Diazotized 2-chloro-4-nitroaniline

Preparation. The precursor, l-chloro-4- o-nitrophenyl)-2-butene (3), is prepared by the Meerwein reaction of diazotized o-nitroaniline (2) with butadiene in acetone in the presence of cupric chloride and sodium acetate. - Dehydrohalogenation with methanolic potassium hydroxide then gives the diene (4). ... 

Chloro-2-nitroaniline. Primary aromatic amines should be protected by acetylation before nitration to avoid the possibility of accidental diazotization.19 Crotonaldehyde. Ignites in concentrated HN03.2... 

While the nitrite must be used in exactly the amount theoretically required, an excess of acid is always used. For laboratory preparations, as a rule, the excess acid used is about 0.5 equivalent over the theoretically required 2 equivalents. The excess of acid must be increased to 1 to 3 equivalents in diazotizations of weakly basic amines whose salts are readily hydrolyzed (e.g., chloro- and nitroanilines). In some cases where even this larger excess of acid is insufficient to dissolve the base (e.g., nitrochloroaniline), the diazotization may be carried out in suspension provided that the base is present in a finely divided state. Thus, a solution of the base in concentrated sulfuric acid may be poured into ice water, the base filtered off and washed and then made up into a paste. Even this method fails to work with some bases such as dinitroaniline and m trodichloroaniline these compounds can be diazotized smoothly only in concentrated sulfiuric acid solution. 

Carbon-carbon bonds can be formed in very varied ways in reactions of diazonium compounds. For example, l-chloro-4-(/ -nitrophenyl)-2-butene (88% yield) is formed from diazotized / -nitroaniline and butadiene in aqueous acetone containing copper chloride and sodium acetate,787 whereas in the same conditions 5-phenyl-2,4-pentadienoic acid gives l-(/ -nitrophenyl)-4-phenyl-1,3-butadiene.788 The latter reaction is a special case of Meerwein arylation, by which stilbenes are formed in good yields from diazonium salts and cinnamic acids 789... 

Definition Diazotized 4-chloro-2-nitroaniline coupled with N-(2-oxo-5-benzimidazolinyl) acetoacetamide Empirical CuFlisCINsOs... 

Classification Monoazo color Definition Diazotized 4-chloro-2-nitroaniline coupled with N-(2-oxo-5-benzimidazolinyl) acetoacetamide Empirical C17H13CIN6O5 Properties Reddish-orange hue si. sol. in org. soivs. m.w. 416.77 sp.gr. 1.53-1.60 m.p. 330 C oil absorp. 80 wt./100 wt. 

Some insoluble azo dyes are used as pigments. Pigment Yellow 3 (Hansa Yellow lOG) illustrates this type. It is prepared by coupling diazotized 4-chloro-2-nitroaniline with o-chloroacetoacetanilide. 

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See also in sourсe #XX -- [ ]

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