Process for the preparation of substituted pyrimidine derivatives

A compound of formula (XI)

• wherein
• PG3 is a nitrogen protecting group selected from the group consisting of —C(O)CH3, —C(O)OCH2CH3, —C(O)OC(CH3)3, —CHO, —C(O)OCH3, —C(O)O—CH2-phenyl, —C(O)-phenyl, —C(O)OCH2CCl3, —C(O)-(4-nitrophenyl), —C(O)CCl3, —C(O)CF3, —SO2CH3, —SO2-phenyl, —SO2-(4-nitrophenyl), and —SO2CF3;
• Rc is selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, —CF3, cyclopropyl, and cyclobutyl;
• or a pharmaceutically acceptable salt thereof.