to 5a 3-desoxy-3-azidovitamin D₃6, which is reduced to 3-desoxy-3-amino-vitamin D₃7 by LiAlH₄ and characterized as its acetamide 7a.     

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.     

Zur Bestimmung von Vitamin D2 und D3 in biologischem Material

Ohne Zusammenfassung     

硼酸对Sr2CeO4荧光粉的物相组成和发光性质的影响

采用正交试验确立了高温固相法合成Sr₂CeO₄的主要影响因素。研究了H₃BO₃和n_Sr/n_Ce(物质的量的比)对Sr₂CeO₄物相组成和发光强度的影响。XRD结果表明保持n_Sr/n_Ce为5.5和添加6.5wt%的H₃BO₃，有利于形成良好的Sr₂CeO₄晶体结构和大幅度提高Sr₂CeO₄的发光强度。荧光光谱测试表明助熔剂法合成样品的发光强度分别比传统固相法合成和溶胶-凝胶法提高了201.2%和15.7%。     

[Bmim]NO2/H3BO3 as an effective nitrosonium source for electrophilic aromatic nitrosation under MW-promoted solvent-free conditions

[Bmim]NO₂/H₃BO₃ was used as a nitrosonium source for the efficient synthesis of nitrosoarenes. The reaction was accomplished under MW irradiation at 60 W in a solventless system. Side processes such as oxidation or dealkylation were not observed during the nitrosation of alkyl phenyl ethers in the presence of this new reagent. The satisfactory results were obtained with very short reaction time, simplicity in the experimental procedure and good to excellent yields.     

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.     

Superstructure and stacking faults in hydrothermal-grown KBe2BO3F2 crystals

The structure of the hydrothermal-grown nonlinear optical crystal KBe₂BO₃F₂ was investigated. A new structure of the R3?c space group with cell parameters of a=4.422(1) Å and c=37.524(3) Å was obtained by powder X-ray diffraction and Rietveld refinement. The new structure is a 1×1×2 superstructure of the previously reported R32 structure with a different stacking sequence of (Be₂BO₃F₂)_∞ layers along the c axis. The relationship between the refined structure and the experimental results is discussed. A stacking fault mechanism is proposed for the formation of the superstructure as well as the nonuniformity of the hydrothermal-grown KBBF crystals.     

1-methyl-(D3)-trishomocubane

The acid catalysed rearrangement of 8-methyl-pentacyclo(5.4.0.0^2,6.0^3,10.0^5,9)undecan-8-endo-o1 ($\text{8}$) to 3-methyl-(D₃)-trishomocuban-4-o1 ($\text{9}$) provided the key step to the synthesis of the title compound ($\text{11}$).     

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.     

Die Farbreaktion zwischen partiell verseiftem Polyvinylacetat und Jod-Jodid in Gegenwart von H3BO3

Ohne Zusammenfassung     

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.     

Luminescence properties of efficient X-ray phosphors of YBa3B9O18, LuBa3(BO3)3, α-YBa3(BO3)3 and LuBO3

The samples of YBa₃B₉O₁₈, LuBa₃(BO₃)₃, α-YBa₃(BO₃)₃ and LuBO₃ powders have been synthesized by the solid-state reaction methods at high temperature and their X-ray excited luminescent properties were investigated. All the studied materials show a broad emission band in the wavelength range of 300-550 nm with the peak centers at about 385 nm for YBa₃B₉O₁₈ and LuBa₃(BO₃)₃, 415 nm for α-YBa₃(BO₃)₃ and 360 nm for LuBO₃ powders, respectively. Even though those compounds have the different atomic structures, they have the common structural feature of each yttrium or lutetium ion bonded to six separate BO₃ groups, i.e., octahedral RE(BO₃)₆ (RE=Lu or Y) moiety. This octahedral RE(BO₃)₆(RE=Lu or Y) moiety seems to be an important structural element for efficient X-ray excited luminescence of those compounds, as are the edge-sharing octahedral TaO₆ chains for tantalate emission.     

New routes to 1α-hydroxyvitamin D3

The sulphone (2) and the methyl ester (3, R=H) were used in stereo-selective syntheses of derivatives of 1α-hydroxyprecalciferol₃ and 1α-hydroxytachysterol₃, which were then converted into the title compound.