Hydrolysis nitrophenyl

Hydrolysis Nitrophenyl ester Pyridin-derivatives of IM-Boc-aminoacids 5 [108]... 

Deming and Pardue studied the kinetics for the hydrolysis of p-nitrophenyl phosphate by the enzyme alkaline phosphatase. The progress of the reaction was monitored by measuring the absorbance due to p-nitrophenol, which is one of the products of the reaction. A plot of the rate of the reaction (with units of pmol mL s ) versus the volume, V, (in milliliters) of a serum calibration standard containing the enzyme yielded a straight line with the following equation... 

The rat LD qS are 13, 3.6 (oral) and 21, 6.8 (dermal) mg/kg. Parathion is resistant to aqueous hydrolysis, but is hydroly2ed by alkah to form the noninsecticidal diethjlphosphorothioic acid and -nitrophenol. The time required for 50% hydrolysis is 120 d ia a saturated aqueous solution, or 8 h ia a solution of lime water. At temperatures above 130°C, parathion slowly isomerizes to 0,%diethyl 0-(4-nitrophenyl) phosphorothioate [597-88-6] which is much less stable and less effective as an insecticide. Parathion is readily reduced, eg, by bacillus subtilis ia polluted water and ia the mammalian mmen to nontoxic 0,0-diethyl 0-(4-aminophenyl) phosphorothioate, and is oxidized with difficulty to the highly toxic paraoxon [511-45-5] diethyl 4-nitrophenyl phosphate d 1.268, soluble ia water to 2.4 mg/L), rat oral LD q 1.2 mg/kg. 

Oxaziridine, 2-t-hutyl-3-(4-nitrophenyl)-hydrolysis rate constant, 7, 207 (71JCS(B)778) Oxaziridine, 2-t-hutyl-3-phenyl-7, 205 (57JOC1263)... 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

Figure 2-8. First-order plot of the hydrolysis of p-nitrophenyl glutarate at 25°C Reaction followed spectrophotometrically at 400 nm b = I cm, A = 0.900, pH 7.14.

Figure 2-11, Semilogarithmic plot of the hydrolysis of p-nitrophenyl glutarate in the presenee of p-methoxycinnamate ion 25.0°C, initial pH 7.53, reaction followed at 400 nm. The plot deviates from linearity after the first half-life.

These are absorbance-time data for the hydrolysis of p-nitrophenyl benzoate in aqueous solution. 

Figure 6-8 is a pH-rate profile for the hydrolysis of p-nitrophenyl acetate. The slopes of the straight-line portions are —1,0, and -L 1, reading in the acid to base direction, and this system can be described by... 

These data are for the nucleophilic catalysis of the hydrolysis of p-nitrophenyl acetate by imidazoles and benzimidazoles at pH 8.0. Tbe apparent second-order catalytic rate constants are defined by... 

Nitration of the 7-phenyl derivative 57 gave the corresponding p-nitrophenyl derivative 58 which upon reduction with SnCl2/HCl gave the amino derivative 59. Hydrolysis of 59 afforded 60 which showed antibacterial activity (92WOP9206099, 94WOP9414819) (Scheme 11). 

In 1965, Breslow and Chipman discovered that zinc or nickel ion complexes of (E)-2-pyridinecarbaldehyde oxime (5) are remarkably active catalyst for the hydrolysis of 8-acetoxyquinoline 5-sulfonate l2). Some years later, Sigman and Jorgensen showed that the zinc ion complex of N-(2-hydroxyethyl)ethylenediamine (3) is very active in the transesterification from p-nitrophenyl picolinate (7)13). In the latter case, noteworthy is a change of the reaction mode at the aminolysis in the absence of zinc ion to the alcoholysis in the presence of zinc ion. Thus, the zinc ion in the complex greatly enhances the nucleophilic activity of the hydroxy group of 3. In search for more powerful complexes for the release of p-nitrophenol from 7, we examined the activities of the metal ion complexes of ligand 2-72 14,15). 

We have disclosed that the ligands 4c, 10, and 77, when complexed with a metal ion such as Zn2 +, Ni2+, or Co2+, become highly active toward the hydrolysis of p-nitrophenyl picolinate (7). The catalysis is most likely to occur through formation of a ternary complex in the transition state or in reactive intermediates. The metal ion in such a complex serves to activate the ligand hydroxyl group for nucleophilic attack and to orient the substrate into a favorable position to undergo the reaction. 

An artificial metalloenzyme (26) was designed by Breslow et al. 24). It was the first example of a complete artificial enzyme, having a substrate binding cyclodextrin cavity and a Ni2+ ion-chelated nucleophilic group for catalysis. Metalloenzyme (26) behaves a real catalyst, exhibiting turnover, and enhances the rate of hydrolysis of p-nitrophenyl acetate more than 103 fold. The catalytic group of 26 is a -Ni2+ complex which itself is active toward the substrate 1, but not toward such a substrate having no metal ion affinity at a low catalyst concentration. It is appearent that the metal ion in 26 activates the oximate anion by chelation, but not the substrate directly as believed in carboxypeptidase. 

Murakami et al. reported that a cyclophane 27 having two imidazole groups is activated by Cu2+ ions in the hydrolysis of p-nitrophenyl dodecanoate 25,26), although the activation seemed to be small. 

A kinetic study of the basic hydrolysis in a water/AOT/decane system has shown a change in the reactivity of p-nitrophenyl ethyl chloromethyl phosphonate above the percolation threshold. The applicability of the pseudophase model of micellar catalysis, below and above the percolation threshold, was also shown [285],... 

Hydrolysis and Transglycosylation Investigated in Micro Reactors Organic synthesis 27 [OS 27] Hydrolysis of p-nitrophenyl-y D-galactopyranoside... 

Figure 4.43 Benchmarking of untreated and pre-treated Y-piece micro reactors to a commercial micro test-tube for the hydrolysis of p-nitrophenyl-/ -D-galactopyranoside. Y-piece micro reactor ( ) commercial micro test-tube ( ) pre-treated Y-piece microreactor (A) [26],...

Numbers used in this cycle AG° for dissociation of sulfuric acid to sulfur tri-oxide AG° for hydrolysis of bis-p-nitrophenyl sulfate, estimated as described above AG° for hydrolysis of mono-p-nitrophenyl sulfate AG° for esterification to give pNP0S02, estimated as described above AG° for ionization of protonated SO3, estimated as described above AG° for ionization of p-nitrophenol. )... 

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