Desulfuration of steroidal thians

1982 ◽  
Vol 47 (11) ◽  
pp. 3148-3159 ◽  
Author(s):  
Alexander Kasal
Keyword(s):  
Raney Nickel ◽  
Optimum Conditions ◽  
Unsaturated Esters ◽  
Aprotic Medium ◽  
Derivatives Of ◽  
By Products

The reaction of 4-thia-5-cholesten-3-one (X) with Raney nickel in protic medium affords alcohol III, while A-nor-5β-cholestan-3-one (XXIII), A-bisnor-2,5-secocholestane (XXXI) and the esters of the type XVIII are formed as by-products. When aprotic medium is used compounds XXIII and XXXI are the main products. During desulfuration with a less active Raney nickel the mentioned substances are accompanied by 5-unsaturated derivatives of the type I, XIV and XXIX. Optimum conditions for the preparation of either saturated alcohols of type III or of unsaturated esters of type XIV were found.

Synthesis of 5-n-alkylresorcinol dimethyl ethers and related compounds via substituted thiophens

1971 ◽  
Vol 24 (12) ◽  
pp. 2655 ◽  
Author(s):  
D Buddhasukh ◽  
JR Cannon ◽  
BW Metcalf ◽  
AJ Power
Keyword(s):  
Raney Nickel ◽  
Stannic Chloride ◽  
Electrophilic Attack ◽  
Related Compounds ◽  
By Products

5-n-Alkylresorcinol dimethyl ethers have been synthesized by desulphurization of 2-(3,5-dimethoxybenzyl)-5-n-alkylthiophens with Raney nickel. The method has been adapted to the preparation of 9-(3,6- dimethoxyphenyl)nonyl alcohol which has been converted into both (2)- and (E)-15-(3,5-dimethoxyphenyl)pentadec-5-ene. ��� Friedel-Crafts acylation of 2-(3,5-dimethoxybenzyl)thiophen with n- hexoyl chloride, or with n-decoyl chloride, in the presence of stannic chloride, yielded the expected 2-(3,6-dimethoxybenzyl)-5-n- acylthiophens, but by-products were formed as the result of competing electrophilic attack on the 3,5-dimethoxybenzyl moiety. The chief by- products, which arise by subsequent Bradsher cyclodehydration, have been formulated as 5,7-dimethoxy-4-n-alkylnaphtho[2,3-b]thiophens. ��� An attempt to synthesize 1,14-bis(3,5-dimethoxyphenyl)tetradecane from 2,2?,6?,2?-terthienyl by an adaptation of this method was unsuccessful.

CHARACTERIZATION OF ACTIVE COMPOUNDS FROM CITRUS PEELS BY-PRODUCTS USING CHROMATOGRAPHIC AND OPTIC METHODS

2017 ◽  
Vol 31 (2) ◽  
pp. 41-47
Author(s):  
Cristina Mihali ◽  
◽  
Thomas Dippong ◽  
Anca Dumuţa ◽  
◽  
...  
Keyword(s):  
Visible Region ◽  
Citrus Fruit ◽  
Volatile Oils ◽  
Complex Composition ◽  
Citrus Peels ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
By Products ◽  
Extracting Agents

Citrus fruits such as orange, grapefruit, lemon and other citrus fruit are widely cultivated and processed generating large amounts of by-products. Citrus peels contain various compounds of economic importance such as volatile oils, flavonoids, polyphenols, carotenoids etc. It is essential to valorize the wastes of citrus processing. In this purpose, peels of orange, grapefruit and lemon, fresh and dried were subjected to extraction using trichloromethane and dichloromethane as extracting agents and analyzed by thin layer chromatography on silica gel plates. Visualization at 366 nm and 254 nm showed a complex composition of extracts that contain terpenes, oxygen heterocyclic substances derivatives of coumarin and carotenoids. The UV-VIS spectra of the extracts were recorded showing absorption in UV and Visible region.

scholarly journals A derivatization-directed three-component synthesis of fluorescent spiro [dihydropyridine-4,3ʹ-indoline]s

2020 ◽  
Vol 44 (9-10) ◽  
pp. 527-531
Author(s):  
Faranak Najafizadeh ◽  
Kurosh Rad-Moghadam ◽  
Soraya Yaghoubi Kalurazi
Keyword(s):  
Ring Opening ◽  
Derivatives Of ◽  
Isatin Derivatives ◽  
Coumarin Ring ◽  
By Products

The synthesis of spiro[chromeno[4,3- b]pyrazolo[4,3- e]pyridine-7,3ʹ-indoline]s is achieved via three-component reactions of 5-amino-3-methylpyrazole, 4-aminocoumarin, and isatin derivatives. This protocol provides expedient synthesis of 10-unsubstituted derivatives of the parent heterocyclic spiro framework and does not lead to coumarin ring opening. The synthesis is highly convergent as no by-products are present in the reaction mixtures. The spiro products show violet fluorescence emissions depending on the nature of their substituents.

SYNTHESES DE LA DL-PROLINE A PARTIR DE L'α-PIPERIDONE

1950 ◽  
Vol 28b (6) ◽  
pp. 245-255 ◽  
Author(s):  
Roger Gaudry ◽  
Louis Berlinguet
Keyword(s):  
Raney Nickel ◽  
Alkaline Solution ◽  
Low Pressure ◽  
Valeric Acid ◽  
Derivatives Of

By treatment of α-piperidone with sulphuryl chloride,β,β′-dichloro-α-piperidone was obtained. It was hydrolyzed to α,α′-dichloro-δ-amino-n-valeric acid, which was simultaneously reduced and cyclized to DL-proline, by low pressure hydrogenation, using Raney nickel, in alkaline solution. All the intermediate compounds were identified and characterized. The over-all yield of DL-proline is 33% calculated from α-piperidone.α-Piperidone was hydrolyzed to δ-amino-n-valeric acid, and the δ-phenylureido-n-valeric and δ-phthalimido-n-valeric acids were prepared. Halogenation of δ-phthalimido-n-valeric acid gave excellent yields of the α-bromo and α-chloro acids. These acids were hydrolyzed to the α-halogenated-δ-aminoacids. On treatment with alkali, they gave DL-proline in 56% and 50% yields respectively, from α-piperidone.Halogenation of δ-phenylureido-n-valeric acid gave the dibromo and the dichloro acids, which ring-close immediately into derivatives of α-piperidone.The different behavior of δ-benzoylamino, δ-phthalimido, and δ-phenylureido derivatives of n-valeric acid with halogens, or halogenating agents is noted.

Thiol esters in organic synthesis. X. A new approach to 1,5-ketols and 5-hydroxy esters using S,S'-diethyl dithiomalonate as an ethanol carbanion equivalent

1982 ◽  
Vol 60 (1) ◽  
pp. 94-96 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Isaac V. Oppong
Keyword(s):  
Organic Synthesis ◽  
Raney Nickel ◽  
Michael Addition ◽  
New Approach ◽  
Unsaturated Esters ◽  
Thiol Esters ◽  
Hydroxy Esters

Michael addition of S,S′-diethyl dithiomalonate to conjugated enones and α,β-unsaturated esters followed by reduction with Raney nickel gave rise to 1,5-ketols and 5-hydroxy esters respectively in good yields.

scholarly journals The Synthesis of the Locating Substitution Derivatives of Chitosan by Click Reaction at the 6-Position of Chitin

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Chen ◽  
Yanchun Ye ◽  
Yanyan Jing ◽  
YuanYuan Gao ◽  
Yanwen Guo ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
High Efficiency ◽  
Click Reaction ◽  
Macrocyclic Compound ◽  
Optimum Conditions ◽  
Structures And Properties ◽  
Acetyl Group ◽  
Novel Method ◽  
Derivatives Of

A novel method to prepare the macrocyclic compound locating substitution derivatives of chitosan was investigated, by using cyclodextrin as the model of macrocyclic compound. The method combines the advantages of activated 6-OH of chitin and high efficiency of click reaction. Chitin C6-OHp-toluenesulfonate (CTN-6-OTs) was generated and subsequently transferred to chitin C6-N3via nucleophilic substitution. Afterwards,β-cyclodextrin was immobilized at 6-OH of chitin via click reaction to afford CTN-6-CD. Ultimately, CTS-6-CD was obtained by removing the acetyl group of chitin unit. The structures and properties of these products were characterized by FTIR, TG, and XRD, respectively. It was found that CTN-6-CD synthesized at the optimum conditions has an immobilized loading of1.6126×10-4 mol/g and that of the corresponding CTS-6-CD, generated by removal of the acetyl group, was1.6891×10-4 mol/g.

Photoreaktionen von Dekacarbonyldirhenium mit Allen und unverzweigten Allenderivaten / Photoreactions of Decacarbonyldirhenium with Allene and Unbranched Derivatives of Allene

1995 ◽  
Vol 50 (4) ◽  
pp. 649-660 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Wolfgang Michels ◽  
Gerhard Heeb
Keyword(s):  
Nmr Spectra ◽  
Crystal And Molecular Structure ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Oxidative Rearrangement ◽  
Dirhenium Complexes ◽  
Derivatives Of ◽  
By Products

Decacarbonyldirhenium (1) reacts upon UV irradiation with allene (2), 1,2-butadiene (3) and 2,3-pentadiene (4) preferentially by CO substitution and oxidative rearrangement to the corresponding enneacarbonyl-μ-η1:3-endiyl-dirhenium complexes 5, 9, and 15 and to the octacarbonyl-μ-η2:2-allene-dirhenium complexes 6, the stereoisomers 10, 11, and 16. At elevated temperature 5, 9, and 15 loose CO and yield by a reductive rearrangement also the complexes 6, 10, 11, and 16. In addition to these main products, depending upon the allene derivative used, various by-products are obtained.By-products of the reaction o f 1 with 2 are octacarbonyl-μ-η3:3-(2,3-dimethylene-buta-1,4- diyl)dirhenium (7) and μ-η2:2-allene-hexacarbonyl-μ-η1:3-1-propene-1,3-diyl-dirheniurn (8). The photo reaction of 1 with 3 yields, in addition to 9-11, tetracarbonyl-η3-(E-5-ethylidene- 4-methyl-2-cyclopenten-1-yl)rhenium (12) and tetracarbonyl-η3-(Z-5-ethyliden-4- methyl-2-cyclopenten-1-yl)rhenium (13) as a mixture of isomers. 1 and 4 form the by-products tetracarbonyl-η3-(EZ-3-penten-2-yl)rhenium (17), tetracarbonyl-η3-(EE-3-penten-2-yl)rhenium (18) and heptacarbonyl-μ-η1:2:1:2-(4,5-dimethyl-2,6-octadiene-3,6-diyl)dirhenium (19) with an unusually bridging and chelating ligand. The constitutions of the reaction products have been concluded from the IR and 1H NMR spectra. For 19 the crystal and molecular structure has been determined by X-ray diffraction analysis.

Isotherme d'adsorption du phénanthrène et de ses dérivés hydrogénés sur du nickel de Raney

1989 ◽  
Vol 67 (3) ◽  
pp. 365-368 ◽  
Author(s):  
François Bossányi ◽  
Chakib Ameziane Hassani ◽  
Hugues Ménard ◽  
Jean Lessard
Keyword(s):  
Raney Nickel ◽  
Adsorption Isotherms ◽  
Hydrogen Atoms ◽  
Position And Orientation ◽  
Derivatives Of

The adsorption isotherms of phenanthrene and its hydrogenated derivatives, of naphthalene, and of tetralin on Raney nickel have been determined by chromatographic studies. The adsorption of these molecules on Raney nickel depends on the number of π electrons and on the position and orientation of hydrogen atoms that can interfere with the interaction of the π electrons with the catalyst. Keywords: adsorption, phenanthrene, chromatographic studies.

Sign in / Sign up

Export Citation Format

Share Document