Xanthine derivatives

Abstract

##STR1## A compound of formula (I) or, if appropriate, a pharmaceutically acceptable salt thereof, wherein R.sup.1 and R.sup.2 each independently represent an alkyl group or a moiety of formula (a): --(CH.sub.2).sub.m --A, wherein m represents zero or an integer 1, 2 or 3 and A represents a substituted or unsubstituted cyclic hydrocarbon radical; R.sup.3 represents hydrogen, NO.sub.2 or a halogen atom, an alkoxy group or a group of formula NR.sup.s R.sup.t wherein R.sup.s and R.sup.t each independently represent hydrogen or alkyl or R.sup.s and R.sup.t together with the nitrogen to which they are attached form a phthalimido group, the phthalimido group being substituted or unsubstituted in the phenylene moiety or R.sup.3 represents a moiety of formula (b), wherein R.sup.5 represents substituted or unsubstituted alkyl or a substituted or unsubstituted aryl group; and R.sup.6 represents hydrogen or a group SO.sub.2 R.sup.7 wherein R.sup.7 represents substituted or unsubstituted alkyl, a substituted or unsubstituted aryl group; R.sup.4 represents SO.sub.2 R.sup.8, wherein R.sup. 8 represents substituted or unsubstituted alkyl or a substituted or unsubstituted aryl group, or, when R.sup.3 represents a moiety of the above-defined formula (b), then R.sup.4 represents hydrogen or a substituted or unsubstituted alkyl group or a benzyl group substituted or unsubstituted in the phenyl ring a process for preparing such a compound, a composition comprising such a compound and the use of such a compound and composition in medicine.