Process for the preparation of basic oxazine dyestuffs

Process for the preparation of a basic oxazine dyestuff of the formula:

• ##STR18## in which R.sub.1 represents:
• hydrogen,
• unsubstituted alkyl, alkenyl or aralkyl,
• alkyl substituted by halogen, hydroxy, cyano, carbamoyl, alkoxy or alkoxycarbonyl, or
• aralkyl substituted by halogen, alkyl, trifluoromethyl, cycloalkyl, hydroxy, alkoxy, aralkoxy, cycloalkoxy, aryloxy, carboxy, acyl, acyloxy, acylamino, acylalkoxycarbonyl, nitro, cyano, carbamoyl, sulfamoyl, amino, alkylamino, dialkylamino, arylamino, mercapto, alkylmercapto, arylmercapto, alkylsulfonyl or arylsulfonyl;
• R.sub.2 represents:
• unsubstituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl,
• alkyl substituted by halogen, hydroxy, cyano, carbamoyl, alkoxy or alkoxycarbonyl, or
• aryl or aralkyl substituted by halogen, alkyl, trifluoromethyl, cycloalkyl, hydroxy, alkoxy, aralkoxy, cycloalkoxy, aryloxy, carboxy, acyl, acyloxy, acylamino, acylalkoxycarbonyl, nitro, cyano, carbamoyl, sulfamoyl, amino, alkylamino, dialkylamino, arylamino, mercapto, alkylmercapto, arylmercapto, alkylsulfonyl or arylsulfonyl;
• R.sub.3 represents hydrogen, alkyl or alkoxy;
• R.sub.4 represents:
• hydrogen,
• unsubstituted alkyl, aryl or aralkyl,
• alkyl substituted by halogen, hydroxy, cyano, carbamoyl, alkoxy or alkoxycarbonyl, or
• aryl or aralkyl substituted by halogen, alkyl, trifluoromethyl, cycloalkyl, hydroxy, alkoxy, aralkoxy, cycloalkoxy, aryloxy, carboxy, acyl, acyloxy, acylamino, acylalkoxycarbonyl, nitro, cyano, carbamoyl, sulfamoyl, amino, alkylamino, dialkylamino, arylamino, mercapto, alkylmercapto, arylmercapto, alkylsulfonyl or arylsulfonyl;
• R.sub.5 represents hydrogen, unsubstituted alkyl or alkyl substituted by halogen, hydroxy, cyano, carbamoyl, alkoxy or alkoxycarbonyl;
• R.sub.6 represents hydrogen, alkyl or alkoxy;
• R.sub.7 represents hydrogen or alkyl or forms with R.sub.6 a fused benzene ring;
• and
• X.sup..crclbar. represents an anion,
• which process comprises reacting in aqueous medium, organic medium or mixture thereof;
• (a) a nitroso compound of formula (II) with an aminophenol of formula (III):
• ##STR19## in which R.sub.1 to R.sub.5 and R.sub.7 have the same meanings as above, R'.sub.6 represents hydrogen or alkyl, and R.sub.8 represents unsubstituted alkyl or alkyl substituted by hydroxy, or
• (b) a nitroso compound of formula (IV) with a compound of formula (V):
• ##STR20## in which R.sub.1, R.sub.2, R.sub.4, R.sub.5 and R.sub.6 have the same meanings as above, R'.sub.3 and R'.sub.7 each represents hydrogen or alkyl, and R.sub.9 represents alkoxy, unsubstituted amino or amino substituted by one or two alkyl,
• said reaction being effected without its being necessary to raise the temperature above the ambient temperature and in the presence of an anhydride of a carboxylic acid of the formula:
• ##STR21## in which Y represents unsubstituted linear or ramified alkyl containing 1 to 6 carbon atoms, linear or ramified halogeno-substituted alkyl containing 1 to 6 carbon atoms, unsubstituted phenyl or phenyl carrying up to three substituents selected from the halogen atoms and the nitro, alkyl and alkoxy groups, Y' is hydrogen or has the same significance as Y, said anhydride being used in a quantity at least equal to the stoichiometry.