Chromogenic 4,4-diaryl-2-oxobenzo-3,1-oxazines

#The invention relates to chromogenic 4,4-diaryl-2-oxobenzo-3,1-oxazines of the general formula ##STR2## wherein X.sup.1, X.sup.2 and X.sup.3, independently of one another, denote hydrogen, halogen, alkyl, aryl, alkanoylamino, aroylamino, heteryl, NY.sup.1 Y.sup.2, OY.sup.3 or SY.sup.3,

#at least one of the radicals X.sup.1, X.sup.2 or X.sup.3 standing for NY.sup.1 Y.sup.2, OY.sup.3 or SY.sup.3,

#R.sup.1 denotes hydrogen, alkyl, cycloalkyl, aralkyl, aryl or the members of a bridge to the o-carbon of ring B,

#26.8 g of Michler's ketone, 10.8 g of ethyl 3-dimethylaminophenylcarbamate, 76.5 g of phosphorus oxychloride and 28.2 g of diphosphorus pentoxide are stirred at room temperature for 48 h. The mixture is subsequently discharged onto 500 g of ice-water, the aqueous solution is decanted from the precipitated oil, the oil is dissolved in 100 ml of glacial acetic acid, the solution is diluted with 500 ml of water and NaOH is added with cooling to precipitate the carbinol base. This carbinol base is dissolved in 750 ml of dimethoxyethane, 15 ml of concentrated NaOH are added, and the mixture is stirred at room temperature for 5 h. The organic phase is separated off and evaporated to dryness in vacuo, and the residue is stirred with methanol until crystallisation occurs. The result obtained is 35 g of product of the formula ##STR14## In glacial acetic acid this product forms a dyestuff having an intensity peak at .lambda..sub.max =596 nm.

#An analogous procedure was used to prepare the following examples:

#______________________________________ ##STR15## Example R.sup.1 R.sup.2 R.sup.3 .lambda..sub.max ______________________________________ 2 N(C.sub.2 H.sub.5).sub.2 N(CH.sub.3).sub.2 N(C.sub.2 H.sub.5).sub.2 594 nm 3 N(C.sub.4 H.sub.9).sub.2 N(CH.sub.3).sub.2 N(C.sub.2 H.sub.9).sub.2 597 nm 4 N(C.sub.12 H.sub.25).sub.2 N(CH.sub.3).sub.2 N(CH.sub.3).sub.2 595 nm ______________________________________