McFadyen-Stevens reaction

A.ldehyde Syntheses. Aromatic (Ar) carboxylic acids are reduced to the corresponding aldehydes by a sequence of steps known as the McFadyen-Stevens reaction. The acid is converted to the hydrazide, derivatized with benzenesulfonylchloride, then decomposed to the aldehyde in hot glycol in the presence of a base ... 

Aldehydes have also been obtained by lithium trialkoxyaluminum hydride reduction of 5-nitriles or 5-acid chlorides, and, as the thio-semicarbazones, by the McFadyen-Stevens reaction in surprisingly good yields (50-60%) considering the severity of the reaction conditions. ... 

Formyl-3-methylisothiazole is prepared by hydrolysis of the appropriate Reissert compound and, as the thiosemicarbazone, in poor yield by the McFadyen-Stevens reaction. 4-Formylisothiazole has been obtained by oxidation of 4-methylisothiazole although no details of the preparation have been reported. 

McFadyen-Stevens reaction, 13 571 McGaskell rotary pressure filter, 11 374 McLafferty ester pyrolysis reaction, 20 43 MCLs (maximum contaminant levels), 17 804... 

Bamford, W. R. Stevens, T. S. M. J. Chem. Soc. 1952, 4735. Thomas Stevens (1900-2000), a chemist centenarian, was bom in Renfrew, Scotland. He and his student W. R. Bamford published this paper at the University of Sheffield, UK. Stevens also contributed to another name reaction, the McFadyen—Stevens reaction (page 354). 

In the McFadyen-Stevens reaction, microwave irradiation has also been employed to convert carboxylic acids to aldehydes via the p-toluenesulphonyl hydrazides65. The p-toluenesulphonyl hydrazide is mixed with sodium carbonate, glass powder and ethylene glycol, and pre-irradiated at 150 W for a few minutes before the actual reaction conditions were applied. The reaction was successfully used in the synthesis of the alkaloid Nauclefidine (Scheme 4.40). 

McFadyen-Stevens reaction. Base-catalyzed thermal decomposition of aroylbenzenesulfo-nylhydrazines to aldehydes. 

Other references related to the McFadyen-Stevens reaction are cited in the literature. ... 

Stevens (see McFadyen-Stevens Reaction) Stevens Rearrangement Stieglitz Rearrangement Stille Coupling Stobbe Condensation... 

The use of 2,4,6-tri-isopropylbenzenesulphonylhydrazides (in place of the tosylhydrazide) allows milder conditions to be used for the preparation of aromatic aldehydes by the McFadyen-Stevens reaction. Addition of hydrazine hydrate and traces of cupric sulphate suppresses formation of aromatic ester and alcohol by-products. Reduction of oxazolinium salts by sodium borohydride, as part of the well known sequence for the conversion of carboxylic acids into aldehydes, can lead to ring cleavage to form amino-alcohols. It is now reported that over-reduction is much less marked if potassium tri-s-butylborohydride is used as reducing agent (Scheme 2) ... 

The amides and hydrazides of pyridine-carboxylic acids arc of some importance, though their chemistry is not marked by unusual properties. Nicotinamide is, of course, an important compound, and isonicotinic acid hydrazide (isoniazid) is an antitubercular drug. Substituted derivatives are used as antidepressants. In general, however, these compounds show normal chemical behaviour. The amides undergo hydrolysis, dehydration and Hofmann bromination without difficulty. Their reduction has been much studied as a route to pyridine aldehydes. The Sonn-Muller reduction is not very satisfactory in this series, but the McFadyen-Stevens reaction is useful . Nicotinic acid diethylamide gives only poor yields of the aldehyde upon reduction with lithium aluminium hydride, but yields from the methyl-phenylamide are high. Most satisfactory is the reduction of nicotinic acid dimethylamide with lithium diethoxyaluminium hydride . 

The Darzens reaction and the McFadyen-Stevens reaction are also useful aldehyde syntheses involving elimination reactions. 

Malonic ester synthesis, 60, 74 Mannich reaction, 157 Markovnikoff addition, 178 anti-, 178, 180 Markovnikoff s rule, 29 McFadyen-Stevens reaction, 50 Michael condensation, 157 Michael reaction, 94... 

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