4-Nitro-phenol structures

Cramer and co-workers (1967) have recently measured rate constants as well as equilibrium constants for the association of p-nitrophenol and a series of azo dyes with cydohexaamylose. The general structure of the dyes employed in this study is illustrated in Fig. 4. p-Nitrophenol and p-nitro-phenolate bind to cydohexaamylose with rate constants of about 108 M l sec-1, near the diffusion-controlled limit. Within the series of dyes, however, binding rates decrease by more than seven orders of magnitude as the steric bulk of the dye is increased. Equilibrium constants, on the other hand, are roughly independent of the steric nature of the substrate, indicating that association and dissociation rates are affected by similar... 

Hodson, P.V., R. Parisella, B. Blunt, B. Gray, and K.L.E. Kaiser. 1991. Quantitative structure-activity relationships for chronic toxicity of phenol, p-chlorophcnol, 2,4-dichlorophenol, pentachlorophenol, p-nitro-phenol and 1,2,4-trichlorobenzene to early life stages of the rainbow trout (Oncorhynchus mykiss). Canad. Tech. Rep. Fish. Aquat. Sci. 1784. 56 pp. 

CST sometimes gives some insight into molecular structure. Thus o-nitro-phenol has a CST with hydrocarbons much lower and with water much higher than do m-nitrophenol and p-nitrophenol. This indicates some hydrogen bonding in the ortho isomer, so that it resembles an ester in its solubility relationships. 

Relationships between the structure and stability of phenol-starch complexes are not clearly understood. Apart from the complexes of phenols listed in Table XXXII, complexes of chlorocresols,712 three isomeric nitro-phenols,715 resorcinol, phloroglucinol, and rutin,716 have been reported. The formation of complexes with nitrophenols has been monitored by ultraviolet... 

Beltrame, R, Beltrame, P.L., Cartini, P. (1984) Inhibiting action of chloro- and nitro-phenols on biodegradation of phenols A structure-toxicity relationship. Chemosphere 13, 3-9. 

Other Names Phenol, m-nitro- l-Hydroxy-3-nitrobenzene 3-Hydroxynitrobenzene 3-Nitro-phenol NSC 1551 m-Hydroxynitrobenzene m-Nitrophenol CA Index Name Phenol, 3-nitro-CAS Registry Number 554-84-7 Merck Index Number 6619 Chemical Structure... 

Aza-peptide p-nitrophenol esters may also be used as active-site titrants of serine proteases by measuring the initial burst of p-nitro-phenol from the acylation step. Since the hydrolysis rate of the acylated enzyme is often very slow, but not zero, aza-peptides may also be employed as reversible blocking groups of the active site of serine proteases. The rate of deacylation is variable and depends on the pH, the enzyme itself, and the structure of the specific aza-peptide. 

Chlorobenzoate, 3-methyl-4-nitro-phenol, and the detergents sodium lauryl sulfate and Tween 80 had increased toxicity with the addition of calcium and EDTA. No correlation between the structure of the chemical and the effect of EDTA and calcium could be ascertained. For example, streptomycin and neomycin are bofli amino glycoside antibiotics. Calcium and EDTA did not affect the toxicity of Streptomycin but nearly eliminated the toxicity of Neomycin. 

Phenol has different chemical properties from those of typical alcohols. Display the electrostatic potential map for phenol. Does this suggest that phenol is likely to be a stronger or weaker acid than any of the compounds discussed above Compare the electrostatic potential map for 4-nitrophenol to that for phenol. What effect does substitution by nitro have on acid strength Explain your result by considering charge delocalization in the conjugate base. Draw all reasonable Lewis structures for phenoxide anion and for 4-nitrophenoxide anion. Which is more delocalized Is this consistent with experimental pKa s ... 

Brightener structures of only moderate molecular size are of interest for white grounds in the transfer printing of polyester fabrics. Derivatives of 6-acetamidoquinoxaline with an electron-donating substituent (X) in the 2-position (11.48) were prepared by converting quinoxalin-2-one to 2-chloro-6-nitroquinoxaline and condensation with amines (X = RNH), alcohols (X = RO) or phenols (X = PhO), followed by reduction and acetylation (Scheme 11.19). The nitro intermediates (11.49) are also of interest as low-energy disperse dyes for polyester [61]. 

The hydroxyphenylbenzotriazole structure was constructed by a coupling of the diazonium salt of o-nitroaniline with 4-ethyl-phenol, followed by reduction of the nitro-azobenzene to the benzotriazole with zinc powder and NaOH. After blocking of the phenol by acetylation, bromination and dehydrobromination were performed as described earlier, and treatment with aqueous NaOH... 

In the Colour Index both conventional sulphur dyes and their leuco counterparts are allocated the same Cl constitution number a different number is given to the related solubilised version. Thus, for example, Cl Sulphur Black 1 and Cl Leuco Sulphur Black 1 have the reference Cl 53185 whereas Cl Solubilised Sulphur Black 1 appears under Cl 53186. Because of the complexity of the final products, sulphur dyes are classified according to the chemical structure of the organic starting material that predominates in the manufacturing process. Typical intermediates include aromatic amines, with or without nitro and phenolic groups, and diphenylamine derivatives. 

The structure of some phenolic metabolites of 3-nitrofluoranthene (231a) and its 2-nitro isomer have been analyzed by one-dimensional and two-dimensional NMR at 500 MHz. Chemical shifts suggest that the nitro group is not strictly coplanar with the aromatic ring system in solution and that metabolism at a distant site can alter the conformation about the C—N bond of the nitro group492. 

Note that m-nitrophenol has pATa 8.4, and is a lot less acidic than o-nitrophenol or p-nitrophenol. We can draw no additional resonance structures here, and the nitro group cannot participate in further electron delocalization. The increased acidity compared with phenol can be ascribed to stabilization of resonance structures with the charge on a ring carbon through the nitro group s inductive effect. 

A nitro group substituted in phenol should increase the acid constant by virtue of the inductive effect of the electronegative group (with N+ attached to the ring) moreover, in the ortho and para positions there would occur an additional resonance effect, due to the contribution of structures such as the following ... 

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