2.4- dinitrophenyl chloride, reaction with

A transient also occurs in the reaction of 2,4-dinitrophenyl chloride (3) with sodium hydroxide in aqueous DMSO, Scheme 9.2 [15]. Isomeric a-adducts, 4 and 5, formed relatively rapidly from 3, are cul de sac species and detectable by UV-vis spectroscopy. A slower separate reaction of 3 yields the phenolate, presumably via intermediate 6, which did not accumulate to UV detectable concentrations. 

Dissolve 1 g. (or 0 01 mol) of the phenol in a solution of 0-40 g. of sodium hydroxide in 5 ml. of water. Add the resulting solution to 2-Og. of 2 4-dinitrochlorobenzene dissolved in 30 ml. of 95 per cent, ethanol add more alcohol, if necessary, to effect solution. Heat the solution under reflux on a water bath until the colour (usually red) is discharged and a copious precipitate of sodium chloride appears (30-60 minutes). Dilute the reaction mixture with an equal volume of water, filter off the precipitated 2 4-dinitrophenyl ether, wash with water, and recrystallise from alcohol. 

In 1904, Zincke reported that treatment of Al-(2,4-dinitrophenyl)pyridinium chloride (1) with aniline provided a deep red salt that subsequently transformed into A-phenyl pyridinium chloride 5 (Scheme 8.4.2). Because the starting salt 1 was readily available from the nucleophilic aromatic substitution reaction of pyridine with 2,4-dinitrochlorobenzene, the Zincke reaction provided access to a pyridinium salt (5) that would otherwise require the unlikely substitution reaction between pyridine and... 

Whether the tellurocarboxylates are present in the tellurono- or the tellurolo-form is not known. Alkylation with alkyl iodides produces Te-alkyl tellurolocarboxylates1,2, while reaction with 2,4-dinitrobenzenesulfenyl chloride gives 7e-benzoyl. S-2,4-dinitrophenyl telluride sulfides. Oxidation with benzenesulfonyl chloride gives dibenzoyl ditelluriums2. The tellurocarboxylates are red, oily substances of low thermal stability and great sensitivity toward oxygen. 

The use of 2,4-dinitroi enyl aromatic quaternary salts prepared directly from the parent isoquinoline compound and 2,4-dinitrophenyl bromide or chloride enhances the electron-deficient nature of the iso-quinolinium salts, accelerates the rate of their [4 + 2] cycloaddition reactions with electron-rich alkenes, and has permitted the use of isoquinolinium s ts previously regarded as unmanageable. The application of these observations in the total syntheses of methylamottianamide and 14-epicorynoline is summarized in Scheme 26. ... 

Nucleophiles other than amines or hydroxyl can cause ring openings analogous to the Zincke reaction. With acetone and sodium carbonate, (139) gives i (141), and in related reactions l-(2,4-dinitrophenyl)pyridinium chloride and active methylene compounds yield cyanines, while pyridine, coumaran-2-one and an aroyl chloride give (142). 

Table 5,34, The Zincke Reaction with - 2,A-Dinitrophenyl)pyridinium Chloride...

The dinitrophenyl derivatives are reduced by titanium(III) chloride in acidic medium in the first step of the reaction to the corresponding aromatic amines these are then diazotized and coupled with N-(l-naphthyl)-ethylenediamine to yield an azo dye (cf. Fig. 21). 

B. 2,4-Dinitrobenzenesulfenyl chloride. Dry 2,4-dinitrophenyl benzyl sulfide (232 g., 0.80 mole) and 400 ml. of dry ethylene chloride are placed in a 2-1., one-necked, round-bottomed flask equipped with a stirrer (Note 3). Sulfuryl chloride (119 g., 0.88 mole) (Note 4) is added to the resulting suspension at room temperature. A mildly exothermic reaction causes the solid to dissolve quickly, usually within 1 to 2 minutes, with a temperature rise of 10-15° (Note 5). The resulting clear yellow solution is concentrated to an oil by heating under aspirator vacuum on a steam bath (Note 6). Caution Do not heat with gas or electricity because the product, like many nitro compounds, can explode if overheated.) The residual oil is cooled to 50-60°, and 3-4 volumes of dry petroleum ether (b.p. 30-60°) are added with vigorous handswirling. The oil quickly crystallizes. The mixture is cooled to room temperature and filtered to separate 2,4-dinitrobenzene-sulfenyl chloride as a yellow crystalline solid. The sulfenyl chloride is washed well with dry petroleum ether and dried at 60-80° (Note 7) weight 150-170 g. (80-90%) m.p. 95-96° (Notes 8, 9). 

Dinitrophenyl benzyl sulfide has been prepared by the reaction of benzyl chloride with 2,4-dinitrothiophenol2 or bis-(2,4-dinitrophenyl) disulfide2 and by the condensation of 2,4-dinitrochlorobenzene with benzyl mercaptan.4... 

Only highly activated aryl halides react with pyridines. Thus, 2,4-dinitrochlorobenzene with pyridine forms l-(2,4-dinitrophenyl)pyridinium chloride active heteroaryl halides such as 2-chloropyrimidine react similarly. To phenylate pyridine, diphenyliodonium ions are needed Ph2I+BF4 + pyridine —>> 1-phenylpyridinium BF4" + Phi. This reaction may involve initial electron transfer. 

There have been a number of studies of the behaviour of benzimidazolium species with nucleophiles, and ring opening is especially easy when there is a l-(2,4-dinitrophenyl) substituent. Even weak bases such as aniline or pyridine can effect the transformations. Under the influence of benzoyl chloride in aqueous alkali, 1,2-disubstituted benzimidazoles are cleaved in a rather complex reaction. Provided that a methylene or methyl group is present at C-2, compounds of type (110) result (Scheme 49) (74CRV279). 

Oryzalin is prepared by a different route. Synthesis starts with chlorobenzene, which is nitrated in a single step into potassium 4-chIoro-3,5-dinitrobenzene sulfonate (I). This is then converted with phosphorus oxychloride and phosphorus pentachloride into 4-chloro-3,5-dinitrobenzene sulfonyl chloride (II). The reaction of the latter with dipropylamine gives 4-dipropylamino-3,5-dinitrophenyl sulfonyl chloride (III), the reaction of which with ammonium hydroxide yields oryzalin. 

Two experimental techniques have improved the observed participation of simple aromatic quaternary salts in [4+ + 2] cycloadditions. The addition of hydroquinone, which forms a stabilized 1 2 complex with the isoquinolinium salts, to the reaction mixture accelerates the rate of observed isoquinolinium salt [4+ + 2] cycloaddition.148b In addition, the use of 2,4-dinitrophenyl aromatic quaternary salts, prepared from the parent base and 2,4-dinitrophenyl bromide or chloride, accentuates the electron-deficient character of the quaternary salt and accelerates their participation in [4+ + 2] cycloadditions with electron-rich dienophiles.152 These observations of Falck and co-workers have proved useful for promoting the [4+ + 2] cycloaddition of isoquinolinium systems previously regarded unmanageable. The application of these observations in the total syntheses of 14-epicorynoline (16) and methyl arrnothanamide (17) have been detailed [Eq. (67)],152... 

If l-(2,4-dinitrophenyl)pyridinium chloride is heated with aniline hydrochloride in benzoic acid for some time at 200°, 2,4-dinitrodiphenylamine is formed in accord with reaction (a) other examples are given by Vompe and Turitsyna.1134... 

Bis-(2,4-dinitrophenyl) sulfide 292 1-Chloro-l,4-dinitrobenzene (100 g) is dissolved in ethanol (11), and a melt of sodium sulfide nonahydrate (65.5 g) and sulfur (9 g) is added in small portions. A violent reaction occurs, which is completed by 3 hours boiling on a sand-bath. After cooling, the product is filtered off and washed, first, with ethanol and then with warm water to remove the sodium chloride. The product (86 g) has m.p. 280° (dec.). 

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