Benzopyranothiazoles

Abstract

A benzopyranothiazole of the formula ##STR1## wherein each of R.sub.1 and R.sub.2 independently represents hydrogen, alkyl of not more than 12 carbon atoms which is unsubstituted or substituted by halogen, hydroxyl, cyano or lower alkoxy, or represents cycloalkyl, phenyl, benzyl, or phenyl or benzyl which is substituted by halogen, lower alkyl or lower alkoxy, or R.sub.1 and R.sub.2 together with the nitrogen atom to which they are attached represent a 5- or 6-membered heterocyclic radical or a N-carbazolyl radical, Q represents hydrogen, lower alkyl, benzyl or groups of the formulae (1a) or (1b) ##STR2## each of X, X.sub.1 and X.sub.2 represents hydrogen, halogen, lower alkyl or lower alkoxy, each of Y.sub.1, Y.sub.2, Y'.sub.1 and Y'.sub.2 represents hydrogen, alkyl of not more than 12 carbon atoms which is unsubstituted or substituted by halogen, hydroxyl, cyano or lower alkoxy, or represents cycloalkyl, phenyl, benzyl, or phenyl or benzyl which is substituted by halogen, lower alkyl or lower alkoxy, or each of the pair of substituents Y.sub.1 and Y.sub.2 and Y'.sub.1 and Y'.sub.2, together with the nitrogen atom to said pair is attached, independently represents a 5- or 6-membered heterocyclic radical or a N-carbazolyl radical and the ring A is unsubstituted or substituted by halogen, nitro, lower alkyl, lower alkoxy, phenoxy or an amino group which is unsubstituted or substituted by lower alkyl, phenyl or benzyl; these compounds are particularly useful as color formers which give intense red to blue color shades of excellent light fastness when they are brought into contact with an electron-accepting co-reactant.