Nitro phenyl-/?-acetate

Second-order rate constants for the reaction of oximate and hydroxamate anions with p-nitro-phenyl acetate... 

Fig. 11.6 (A) Spectroscopic detection of acetylimidazole in the imidazole-catalysed hydrolysis of 4-nitro-phenyl acetate at pH 5 (D) and at pH 6 (E) curves are calculated from data in reference [12] and the curve for the acetate ion product (C) is for pH 5. (B) Reaction of imidazole with 4-nitrophenyl acetate (k) and the hydrolysis of acetyl imidazole (k2) curves constructed from data in references [13] and [12].

Nitro-phenyl)-acetic acid methyl ester (24)... 

To a solution of (4-nitro-phenyl)-acetic acid methyl ester 24 (8.11 g, 41.6 mmol) in ethanol (208 mL) was added 10% Pd/C (3.20 g) and NH4HCOO (14.0 g in 10 equal portions every 5 min) while stirring at room temperature. The reaction was stirred for 24 h, followed by... 

He, B., Huang, W Guo, X., and Yu, Y Catalysis by condensation polymers containing salicylic acid for hydrolysis of p-nitro-phenyl acetate in aqueous solution, Gaofenzi Tongxun, 416,1982 Chem. Abstr., 99,21670,... 

Oxindole.—When ortho-nitro phenyl acetic acid is reduced to the ortho-amino phenyl acetic acid, the latter, being a gawwa-amino acid, loses water yielding a lactam which is known as oxindole. 

From ortho-Nitro Phenyl Acetic Acid.—Several other syntheses were developed by Baeyer. Starting with ortho-nitro phenyl acetic. CH2—COOH (i)... 

Both these copolymers were found to enhance the catalytic effect of the polymer, per imidazole residue, on the hydrolysis rate of p-nitro-phenyl acetate 45). In the case of VI/VP, the relative catalytic efficiency of a copolymer with two-thirds of VP residues, as compared to the PVI homopolymer, increased from 1.4 at pH 7.4 to 1.7 at pH 8.2 and to 8.9 at pH 9.1. This result suggests strongly that a cooperative attack of a phenolate and an imidazole residue on the ester group makes an important contribution to the catalysis at higher pH values. With the VI/VA copolymers, the enhancement of the imidazole catalysis by hydroxyl groups attached to the same chain was less marked, leading to efficiencies increased by factors which reached, in the most favorable case, only 1.7. 

The first artificial catalytic antibody for the hydrolysis of p-nitro-phenyl acetate was prepared using a transition state analog, p-nitro-... 

This turns out to be the case, but what we are really looking for in a good enzyme is a cooperative eflFect. We already know that the nucleophilic functional group is a good catalyst for the deacylation of p-nitro-phenyl acetate, but what we want to see is how much help we get from the hydrophobic binding. 

The work of Kawanami et al., who produced a MIP to catalyse p-nitro-phenyl acetate hydrolysis, serves to illustrate the methodology (Fig. 6) [124]. p-Nitrophenyl phosphate, employed as a template molecule, was observed to form an insoluble complex when mixed in solution with a 10-fold excess of the chosen functional monomer, 1-vinylimidazole this was then copolymerised with a 20-fold excess of divinylbenzene. Following polymerisation. 

This paper reports that we modified 3-CD by a histamine group and we realized enzymatic turnover reaction in the hydrolysis of p-nitro-phenyl acetate with this compound at around neutral pH value for the first time. 

At pH 7—8, but not at pH 5—6, a copolymer of 1-alkyl-4 or S-vinylimidazole and 4(5)-vinylimidazole is more efficient at catalysing the hydrolysis of 4-nitro-phenyl acetate in 28.5% EtOH-HjO than a mixture of the respective homopolymers. The most efficient esterolytic activity is with a copolymer containing 75 mol % 4(5)-vinylimidazole and containing l-methyl-4-vinylimidazole rather than 1 -methyl-5-vinylimidazole. ... 

This paper reports that we synthesized amino-6-CD to compare catalytic activity with 3-CD-histamine and it was clear that an imidazole group acted as an active site in the hydrolysis of p-nitro-phenyl acetate. And it also shows that in the hydrolytic reactions, 3-CD-histamine has a structural selectivity for substrates which are structurally different to each other. 

CD-histamine has an imidazole group and a secondary amino group (Figure 1). It is thought that the active site in the hydrolysis of p-nitro-phenyl acetate is an imidazole group which has a high activity at around neutral pH value. But a secondary amino group has a possibility to act as a catalytic site. 

Means, G.E., Bender, M.L., 1975. Acetylation of human serum albumin by p-nitro-phenyl acetate. Biochemistry 14 (22), 4989-4994. 

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