2.4- Dichloro-3-nitrophenol

Diclofenac sodium, famotidine and ketorolac were analysed utilising their formation of a coloured charge transfer complex with 2,4 dichloro-6-nitrophenol. The complexes were detected by UV/visible spectrophotometry at 450 nm. The method was not affected by the presence of common excipients in the formulations analysed. The precision and accuracy of the method was comparable to that of HPLC methods used to analyse the same samples. ... 

Dichloro-6-nitrophenol [609-89-2] M 208.0, m 122-123". Crystd from acetic acid. 

It was found by Steinkopf and Kiihnel [106] that the so-called nitryl chloride is an agent that both nitrates and chlorinates aromatic hydrocarbons. However, the reaction could be selective. Thus, only o- nitrophenol was formed when nitryl chloride interacted with phenol below room temperature, but at room temperature 2,4-dichloro-6-nitrophenol was obtained. Naphthalene was chlorinated and nitrated simultaneously to give a- nitro- and a- chloro-naphthalene. 

Thus, p- xylene yielded 2,5-dichloro-p-xylene. The principal reaction with anisole was also chlorination and with phenol nitration when nitration temperature was low (-80°C) both o- and p- nitrophenols were formed. At room temperature chlorination also occurred yielding 2,4-dichloro-6-nitrophenol and 3,6-dichloro-2-nitro-phenol. 

Uses. (9-Nitrochlorobenzene is used in the synthesis of azo dye intermediates such as o-chloroaniline (Fast YeUow G Base), i9-nitroani1ine (Fast Orange GR Base), o-anisidine (Fast Red BB Base), o-phenetidine, and (9-aminophenol (see Azo dyes). It also is used in corrosion inhibitors, pigments, and agriculture chemicals. -Nitrochlorobenzene is used principally in the production of intermediates for azo and sulfur dyes. Other uses include pharmaceuticals (qv), photochemicals, mbber chemicals (qv), and insecticides (see Insectcontroltechnology). Typical intermediates manufactured from the para isomer are -lutioaruline (Fast Red GC Base), anisidine, -aminophenol, -nitrophenol, -phenylenediamine, 2-chloro-/)-anisidine (Fast Red R Base), 2,4-dinitrochlorobenzene, and l,2-dichloro-4-nitrobenzene. 

Dichloro-4-nitrophenol [618-00-4] M 208.0, m 125°, pK 3.55. Crystd from EtOH and dried in vacuo over anhydrous MgSOa. 

In this solvent the reaction is catalyzed by small amounts of trimethyl-amine and especially pyridine (cf. 9). The same effect occurs in the reaction of iV -methylaniline with 2-iV -methylanilino-4,6-dichloro-s-triazine. In benzene solution, the amine hydrochloride is so insoluble that the reaction could be followed by recovery. of the salt. However, this precluded study mider Bitter and Zollinger s conditions of catalysis by strong mineral acids in the sense of Banks (acid-base pre-equilibrium in solution). Instead, a new catalytic effect was revealed when the influence of organic acids was tested. This was assumed to depend on the bifunctional character of these catalysts, which act as both a proton donor and an acceptor in the transition state. In striking agreement with this conclusion, a-pyridone is very reactive and o-nitrophenol is not. Furthermore, since neither y-pyridone nor -nitrophenol are active, the structure of the catalyst must meet the conformational requirements for a cyclic transition state. Probably a concerted process involving structure 10 in the rate-determining step... 

In an aqueous solution, 4-nitrophenol (100 pM) reacted with Fenton s reagent (35 pM). After 15 min into the reaction, the following products were identified 1,2,4-trihydrottybenzene, hydroquinone, hydroxy-p-benzoquinone, p-benzoquinone, and 4-nitrocatechol. After 3.5 h, 90% of the 4-nitrophenol was destroyed. After 7 h, no aromatic oxidation products were detected. The pH of the solution decreased due to the formation of nitric acid (Lipczynska-Kochany, 1991). In a dilute aqueous solution at pH 6.0, 4-nitrophenol reacted with excess hypochlorous acid forming 2,6-dichlorobenzoquinone, 2,6-dichloro-4-nitrophenol, and 2,3,4,6-tetrachlorophenol at yields of 20, 1, and 0.3%, respectively (Smith et al., 1976). 

CASRN 1836-75-5 molecular formula C13H7F3N2O5 FW 284.10 Chemical/Physical. When nitrofen as an aqueous suspension was irradiated using UV light (A. = 300 nm), 2,4 -dichloro-4 -aminodiphenyl ether formed as the major products (>80% of total product formation). In addition, 4-nitrophenol and 2,4-dichlorophenol formed as minor products (<10%). In cyclohexanone, the major photooxidation product was aminonitrofen (Ruzo et al., 1980). 

Induction of DNA single-strand breakage in rat liver after in-vivo exposure to N-nitrosodiethanolamine was demonstrated in three studies and dose-dependent effects were shown. In one of these studies, the DNA strand-breaking potential of 7V-nitroso-diethanolamine was found to be abolished by inhibition of sulfotransferase by 2,6-dichloro-4-nitrophenol. Unscheduled DNA synthesis was not detected in rats or mice in an in-vivo/in-vitro hepatocyte DNA repair assay after treatment with 7V-nitrosodi-ethanolamine. A single study in mice exposed in vivo to 7V-nitrosodiethanolamine did not find any significant induction of structural or numerical chromosomal aberrations or micronuclei in bone-marrow cells. 

It has been proposed that 8-aminodcoxyguanosinc is formed from the nitronate tautomer of 2-nitropropane either by base nitrosation followed by reduction, or via an enzyme-mediated conversion of the nitronate anion to hydroxyiam ine-O-sulfonate or acetate, which yields the highly reactive nitrenium ion NHj (Sodum et al., 1993). Sodum et al. (1994) have provided evidence for the activation of 2-nitropropane to an aminating species by rat liver aryl sulfotransferase in vitro and in vivo. Pretreatment of rats with the aryl sulfotransferase inhibitors pentachlorophenol or 2,6-dichloro-4-nitrophenol significantly decreased the levels of nucleic acid modifications produced in the liver by 2-nitropropane treatment. Partially purified rat liver aryl sulfotransferase activated 2-nitropropane and its nitronate at neutral pH to a reactive species that aminated guanosine at the position. This activation was dependent on the presence of the enzyme, its specific cofactor adenosine 3 -phosphate 5 -phosphosulfate, and mercaptoethanol. It was inhibited... 

In general, the rate of the reaction of arylation of phenols by aryllead triacetate increases with the electron density of the phenolic substrate. When pyridine is used as a base, no reaction takes place with electron-poor phenols, such as 2,6-dichlorophenol or 2,6-dichloro-4-nitrophenol.45 45a However, the reaction of the sodium salt of perfluorophenol 43 with phenyllead triacetate under more forcing conditions led to a range of products the product of >rtfe -arylation, the 6-aryl-2,4-cyclohexadienone 44 together with minor amounts of the product of / zra-arylation 45 and the unsymmetrical diaryl ether 46 (Equation (43)).69... 

C6H2Br2FI 1,3-dibromo-5-fluoro-2-iodobenzene 62720-29-0 25.00 2.5671 2 6272 C6H3CIN03 2,6-dichloro-4-nitrophenol 618-80-4 25.00 1.8220 1... 

Fig. 5-53. Separation of various mono- and polyvalent phenols. - Separator column Ion Pac NS1 (10 pm) eluent (A) 0.01 mol/L KH2P04 (pH 4.0) / acetonitrile (90 10 v/v), (B) 0.01 mol/L KH2P04 (pH 4.0) / acetonitrile (20 80 v/v) gradient linear, 15% B in 20 min to 55% B flow rate 1 mL/min detection UV (280 nm) injection volume 50 pL solute concentrations 100 ppm each of pyrogallic acid (1), resorcinol (2), phenol (3), o-cresol (4), 2,4-di-methylphenol (5), /J-naphthol (6), 2,4-dichloro-3-nitrophenol (7), and thymol (8).

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