Sunscreen compounds

A compound of formula I ##STR44## wherein:

• R.sup.1 is selected from the group consisting of C.sub.1 to C.sub.18 alkyl;
• C.sub.1 to C.sub.9 alkyl substituted with a substituent selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkoxy, C.sub.2 to C.sub.9 alkenyloxy, C.sub.1 to C.sub.9 alkanoyl, (C.sub.1 to C.sub.9 alkoxy) carbonyl, carbamoyl, (C.sub.1 to C.sub.6 alkyl)carbamoyl and phenyl;
• C.sub.2 to C.sub.18 alkenyl;
• C.sub.2 to C.sub.9 alkenyl substituted with a substituent selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkoxy, C.sub.2 to C.sub.9 alkenyloxy, C.sub.1 to C.sub.9 alkanoyl, carbamoyl, (C.sub.1 to C.sub.6 alkyl)carbamoyl, and phenyl;
• C.sub.2 to C.sub.18 alkynyl;
• phenyl;
• benzyl;
• the groups phenyl and benzyl substituted on the benzene ring with a substituent selected from the group of C.sub.1 to C.sub.12 alkyl, C.sub.1 to C.sub.12 alkoxy, C.sub.2 -C.sub.9 alkylene, C.sub.2 to C.sub.12 alkenyloxy, C.sub.1 to C.sub.12 alkylamino N,N-di(C.sub.1 to C.sub.6 alkyl)amino, (C.sub.1 to C.sub.12 alkoxy)carbonyl and C.sub.1 to C.sub.12 alkanoyl;
• C.sub.5 to C.sub.7 cycloalkyl;
• C.sub.5 to C.sub.7 cycloalkenyl;
• the groups substituted C.sub.5 to C.sub.7 cycloalkyl and substituted C.sub.5 to C.sub.7 cycloalkenyl wherein the substituent is selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkyl, C.sub.1 to C.sub.9 alkoxy, and C.sub.1 to C.sub.9 alkenyloxy;
• R.sup.3 is selected from the group consisting of C.sub.2 to C.sub.18 alkyl;
• C.sub.1 to C.sub.9 alkyl substituted with a substituent selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkoxy, C.sub.2 to C.sub.9 alkenyloxy, C.sub.1 to C.sub.9 alkanoyl, (C.sub.1 to C.sub.9 alkoxy)carbonyl, carbamoyl, (C.sub.1 to C.sub.6 alkyl)carbamoyl and phenyl;
• C.sub.2 to C.sub.18 alkenyl;
• C.sub.2 to C.sub.9 alkenyl substituted with a substituent selected from the group consisting of hydroxy, amino C.sub.1 to C.sub.9 alkoxy, C.sub.2 to C.sub.9 alkenyloxy, C.sub.1 to C.sub.9 alkanoyl, (C.sub.1 to C.sub.9 alkoxy)carbonyl, carbamoyl, (C.sub.1 to C.sub.9 alkyl) carbamoyl and phenyl;
• C.sub.2 to C.sub.18 alkynyl;
• phenyl;
• benzyl;
• benzoyl;
• the groups phenyl, benzyl and benzoyl optionally substituted on the benzene ring with a substituent selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.12 alkyl, C.sub.2 to C.sub.12 alkenyl, C.sub.1 to C.sub.12 alkoxy, C.sub.2 to C.sub.12 alkenyloxy, C.sub.1 to C.sub.12 alkylamino, N,N-di(C.sub.1 to C.sub.6 alkyl)amino, (C.sub.1 to C.sub.12 alkoxy)carbonyl, and C.sub.1 to C.sub.12 alkanoyl;
• C.sub.5 to C.sub.7 cycloalkyl;
• C.sub.5 to C.sub.7 cycloalkenyl;
• the groups substituted C.sub.5 to C.sub.7 cycloalkyl and substituted C.sub.5 to C.sub.7 cycloalkenyl wherein the substituent is selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkyl, C.sub.1 to C.sub.9 alkoxy, and C.sub.1 to C.sub.9 alkenyloxy;
• C.sub.1 to C.sub.18 alkanoyl;
• C.sub.2 to C.sub.9 alkanoyl substituted with a substituent selected from the group consisting of hydroxy, amino, C.sub.1 to C.sub.9 alkoxy, C.sub.2 to C.sub.9 alkenyloxy, C.sub.1 to C.sub.9 alkanoyl, carbamoyl, C.sub.1 to C.sub.6 alkyl)carbamoyl, (C.sub.1 to C.sub.9 alkoxy)carbonyl and phenyl;
• and the group --OROROR.sup.9 wherein R which may be the same or different are bivalent hydrocarbon radicals of 2 to 6 carbon atoms and R.sup.9 is a hydrocarbon radical selected from C.sub.1 to C.sub.6 alkyl, C.sub.2 to C.sub.6 alkenyl phenyl, benzyl, (C.sub.1 to C.sub.6 alkyl) phenyl and (C.sub.1 to C.sub.6 alkyl)benzyl;
• R.sup.2 is selected from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 alkoxy;
• R.sup.4 is selected from the group consisting of C.sub.1 to C.sub.6 alkyl and C.sub.1 to C.sub.6 alkoxy;
• n is an integer selected from 0 to 4 inclusive;
• R.sup.5 and R.sup.6 which may be the same or different are selected from hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 alkoxy, C.sub.1 to C.sub.10 alkanoyl, C.sub.1 to C.sub.10 alkanoyl substituted by carboxyl or (C.sub.1 to C.sub.6 alkoxy) carbonyl;
• with the proviso that when R.sup.1 is methyl then R.sup.3 is not selected from the group of hydroxyethyl, methoxymethyl and benzyl and when R.sup.1 is phenol, R.sup.3 is not acetyl or alkyl substituted with phenyl.