2.4- Dinitrobenzene-1 -fluorobenzen

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 /]. 

Although the attack of nucleophiles upon aromatic rings in the gas phase was reported more than a decade ago, not many publications on this topic have appeared since then. Thus, it was shown in earlier work that alkoxide ions react with fluorobenzene to give F and with hexafluoro-benzene to give pentafluorophenoxide anions (Briscese and Riveros, 1975), that (M + N02) adducts can be formed from reaction of N02 with < -, m-and /7-dinitrobenzenes (Bowie and Stapleton, 1977) and that (M — H + 0) ions are generated in reactions of Ot ions with benzene, naphthalene, pyridine, alkylbenzenes, methylpyridines and fluorotoluenes by displacement of a ring hydrogen atom (Bruins et al., 1978). 

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).

Dinitration, to give l-fluoro-2,4-dinitrobenzene, is achieved in 87 % yield by dropping fluorobenzene (40 g) into an ice-cold mixed acid composed of nitric acid (d 1.52 120 g) and sulfuric acid (d 1.84 280 g) and subsequent warming for 2 h on a boiling water-bath.179... 

Pyridinecarbonitrile 1,3-Dinitrobenzene Bromobenzene Chlorobenzene o-Chlorophenol w-Chlorophenol / -Chlorophenol Benzenesulfonyl chloride 4-Chlorobenzenethiol Fluorobenzene lodobenzene A -Sulfinylaniline Nitrobenzene o-Nitrophenol w-Nitrophenol / -Nitrophenol Benzene w-Bromoaniline o-Chloroaniline w-Chloroaniline o-Nitroaniline... 

Synonyms Benzene, 2,4-diitro-1-fluoro- Benzene, 1-fluoro-2,4-dinitro- 2,4-Dinitrobenzene fluoride 1,3-Dinitro-4-fluorobenzene 2,4-Dinitro-1-fluorobenzene DNFB 2,4-DNFB DNP-F FDNB 1-Fluoro-2,4-dinitrobenzene... 

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