2.4- dinitro fluorobenzene

Polymer-supported tetraphenylphosphonium bromide is a recyclable catalyst for halogen-exchange reactions. The reaction of 1 equivalent of chloro-2,4-dinitrobenzene with 1 5 equivalents of spray-dned potassium fluoride and 0.1 equivalent of this catalyst in acetonitnle at 80 C for 12 h gives 2,4-dinitro-fluorobenzene m 98% yield An 11% yield is obtained without the catalyst [3 /]. 

The method used at PicArsn for prepg TNFB involved foe nitration of 2,4-dinitro-fluorobenzene, but the attempts, based on literature references, were unsuccessful Refs 1) Beil, not found 2) L.G. Wesson, USP 2179605(1940) CA 34, 1852(1940)... 

Fluoro-2,4-dinitro- fluorobenzene CM O Useful for derivatizing C,-C4 primary and secondary amines, providing high electron capture detector response this reagent is also useful for primary alicyclic amines... 

The DMF used in SPPS coupling reactions must be anhydrous and free of dimethylamine. Spectroscopic quality DMF may be anhydrous, but may contain excessive amounts of dimethylamine. Every new batch of DMF received should be tested with 2,4-dinitro-fluorobenzene (DNFB) for the presence of dimethylamine as follows. 

A very successful method of identifying the N-terminal residue (introduced in 1945 by Frederick Sanger of Cambridge University) makes use of 2,4-dinitro-fluorobenzene (DNFB), which undergoes nucleophilic substitution by the free amino group to give an N-dinitrophenyl (DNP) derivative. The substituted peptide... 

A problem arises here, however, in that eisenine has only one free carboxyl group. The fact that ammonia is released upon hydrolysis would indicate that the carbonyl is tied up in the form of an amide. Another factor in the determination of eisenine s structure is its inability to rdact with Sanger s reagent (2,4-dinitro-fluorobenzene). This would be indicative of the amino terminus being tied up in an amide form. Hence, a possible form for eisenine which would fit the data would be structure B. 

Both nucleophilic substitution (Eq. 14) and direct nitration (Eq. 15) have been employed with varying degrees of success. When 2,4-dinitro-fluorobenzene is used in the substitution (Eq. 14), an equal amount of the N-2 isomer of 7.1-5 is obtained. The nitration yields (Eq. 15) are variable— for example, 83% with 2-(2,4,6-trinitrophenyl) and no reaction for 1-(2,4,6-trinitrophenyl) ... 

The general overall kinetic behaviour of Figure 1 may be observed (under the experimental conditions [ArFJo < [RNH2]o) if a large range of concentration values of amine is used, as in the case of the reactions between 2,4-dinitro-fluorobenzene and n-butylamine in benzene or toluene . The major part of cases reported in the Uteature concerns a more restricted range of [aminejo values. 

Some earlier efforts in this direction are reported by Stec et al. (25), who tried to convert internucleotide phosphorothioate into corresponding phosphorofluoridates, further convertible into dinucleoside 0-alkyl phosphates. Unfortunately, 2,4-dinitro fluorobenzene, used in their studies, caused nonstereospecific conversion. 

BOUR, H PEYRON, E GAUCHERAND, M GARRIGUE, J-L., DESVIGNES, C KAISERLIAN, D., REVILLARD, J.-P. NICOLAS, J.-F. (1995) Major histocompatibility complex class 1-restricted CD8+ T cells and class Il-restricted CD4+ T cells, respectively, mediate and regulate contact sensitivity to dinitro-fluorobenzene. European Journal of Immunology, 25, 3006-3010. 

Derivatisation of samples in HPLC is undertaken principally for two reasons. First, there is no detector for HPLC that has universally high sensitivity for all solutes hence a suitable chemical transformation of the solute can greatly extend the sensitivity and versatility of a selective detector. Second, sample derivatisation may be undertaken to enhance the detector response to sample bands relative to overlapping bands of no analytical interest. This experiment involves the pre-column derivatisation of sample with dinitro-fluorobenzene so enhancing the spectrophotometric response of the sample, that is, the amino acids from a protein hydrolysate. The conversion of the amino acids to their apolar DNP derivatives allows them to be analysed using reverse phase chromatography. Thus, polar DNP-amino acids, such as DNP-aspartate, will elute early whereas apolar DNP-amino acids, such as DNP-alanine, will elute later. The DNP-amino acids are detected by an... 

Sat er A-terminal analysis (Section 24.5B) A method for determining the A -terminal amino acid residue of a peptide by its SiqAr (nucleophilic aromatic substitution) reaction with dinitro-fluorobenzene, followed by peptide hydrolysis and comparison of the product with known standards. 

Fluorobenzene or fluoropyridine, e.g., 2,4-dinitro-5-fluorobenzene analogues [54] and 2-fluoro-l-methyl-2-pyridinium p-toluenesulfonate [61]... 

Fluorobenzene and fluoropyridine 2,4-Dinitro-5-fluorobenzene analogues [54] 2-Fluoro-1 -methyl-2-pyridinium z>-toluenesulfonate T611 Phenolic OH LC-ESP/MS/ MS... 

Trioitro derivatives of chlorobenzene Picryl chloride Ph> ical properties Chemical properties ] Ch]oro-2,4,5-irinitrobenzcnc Diagram of the nitration of chlorobenzene Thermochemical and explosive properties of chloronitrobenzenes Nitro derivatives of p-chlorobenzene Mononitro derivative ofp-chlorobenzene Dinitro derivative of p dichIorobenzene 2 4,6 Trinitroderivative of 1.3.S-trichtorobenzene Manufacture of l,3,5-trichloro-2.4.6-irinitrobenzenc Nitro derivatives of fluorobenzene Literature... 

Fig. 12.1. Some active molecules used for the haptenation of antibodies. In (a) /i-aminobenzenearsonic acid or A -(4-aminobenzoyl)-L-glutamic acid are diazotized (according to Table 12.4) and reacted separately with 4-hydroxyphenylisothiocyanate to yield ars-azo-hydroxyphenylisothiocyanate (RAPITC) and glut-azo-hydroxyphenyl-isothiocyanate (GAPITC), respectively, which differ in R. 2,4-Dinitro-l-fluorobenzene and 2,4-dinitrobenzene sulfonate are presented in (b).

Chlorobenzene is nitrated almost quantitatively by mixed acid in 4 h even below room temperature, giving two-thirds p- and one-third o-chloronitro-benzene. Further nitration gives a mixture of, mainly, 2,4- with a small amount of 2,6-dinitro compound. Fluorobenzene is nitrated almost exclusively in the /rara-position. 

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