We reported earlier the refinement of our initial five-point pharmacophore model for the Histamine 3 receptor (H3R), with a new acceptor feature important for binding and selectivity against the other histamine receptor subtypes 1, 2 and 4. This approach was validated with a new series of H3R inverse agonists: the naphthalene series. In this Letter, we describe our efforts to overcome the phospholipidosis flag identified with our initial lead compound (1a) ...