2-Cyano-6-nitrophenol

Enolization involves a deprotonation step at carbon, which is a fundamental reaction step of interest in studying the principles of enzyme action. Investigations of biocatalytic carbon deprotonation have focused on the chromogenic ring opening of nitrobenzoxazole 15 to form the yellow product 2-cyano-4-nitrophenol 16. The reaction is promoted by weak bases such as carboxylate side chains in a hydrophobic environment, in particular with albumins and catalytic antibodies [18-21]. The unstable aldehyde 4 (Scheme 1.1) and related carbonyls also provide interesting fluorogenic substrates for such reactions and the P-elimination process is indeed catalyzed by BSA in an enzyme-like manner [3]. 

Promoter (metal) Promoter in alloy (%) Butyronitrile (cyano) Acetone (carbonyl) Sodium p-nitrophenolate (nitro) Sodium itaconate (vinyl)... 

TT-Stacking interactions and solvation effects within the highly preorganized cleft of a bifunctional C-shaped host are believed to benefit the base-promoted conversion of 5-nitrobenzisoxazole to 2-cyano-5-nitrophenolate relative to the acetate-promoted reaction structural variation of the host has been explored. ... 

Cyano-3-nitrotoluene, 2917 2,6-Di-teri-butyl-4-nitrophenol, 3666 Dichloronitrobenzene, 2103... 

Its rate can be followed by measurement of the increase in absorbance due to the release of 2-cyano-5-nitrophenol (IV). 

Finally, the case of benzene derivatives having electron withdrawing substituents will be discussed. Experimental support for mein electron withdrawal by nitro and cyano groups has been found (3, (>, 20) in the photochemical solvolyses of nitrophenyl and cyanophenyl trityl ethers. For example, it is found that in the dark w-nitrophenyl trityl other (XLII) is essentially unreactive in 90% aqueous dioxanc while the para isomer (XLIII) solvolyzes smoothly this is in accord with ground-state, expectation, for p-nitrophenolate is a better departing anion than -nitropheiiolate. In contrast, on irradiation under the same conditions, m-nitrophcnyl trityl other solvolyzes rapidly to m-nitrophenol and tri-phenylcarbinol, as major products, while the para isomer s (XLIII) solvolysis is scarcely enhanced beyond experimental error. V similar... 

Curtius arrangement, 300 Cram s rules, 209 la-Cyanocholestanone, 225 2-Cyano-5-nitrophenol, 299 Cycloaddition of nitrone, 317-318 3a,5-Cyclocholestan-6-ones, 246 3a,5-Cyclocholestan-6-ones, 246... 

Eschenmoser and collaborators (28) have reported the base induced fragmentation of a.B-epoxy-tosylhydrazones to produce acetylenic ketones (e.g. 69 71). Interestingly, in this fragmentation, both the triple-bond and molecular nitrogen are produced from the key intermediate 70 via an anti mode. The decarboxylation of nitrobenzisoxazole carboxylate (72) into 2-cyano-5-nitrophenol (73) can also be viewed as a trans-elimination (29, 30). 

Cyano-4-nitrobenzenediazonium hydrogen sulfate, 2664 2,6-Di-terf-butyl-4-nitrophenol, 3659 Dichloronitrobenzene, 2096... 

The solvatochromic effects on UV/visible spectra of certain solutes are so large, that they can conveniently be employed as probes for certain solvating properties of the solvents. Those that have enjoyed widespread application in this capacity are discussed in Chapter 4. They include 2,6-diphenyl -4-(2,4,6-triphenyl-l-pyridino)-phenoxide, 4-methoxynitrobenzene, 4-(dimethylamino)-nitrobenzene, for the estimation of the polarity of solvents, acetylacetonato-N,N,N, N -tetramethylethylenediamino-copper(II) perchlorate, 4-nitrophenol, and 4-nitroaniline, for the estimation of the electron pair donicity of solvents, 4-carboxymethyl-l-ethylpyridinium iodide, 4-cyano-l-ethylpyridinium iodide, and bis-c/.v-1, lO-phenanthrolinodicyano-iron(II) for the estimation of the hydrogen bond donation abilities of solvents (Marcus 1993). 

The cyano group of jp-cyanoaniline exerts an electron-withdrawing inductive effect and can delocalize the electron pair of the base by resonance. On the basis of reasoning identical to that presented for jp-nitrophenol, the conjugate acid of / -cyanoaniline should be a stronger acid than the conjugate acid of aniline. Indeed, this is the case the pKais 1.74. 

The important phenols that have shown marked activity against roundworms are hexylresorcinol (9), 2,4,5-trichlorophenol (10), 2,6-diiodo-4-nitrophenol (disophe-nol, 11), thymol (12), iodothymol (13) and 4-cyano-2-iodo-6-nitrophenol (nitro xynil,14) and butyphen (15). Of these disophenol (11) and nitroxynil (14) are commonly used as veterinary anthelmintics [11,23]. 

Nitroxynil is obtained either by iodination of 4-cyano-2-nitrophenol (47) [47,48] or by nitration of 4-cyano-2-iodophenol (48) [49] (Scheme 3). 

The Smiles-mediated aryl transfer requires the presence of strong electron-withdrawing substituents such as nitro on the phenol, yet no reaction was observed with a cyano or a phosphonate group. 4-Hydroxybenzoates and 2- and 4-hydroxybenzamides are not reactive in this reaction, but salicylic acid esters give the desired Ugi-Smiles adducts in good yields. The high acidity of nitrophenols could justify their good reactivity, but the behavior of other phenols could not be simply correlated with their pKg. For instance, 4-hydroxybenzoic acid... 

Fascioliasis - Comparative studies on the more frequently used preparations have been made and the importance of age and size of infection has been emphasized . Emetine is reported to be effective against the immature forms of Fasciola hepatica in the liver tissue in both rats and sheep . Synergism has been demonstrated between hexachlorophane and 4-cyano-2-iodo-6-nitrophenol in sheep . ... 

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