Scheme 2. Synthesis of diaminoquinazolines in Table 3. Reagents and conditions: (i) benzyl bromide, K₂CO₃, DMF, 0 °C – RT, 18 h; (ii) HNO₃, Ac₂O, RT, 18 h; (iii) Fe, NH₄Cl, i-PrOH/H₂O, reflux, 18 h; (iv) a) NaOCN, H₂O/AcOH, RT, 18 h; b) NaOH, MeOH, reflux, 6 h; (v) POCl₃, DIEA, acetonitrile, reflux, 6 h; (vi) various amines, Et₃N (or DIEA), THF (or DMF), RT, 18–24 h; (vii) various amines (5–10 equiv.), microwave, toluene (or neat), 130–185 °C, 30–50 min or i-PrOH, 4 M HCl/dioxane, microwave, 160 °C, 15 min; (viii) TFA, reflux, 3 h; (ix) K₂CO₃ (or Cs₂CO₃), DMF, alkyl halides, 3–18 h 80 °C or PPh₃, DIAD, THF, 20 h, RT.