- Crystal structures of conformationally locked cyclitols: An analysis of hydrogen-bonded architectures and their implications in crystal engineering
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A qualitative study has been carried out on selected polycyclitols to evaluate the potential of conformational locking of hydroxy groups in lending predictability to the O-H...O hydrogen-bonding network observed in the crystal structures of such compounds. The polycyclitols employed in this study are conformationally locked with all the hydroxy groups destined to be axial owing to the trans ring fusion(s) in the polycyclic carbon framework. The consequent formation of intramolecular O-H...O hydrogen bonds between the 1,3-syn diaxial hydroxy groups now permits any packing pattern in the polycyclitols to be described in terms of a small group of intramolecularly bonded molecular motifs linked to their respective neighbors by four O-H...O bonds. By using this model and the results of CSD analyses of polyols as a guide, the O-H...O hydrogen-bonded packing motifs most likely to be observed in the crystal structure of each polycyclitol were proposed and compared with those obtained experimentally. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Mehta, Goverdhan,Sen, Saikat,Ramesh, Senaiar S.
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- Reduction method of electronic salt reaction liquid and unsaturated aromatic hydrocarbon compound
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To the reduction method, tetrahydrofuran is used as a solvent and an electron trapping agent, metal lithium is used as a reducing agent, tertiary butanol is used as a reducing agent, and the unsaturated aromatic hydrocarbon compound is reduced under -10 - 0 °C conditions. The raw material tetrahydrofuran is used in the invention. Metal lithium and tert-butyl alcohol are all conventional chemical products, and are simple and easy to obtain. After the reaction is finished, excess lithium and solvent are recovered, and directly used to realize low cost, low pollution and high yield.
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Paragraph 0068-0071
(2021/11/10)
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- Electroreduction in Aqueous Media, Saturation of Polycyclic Aromatics.
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The preparative cathodic reduction of anthracene and phenanthrene was investigated aiming at obtaining Birch-type products in aqueous solutions.Following previous reports, reductions were carried out using mercury pool cathodes and tetrabutylammonium electrolytes.Optimum conditions were found to involve tetrabutylammonium hydroxide as the electrolyte and water as the sole solvent.Reactions were carried out in a simple cell, using constant current and the products were isolated and identified.Anthracene formed initially 9,10-dihydroanthracene which reduced with additional charge transfer to 1,4,5,8,9,10-hexahydroanthracene in high yield.To obtain more saturated anthracene derivatives, a process was developed which involves a "one pot" reduction-isomerization-reduction sequence.Anthracene was electrolyzed first to completion, the product was isomerized by reflux in the electrolyte solution (in the cell but without charge transfer) and was then electrolyzed again.Using this process 1,2,3,4,5,6,7,8-octahydroanthracene and 1,2,3,4,5,6,7,8,9,10-decahydroanthracene were formed in significant yields.Reduction of phenanthrene resulted in mixtures of high saturated derivatives without need for isomerization steps.The major products varied with the amount of charge transferred from dihydrophenanthrene (3F/mol) to octahydrophenanthrene (10F/mol) and decahydrophenanthrene (20F/mol).In general it was shown that cathodic hydrogenation of polycyclic aromatics is possible in aqueous solutions.The products resemble those obtained by metal-ammonia or amine reductions.The degree of saturation can be controlled by the amount of charge transferred and can be increased by a combination of alternate reductions and isomerization.
- Kariv-Miller, Essie,Pacut, Ryszard I.
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p. 2185 - 2192
(2007/10/02)
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- A SAFE AND CONVENIENT NEW PROCEDURE FOR REDUCING AROMATIC COMPOUNDS TO BIRCH-TYPE PRODUCTS
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Aromatic compounds can be reduced by a calcium-amine-t-butyl alcohol system to products which are identical to those obtained by a Birch reduction of the same substrates.
- Benkeser, Robert A.,Laugal, James A.,Rappa, Angela
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p. 2089 - 2092
(2007/10/02)
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