Nickel and hydrogen

From 13.1 g of N-preduction with Raney-nickel and hydrogen, in which reaction the substance may be suspended in methanol or dissolved in methanol-ethyl acetate at normal pressure and at about 40°C with combination of the theoretical quantity of hydrogen, 12.2 g are obtained of o-emino-N-pfrom aqueous methanol hasaMPof90°C. 

The deposit resists atmospheric tarnish even in the presence of high pollution by sulphur dioxide (in contrast to nickel) and hydrogen sulphide, and coatings exposed to the outdoor atmosphere remain bright indefinitely, sometimes taking on a slightly more pink colour as the oxide film thickens. 

Partial reduction of l-aryl-8-chloro-3-methoxy-3//-2-benzazepines, e.g. 8, to their 4,5-dihydro derivatives, e.g. 9, is effected in low yield with Raney nickel and hydrogen at room temperature.78... 

T-4)-J or Raney nickel and hydrogen.8 Alcohols of the benzylic type have also been reduced directly with hydrogen under pressure in the presence of various catalysts,9 and benzoic acids have been reduced to toluenes with rhenium-type catalysts and hydrogen at high temperatures and pressures.10... 

The reduction of 2 - 2 -fluoroethoxyethyl cyanide, using Raney nickel and hydrogen, was examined under a variety of conditions. Defluorination readily took place, but finally conditions were found which permitted the conversion of CN to CHa NH2 without the removal of the fluorine atom, giving 3-2 -fluoro-ethoxypropylamine as a stable distillable liquid. 

Cyclododecene may be prepared from 1,5,9-cyclododecatriene by the catalytic reduction with Raney nickel and hydrogen diluted with nitrogen, with nickel sulfide on alumina, with cobalt, iron, or nickel in the presence of thiophene, with palladium on charcoal, with palladimn chloride in the presence of water, with palladium on barium sulfate, with cobalt acetate in the presence of cobalt carbonyl, and with cobalt carbonyl and tri- -butyl phosphine. It may also be obtained from the triene by reduction with lithium and ethylamine, by disproportionation, - by epoxidation followed by isomerization to a ketone and WoliT-Kishner reduction, and from cyclododecanone by the reaction of its hydrazone with sodium hydride. ... 

Reductions of these ring systems are common. Most often, active hydrogen techniques are employed to cleave weak heteroatom-heteroatom bonds. Reductions of the glycoluril derivatives are less common due to the lack of such a weak bond. Some recent examples include reactions by Chan et al. <2003TL395> who employed Raney nickel and hydrogen to effect cleavage of an N-O bond in their synthesis of new heterocyclic compounds via 1,3-dipolar cycloaddition chemistry (Equation 15). 

Catalytic reduction of pyrroles gives successively A3-pyrroles and pyrrolidines. Tetrahydrofurans are formed by the catalytic reduction of furans with Raney nickel and hydrogen ring cleavage products... 

Iodo-desoxy derivatives of methylene, benzylidene and isopropylidene compounds have been transformed into their desoxy analogues with Raney nickel and hydrogen in basic media (e.g. hydroxides, methoxides and diethylamine). 0 47,60,81,82 Under similar conditions, l,3 2,4-diben-zylidene-5,6-sorbitoleen has been hydrogenated 8 and 2,4-benzylidene-6-nitro-6-desoxy-D-sorbitol has been converted into the corresponding amine.84 We are not aware of any report in this field of the removal of a benzylidene group by Raney nickel, as is the case with certain sugar derivatives.88... 

The reduction of nitroalcohols to aminoalcohols is complicated to some extent by the instability of the nitroalcohols in the presence of bases due to the reversal of the aldehyde-nitroparaffin condensation reaction. This reduction can be carried out smoothly, however, with Raney nickel and hydrogen.21 Thus the interesting sugar aminoalcohols are readily available from the corresponding sugar nitroalcohols. 

Halogens in the allyl position seem to be readily replaceable by hydrogen. Anglade (110) treated bis-2,4-(chloromethyl)anisole with Raney nickel and hydrogen in alcohol at ordinary temperatures. A 25% yield of 2,4-dimethylanisole was obtained, with ethyl ether formed as a by-product by interaction with the solvent. 

The condensation of tryptamine (XXVI) with the glutaric ester XCIX in the presence of Raney nickel and hydrogen yields a pair of isomeric lactams (Ca and Cb) of which the former on cyclization with phosphorus oxychloride followed by catalytic reduction gave the... 

A new method of synthesis162 of the imidazole ring by the use of A-cyaniminodithiocarbonic esters (41) involves formation of the 4 5-bond. Reaction of (42) with KNCO in acetic acid yielded the corresponding amide (43) which was cyclized by sodium hydroxide to the substituted purine (44). Treatment of (42) with Raney nickel and hydrogen produced 4-amino-5-carbethoxy-l-methyl-4-imidazo-line (45), which could also be cyclized to a purine (46).162... 

Raney nickel was recommended as a convenient reagent for desulfurization of phenothiazine, and it has been used in many structural investigations. More recently, the method has been applied to various phenothiazines, - in its classical form, that is Raney nickel and hydrogen, as well as in some modified variants. Thus, working with a special Raney nickel, without hydrogen, 1,3,7,9-tetrachlorophenothiazine was desulfurized without dehalogenation the usual procedure leads, for example, to diphenylamine, when applied to 3,7-dichlorophenothiazine. ... 

Both exo- and endo-cyclic alicyclic and heterocyclic ketones have been reduced. Important examples are found in the preparations of cyclo-pentanol (95%), cycloheptanol (92%), /S-pyridylmethylcarbinol (85%), and l-alkyl-4-piperidinols (90%). A comparison of four reagents—sodium and alcohol, lithium aluminum hydride, hydrogen and Raney nickel, and hydrogen and copper-chromium oxide—has been made in the preparation of methyl cyclopropylcarbinol. The last method is superior for the preparation of this compound (SH)%). ... 

Hydrogenolysis of compounds with sulfur atoms attached to aromatic rings such as benzenethiols, and aryl sulfides, disulfides, sulfoxides and sulfones takes place on refluxing with Raney nickel or nickel boride. Sulfur combines with nickel, and hydrogen replaces the sulfur-containing group. 

Assumptions Nickel and hydrogen are in thermodynamic equilibrium at the interface. 

The complex [Ni(2,3-Me2[14]-l,3-diene-l,4,8,lI-N4)] [ZnCU] is square planar and low-spin. The visible spectra show bands near 21.3 kK (characteristic of square planar nickel(II)), near 26.1 kK (due to the imine functions), and near 35.1 kK. The infrared spectra of all of the nickel complexes prepared show absorptions near 3195 and 1595 cm assignable to the N—H stretching vibration and to the symmetric imine vibration, respectively. A strong sharp band also occurs near 1210 cm and is characteristic of the a-diimine function. The NMR spectrum of the perchlorate complex in nitromethane shows a methyl singlet at 2.33 ppm. The ligand can be hydrogenated on nickel(II) with Raney nickel and hydrogen to produce the fully saturated macrocyclic complex [Ni(2,3-Me2[14]-ane-1,4,8,1 1-N4] ... 

In order to reduce the crystallinity of the polyketal an unsymmetrical cyclic diketone was prepared from 2,7-dihydroxy-naphthalene. Reduction of the naphthalene nucleus with Raney nickel and hydrogen gave a 90% yield of the 2,7-decalindiol, which on oxidation with chromic acid gave a 50% yield of the 2,7-deca-lindione. When this diketone was condensed with the tetrakis-(hydroxymethyl) cyclohexane, an 89% yield of a white polymer VIII was obtained which did not melt and was soluble only in hexa-fluo ro isopropano1. 

Reduction of the o-nitrobenzoyl derivative of 185 (R = NH2) with Raney nickel and hydrogen brings about ring transformation to 5,6,7,8-tetrahydro-2-(o-aminophenyl)pyrimidin-4-one.269... 

Thionyl chloride has been used to convert the alcohol 56 into the cyclized quaternary salt 57. Reduction of the nitrile 58 with Raney nickel and hydrogen gave the 1-oxo compound 60 (R = H), ° presumably by way of the intermediate 59. This intermediate is also involved in the preparation of compound 60 (R = H) by treatment of the ester 61 with ethyleneimine. The optically active ester 61 has been converted by this route into perhydropyrido[l,2-a]pyrazines of known configuration. When this reaction was repeated with the methyl-substituted piperidine... 

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