Hydroxamic acids acidity

When primary nitro compounds are treated with sulfuric acid without previous conversion to the conjugate bases, they give carboxylic acids. Hydroxamic acids are intermediates and can be isolated, so that this is also a method for preparing them. Both the Nef reaction and the hydroxamic acid process involve the aci form the difference in products arises from higher acidity, for example, a difference in sulfuric acid concentration from 2 to 15.5 M changes the product from the aldehyde to the hydroxamic acid. The mechanism of the hydroxamic acid reaction is not known with certainty, but if higher acidity is required, it may be that the protonated aci form of the nitro compound is further protonated. 

Rhodotorulic acid Hydroxamic acid 2 Species of Rhodotorula, Sporo-bolomyces, Sporidiobolus, Leuco-sporidium and Rhodosporidium... 

Dimerum acid Hydroxamic acid 2 Fusarium dimerum... 

The identification of the first small molecule HDAC inhibitors in the late seventies triggered an exponential growth in medicinal chemistry activity. Three decades and many thousand compounds later, the availabiUty of diverse HDAC inhibitors such as short-chain fatty acids, hydroxamic acids, benzamides and tetracyclic peptides, has not only enabled the elucidation of the catalytic mechanism underlying the deacetylating capacity of HDACs, but has also assisted in the investigation of the biological role of the various HDAC subtypes. Furthermore, HDAC inhibitors are currently being evaluated in the clinic and have shown therapeutic potential in the treatment of cancer. 

Alternatively, DIBOA and DIMBOA in a THF solution have been methylated witii a solution of diazomethane in diethyl ether at their more acidic hydroxamic acid unit, regioselectively. 

Amides and ureas The sulfonamides undergo functional group exchange on reaction with thiolacetic acid, hydroxamic acids, and R2NC(=S)SH, in the presence of cesium carbonate. Reaction of the sulfonamides with dithioacids affords thioamides. 

Liver Slices Anthranilic acid, hydroxamic acid — 33... 

Carboxylic acid hydrazides from carboxylic acids—Hydroxamic acids from 1-acylimidazoles—Carboxylic acid amides s. 18, 441... 

Con 1 A number of allelopathic agents besides phenolic acids have been identified in wheat tissue/residues, for example, organic acids, hydroxamic acids, and volatile compounds (Patrick 1971 Lynch 1977 Willard and Penner 1976 Tang and Waiss 1978 Buttery et al. 1985 Shilling et al. 1985 Niemeyer et al. 1989 Blum et al. 1991 Wu et al. 2001 Macias et al. 2005 Mathiassen et al. 2006). A number of these are just as or more phytotoxic than simple phenolic acids. 

Analysis of hydroxamic acid. Hydroxamic acid was analyzed by the method of Bergmann and Segal (21). 

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