Dual M3 antagonists-PDE4 inhibitors.: Part 2:: Synthesis and SAR of 3-substituted azetidinyl derivatives

Introduction of 3-substituted azetidinyl substituents onto the 4,6-diaminopyrimidine scaffold allowed the improvement of PDE4 inhibiting activities. Preliminary in vivo activity in pulmonary inflammation models is reported. (C) 2007 Elsevier Ltd. All rights reserved.