Part A. To the product (1.0 g, 4.2 mmol) from Example 2, Part B, was added N,N-dimethylglycine (490 mg, 4.7 mmol), triethylamine (1.80 ml, 13 mmol), and DMF (30 mL). To this mixture was added benzotriazol-1-yloxytripyrrolidino-phosphonium hexafluorophosphate (2.2 g, 4.3 mmol). After 10 min, the clear yellow solution was poured into EtOAc (80 mL) and washed with H2O (2×50 mL). The organic layer was washed with brine, dried over Na2SO4, and filtered. The resulting residue was purified by radial chromatography (5% MeOH in CH2Cl2) to afford tert-butyl 5-[(N,N-dimethylglycyl)amino]-1-indolinecarboxylate (1.50 g, 110%) containing a small amount of DMF. LC/MS (ESI+): 320.1 (M+H)+.
