Phosphorus oxychloride → 4-((4-Chloropyrimidin-2-yl)amino)benzonitrile

Participants

Reaction Steps

A mixture of 4-[(1,4-dihydro-4-oxo-2-pyrimidinyl)amino]benzonitrile, (0.12 mol) in POCl3 (90 ml) was stirred and refluxed under Argon for 20 minutes. The reaction mixture was slowly poured onto 750 ml ice/water, and the solid was separated by filtration. The solid was suspended in 500 ml water, and the pH of the suspension was adjusted to neutral by adding a 20% NaOH solution. The solid was again separated by filtration, suspended in 200 ml 2-propanone, and 1000 ml CH2Cl2 was added. The mixture was heated until all solid had dissolved. After cooling to room temperature, the aqueous layer was separated, and the organic layer was dried. During removal of the drying agent by filtration, a white solid formed in the filtrate. Further cooling of the filtrate in the freezer, followed by filtration, yielded 21.38 g (77.2%) of 4-[(4-chloro-2-pyrimidinyl)amino]benzonitrile (interm. 10). b) Intermediate (10) (0.005 mol), 1-bromo-2,5-pyrrolidinedione (0.006 mol) and trichloromethane (10 ml) were combined in a sealed tube and heated at 100° C. overnight. The reaction mixture was allowed to cool to room temperature. Silica gel (2 g) was added, and the solvent was evaporated. The residue was purified by flash column chromatography over silica gel (eluent: CH2Cl2/hexanes 9/1). The pure fractions were collected and the solvent was evaporated, yielding 1.31 g (84.5%) of 4-[(5-bromo-4-chloro-2-pyrimidinyl)amino]benzonitrile (interm. 11).

Provenance & Evidence