2.4- dinitrophenyl derivatives

Dinitrophenyl derivatives. The halogen atom in 2 4-di-nitrochlorobenzene is reactive and coloured crystalline compounds (usually yellow or red) are formed with primary and with secondary amines ... 

Sugars and Amino Acids, Using the AT-(2 4-dinitrophenyl) Derivatives. Science [Washington] 113, 354 (1951). 

Stability of the compounds 86 varies dramatically with the nitrogen substituent. Methyl" and phenyl s derivatives (86 R = Me or Ph) are moderately stable crystalline solids—often hydrated (87 or 88 X = OH). The 2,4-dinitrophenyl derivative [86 R = C6H3(NO2)2, R = H] is less stable but can be isolated as orange prisms (mp 112°C)5° It readily rearranges to the diaryl ether 96 (mp 128°C) with which it was originally confused.5The monomeric 5-nitro-2-pyridyI derivative is similarly unstable and in solution dimerizes giving adduct 97a. 5 5 The 4,6-di-methylpyrimidin-2-yl derivative can only be isolated as the dimers 97b and... 

Hint Note that the 2,4-dinitrophenyl derivative involves the amino group of a side chain rather than the a-amino group.)... 

Dinitrophenyl derivatives of the ct-amino groups of other amino acids could not be found. 

These considerations indicate that the nature of Ri and R2 is an important factor in determining the alkaline lability of the O-glycosidic bond. / -Elimination usually occurs most readily when there are no free amino or carboxyl groups on the serine or threonine residue to which the glycosyl is attached. When both functional groups are unsubstituted / -elimination does not occur (I, II, IX). The N-2,4-dinitrophenyl derivatives of Vercellotti et al. represent an extreme case, possibly involving a different mechanism of / -elimination. 

Determination of the iV-terminal acid in the peptide can be made by treatment of the peptide with 2,4-dinitrofluorobenzene, a substance very reactive in nucleophilic displacements with amines but not amides (see Section 14-6B). The product is an N-2,4-dinitrophenyl derivative of the peptide which, after hydrolysis of the amide linkages, produces an iV-2,4-dinitrophenyl-amino acid ... 

Treatment of the peptide (P) with carboxypeptidase released alanine, and with 2,4-dinitrofluorobenzene followed by hydrolysis gave the 2,4-dinitrophenyl derivative of valine. These results establish the TV-terminus as valine and the C-terminus as alanine. The known structural elements now are... 

At this point, you can deduce two possible sequences for Q.) (5) Trypsin hydrolysis of L gives a peptide of composition Ala, Asp, Phe which, with 2,4-dinitrofluorobenzene, gives the 2,4-dinitrophenyl derivative of aspartic acid. (6) Partial acid hydrolysis of eledoisin gives several dipeptides, among them Ser-Lys and Pro-Ser. 

A new method of prepn of 2,4-dinitrophenyl derivs of amino alcohols, among them amino-ethanols)... 

The nitration of the reduced l//-pyrazolo[5,l-n]isoindole (54) gives the 2,4-dinitrophenyl derivative, without attack at the benzo ring (47JCS829 48JCS1249). 

Cohen and Wheals [334] determined ten hydrolysable carbamate and substituted urea herbicides in soil in amounts down to 0.001-0.05 ppm. In this method, a solution of the herbicide-containing extract of the soil is spotted onto a silica gel G plate and developed with hexane acetone (5 1). The plate is sprayed with 1-fluoro-l,4-dinitrobenzene in acetone and heated to 190 °C to produce the 2,4-dinitrophenyl derivative of the herbicide amine moiety acetone extracts of the areas of interest are subjected to gas chromatography. 

The photochromic properties of DHA systems depend strongly upon the substituents on the five-membered ring, the reaction media, and the temperature. For example,1201 to obtain a steady state equilibrium mixture of 22a and 22b (Scheme 3), the 2,4-dinitrophenyl derivative of the DHA 22a had to be irradiated (in acetonitrile, 366 nm irradiation wavelength) at low temperature (200 K). In contrast to this, arene derivatives 21a and 23a, on irradiation at 250 K, were quantitatively converted to the corresponding VHFs 21b and 23b, respectively. In the case of the DHA 24a, a stationary equilibrium between 24a and 24b could be observed at room temperature. Thus, in general, it was observed that the presence of electron-withdrawing substitu-... 

Photomodulation amperometry of the DHAs (21-24)a is shown in Figure 20. Because of the increased acceptor strength in 22b, the 2,4-dinitrophenyl derivative 22a exhibits oscillating behavior at an electrode potential less negative than that required for the constitutional isomer 21a (Figure 20 21a, 22a). On the other hand, the 4-cyanophenyl derivative 23a displays increased sensitivity, which seems to be the result of the higher quantum yield of the photoreaction from 23a to 23b (Figure... 

Used to introduce chromophores into aldehydes and ketones in a solution of carbonyl-free methanol detection of the more common 17-keto steroids as their 2,4-dinitrophenyl derivatives from urine and plasma suggested potential for clinical use Reference 20... 

The bis-adducts of 3,3-dimethylpentane-2,4-dione with phenyl and 2,4-dinitrophenyl hydrazines 77 [R1 = R2 = Ph, 2,4-(N02)2C6H3] have been obtained (85KGS854 86ZOR1096 88ZOR426), and the irreversible isomerization 77A — 77B (R1 = R2 = Ph) has been observed in benzonitrile solution at 60°C. The analogous isomerization for the 2,4-dinitrophenyl derivative does not take place at all. The isomerization 77A —> 77B (R1 = R2 = Ph) has also been detected in the gas phase under the conditions of the mass-spectrometric experiment. 

A reaction worth noting in the context of nitro-group interactions with <-amino functions involves the rapid photolytic breakdown of 2,4-dinitrophenyl derivatives of a-amino acids. The lability of such derivatives in sunlight has long been known to protein chemists who... 

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