Raney nickel hydrogen

Sulfolane (tetramethylenesulfone) [126-33-0] M 120.2, m 28.5 , b 153-154 /18mm, 285 /760mm, d 1.263, n 1.4820. Prepared commercially by Diels-Alder reaction of 1,3-butadiene and sulfur dioxide, followed by Raney nickel hydrogenation. The principle impurities are water, 3-sulfolene, 2-sulfolene and 2-isopropyl sulfolanyl ether. It is dried by passage through a column of molecular sieves. Distd... 

A solution of 10 g of 9 10-dihydro-9 10-ethano-(1 2)-anthracene-(9)aldehyde (made from anthracene and acrolein) and 10 g of monomethylamine in 100 cc of ethanol is heated at 80°C for 4 hours in an autoclave. The reaction mixture is then evaporated to dryness under reduced pressure to leave a crystalline residue which is dissolved in 150 cc of ethanol and, after the addition of 2 g of Raney nickel, hydrogenated at 40°C under atmospheric pressure. When the absorption of hydrogen has subsided, the catalyst is filtered off and the filtrate evaporated under reduced pressure. An oil remains which is covered with 100 cc of 2N hydrochloric acid. The 9-methylamino-methyI-9 10-dihydro-9 10-ethano-(9 10)-anthracene hydrochloride crystallizes immediately after crystallization from methanol it melts at 320°-322°C. 

Raney nickel hydrogenation of aromatic and aliphatic nitriles in ethanol containing 4 equivalents of phenyl hydrazine gives 90% of aldehydes. 

Kozikowski and Stein (281) used the INOC strategy to prepare the 2-methyle-necyclopentanone derivative 172, which in turn was converted to sarkomycin (173), an antitumor agent (Scheme 6.81). The key step involved the treatment of nitroalkene 169 (obtained from bromide 168) with p-chlorophenyl isocyanate-triethylamine, which furnished a single diastereomeric isoxazoline 170 in 55% yield. This compound was transformed to the aldol product 171 by Raney nickel hydrogenation using wet acetic or boric acid, followed by dehydration to the a,p-enone 172 (281), a precursor of 173. 

Cyanoethyl groups can be conveniently reduced to 2-aminoethyl groups using Raney nickel-hydrogen to give 2-aminoethyl-substituted ortho esters [149] (Eq. 49). 

Raney nickel hydrogenation. The principle impurities are water, 3-sulpholene, 2-sulpholene and 2-isopropyl... 

In 2005, the Yamanouchi process group (postacquisition by Astellas) reported further refinements of their initial synthesis of conivaptan HCl (1), leading to a process for the multikilogram synthesis of l.34 Key features of this second-generation process route included (1) improved overall yield, (2) increased synthetic convergence, (3) elimination of the use of chlorinated solvents, and (4) elimination of the Raney nickel hydrogenation. 

Raney nickel hydrogenation, produced an epimeric mixture of hydroxy-esters (446 R = C02Et) and diols (446 R = CH2OH). Treatment of the corresponding hydroxy-acids (446 R = CO2H) with methyl-lithium, followed by Jones oxidation, yielded the two epimeric diketones (447) in the ratio 9 1. Aldoliza-tion of (447 / -Me) with potassium t-butoxide gave epipatchoulenone (448 R = H, R = Me) while similar treatment of (447 a-Me) afforded patch-oulenone (448 R = Me, R = H). 

Bis[2-nitrobenzoyl] and bis[4-nitrobenzoyl] tellurium dichlorides were reduced to the corresponding amino derivatives by Raney Nickel/hydrogen or hydrazine. The bis[ami-nobenzoyl] tellurium dichlorides were converted to the hydroxy derivatives via the diazonium salts. The same hydroxy derivatives were obtained through demethylation of the methoxy compounds with aluminum trichloride . ... 

Raney nickel hydrogenation of nitriles is aqueous acetic acid or in aqueous acetic acid-pyridine in the presence of sodium hypophosphite (NaH PO-i), which becomes oxidized to the phosphate, converts the nitriles into the corresponding aldehydes. The reaction takes place at room temperature and pressure. Yields are in the range 50-90%. Thus a solution of 1 g. of benzonitrile and 2 g. of hydrated sodium hypo-phosphite in 29 ml. of a 1 1 2 water-acetic acid-pyridine mixture was stirred with 0.3-0.4 g. of Raney nickel at 40-45° for 1 hr. benzaldehyde was isolated as the 2,4-dinitrophenylhydrazone. 

Kenner and Murray found that Raney nickel hydrogenation reduces phenyl tosylates to the corresponding hydrocarbons, at room temperature and pressure." Other examples. On the other hand, tosylates of aliphatic alcohols are merely hydrolyzed to the corresponding alcohols. "... 

Nlirtles. Aromatic " and aliphatic nitriles on Raney nickel hydrogenation in elhanol containing phenylhydrazine are reduced to the aldehydes, which are trapped HN Ihc phenylhydrazones (8 hrs. at atmospheric pressure or 5 hrs. under pressure). Yields are around 30 K< if I equivalent of phenylhydrazine is used but are increased to about 90%> by use of 4 equivalents of the reagent. 

Reduction to Alcohols — The industrial scale reduction involves either NaBH4 or electrochemical and catalytic (Raney nickel) hydrogenation. Resulting open-chain polyols, the sugar alcohols (5.12 and 5.13), have a new chiral center. In consequence, each ketose (5.14) yields two alcohols, whereas aldoses (5.11a and 5.11b) yield only one alcohol. 

Reactions of 4,7-phenanthroline-5,6-dione have been the subject of considerable study. It is reduced to 5,6-dihydroxy-4,7-phenanthroline by Raney nickel hydrogenation or by aromatic thiols in benzene, and oxidized by permanganate to 3,3 -bipyridyl-2,2 -dicarboxylic acid. It forms bishemiketals with alcohols and diepoxides with diazomethane. The diepoxides by reaction with hydrochloric acid form diols of type 57, R = Cl, which on oxidation with lead tetraacetate give 3,3 -bipyridyl diketones of type 58, R = Cl. Methyl ketones of type 58, R = H, are also obtained by lead(IV) acetate oxidation of the diol 57, R = H, obtained by lithium aluminum hydride reduction of 57, R = Cl. With phenyldiazomethane and diphenyldiazomethane the dione forms 1,3-dioxole derivatives, which readily hydrolyze back to the dione with concomitant formation of benzaldehyde and benzophenone, respectively. 

Aimed at investigating the taste enhancing activity of the individual enantiomers of alapyridaine, enantiopure 1 was prepared upon reductive animation of 5-(hydroxymethyl)-2-furanaldehyde and L-alanine with Raney nickel/hydrogen. This reaction resulted in the corresponding ( S)-A -(1-carboxyethyl)-2-hydroxymethyl-5-(methylamino)furan (Figure 7). The latter was converted into the target pyridinium betain compound by mild oxidation with bromine in water/methanol to yield (+)-(iS)-l. Similarly, the reaction with D-alanine resulted in (-)-(R)-l. After purification, the presence of (5)-l and (R)-1 was proven by polarimetry, revealing optical rotations of +40.2° and -38.6°, respectively (72). 

Condensation of diethyl butyl malonate and />-benzyloxyhydrazo-benzene is done in the presence of sodium ethoxide in anhydrous ethanol to yield l-(benzyloxy)-2-phenyl-4-butyl-3, 5-pyrazolidinedione. The reaction mixture is heated with xylene to about 140°C for several hours which aids in the removal ethanol eliminated by cyclization. The resulting product is debenzylated by the aid of Raney Nickel hydrogenation at an ambient temperature and pressure. The crude product may be recrystallized from ether/petroleum ether. 

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