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 prostaglandin D1 and D2 via the three-component coupling process

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

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.     

The diffraction of H2, D2 from solid LiF

The collision of H₂ and D₂ molecules with the (001) face of LiF is studied theoretically using the close coupling formalism. The method includes excited states of the diatomic molecule but neglects all couplings to phonons or the possibility of fragmentation of the incident molecule. Using a simple model potential a series of calculations for comparison with experimental data is carried out. Excellent agreement is obtained with the trends obeserved experimentally, and the quantitative agreement is also good.     

The convergent synthesis of novel cytotoxic certonardosterol D2 from diosgenin

Certonardosterol D₂, a polyhydroxysterol isolated from starfish Certonardoa semiregularis with exceptionally potent antitumor activity, was stereoselectively synthesized from natural rich diosgenin via the protocol of Julia olefination and Evans aldol reaction.     

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.     

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 ($\text{11}$).     

Intermolecular forces for D2, N2, O2, F2 and CO2

The intermolecular potentials for D₂, N₂, O₂, F₂ and CO₂ are determined on the basis of the second virial coeffincients, the polarizabilities parallel and perpendicular to the molecular axes, and the electric quadrupole moment. The repulsive parts of the potentials are taken from the corresponding Kihara core-potentials. Effects of the octopolar induction are taken into consideration in a unique way. The potential depends on relative orientations of the two molecules as well as the distance r between the molecular centers. This dependence is shown in graphs. A measure of the anisotropy of the potential depth is 0.72 for CO₂ 0.36 for D₂, and smaller than 0.27 for N₂ O₂ and F₂. The remarkable anisotropy for CO₂ and D₂ is due to strong electrostatic quadrupole interactions.     

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     

Synthesis of the sulfones of leukotriene C4, D4, and E4

A simple one-step preparation of the sulfones of Leukotriene C₄, D₄ and E₄ has been developed by the direct oxidation of the parent compounds. An alternative synthesis of these sulfones has also been carried out by reduction of an acetylenic precursor.     

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.     

Electronic structures of dihedral (D5h, D5d, D6h, D6d) fullerenes

By means of our proposed method for Hückel theory calculation, we have calculated the electronic structures of dihedral (D_5h, D_5d, D_6h, D_6d) fullerences, which are generated from icosahedral C₂₀, C₆₀, C₈₀, C₁₈₀, C₂₄₀ and C₅₄₀, respectively. From the calculated results of 1224 fullerence molecules, certain rules on the stability and chemical reactivity have been drawn for such types of dihedral fullerenes.     

Triterpene Glycosides from Kalopanax septemlobum. III. Glycosides D2, I1, and K1 from Leaves of Kalopanax septemlobum var. maximowiczii Introduced in Crimea

The new caffeylated triterpene glycosides hederagenin 3-O-(6-O-caffeyl-β-D-glucopyranosyl)-(1→4)-O-β-D-xylopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→2)-O-β-L-arabinopyranoside and its 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl and 28-O-α-L-rhamnopyranosyl-(1→4)-O-6-O-acetyl-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl esters were isolated from leaves of Kalopanax septemlobum var. maximowiczii introduced in Crimea. The structures of these compounds were established using chemical methods and NMR spectroscopy.__________Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 263–267, May–June, 2005.     

Endothermic reactions of Ni+ with H2, HD and D2

An ion-beam apparatus is employed to study the reaction of Ni⁺ with H₂, HD, and D₂ as a function of kinetic energy. These reactions lead to the endothermic formation of NiH⁺, NiH⁺ and NiD⁺, and NiD⁺, respectively. Interpretation of the threshold for these processes yields the average bond energies, D⁰(Ni⁺H) = 1.86 ± 0.09 eV and D⁰(Ni⁺D) = 1.90 ± 0.14 eV. The total reaction cross sections for all three systems are similar; however, a striking isotope effect is observed for Ni⁺ reacting with HD. The dependence of the cross sections on relative kinetic energy is discussed in terms of simple models for reaction.     

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 ($\text{2C}$).     

Predissociation of the 3pπ D 1Πu+ state in H2, HD,and D2

Predissociation linewidths and lineshapes are reported for selected vibrational levels of the 3_pπ D ¹Π⁺_u state of H₂, HD, and D₂. We also discuss the effect of a perturbation by the 4_pδ B″B? ¹|gs_u⁺ state on the predissociation rate of the D state.     

Heat capacity and thermodynamic functions of MnBr2 · 4D2O and MnCl2 · 4D2O

The heat capacities of MnBr₂ · 4D₂O and MnCl₂ · 4D₂O have been experimentally determined from 1.4 to 300 K. The smoothed heat capacity and thermodynamic functions (H°_TH°₀) and S°_T are reported for the two compounds over the temperature range 10 to 300 K. The error in the thermodynamic functions at 10 K is estimated to be 3%. Additional error in the tabulated values arising from the heat capacity data above 10 K is thought to be less than 1%. A λ-shaped heat capacity anomaly was observed for MnCl₂ · 4D₂O at 48 K. The entropy associated with the anomaly is 1.2 ± 0.2 J/mole K.