Abstract: Novel 4,5-diamino pyrimidine derivatives are described by the following general formula I: in which X is a direct bond, C1-4 alkylene, C1-4 alkyleneoxy, C1-4 alkoxyphenyl or phenyl C1-4 alkylene; Y is a direct bond or C1-2 alkyl, R1 is (i) 5-15 membered cyclic or fused heterocompound which includes one or two atoms selected from a group consisting of nitrogen, oxygen and sulfur and which is substituted with one or two substituents selected from a group consisting of hydrogen, halogen, nitro, hydroxy, C1-6 alkyl, C3-6 alkenyl and halogen C1-4 alkoxy, (ii) C4-10 carbocyclic compound or (iii) hydroxy C1-4 alkoxy, R2 is 5-15 membered cyclic or fused heterocompound which includes one or two nitrogen atoms and, optionally, one oxygen or sulfur atom, and which is substituted with one or two substituents selected from a group consisting of hydrogen, hydroxy, halogen, nitro, hydroxy C1-5 alkyl, C1-6 alkyl, C3-6 alkenyl and halogen C1-4 alkoxy; R3 is hydrogen, in which R4 and R5 are

Abstract: A phosphodiesterase IV inhibiting cathecol derivatives of the general formula I: ##STR1## or a pharmaceutically acceptable salt thereof in which R1 is C.sub.1-7 alkyl; C.sub.3-7 cycloalkane; phenyl optionally substituted with lower alkyl lower alkoxy, nitro or halogen; pyrimidine optionally substituted with lower alkyl, lower alkoxy, nitro or halogen; or pyridine optionally substituted with lower alkyl, lower alkoxy, nitro or halogen; X, Y and Z are each independently oxygen, nitrogen or sulfur optionally substituted with C.sub.1-7 alkyl, C.sub.3-7 cycloalkane or phenyl; W is oxygen or sulfur is disclosed. In addition, a process for producing the compound of the general formula I and a pharmaceutical composition containing pharmaceutically effective amount of the compound of the general formula I are disclosed.