Carboxylic acid thioamides nitriles

Carboxylic acid thioamides from nitriles GN GSNH2... 

Nitriles from carboxylic acid thioamides CSNHg CN... 

Chloroform-sodium hydroxide benzyltriethylammonium chloride Nitriles from carboxylic acid thioamides s. 29, 456... 

Via intermediates Amidines from nitriles via carboxylic acid thioamides and thioiminoester salts... 

Simple isothiazole-4-carboxylic acids have been made from the corresponding nitriles, which are available in turn from the halogeno derivatives, or directly by the olefin route.5-Aminoiso-thiazole-4-esters and -nitriles are readily obtained by the thioamide route. The 4-acids behave normally and form acid chlorides, esters, amides, and hydrazides. In contrast to the 5-series... 

Methylisothiazole-5-carboxylic acid has also been prepared by alkaline hydrolysis of the 5-nitrile. The 5-acids decarboxylate readily at or near their melting points but otherwise behave normally, forming acid chlorides, esters, amides, hydra-zides, and nitriles. The esters undergo the Claisen condensation to form ]8-ketoesters, and the nitriles form thioamides with hydrogen sulfide in pyridine. An anomalous reaction is the reduction of 5-cyano-... 

A few 6- and 8-cyanopurines have been prepared and undergo characteristic nitrile addition reactions rather readily. Thus, alkaline hydrolysis produces carboxamides, then carboxylic acids, alcoholysis leads to imidates, ammonolysis to amidines, hydrazinolysis to amidhydrazines, hydroxylamine to amidoximes, and hydrogen sulfide to thioamides. Acid hydrolysis tends to give the decarboxylated acid derivative. Reduction either by sodium-ethanol or, preferably, by catalytic hydrogenation affords aminoalkylpurines and addition of Grignard reagents produces, in the first place, acylpurines. As with aldehydes, most of the compounds examined have been relatively non-polar derivatives. Table 28 lists some reactions and relevant literature. 

In most cases these C,N2 fragments are prepared by reaction of activated carboxylic acid derivatives (C, fragment), such as dithiocarboxylates 2, thioesters 3. nitriles 5, imidates 6, amidines 7, thioamides 8, selenoamides 9, selenoesters 11, orthocarboxylates 14, with hydrazine (N2 fragment) and are transformed to l,4-dihydro-l,2,4,5-tetrazines 17 without isolation. Therefore, these syntheses are treated as a (2 + 1 +2+1) fragment method. 

Reactions of a silyllithium reagent with carboxylic acid derivatives, including esters, nitriles, acid chlorides, and thioamides, have been extensively investigated by Fleming. He found that the reaction of acid chlorides with 2 equiv. of PhMe2SiLi affords 1,1-disilylalkoxide 80, in... 

Nitriles from carboxylic acid amides and thioamides... 

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