2-nitrophenolate

Nitrophenol [554-84-7] M 139,1, m 96 , b 160-165 /12mm, pK 8.36. Crystd from water, CHCI3, CS2, EtOH or pet ether (b 80-l(K)°), and dried under vacuum over P2O5 at room temperature. Can also be distd at low pressure. 

Attempts to prepare 6-hydroxybenzofuroxan by demethylation of 5-methoxybenzofuroxan, by pyrolysis of 4-azido-3-nitrophenol, and by hypochlorite oxidation of 4-amino-3-nitrophenoD failed. This rather unstable compound was finally prepared by hydrolysis of 5-acetoxybenzofuroxan its tautomeric possibilities are numerous, but from the similarity of its ultraviolet spectrum to that of 5-methoxybenzofuroxan it was considered to be largely in the hydroxy form. It is a fairly strong acid, of pK 6.76 (cf. 5-hydroxybenzo-furazan, pK 7.28). 7-Hydroxy-4,6-dinitrobenzofuroxan has been reported as arising from oxidation and nitration of dinitrosoresorcinol monooxime (tetraoxocyclohexene trioxime). ... 

N)4C6(0H)Cl, colorl crysts from chlf or C tetrachloride, mp 174°. Can be prepd by the nitration of 5-chloro-3-nitrophenol with mixed nitric-sulfuric acids. It is an expl 5-Bromo-2,3,4,6-Tetranitrophenol. (02N)4C6(0H)Br, colorl crysts from chlf or C tetrachloride, mp 157°. Can be prepd by the nitration of 5-bromo-3-nitrophenol with mixed nitric-sulfuric acids. It is an expl Ref Bell 6, 293... 

The rates of bromination of 3-nitrophenol in aqueous solution at 25 °C have been measured at various concentrations of perchloric acid and sodium bromide294. An increase in both caused a decrease in rate the latter again shows that Br is much less reactive than Br2, whilst the former shows that reaction occurs principally on the 3-nitrophenoxide ion and the difference from the observation for phenol in acetic acid (above p. 117) is undoubtedly partly due to the greater stability of the 3-nitrophenoxide relative to the phenoxide ion. The... 

Dinitrophenol (hRf 0-5, yellow-brown), 2,6-dinitrophenol (h/ f 10-15, yellow-brown), 2,5-dinitrophenol (hRf 30-35, yellow-brown), 4-nitrophenol (h/ f 40-45, yellow), 3-nitrophenol (h/ f 50-55, light brown) and 2-nitrophenol (hRj 60-65, pale beige) appeared on a light beige-colored background. 

Fig. 1 Reflectance scan of a chromatogram track with 30 ng each of 2,4-dinitrophenol (1) and 2,6-dinitrophenol (2), 60 ng each of 2,5-dinitrophenol (3), 4-nitrophenol (4) and 120 ng each of 3-nitrophenol (5) and 2-nitrophenol (6) per chromatogram zone.

Dioxygenation may result in the elimination of nitrite in reactions that are analogous to the elimination of sulfite from aromatic sulfonates, or halogen from 2-halobenzoates. As an alternative to dioxygenation, toluene-3- and toluene-4-monooxygenases can transform nitrobenzene to 4- or 3-nitrophenol, with the former dominating (Fishman et al. 2004) ... 

Meulenberg R, M Pepi, JAM de Bout (1996) Degradation of 3-nitrophenol by Pseudomonas putida B2 occurs via 1,2,4-benzenetriol. Biodegradation 1 303-311. 

Schenzle A, H Lenke, P Fischer, PA Williams, H-J Knackmuss (1997) Catabolism of 3-nitrophenol by Ralsto-nia eutropha IMP 134. Appl Environ Microbiol 63 1421-1427. 

Synthetic routes that access appropriately substituted thienobenzazepines are also quite important for medicinal chemistry stracture activity relationship studies, and many involve similar bond connectivity strategies. One notable example employs the use of conunercially available 4-methyl-3-nitrophenol (Scheme 6.3). Methylation of the phenol followed by bromination, hydrolysis, and oxidation of the benzylic alcohol afforded aldehyde 9 in quantitative yield. Treatment of this aldehyde with 5-lithio-2-methylthiophene provided, after dehydroxylation, nitro intermediate A in good overall yield. Reduction of the nitro functionality and treatment with phosgene presented the corresponding isocyanide which upon cychzation using aluminum trichloride in a Friedel-Crafts fashion afforded the... 

Other electrophilic substitution reactions on aromatic and heteroaromatic systems are summarized in Scheme 6.143. Friedel-Crafts alkylation of N,N-dimethyl-aniline with squaric acid dichloride was accomplished by heating the two components in dichloromethane at 120 °C in the absence of a Lewis acid catalyst to provide a 23% yield of the 2-aryl-l-chlorocydobut-l-ene-3,4-dione product (Scheme 6.143 a) [281]. Hydrolysis of the monochloride provided a 2-aryl-l-hydroxycyclobut-l-ene-3,4-dione, an inhibitor of protein tyrosine phosphatases [281], Formylation of 4-chloro-3-nitrophenol with hexamethylenetetramine and trifluoroacetic acid (TFA) at 115 °C for 5 h furnished the corresponding benzaldehyde in 43% yield, which was further manipulated into a benzofuran derivative (Scheme 6.143b) [282]. 4-Chloro-5-bromo-pyrazolopyrimidine is an important intermediate in the synthesis of pyrazolopyrimi-dine derivatives showing activity against multiple kinase subfamilies (see also Scheme 6.20) and can be rapidly prepared from 4-chloropyrazolopyrimidine and N-bromosuccinimide (NBS) by microwave irradiation in acetonitrile (Scheme... 

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