Hydrazides Raney nickel

The product is hydrogenated in 4,000 cc of ethanol at room temperature and under normal atmospheric pressure with a catalyst prepared In the usual manner from 400 g of Raney nickel alloy. The calculated amount of hydrogen is taken up in approximately 75 hours. After filtration and evaporation to a small volume, the residue Is distributed between 1,000 cc of chloroform and water each. The chloroform solution is then dried over sodium sulfate and evaporated to a small volume. Precipitation of the hydrogenation product with petroleum ether yields an amorphous white powder which Is filtered by suction, washed with petroleum ether and dried at 50°C In a high vacuum. 1. athyl-2-podophyllinic acid hydrazide is obtained in a practically quantitative yield. 

Bromonaphthalene has been reduced to naphthalene in good yield by hydrogenation over Raney nickel in methanolic potassium hydroxide, by triphenyltin hydride in benzene, by magnesium in isopropyl alcohol, by sodium hydrazide and hydrazine in ether, and by copper(I) acetate in pyridine. ... 

Hydrolysis of the homologous esters has been reported but the direct amidation of these esters failed.131 133,261 The 3-acetamide derivative was prepared from the corresponding hydrazide with the aid of Raney nickel.131,133... 

Thiazolecarboxylic acids, esters or acid chlorides react readily with ammonia or various amines, affording the corresponding carboxamides. Dehydration of the amides with phosphorus pentoxide or phosphoryl chloride occurs readily and gives the corresponding nitriles (Scheme 99). Thiazolecarboxylic acid hydrazides are obtained in a similar way, using hydrazine or substituted hydrazines instead of ammonia or amines. The Raney nickel reduction of cyanothiazoles leads to the corresponding amino compounds, the 4-cyano derivative being the isomer most readily reduced. 

Finally, the hydrazides 3 5 are easily transformed to the corresponding enantiomerically pure a-hydrazino and a-amino acid derivatives16. In a representative example hydrazido acid 3 (R = C6H5) is esterified (CH2N2) and deprotected to 6 with trifluoroacetic acid. The resulting solution is directly hydrogenated over a Raney nickel catalyst. The unpurified amino acid is acylated with ( + )-(5 )-methoxy(trifluoromethyl)phenylacetyl chloride [( + )-MTPA-Cl], to afford the amide 7 in 99% overall yield for the three steps. 

The 3-hydroxypyrazolopyrazine (54) undergoes reductive ring-opening with Raney nickel. A lower reaction temperature suffices for its 1-methyl derivative (Scheme 21) (58JA421). This reaction often succeeds with cyclic hydrazides of this type. 

Hydrazides are hydrogenated by a substantial excess of Raney nickel. Phenylhydrazides are reduc-tively cleaved over palladium/charcoal as catalyst, and the corresponding amides are obtained in good... 

Hydrazides into Amides or Amines 759 TFA-SmI2 233,481,760 peracids 761 Raney nickel 405,432,460,762-765 sodium in liquid ammonia 762,766 N203 or NaN02/H0Ac 767,768 H2/Pt411,769,770... 

Tetrahydroindoxazene-3-carboxylic acids (89) are transformed into 3-amino-2-phenyl-4,5,6,7-tetrahydroindazoles by boiling phenylhydra-zine.98 On reduction with hydrogen and Raney nickel in ethanol, the acid hydrazides of 89 undergo ring opening to the imines 90 followed by cyclization to 4-amino-5,6,7,8-tetrahydrocinnolin-3-ones." The phenylhydrazone of 3-benzoyl-4,5,6,7-tetrahydroindoxazene behaves similarly.100... 

Hydrazides of carboxylic144 148 and sulfonic acids144,148,149 are cleaved to amides by hydrogenation over Raney nickel in boiling alcohol ... 

General procedure A mixture of a hydrazide (1-2 g), 95% ethanol (100 ml), and Raney nickel (10 g) is stirred and heated under reflux for 3 h, then filtered and evaporated. The residue is extracted with hot water or benzene. As the extract cools, the amide is obtained in 60-80% yield. 

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