Raney nickel catalytic hydrogenation with

Reduction. Just as aromatic amine oxides are resistant to the foregoing decomposition reactions, they are more resistant than ahphatic amine oxides to reduction. Ahphatic amine oxides are readily reduced to tertiary amines by sulfurous acid at room temperature in contrast, few aromatic amine oxides can be reduced under these conditions. The ahphatic amine oxides can also be reduced by catalytic hydrogenation (27), with 2inc in acid, or with staimous chloride (28). For the aromatic amine oxides, catalytic hydrogenation with Raney nickel is a fairly general means of deoxygenation (29). Iron in acetic acid (30), phosphoms trichloride (31), and titanium trichloride (32) are also widely used systems for deoxygenation of aromatic amine oxides. 

Nickel(II) chlorophyll derivatives undergo catalytic hydrogenation with Raney nickel as catalyst to yield stereoisomeric isobacteriochlorins in which ring A of the chlorophyll derivatives is reduced.16... 

Nakazaki s synthetic approach is conspicuous by its remarkable straightforwardness it has been proved to be so far the simplest synthetic route to the target compounds. In their first synthesis of 61a54a), Nakazaki and coworkers started from cyclododecyne (62a), whose oligomerization with two molecules of butadiene afforded the bicyclic 63a. The cis[10.8] precursor 64a, obtained by partial catalytic hydrogenation with Raney nickel catalyst, was dissolved in cyclohexane, which contained xylene as photosensitizer, and the solution was irradiated with a medium pressure Hg lamp for 12 h. Examination of the reaction mixture by means of GLC indicated that the product was a 2.4 1 mixture of (Z) 64a and (E) 61 a, and the further study54b) showed that this ratio could be raised to 1 2 by irradiation of a hexene solution with a low pressure Hg lamp. 

The starting material in our synthesis was cyclododecyne whose oligomerization with two moles of butadiene gave the bicyclic triene 44, which in turn was converted into the cis doubly bridged ethylene 46 by partial catalytic hydrogenation with Raney nickel. Irradiation of 46 with a low-pressure mercury lamp in cyclohexane led to a 1 2 cis-trans mature, from which the trans isomer48, m.p. 37-38°C, was isolated after removal of the unchanged cis isomer as a dichlo-rocarbene adduct. 

The use of formic acid for reduction of enamines is so characteristic that this reaction can be used for detection of the enamine group.128,129 Even enamines that are resistant to catalytic hydrogenation with Raney nickel or palladium can be reduced smoothly by formic acid.130... 

Reduction of cyclopropyl methyl ketone has been attempted by four different methods 415 Only poor yields of the alcohol were obtained by use of sodium and alcohol on use of LiAlH4 difficulties were encountered for larger batches and catalytic hydrogenation with Raney nickel caused partial cleavage of the cyclopropane ring however, excellent yields of 1-cyclopropylethanol were obtained in the presence of a copper-chromium oxide catalyst activated by barium, at 100°. 

The carbonyl group of ketones and aldehydes can be reduced by catalytic hydrogenation, with Raney nickel as the metal catalyst. (Raney nickel is finely dispersed nickel with adsorbed hydrogen, so an external source of H2 is not needed.) Aldehydes are reduced to primary alcohols, and ketones are reduced to secondary alcohols. 

The use of primary amines instead of ammonia affords l,2-dialkyl-/l -pyrrolines or l,2-dialkyl-/l -piperideines. Amino ketones with a primary amino group are intermediates in the reduction of y-nitropropylalkyl ketones (14,15) or S-nitrobutylalkyl ketones (16-18) by catalytic hydrogenation over Raney nickel or with zinc and hydrochloric acid (Scheme 1). 

Epimerization of 50 at C-3 furnished carba-a-DL-allopyranose (60). Stepwise, 0-isopropylidenation of 50 with 2,2-dimethoxypropane afforded compound 56. Ruthenium tetraoxide oxidation of 56 gave the 3-oxo derivative 57, and catalytic hydrogenation over Raney nickel converted 57 into the 3-epimer 58 exclusively. Hydrolysis of 58, and acetylation, provided the pentaacetate 59, which was converted into 60 on hydrolysis. ... 

The JV-oxide of (l,4-benzodiazepin-2-ylidene)malonate (503, R = H, n = 1) was deoxygenated by catalytic hydrogenation over Raney Nickel in a mixture of methanol and THF at atmospheric pressure for 5 hr (83USP4401597) and by treatment with phosphorus trichloride in methylene chloride at ambient temperature overnight (75JOC153 83USP-4401597). 

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. ... 

The 6-oxopyrido[l,2-a] pyrimidine remained unchanged on catalytic hydrogenation (PtOz, Raney nickel) but decomposed when treated with lithium aluminum hydride.255 The oxo group of the 6-oxo-9a-phenylpyrido-[l,2-a]pyrimidine (179) was reduced with lithium aluminum hydride.230,232 On reduction with sodium borohydride, the 2-phenylpyrido[l,2-a]pyrimi-dine (184) gave the piperidine derivative (182).240,241 The 6-oxoperhydro-pyrido[ 1,2-a]pyrimidines were acylated at the N-l atom with dichloroacetyl chloride.343... 

Catalytic Reductions with Raney Nickel in the Presence of Various Types of Hydrogen... 

NTII was prepared by reacting naltrexone with (4-nitrophenyl)hydrazine to form 5 -nitroindole (142) which was reduced by catalytic hydrogenation over Raney nickel to the 5 -amino derivative (143). Treatment with thio-phosgene yielded NTII [203]. 

Certain aryl-substituted a- and /S-amino Intones have been successfully reduced to amino alcohols by catalytic hydrogenation over palladium, platinum, or nickel catalysts. Cleavage of the carbon chain sometimes occurs during catalytic hydrogenation of /S-amino ketones. Fair yields of the amino alcohols ate obtained in these cases by reduction with sodium amalgam in dilute acid or aluminum amalgam and water. /S-Amino aldehydes from the Mannich reaction (method 444) are reduced in excellent yields to amino alcohols by lithium aluminum hydride or by catalytic hydrogenation over Raney nickel. Lithium aluminum hydride reduces diazo ketones to 1-amino-2-alkanols (93-99%)- ... 

JV-Hydroxy functions can be removed by catalytic hydrogenation over Raney nickel, and an unprecedented dehydroxylation occurs when l-hydroxyl-2-methyl-5-phenylimidazole is treated in turn with butyl lithium and hexachlorodisilane." Dehydrogenation of l-hydroxy-2,4,5-triphenylimidazole and its 3-oxide produces the 1-oxide and 1,3-dioxide, respectively. JV-Hydroxyimidazole esters can act as acyl transfer reagents. ... 

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