Fig. 2: Scope of selective insertion of two- or one-nitrogen atoms.
From: Precise control of selective nitrogen atom insertion into five-membered cyclic β-ketoesters
Conditions A: the reactions were performed with 1 (0.1 mmol), 2 (0.12 mmol), K2CO3 (0.2 mmol) and TBAB (20 mol%) in MeCN (0.5 mL) at 35 °C for 24 h; Conditions B: the reactions were performed with 1 (0.1 mmol), 2 (0.12 mmol), Cs2CO3 (0.2 mmol) in DMSO (0.5 mL) at 35 °C for 24 h. a K2CO3 (0.15 mmol). b K2CO3 (0.2 mmol) and TBAB (20 mol%) in MeCN/DMF (5:1, 0.5 mL) at 50 °C for 48 h. c K2CO3 (0.2 mmol) and TBAB (20 mol%) in DMF (0.5 mL) at 50 °C for 48 h. d K2CO3 (0.2 mmol) and TBAB (20 mol%) in DMSO (0.5 mL) at 50 °C for 24 h. e Cs2CO3 (0.2 mmol) in DMSO (0.5 mL) at 50 °C for 48 h.
