Dimethylaniline, acetylation

On acetylation it gives acetanilide. Nitrated with some decomposition to a mixture of 2-and 4-nitroanilines. It is basic and gives water-soluble salts with mineral acids. Heating aniline sulphate at 190 C gives sulphanilic add. When heated with alkyl chlorides or aliphatic alcohols mono- and di-alkyl derivatives are obtained, e.g. dimethylaniline. Treatment with trichloroethylene gives phenylglycine. With glycerol and sulphuric acid (Skraup s reaction) quinoline is obtained, while quinaldine can be prepared by the reaction between aniline, paraldehyde and hydrochloric acid. 

Commercial preparations of acetyl chloride are best freed from volatile phos. phorus compounds and dissolved hydrogen chloride by redistillation from 5-10 per cent, of the volume of pure dimethylaniline. 

Acetyl chloride [75-36-5] M 78.5, b 52 , d 1.1051, n 1.38976. Refluxed with PCI5 for several hours to remove traces of acetic acid, then distd. Redistd from one-tenth volume of dimethylaniline or quinoline to remove free HCl. A.R. quality is freed from HCl by pumping it for Ih at -78 and distg into a trap at -196 . 

In a 2-1. flask equipped with a reflux condenser, mercury-sealed stirrer, and a dropping funnel are placed 147 ml. (114 g., 1.5 moles) of ferf.-butyl alcohol (Note 1), 212 ml. (202 g., 1.67 moles) of dimethylaniline, and 200 ml. of dry ether. The solution is heated to refluxing, and 113 ml. (124 g., 1.58 moles) of acetyl chloride is run into the stirred solution at such a rate that moderate refluxing continues after the source of heat is removed. When approximately two-thirds of the acetyl chloride has been added, dimethylaniline hydrochloride begins to crystallize and the mixture refluxes very vigorously. An ice bath is applied immediately, and, after refluxing ceases, the remainder of the acetyl chloride is added. Finally, the mixture is heated for 1 hour on a water bath. The mixture is cooled to room tempera-... 

Many gas chromatographic methods for amphetamine have been developed since then, most of which include a recommended internal standard such as N,N-dimethylaniline, phenethylamine, and di-phenylamine. These methods also include the formation of derivatives such as the acetylated amines and the ketone derivative of amphetamine as a further check on identity. 

Highly substituted pyridinium salts of type 1 are easily accessible by Hantzsch-type synthesis. They are valuable products in that they can often be transformed easily into otherwise difficultly accessible, highly substituted benzenes or pyridines by base-catalysed rearrangement. For example, treatment of the salt 2 with ethanolic sodium hydroxide at room temperature for one hour gives 2,4-diacetyl-lV,5-dimethylaniline 3 in 85% yield, while 3-acetyl-5-cyano-6-methyl-2-methylamino-4-phenylpyridine 5 is obtained in 88% yield from the salt 4 under the same conditions. 

Methylation with dimethyl sulfate in alkali gave the methyl derivatives 28 and 29. Although formaldehyde attacks at N-2, aldol condensation of 10 with benzaldehyde gave the 3a-hydroxybenzyl compound (30) which is dehydrated to the 2-acetyl-3-benzylidene compound (31) with acetic anhydride.27 With acid anhydrides the2-acyl derivatives are obtained however, with acid chlorides in pyridine or dimethylaniline the bicyclic ketone (32) is formed.31 Despite the occurrence of the bicyclic product (32) and the bicyclic intermediate (13) there is no evidence for the existence of a bicyclic tautomer of 10.37... 

Olefinic ketones have been obtained from the reaction of acyl chlorides or anhydrides with olefins using the conditions of the Friedel-Crafts reaction. The intermediate chloro ketones are oftentimes stable and must be treated with sodium bicarbonate or dimethylaniline to complete the de-hydrohalogenation. In this manner, 1-acetyl-1-cyclohexene (62%) ° and 1-butyryl-1-cyclohexene (60%) are prepared. 

D) Acetylation of Amines. Place 1 ml of aniline, dimethylaniline, and n-hutylamine in separate test tubes. Add to each of the tubes 2 ml of acetic acid (glacial) and 3 ml of acetic anhydride. Heat the tubes in boiling water for 3 minutes. Add slowly 10 ml of water. If no acetyl derivative forms, neutralize carefully with dilute ammonium hydroxide. Filter with suction, and wash the crystals with a small amount of water. Dry, place in small vials, label, and hand to the instructor. 

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