PDE4 inhibition is achieved by novel nitroxide compounds, e.g., N-substituted aniline and diphenylamine analogs. The compounds of the present invention are of Formulas I-III: ##STR00001## wherein A, B, D, R.sup.1, R.sup.2, R.sup.3, R.sup.7, R.sup.8, R.sup.9, R.sup.10 and R.sup.6 are as defined herein.