反应详情

温度

60 °C

To a colorless, homogeneous solution of (E)-picolinaldehyde oxime (6.75 g, 55.3 mmol) in N,N-dimethylformamide (55 mL) at room temperature was added N-chlorosuccinimide (7.38 g, 55.3 mmol) portion-wise. After the addition of ˜⅕ of the NCS, the reaction mixture was immersed in an oil bath at 60° C., and the remaining NCS was added portion-wise over 1.5 h. After the addition was complete, the homogeneous reaction mixture was stirred for 60 min. at 60° C. and was then cooled to room temperature. Water (400 mL) was added, and the aqueous mixture was extracted with ether (3×200 mL). The organic layer was collected, washed with water (2×200 mL), washed with a saturated aqueous solution of brine (100 mL), and dried over anhydrous magnesium sulfate. Concentration under reduced pressure afforded N-hydroxypicolinimidoyl chloride (6.45 g, 41.2 mmol, 75% yield) as a tan solid. The compound had an HPLC retention time=0.515 min.—Column: CHROMOLITH® SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=156.8. 1H NMR (400 MHz, CDCl3) δ ppm 7.37-7.43 (m, 1H), 7.80 (td, J=7.78, 1.76 Hz, 1H), 7.91-7.97 (m, 1H), 8.72 (d, J=4.02 Hz, 1H), and 9.85 (br. s., 1H).

1. customthe reaction mixture was immersed in an oil bath at 60° C.
2. additionAfter the addition
3. temperaturewas then cooled to room temperature
4. extractionthe aqueous mixture was extracted with ether (3×200 mL)
5. customThe organic layer was collected
6. washwashed with water (2×200 mL)
7. washwashed with a saturated aqueous solution of brine (100 mL)
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationConcentration under reduced pressure