Scheme 2. Syntheses of phthalazine derivatives 11 and 15. Reagents and conditions: (a) (COCl)2, DMF, DCM, rt, overnight; (b) NH3/MeOH-DCM, rt, overnight; (c) bis(pinacolate)diboron, KOAc, PdCl2(dppf), dioxane, reflux, overnight, yield: 10 (45%), 14 (17%); (d) Na2CO3, ethanol/water/toluene, Pd(PPh3)4, 80 °C, 8 h, yield: 11 (44%), 15 (19%); (e) NH2NH2/EtOH, DCM, rt, overnight, yield: 30%; (f) triethylorthoformate, 145 °C, 11 h, yield: 65%.
