Oxidation carboxylic acid amides

The preparation of acyliminium ions is not restricted to aldehyde or ketone derivatives as starting materials, but can also use the more highly oxidized carboxylic acid amides as precursors, e.g. reduction of imides (66) affords (67 Scheme 33). For constitutionally unsymmetrical imides, regiocontrol can be achieved in many cases by the choice of the appropriate hydride-transfer reagent. ... 

Bahrami K, Khodaei MM, Farrokhi A (2009) Highly efficient solvent-free synthesis of dihydropyrimidinones catalyzed by zinc oxide. Synth Commun 39 1801-1808 74. Gross GA, Wurziger H, Schober A (2006) Solid-phase synthesis of 4,6-diaryl-3,4-dihydro-pyrimidine-2(lH)-one-5-carboxylic acid amide derivatives a Biginelli three-component-condensation protocol based on immobilized beta-ketoamides. J Comb Chem 8 153-155 Desai B, Dallinger D, Kappe CO (2006) Microwave-assisted solution phase synthesis of dihydropyrimidine C5 amides and esters. Tetrahedron 62 4651 664 Kumar A, Maurya RA (2007) An efficient bakers yeast catalyzed synthesis of 3,4-dihydro-pyrimidin-2-(lH)-ones. Tetrahedron Lett 48 4569-4571 77. Zalavadiya P, Tala S, Akbari J, Joshi H (2009) Multi-component synthesis of dihydropyrimidines by iodine catalyst at ambient temperature and in-vitro anti mycobacterial activity. Arch Pharm 342 469-475... 

Arylhydrazides can serve as safety-catch linkers for C-terminal carboxylic acids, amides, or esters. Cleavage proceeds via oxidation with copper(II) salts and subsequent cleavage of the diazenyl moiety by means of a nucleophile [39] (Scheme 6.1.8). 

Diaryl tellurium oxides and carboxylic acid amides react in refluxing chloroform to produce diaryl tellurium imides6,7. Sulfonamides react similarly4 8. 

An example of a more standard, carboxyhc acid amide functionalised imidazolium salt and its apphcations come from the Ghosh group [120]. They reacted chloroacetic acid anilide with A-mesityl imidazole and obtained the respective carboxylic acid amide functionalised imidazolium salt which was reacted with sUver(I) oxide to form the corresponding silver(l) carbene complex featuring two trans-coordinated carbene ligands on the silver(I) ion (see Figure 4.39). 

The mass spectrum of I-methyl-4-nitroimidazole-5-carboxylic acid amide shows the elimination of water by an electron impact as distinct from the usual thermal process. In l,4,5-trimethylimidazole-2-carboxylic acid the principal loss is that of CO2. Subsequent loss of O, OH, and HCN was also observed (Schofield et al., p. 173). Ferguson and Schofield (pp. 172,173) have reported considerable data for imidazole JV-oxides. Thus 1-methoxy-4,5-dimethyl-2-phenylimidazole (which loses OCH3 and CH3CN from the fragment m/e 171) is readily distinguished from l,4,5-trimethyl-2-phenyl-imidazole 3-oxide (loss of O and OH). The spectra of 1-benzylimidazoles are dominated by the tropylium ion. ... 

In the course of these reactions, P450 3A4 catalyzes examples of some atypical reactions " including desaturation , oxidative carboxylic acid ester cleavage , and oxidation of a nitrile to an amide . An unexpected reaction encountered in this laboratory was the oxidation of alkylphenyl ether non-ionic detergents, which have been commonly used in enzyme purifications and also have some medical and industrial applications . Methylene hydroxylations yield hemiacetals, which break down to shorten the chains . 

Carboxylic acids can be prepared by the oxidation of primary alcohols or aldehydes, the hydrolysis of nitriles, or the hydrolysis of esters which can be used as protecting groups for carboxylic acids. Amides can also be hydrolysed to carboxylic acids. However, drastic reaction conditions are needed due to the lower reactivity of amides and so amides are less useful as carboxylic acid protecting groups. 

Carboxylic acid amides and ketones from enamines by oxidative cleavage... 

The polyketals can be readily derivatized. For example, aldehyde groups of an intermediate product of a polysaccharide oxidation can be converted into alcohol groups, amines, thioacetals, carboxylic acids, amides, esters, or thioesters. 

Electrochemical oxidation of N-subst. carboxylic acid amides 5,6-Dihydro-l,3-oxazinium salts from ethylene derivs. 

Trimethylsilyl) ethoxy acetylene jmercuric oxide 14-dimethylaminopyridine Carboxylic acid amides from carboxylic acids COOH... 

Phosphorus oxide chloride Enamines from carboxylic acid amides s. 17, 890... 

Phosphorus oxide chloride 1,3-Heterocyclics from carboxylic acid amides Benzothiazoles s. 18,671... 

Phosphorus oxide chloride Subst. carboxylic acid amides from carboxylic acids... 

Phosphorus oxide chloride Ring closures with N,N-disubst. carboxylic acid amides O... 

Phosphorus oxide chloride pyridine Nitriles from carboxylic acid amides... 

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