I Aminobenzoic acid

A chance observation made some time prior to the full structural elucidation of cocaine in fact led to one of the more important lasses of local anesthetics. It was found that the simple ethyl e. ter of p-aminobenzoic acid, benzocaine (25), showed activity. 1-. a local anesthetic. It is of interest to note that this drug, I 1rst introduced in 1903, is still in use today. Once the struc-iiire of cocaine was established, the presence of an alkanolamine iiiniety in cocaine prompted medicinal chemists to prepare esters "I aminobenzoic acids with acyclic alkanolamines. Formula 26 11 presents the putative relationship of the target substances with cocaine. 

Ethyl /i-aminobenzoate may be prepared by adding 274 g. (2 moles) of /i-aminobenzoic acid to 1400 g. of ethyl alcohol which has been saturated with dry hydrogen chloride, and then refluxing the mixture for twenty-four hours. The reaction mixture is poured into water, neutralized with sodimn carbonate, and the insoluble ester is separated by filtration. The yield is 80 per cent of the theoretical amount. 

The preliminary treatment of the nanofiller to make it compatible is carried out with a substance having an affinity for both the montmorillonite and the chosen polymer, e.g., cetyl pyridinium chloride or bromide, hexadecyl trimethylammonium bromide, 7V-[4-(4 -aminophenyl)]phenyl phthalimide, /i-aminobenzoic acid hydrochloride, or a combination of octadecylamine hydrochloride and stearic acid. 

General Analine Film Corporation (o-Aminobenzoic acid), and H. R. Rosenberg, E. I. du Pont de Nemours Co., Inc., Aminobenzoic acid) iu ECT... 

Tribromobenzoic acid has been prepared by the deamination of 2,4,6-tribromo-3-aminobenzoic acid (reagents not specified), by hydrolysis of 2,4,6-tribromobenzonitrile, " and by oxidation of the tribromotoluene, the benzyl chloride, the aldehyde,and the glyoxylic acid.i The present method is a modification of that of Bunnett, Robison, and Pennington.i ... 

There is evidence the drug acts as an antimetabolite for the i ira-aminobenzoic acid required for bacterial metabolism.) One oT the more recent of the many preparations for this drug involves carboxylation of meta-aminophenol (6) by means of ammonium i.ii bonate under high pressure. ... 

Hydrogenation A mixture of 27.4 g (0.20 mole) of /7-aminobenzoic acid, 200 ml of water, and 2 g of the catalyst is hydrogenated at 50 psi in a Parr apparatus. At the completion of the hydrogenation (absorption of 0.6 mole of hydrogen), the mixture is filtered and concentrated under vacuum. When crystals start to form, the mixture is diluted with 200 ml of DMF and cooled in an ice bath. The crystals are collected by filtration, washed with DMF followed by methanol, and dried. About 20 g of cis- and fr[Pg.42]

Table I. Fluorescence and Phosphorescence Quantum Yield Values for the Anion of p-Aminobenzoic Acid Adsorbed on Sodium...

Convert, O. Mazaleyrat, J.-P. Wakselman, M. Morize, I. Reboud-Ravaux, M. NMR conformational analysis of cyclopeptidic substrates of serine proteases, containing an ortho or meta aminobenzoic acid residue. Biopolymers 1990, 30, 583-591. 

Aminobenzoic acid [119-92-3] 282B I(2)189A, N(2)186B CB2450000... 

Aminobenzoic acid methyl ester 2295A I(3)1371A, N(2)284A CB3325000... 

Aminobenzoic acid [150-13-0] 138B I(2)198C, N(2)195B DG1400000, USP... 

Aminobenzoic acid ethyl ester 1571A I(3)1372B, N(2)287D DG2450000, USP... 

Removal of calcium from HRP C has a significant effect not only on enzyme activity and thermal stability, but also on the environment of the heme group. The calcium-depleted enzyme has optical, EPR, and H NMR spectra that are different from those of the native enzyme (211). Temperature dependence studies indicate that the heme iron exists as a thermal admixture of high- and low-spin states. Kinetic measurements at pH 7 show that ki, the rate constant for compound I formation, is only reduced marginally from 1.6 0.1 x 10 to 1.4 x lO M s , whereas k, the rate constant for compound II reduction, is reduced from 8.1 1.6 x 10 to 3.6 x lO M s (reducing substrate p-aminobenzoic acid), 44% of its initial value (211). There can be little doubt that this is the main reason for the loss of enzyme activity on calcium removal. 

Finally, the zwitterion is not the major form for all amino acids. For both o-aminobenzoic acid (anthrani-lic acid) and p-aminobenzoic acid, the uncharged species is the more prevalent form whereas the zwitterion/uncharged ratio for m-aminobenzoic acid is about 2.31. This behavior arises primarily from the low pK values for the aromatic ring s amino group e.g., the pi i and pKi values for anthranUic acid are 2.05 and 4.95 and the pA"a value for the ester is only 2.09). 

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