反应详情

温度

143 °C

To Intermediate 3A (11.35 g, 58.2 mmol) in DMF (15 ml) was added 1-tert-butoxy-N,N,N′,N′-tetramethylmethanediamine (39.6 ml, 192 mmol). The mixture was heated at 143° C. for 3.0 h. DMF was removed by vacuum distillation at 70° C. to leave a semi solid. The semi-solid was triturated with EtOAc/hexanes (1:4) and stored at 4° C. overnight. The precipitate was collected by filtration to give Intermediate 3B (10.2 g, 40.8 mmol, 70.1% yield) as a dark solid. 1H NMR (400 MHz, chloroform-d) δ ppm 8.21 (d, J=2.20 Hz, 1H) 7.87 (d, J=8.79 Hz, 1H) 7.66 (dd, J=8.79, 2.20 Hz, 1H) 7.02 (d, J=13.19 Hz, 1H) 6.12 (d, J=13.74 Hz, 1H) 3.91 (s, 3H) 2.94 (s, 6H).

1. customDMF was removed by vacuum distillation at 70° C.
2. customto leave a semi solid
3. customThe semi-solid was triturated with EtOAc/hexanes (1:4)
4. filtrationThe precipitate was collected by filtration