Scheme 3. Synthesis of Drug-Oxazoline Conjugates (1–3)a.
aReagents and conditions: (a) Et3N, DMSO, RT, 82%; (b) Et3N, DMSO, RT; (c) DMC, Et3N, H2O/DMSO, 0 °C, 1, 73% for 2 steps, 2, 80% for 2 steps, 3, 70% for 2 steps.
aReagents and conditions: (a) Et3N, DMSO, RT, 82%; (b) Et3N, DMSO, RT; (c) DMC, Et3N, H2O/DMSO, 0 °C, 1, 73% for 2 steps, 2, 80% for 2 steps, 3, 70% for 2 steps.