Xanthine derivatives

摘要

PCT No. PCT/GB91/02286 Sec. 371 Date Jul. 7, 1993 Sec. 102(e) Date Jul. 7, 1993 PCT Filed Dec. 19, 1991 PCT Pub. No. WO/9211260 PCT Pub. Date Jul. 9, 1992. (I) (b) A compound of formula (I) or, if appropriate, a pharmaceutically acceptable salt thereof, wherein R1 and R2 each independently represent an alkyl group or a moiety of formula (a): -(CH2)m-A, wherein m represents zero or an integer 1, 2 or 3 and A represents a substituted or unsubstituted cyclic hydrocarbon radical; R3 represents hydrogen, NO2 or a halogen atom, an alkoxy group or a group of formula NRsRt wherein Rs and Rt each independently represent hydrogen or alkyl or Rs and Rt 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 R3 represents a moiety of formula (b), wherein R5 represents substituted or unsubstituted alkyl or a substituted or unsubstituted aryl group; and R6 represents hydrogen or a group SO2R7 wherein R7 represents substituted or unsubstituted alkyl, a substituted or unsubstituted aryl group; R4 represents SO2R8, wherein R 8 represents substituted or unsubstituted alkyl or a substituted or unsubstituted aryl group, or, when R3 represents a moiety of the above-defined formula (b), then R4 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.