Purine derivative

A method for inducing .alpha.-interferon in a patient having Hepatitis B or C, comprising:

• administering to said patient an effective amount of a purine derivative represented by formula (I):
• ##STR16## wherein R.sup.2 is a hydrocarbon group containing at most 14 carbon atoms;
• any --CH.sub.2 -- group in said hydrocarbon group may be replaced with a carbonyl group, a sulfonyl group, --O-- or --S-- when said --CH.sub.2 -- group is not directly attached to the purine ring or is in --CH.sub.3 group not directly attached to the purine ring;
• any .dbd.CH.sub.2 group may be replaced with .dbd.O or .dbd.S;
• C--H group in said hydrocarbon group may be replaced with N, a C-halogen group or a C--CN group when said C--H group is in --CH.sub.2 -- group not directly attached to the purine ring, in --CH.sub.3 group not directly attached to the purine ring, in >CH-- group not directly attached to the purine ring, in .dbd.CH-- group not directly attached to the purine ring or in .dbd.CH.sub.2 group;
• R.sup.6 is an amino group;
• R.sup.8 is a hydroxyl group, a mercapto group, a group of the formula:
• R.sup.10 --CO.sub.2 --
• wherein R.sup.10 is a hydrogen atom or a hydrocarbon group containing at most 17 carbon atoms,
• or an oxycarbonyloxy group substituted with a hydrocarbon group containing at most 19 carbon atoms,
• R.sup.9 is a hydrocarbon group containing at most 14 carbon atoms;
• any --CH.sub.2 -- group in said R.sup.9 may be replaced with a carbonyl group, a sulfonyl group, --O-- or --S-- when said --CH.sub.2 -- group is not directly attached to the purine ring or is in --CH.sub.3 group not directly attached to the purine ring;
• any .dbd.CH.sub.2 group may be replaced with .dbd.O or .dbd.S;
• C--H group in said R.sup.9 may be replaced with a C-halogen group or a C--CN group when said C--H group is in --CH.sub.2 -- group not directly attached to the purine ring, in --CH.sub.3 group not directly attached to the purine ring, in >CH-- group not directly attached to the purine ring, in .dbd.CH-- group not directly attached to the purine ring, in .dbd.CH.sub.2 group or in .tbd.CH group;
• or its tautomer or pharmaceutically acceptable salts thereof, effective to treat said patient having Hepatitis B or C.

A method for promoting a secretion of .alpha.-interferon in a cell capable of secreting .alpha.-interferon, comprising administering an amount of a purine derivative represented by formula (I) to said cell:

• ##STR17## wherein R.sup.2 is a hydrocarbon group containing at most 14 carbon atoms;
• any --CH.sub.2 -- group in said hydrocarbon group may be replaced with a carbonyl group, a sulfonyl group, --O-- or --S-- when said --CH.sub.2 -- group is not directly attached to the purine ring or is in --CH.sub.3 group not directly attached to the purine ring;
• any .dbd.CH.sub.2 group may be replaced with .dbd.O or .dbd.S;
• C--H group in said hydrocarbon group may be replaced with N, a C-halogen group or a C--CN group when said C--H group is in --CH.sub.2 -- group not directly attached to the purine ring, in --CH.sub.3 group not directly attached to the purine ring, in >CH-- group not directly attached to the purine ring, in .dbd.CH-- group not directly attached to the purine ring or in .dbd.CH.sub.2 group;
• R.sup.6 is an amino group;
• R.sup.8 is a hydroxyl group, a mercapto group, a group of the formula:
• R.sup.10 --CO.sub.2 --
• wherein R.sup.10 is a hydrogen atom or a hydrocarbon group containing at most 17 carbon atoms,
• or an oxycarbonyloxy group substituted with a hydrocarbon group containing at most 19 carbon atoms;
• R.sup.9 is a hydrocarbon group containing at most 14 carbon atoms;
• any --CH.sub.2 -- group in said R.sup.9 may be replaced with a carbonyl group a sulfonyl group, --O-- or --S-- when said --CH.sub.2 -- group is not directly attached to the purine ring or is in --CH.sub.3 group not directly attached to the purine ring;
• any .dbd.CH.sub.2 group may be replaced with .dbd.O or .dbd.S;
• C--H group in said R.sup.9 may be replaced with a C-halogen group or a C--CN group when said C--H group is in --CH.sub.2 -- group not directly attached to the purine ring, in --CH.sub.3 group not directly attached to the purine ring, in >CH-- group not directly attached to the purine ring, in .dbd.CH-- group not directly attached to the purine ring, in .dbd.CH.sub.2 group or in .tbd.CH group;
• or its tautomer or pharmaceutically acceptable salts thereof, effective to promote a secretion of interferon in said cell.