Xanthine derivatives, their preparation and pharmaceutical compositions containing them.

摘要

A compound of formula (I): <CHEM> or a pharmaceutically acceptable salt thereof, wherein R1 and R2 are independently n-butyl, -(CH2)2CHOHCH3, -(CH2)2CHOHCH2OH, -(CH2)2COCH3 or -(CH2)2C(OR4)(OR5)CH3 where R4 and R5 are each C1-4 alkyl or together are C2-4 polymethylene, provided that R1 and R2 are not both n-butyl, and R3 is -CH2CHOHCH3, -CH2COCH3 or -CH2C(OR6)(OR7)CH3 where R6 and R7 are each C1-4 alkyl or together are C2-4 polymethylene.