Hydrogenolysis reduction reaction

Various catalytic reactions are known to be structure sensitive as proposed by Boudart and studied by many authors. Examples are the selective hydrogenation of polyunsaturated hydrocarbons, hydrogenolysis of paraffins, and ammonia or Fischer-Tropsch synthesis. Controlled surface reactions such as oxidation-reduction reactions ° or surface organometallic chemistry (SOMC) " are two suitable methods for the synthesis of mono- or bimetallic particles. However, for these techniques. 

Dealkoxylation (see Hydrogenolysis, Reduction of acetals and ketals) Debenzylation (see Reduction reactions) Debromination (see Elimination reactions)... 

The most established technology for treating contaminants by abiotic reduction reactions relies on zero-valent iron metal (82). In addition to effecting hydrogenolysis (Equation (4)) and reductive elimination (Equation (5)), Fe° readily reduces nitro aromatics (Equation (6)), azo dyes, nitrate, chromate, chlorine residual, and some radionuclides. Recently, an investigation of soils contaminated with the herbicide alachlor provided evidence for reductive N-dealkylation (as well as dechlorination) by Fe° (83). 

Hydrogenation of anilines usually affords a saturated amine as the major product, but several side reactions, including hydrogenolysis, reductive hydrolysis, and reductive coupling, may accompany and even dominate the reduction. Hydrogenolysis is important only in certain activated molecules (10). 

Other reactions that may occur before the PK are hydrogenolysis, reductions of the alkyne complex and, when using dienes as the alkene part, a Diels-Alder reaction. When hydrogenolysis is observed in enynamides or enynethers, the resulting products usually do not cyclize, so no PK products are obtained [136]. One interesting case of previous reduction of a cobalt-hexacarbonyl complex, shown in Scheme 34, implied that in the presence of TFA, part of complex 121 was reduced to alkene 122 which reacted further with other complex molecules to give the PK product 123 [137]. 

Reductive amination. Reductive amination of 3-ketosteroids with ammonia, hydrogen, and Pd-C gives 3)3-aminosteroids, but in poor yield. It is preferable to use benzylamine the intermediate secondary amine undergoes hydrogenolysis. The reaction is selective for 3-ketosteroids carbonyl functions at C17 and Cm are not affected. Thus hydrogenation of progesterone in the presence of benzylamine and Pd-C afforded 3/3-amino-5)3-pregnane-20-one in 71% yield. 

ESI Reaction monitoring and mechanistic studies (Negishi cross-coupling, hydrogenolysis, reductive amination) Yan eta/. [331]... 

Our results showed that the hydrogenation of benzaldehyde over perovskite catalysts depended on chemical compositions. CaTiOs is more active than the substituted perovskites. Benzene, hydrogenolysis product, is the main product formed over CaTiOs catalyst and toluene, hydrogenation product, over substituted perovskites. In conclusion, the perovkite oxides can be used as catalysts in reduction reactions and their catalytic properties depend of the subtitution degree of Ca, Ti and oxygen by Mg, Li and F respectively. 

Hydrogenolysis of aryl and alkenyl halides and triflates proceeds by the treatment with various hydride sources. The reaction can be explained by the transmetallation with hydride to form palladium hydride, which undergoes reductive elimination. Several boro hydrides are used for this purpose[680], Deuteration of aromatic rings is possible by the reaction of aryl chlorides with NaBD4681]. 

The Pd-catalyzed hydrogenoiysis of acyl chlorides with hydrogen to give aldehydes is called the Rosenmund reduction. Rosenmund reduction catalyzed by supported Pd is explained by the formation of an acylpalladium complex and its hydrogenolysis[744]. Aldehydes can be obtained using other hydrides. For example, the Pd-catalyzed reaction of acyl halides with tin hydride gives aldehydes[745]. This is the tin Form of Rosenmund reduction. Aldehydes are i ormed by the reaction of the thio esters 873 with hydrosilanes[746,747]. 

Purines, N-alkyl-N-phenyl-synthesis, 5, 576 Purines, alkylthio-hydrolysis, 5, 560 Mannich reaction, 5, 536 Michael addition reactions, 5, 536 Purines, S-alkylthio-hydrolysis, 5, 560 Purines, amino-alkylation, 5, 530, 551 IR spectra, 5, 518 reactions, 5, 551-553 with diazonium ions, 5, 538 reduction, 5, 541 UV spectra, 5, 517 Purines, N-amino-synthesis, 5, 595 Purines, aminohydroxy-hydrogenation, 5, 555 reactions, 5, 555 Purines, aminooxo-reactions, 5, 557 thiation, 5, 557 Purines, bromo-synthesis, 5, 557 Purines, chloro-synthesis, 5, 573 Purines, cyano-reactions, 5, 550 Purines, dialkoxy-rearrangement, 5, 558 Purines, diazoreactions, 5, 96 Purines, dioxo-alkylation, 5, 532 Purines, N-glycosyl-, 5, 536 Purines, halo-N-alkylation, 5, 529 hydrogenolysis, 5, 562 reactions, 5, 561-562, 564 with alkoxides, 5, 563 synthesis, 5, 556 Purines, hydrazino-reactions, 5, 553 Purines, hydroxyamino-reactions, 5, 556 Purines, 8-lithiotrimethylsilyl-nucleosides alkylation, 5, 537 Purines, N-methyl-magnetic circular dichroism, 5, 523 Purines, methylthio-bromination, 5, 559 Purines, nitro-reactions, 5, 550, 551 Purines, oxo-alkylation, 5, 532 amination, 5, 557 dipole moments, 5, 522 H NMR, 5, 512 pJfa, 5, 524 reactions, 5, 556-557 with diazonium ions, 5, 538 reduction, 5, 541 thiation, 5, 557 Purines, oxohydro-IR spectra, 5, 518 Purines, selenoxo-synthesis, 5, 597 Purines, thio-acylation, 5, 559 alkylation, 5, 559 Purines, thioxo-acetylation, 5, 559... 

The last isomer, the so-called aldotripiperideine (185), is obtained by the action of acid catalysts on a-tripiperideine at its boiling point (298,299), or in aqueous solution at pH 9.2 and 100°C. Further aldol reaction between tetrahydroanabasine and A -piperideine obviously occurs. Hydrogenolysis of this compound gives dihydroaldotripiperideine (186) which is convertible into matridine (187), a reduction product of the alkaloid matrine. 

The monoimines of the substituted -diketones formed can usually be isolated but sometimes they undergo further reactions. Thus, 5-substituted 3-chloroisoxazoles yield / -ketonitriles, and hydrogenation of 5-acylaminoisoxazoles (174) is a general method of synthesizing 4-hydroxypyrimidines (175). 2 3,214 One should note the increased stability of the isoxazole ring in styrylisoxazoles toward reduction. No hydrogenolysis of the 0—N... 

Under the conditions used for the reductive cleavage of the O—N bond in isoxazoles, a similar reaction readily occurs with isoxa-zolines, e.g. on treatment with organomagnesium compounds and on catalytic hydrogenation.- Hydrogenolysis of the O—N bond (180 181 182 183) was used to elucidate the structure of isoxa-zolones from -ketoesters. -... 

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