5-a]-1,3,5-triazines were considered as a bioisosteric replacement for the 9-substitutedadenine derivatives resulting in the discovery of 8-(2-methoxybenzyl)-4-(N-methylamino)-2-n-propylpyrazolo[1,5-a]-1,3,5-triazine (14d) and 2-trifluoromethyl-8-(2-methoxybenzyl)-4-(N-methylamino)pyrazolo[1,5-a]-1,3,5-tria zine (14e) as a new structural class of potent phosphodiesterase type 4 inhibitors (IC(50)=13