1,10-Phenanthroline → tert-Butyl 4-(isoquinolin-5-yl)-3-oxopiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To 5-bromoisoquinoline (0.3 g, 1.442 mmol) and tert-butyl 3-oxopiperazine-1-carboxylate (0.289 g, 1.442 mmol) was added DMSO (4 mL), 1,10-phenanthroline (0.026 g, 0.144 mmol), K2CO3 (0.498 g, 3.60 mmol). The mixture was degassed for 10 min. to the above mixture was then added CuI (0.055 g, 0.288 mmol). The reaction was heated in a sealed tube in oil bath at 130° C. After 24 h, the reaction was incomplete. Cooled and degassed with Ar, added more CuI and heating was repeated. After 24 h, the reaction was quenched with dilute NH4OH (15 mL) and extracted with EtOAc (3×30 mL). The combined organic layers were washed with brine (15 mL) and dried (MgSO4). The product was purified by normal phase chromatography followed by prep. HPLC. After partitioning with saturated NaHCO3 (15 mL) and EtOAc (50 mL), the organic layer was washed with brine and dried (MgSO4) to afford 0.157 g (54%) of Intermediate 18A as a white solid with recovered starting material. MS (ESI) m/z: 328 (M+H)+.

Provenance & Evidence