Monoazo compounds having a thiazolium or substituted thiazolium diazo component radical and a 1,4-phenylene coupling component radical having a C.sub.1-4 alkyl group in each ortho position

A compound of the formula ##STR27## wherein R.sub.1 ' is n-C.sub.1-6 alkyl;

• n-C.sub.1-6 alkyl monosubstituted by halo, hydroxy, cyano, C.sub.1-4 alkoxy or carbamoyl or disubstituted by halo and hydroxy or halo and cyano;
• or allyl,
• each of R.sub.2 ' and R.sub.3 ' is independently C.sub.1-4 alkyl,
• R.sub.4 ' is hydrogen;
• C.sub.1-4 alkyl;
• C.sub.1-4 alkyl monosubstituted by halo, hydroxy, cyano, phenyl, benzoyloxy, (C.sub.1-4 alkoxy)carbonyl, phenylcarbamoyl, phenoxy, di-(C.sub.1-4 alkyl)carbamoyl, carbamoyl, phenylcarbamoyloxy, di-(C.sub.1-4 alkyl)carbamoyloxy or C.sub.1-4 alkoxy or disubstituted by halo;
• phenyl;
• p-(C.sub.1-4 alkoxy)phenyl or cyclohexyl,
• R.sub.5 ' is hydrogen, C.sub.1-4 alkyl or C.sub.1-4 alkyl monosubstituted by halo, hydroxy, cyano, phenyl, benzoyloxy, (C.sub.1-4 alkoxy)carbonyl, di-(C.sub.1-4 -alkyl)carbamoyl, carbamoyl, phenoxy, phenylcarbamoyl or C.sub.1-4 alkoxy or disubstituted by halo or
• R.sub.4 ' and R.sub.5 ' taken together and with the nitrogen atom to which they are joined are morpholino,
• R.sub.6 ' is methyl when R.sub.4 ' and R.sub.5 ' are hydrogen and is otherwise hydrogen,
• R.sub.9 is hydrogen, C.sub.1-4 alkyl or phenyl,
• R.sub.10 is hydrogen, C.sub.1-4 alkyl or phenyl, with the proviso that when one of R.sub.9 and R.sub.10 is phenyl, the other is hydrogen, and
• A.sup..crclbar. is an anion.