N6 -tricyclic adenosines

Claim 1

A compound of the formula: ##STR6## wherein R 6a is hydrogen or lower alkyl; R 6b is hydrogen, hydroxy, lower alkyl, lower alkanoyloxy- or benzoyloxy; R 6c and 6d are each independently hydrogen or one or more substituents selected from halogen, hydroxy, lower alkoxy, lower alkanoyloxy, benzoyloxy, lower S(O)n-alkyl in which n is 0, 1, or 2, sulfonamide, trifluoromethyl, lower alkyl, lower mono- or dialkylamino, nitro or sulfhydryl; X is a valence bond or a straight or branched alkylene of 1 to 8 carbon atoms; Y is a valence bond, oxygen, sulfur, NR in which R is hydrogen, lower alkyl, lower alkanoyl or benzoyl, --(CH 2 )n-- in which n is 1 or 2 or --CH═CH--; R 2 is hydrogen, halogen, NR i R ii , or i or SR i in which R i and R ii are each independently hydrogen, lower alkyl or phenyl, lower alkyl; R 2' , R 3' , and R 5' are each independently hydrogen, lower alkanoyl, benzoyl, benzoyl substituted by lower alkyl, lower alkoxy, halogen or trifluoromethyl, or R 2' and R 3' may be bonded together to form a lower alkylidene group, on a pharmaceutically acceptable acid form salt thereof.