US8017791B2 - Tri-Substituted 2-Benzhydryl-5-Benzylamino-Tetrahydro-Pyran-4-Ol and 6-Benzhydryl-4-Benzylamino-Tetrahydro-Pyran-3-Ol Analogues, and Novel, 3,6-Disubstituted Pyran Derivatives