2-Bromo-4,6-dimethylaniline

N)2csH2Br.N(NO).CH3 mw 305.06, K 17.14% lt-yel ndls(from ale), mp 124° was prepd by treating 4-bromodimethylaniline with mixed HN03 H2S04 below 40° or 2-nitro-4-bromo-dimethylaniline with 52% HN03 betw 10-35°... 

The following rate constants are reported for the reaction between p-bromo-dimethylaniline and methyliodide in nitrobenzene ... 

A soln. of 0.5 mole of ethyl a-hydroxyisobutyrate in ether added dropwise to a soln. of p-dimethylaminophenyllithium prepared from 2 moles of p-bromo-dimethylaniline and 4 moles of small pieces of Li-ribbon (preferably containing ca. 0.6% Na) in anhydrous ether under Ng, and refluxed 5 hrs. l,l is-(p-di-methylaminophenyl)-2-methyl-1,2-propanediol. Y 86% based on ethyl a-hydroxyisobutyrate. F. e., also with a-alkoxyesters and a-alkoxylactones, s. J. B. Wright and E. S. Outsell, Am. Soc. 81, 5193 (1959) optically active compounds s. D. J. Gram et al.. Am. Soc. 81, 5740 (1959) effect of sodium content of lithium on the prepn. of organolithium compounds s. a. G. W. Kamienski and D.L. Esmay, J. Org. Ghem. 25, 1807 (1960). 

A mixture of 800 g of potassium o-bromo-benzoate, 1,500 ml of bis-(2-methoxyethyl)ether, 355 g of N-ethyl-morpholine, 375 g of 2,3-dimethylaniline, and 30 g of cupric acetate is heated gradually with stirring to 140°C over a period of 90 minutes. The hot reaction mixture is then acidified with 260 ml of concentrated hydrochloric acid and the acidified mixture divided into 2 equal portions. One liter of water is added to each portion and the mixtures allowed to cool. The N-(2,3-dimethylphenyl)anthranllic acid which separates upon cooling is collected by filtration and recrystallized from bis(2-methoxyethyl)ether MP 229° to 230°C (corr.). 

Halogenation of thiochromanones is a fruitful entry into other systems. As shown in Scheme 2, bromination of 6-methylthiochroman-4-one produces the perbromide (22), converted by water into the sulfoxide (23). Upon standing, 22 loses hydrogen bromide to form the 3-bromo compound (24), which yields the 3-amino analog and 6-methylthiochrom-4-one with ammonia and dimethylaniline, respectively.43-44... 

This method was not suitable to prepare phenyIbis (p-dimethylaminophenyl) phosphine (abbreviated as L2). This ligand was prepared in 23% yield by the method of Venanzi and co-workers (10) using the reaction of the lithium derivative from p-bromo-N,N-dimethylaniline with phenyldichlorophosphine. 

Gilman s colour test 2, which depends on rapid metal-halogen exchange with 4-bromo-./V,7V-dimethylaniline, is positive for alkyllithium compounds [3], but not for organomagnesium compounds. 

A mixture of 200 g. (1.08 moles) of 4-bromo-o-xylene [Org. Syntheses, 28, 22 (1948)], 14 g. of copper wire, and 600 ml. of concentrated ammonium hydroxide solution containing 12 g. of cuprous chloride is placed in a bomb and heated to 195° for 14 hours with agitation. The pressure is 900-1000 lb. The organic layer is separated from the resulting reaction mixture, and to the organic layer is added 40 ml. of 40% aqueous sodium hydroxide solution. The mixture is steam-distilled to remove the 3,4-dimethylaniline which is separated from the distillate and further purified by solution in 500 ml. of 8% aqueous hydrochloric acid, extraction with ether, and reprecipitation from the aqueous solution with 160 ml. of 40% alkali. The resulting alkaline solution is steam-distilled. The amine is separated from the distillate, dried, and distilled under vacuum. The product boils at 116-118°/22-25 mm., and the yield is 103 g. (79%). 

Figure 23. The family of curves recorded during measurements of the flow of heat during photo-initiated polymerization of TMPTA initiated by benzophenone-4-bromo-A,iV-dimethylaniline initiating photo-redox pairs. The benzophenones were 1) 4-Ph, 2) 4-C(0)0Et, 3) 4-Me, 4) 4-H, 5) 4-Cl, 6) 4-F, 7) 4-OMe, 8) 4-N02-...

Bromo-3-methoxycarbonylpyrazine with 2,3-dimethylaniline in refluxing toluene gave 2-(2, 3 -dimethylphenyl)amino-3-methoxycarbonylpyrazine (950) [hydrolysis of this product with sodium hydroxide in ethanol gave 2-carboxy-3-(2, 3 -dimethylphenyl)aminopyrazine, which was also obtained by treatment of l-(2, 3 -dimethylphenyl)lumazine with sodium hydroxide in refluxing ethanol (950)]. 3-Bromo-2-hydroxy-5-phenylpyrazine with ammonium hydroxide and copper at 150° gave 3-amino-2-hydroxy-5-phenylpyrazine (365a). Replacement of the iodo substituent from 2-amino-5-iodo-3,6-dimethylpyrazine has been effected with ammonium hydroxide (887). 

This material is of sufficient purity for most uses, including the conversion to 3,4-dimethylaniline (p. 46). It is reported that the boiling point of the product can be raised slightly (from 211-212° to 214-21S°/760 mm.) by sulfonation, recrystallization of the barium sulfonate, and regeneration of the bromo compound by acid hydrolysis. 

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