Scheme 5. Synthesis of final derivatives by assembling of the building blocks. Conditions: a (SOCl₂, 90 °C 27a then 35b, DIPEA) or [27c and (25a, 25b, 33a, 33b or 35a), NEt₃], THF, 0 °C → 25 °C; b Zn, EtOH/AcOH (4 : 1) or CHCl₃/AcOH (9 : 1), 0 °C, 2 steps: 82% (36a), 54% (36b), 41% (36c), 32% (36d), 76% (36e), 75% (36f); c EEDQ, 38, THF, 25 °C; d Pd(PPh₃)₄, morpholine, THF or Pd/C, H₂, EtOH/THF/MeOH (1 : 1 : 1); e 4N HCl, dioxane, 25 °C, 3 steps: 65% (37a), 66% (37b), 20% (37c), 53% (37d), 51% (37e), 37% (37f); f (37a–f, 39) or (37g, 22a–b) or (first 22a or 22b, TFA/CH₂Cl₂ (1 : 1), 0 °C, then 37g), NEt₃, DMF, 25 °C, g 3N KOH, DMF, 25 °C, 2–3 steps: 15% (3), 25% (4), 8% (5), 12% (6), 23% (7), 16% (9), 12% (10), 5% (12), 8% (13), 15% (15).