The present invention relates to novel Phosphodiesterase type 4 (PDE4) inhibitors of the formula (1) and analogs, tautomers, enantiomers, diasteromers, regioisomers, stereoisomers, polymorphs, pharmaceutically acceptable salts, appropriate N-oxides, pharmaceutically acceptable solvates thereof and the pharmaceutical compositions containing them which are useful in the treatment of allergic and inflammatory diseases including asthma, chronic bronchitis, atopic dermatitis, urticaria, allergic rhinitis, allergic conjunctivitis, vernal conjuctivitis, eosinophilic granuloma, psoriasis, rheumatoid arthritis, septic shock, ulcerative colitis, Crohn's disease, reperfusion injury of the myocardium and reperfusion injury of the brain, chronic glomerulonephritis, endotoxic shock and adult respiratory distress syndrome.