The invention claims compounds of the formula wherein is a 5-membered heteroaryl; X is S or O; R1 is H, alkyl, cycloalkyl, cylcoalkylalkyl-, —CH2F, —CHF2, —CF3, —C(O)alkyl or —C(O)NR18R19; R3 and R4H, alkyl, hydroxyalkyl or —C(O)Oalkyl; R5 and R6 are H, alkyl, hydroxyalkyl, alkoxyalkyl, mercaptoalkyl, —CH2F, —CHF2, —CF3, —C(O)OH or —C(O)Oalkyl; R7 is H, alkyl, alkenyl, hydroxyalkyl, cycloalkyl, alkoxyalkyl, aminoalkyl, (R17-phenyl)alkyl or —CH2—C(O)—O-alkyl; and R8 comprises alkyl, heteroaryl, phenyl or cycloalkyl, or heterocycloalkyl, all optionally substituted, or a cycloalkyl- or heterocycloalkyl-substituted amide; or R7 and R8 and the nitrogen to which they are attached together form an optionally substituted ring; and the remaining variables are as defined in the specification. Also claimed are pharmaceutical compositions, the use of the compounds as PDE4 inhibitors, and combinations with other actives.