Dichlorotoluene

A solution of nitrosylsulfuric acid is prepared by dissolving 32 g. of sodium nitrite in 320 ml. of concentrated sulfuric acid at 70°. To this solution is added slowly, with stirring and cooling to hold the 

Breslow, Walker, Yost, Sdhivers, and Hauser, 1. Am. Chem. Soc., 68, 101 (1946). 

A solution of 200 g. (2.73 moles) of diethylamine in 150 ml. of ether is added slowly with intermittent cooling to 126 g. (1.37 moles) of chloroacetone. After the exothermic reaction has subsided, the mixture is heated under reflux for 5 hours. After cooling, the precipitated diethylamine hydrochloride is filtered off and the precipitate washed with ether. The combined filtrate and ether washings are distilled through a 15-cm. Vigreux column to give 127 g. (72%) of diethyl-aminoacetone boiling at 55-58 °/16 mm. 

Solid sodium metabisulfite (200 g.) is added to 81 g. of 37% aqueous formaldehyde solution with cooling to form an aqueous solution of the aldehyde bisulfite compound. After no more heat is evolved from 

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Dichlorotoluene (2,4-dichloro-l-methylben2ene) constitutes 80—85% of the dichlorotoluene fraction obtained in the chlorination of PCT with antimony trichloride (76) or zirconium tetrachloride (77) catalysts. It is separated from 3,4-dichlorotoluene (l,2-dichloro-4-methylben2ene), the principal contaminant, by distillation. Chlorination of OCT with sulfuryl chloride gives mainly 2,4-dichlorotoluene and small amounts of the 2,3 isomer (78). 

Dichlorotoluene is an intermediate for manufacture of herbicides. It is also used to obtain 2,4-dichloroben2yl chloride and 2,4-dichloroben2oyl chloride. 2,6-Dichlorotoluene is appHed as a herbicide and dyestuff intermediate. 2,3,6-Trichlorotoluene is used as a herbicide intermediate. The other polychlorotoluenes have limited industrial appHcation. 

Miconazole nitrate was prepared by Godefori and co-workers [5-7]. Imidazole 1 was coupled with brominated 2,4-dichloroacetophenone 2 and the resulting ke-tonic product 3 was reduced with sodium borohydride to its corresponding alcohol 4. The latter compound 4 was then coupled with 2,4-dichlorotoluene by sodium borohydride in hexamethylphosphoramide (an aprotic solvent), which was then extracted with nitric acid to give miconazole nitrate. 

Method A solution of p-methoxyphenyltellurium trichloride (0.34 g, 1.0 mmol) in benzene (200 mL) is irradiated with a high-pressure mercury lamp in the presence of atmospheric oxygen for 1 h (formation of a black precipitate). The mixture is filtered and the filtrate is washed with brine and then dried (MgS04). GLC analysis shows the presence of p-chloromethoxybenzene [0.14 g (70%)] (and minor amounts of o,p-dichloro-methoxy-benzene and p-methoxybiphenyl) using p-chlorotoluene, 2,4-dichlorotoluene and p-methylbiphenyl as the internal standard, respectively. 

An interesting variation in reactivity has also been shown20 in the carbocyclic series on reaction of Schiff s base derived from aniline and p-chlorobenzaldehyde with a number of isomeric dichlorotoluenes. 2,4-Dichlorotoluene yields only the expected stilbene 2,5-dichloro-toluene, according to reaction conditions and molar ratios, gives either the stilbene or 1,2,3-triarylpropane, whereas 2,6-dichlorotoluene yields only the addition product 24. 

Common Name 2, 4-Dichlorotoluene Synonym 2, 4-dichloro-l-methylbenzene Chemical Name 2, 4-dichlorotoluene CAS Registry No 95-73-8 Molecular Formula C7H6C12 Molecular Weight 161.029 Melting Point (°C) ... 

Bromine (117 g., 0.73 mole) is added slowly to 51.5 g. (0.29 mole) of 2,4-dichlorotoluene (p. 113), during which operation the reaction mixture is held at a temperature of 180-200°. (Hood.) The reaction mixture is stirred for 1 hour at 100° with 80 ml. of concentrated sulfuric acid followed by a short period at 140° imtil no more bromine or hydrogen bromide is evolved. The resulting mixture is cooled and poured into crushed ice. The precipitated solid is removed by filtration and placed in a steam-distillation apparatus with some sodium carbonate. Steam distillation gives the aldehyde in the distillate, from which it is collected by filtration. There is obtained 51.6 g. (92%) of 2,4-dichlorobenzaldehyde, m.p. 74.5°. 

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