Dinitrophenol indicator

Dinitrophenol (indicator) dissolve 0.1 g in a few mL alcohol, then dilute with water to 100 mL pH range colorless 2.6-4.0 yellow. 

The maturation of fat body mitochondria is affected by the neuroendocrine balance in adult male B. discoidalis. Removal of the CC arrests the maturation of the respiratory enzymes at their partly developed, 5-day level (58, Figure 1). Injections of CC extracts on days 0 to 5 result in precocious, 10-day levels of respiratory activity by 5 days of age. Administration of the uncoupling agent 2,4-dinitrophenol indicates that electron transport, rather than phosphorylation, is the rate-limiting step for respiration in fat bcxiy mitochondria (59). A situation that differs from vertebrate mitochondria where phosphorylation is limiting. This indicates that the levels of cytochrome enzymes available for electron transport in fat body mitochondria determine the respiratory and ATP synthesis capacities of the tissue and influence its biosynthetic potential. 

One of the major problems in rice production is grass control. Various grasses compete with rice and drastically reduce yields. Results of preliminary experiments in Venezuela (9) indicate that rice yields may be increased by the application of dinitrophenol as a pre-emergence herbicide, even though rice stands are reduced by this chemical. Additional research is needed in this field, as the possibility exists... 

Since the enzymes involved in PS synthesis are located in ER or MAM, and PSD is exclusively located at the inner mitochondrial membrane, the conversion of PS to PE by PSD has been used as an indicator of PS translocation into the inner mitochondrial membrane (Dennis and Kennedy, 1972 Voelker, 1990). Recent studies have shown that the transport of newly synthesized PS to the outer mitochondrial membrane requires no cytosolic proteins and is probably mediated by direct contact region between MAM and mitochondria (Voelker, 1989 Voelker, 1993 Shiano et al., 1995). It is also suggested that the translocation of PS from the outer to iimer mitochondrial membrane occurs through the contact sites where the two mitochondrial membranes are closely apposed and linked in a stable manner, since agents that dismpt the contact sites such as 1,4-dinitrophenol and adriamycin inhibit the PS transport (Hovius et al., 1992 Voelker, 1991). 

The a- and /3-cyclodextrins have been found to accelerate the Smiles rearrangement of 4-nitrophenyl salicylate. The reaction of 2,4-dinitrobenzenesulfonamide with acyl chlorides in the presence of excess triethylamine has been found to produce the corresponding nitrile in good yield. Mechanistic studies have indicated that the reaction proceeds via a Smiles rearrangement of the initially formed iV-(2,4-dinitrobenzenesulfonyl)amide to form the nitrile, 2,4-dinitrophenol, and sulfur dioxide (see Scheme 12). l-Chloro-3-fluorophenothiazines have been prepared by Smiles rearrangement of 3-chloro-5-fluoro-2-formamido-2 -nitrophenyl sulfides in alcoholic... 

In the only study that measured 1,3-DNB metabolite production in humans after dermal exposure, the total production of both amino and nitro metabolites in urine was reported using 2,4-dinitrophenol as a standard (Ishihara et al. 1976). The results indicate that 1,3-DNB (in solution) rapidly penetrated skin and was also rapidly converted and excreted in urine. A maximum amount of amino and nitro metabolites was reached within the first hour after exposure and returned to normal levels after 10 hours. The limitations of this study are a small sample size (one person) and no detailed information on the nature of 1,3-DNB metabolites. 

Hydroxy-1,2,4-thiadiazoles are generally distinctly acidic. 3-Ethyl-5-hydroxy-1,2,4-thiadiazole, for example, is more acidic than nitrophenol and 4-hydroxypyrimidine, but less so than 2,4-dinitrophenol. 3-Hydroxy-1,2,4-thiadiazoles fail to afford ketonic derivatives and give red to purple colors with iron(III) chloride, indicating their phenolic nature <65AHC(5)119>. Their IR spectra in... 

Also consistent with LCM uptake being an active (endo-cytic) process is the separate finding, in an in vitro kinetic study with both C6 and 9L tumor cells, that both dinitrophenol and sodium azide (i.e., energy blockers) inhibit LCM uptake in both tumor cell lines. Addition of glucose to the medium as an alternate source of energy restored the LCM uptake, indicating an energy-dependent uptake (ref. 534). 

The ability of nitrophenols to appear in the coloured quinoid form has been utilized in acidimetry, where some of them are used as indicators, e.g. m- and p- nitrophenols, 2,4-, 2,6- and 2,5-dinitrophenols, nitrohydroquinone etc. 

Workers in the dinitrophenol plant should be protected in the usual way (i.e. gloves, respirators, chMige of clothes, bath, etc.). Selection of workers hMidling dinitrophenol is also recommended since it has been shown that a great mMiy people are resistant to its toxic effects, Selection is based on 15 days medical observation of each new worker in the dinitrophenol plant, in particular in the analysis of the mine every other day. A test for the presence of Mninonitrophenols is particularly importance. Usually Denien s reaction [33] is used. According to Lazarev [31], the reaction comprises acidification of the mine with 10% sulphuric acid and diazotization with sodium nitrite, followed by shaking up the prepMed solution with an ammoniacal solution of p- naphthol. If a red colour appeMS it indicates the presence of 4-amino-2-nitrophenol in the mine, while a violet shade is evidence for the presence of 2-Mnino-4-nitrophenol. 

As this scheme indicates, phenolsulphonic acid is first nitrated to 2-nitro-4-sul-phonic and 4-nitro-2-sulphonic acids. The former yields 2,4-dinitrophenol and 2,6-dinitro-4-sulphonic acid, and the latter 2,4-dinitro-6-sulphonic acid. All these dinitro compounds are finally converted into picric acid. 

Absence of nitro derivatives was also observed upon irradiation of nitro-phenols and nitrate. Also in this case, the electron-withdrawing character of the nitro group can account for the inhibition of nitration [109]. The difficulty to nitrate nitrophenols to dinitrophenols is widely recognised [125] and also constitutes a problem in environmental chemistry, since field data seem, in contrast, to indicate that the nitration of 2-nitrophenol to 2,4-dinitrophenol in the atmospheric aqueous phase (e.g. cloud water) is an important process [126]. In fact, aqueous-phase nitration might be a relevant sink for 2-nitrophenol and possibly the main source of the dinitro compound, which is a powerful phytotoxic agent [127,128]. In the presence of nitrate under irradiation the main transformation intermediates of nitrophenols are the hydroxyl derivatives, while other compounds may derive from the direct photolysis of the substrates (catechol and 2-nitrosophenol from 2-nitrophenol hydroquinone, benzoquinone, hydroxybenzoquinone and 4-nitrosophenol from 4-nitrophenol) [109]. 

Fig. 58. Variable-temperature electronic spectra of the complex between decyloxystilbazole and 2,4-dinitrophenol. A and C indicate the absorption maxima for the stilbazole and stilbazolium moieties, respectively, while B and D indicate the absorption maxima for the phenol and phenate moeities, respectively. Reprinted with permission from J. Mater. Chem. 1997, 7, 883. Copyright 1997 Royal Society of Chemistry.

The first indication of the existence of an energy-linked NADP reduction was brought forward by Krebs (SO) who found that NADPH-dependent dehydrogenase reactions in pigeon heart homogenate were, sensitive to dinitrophenol. This finding formed the basis for the postulate... 

When benzyl alccdiol, 2,4-dinitrophenol, dioxane, etc. were added to the reaction system, the competitive inhibition was observed as inferred from the chai of the lineweaver-Burk plot (70). The fact that mutral molecules sudi as benzyl alccdiol competitively inhibit the catalysis, indicates that the hydrophobic nature of the catalytic site makes a major contributicxi to substrate binding. 

Available experimental data indicates that cephal-oridine-induced nephrotoxicity is dependent upon its renal cortical concentration [67]. Experimental data showed that probenecid, 2-4-dinitrophenol, ouabain and anoxia decreased the renal cortex accumulation... 

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