Tricyclic Pyrazoles. Part 5. Novel 1,4-Dihydroindeno[1,2-c]pyrazole CB2 Ligands Using Molecular Hybridization Based on Scaffold Hopping

Scheme 1 Reagent and conditions: a) Na, dry EtOH, (COOEt)₂, RT, 24 h; b) 2,4-Cl₂-C₆H₃NHNH₂·HCl, AcOH, rfx, 8 h; c) KOH, EtOH/H₂O, rfx, 4 h; d) HOBt/EDC, CH₂Cl₂, RT, 1 h, then Q-NH₂, (TEA for 11 and 20), CH₂Cl₂, RT, 22 h; (e) SOCl₂, toluene, rfx, 3 h (for 18), then 1-naphthylamine, CH₂Cl₂, RT, overnight.