Triethylamine → 6-Fluoro-7-methylisoquinolin-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 10.0 g (55.5 mmol) of 3-fluoro-4-methyl-cinnamic acid in 80 ml of acetone were subsequently added at 0° C. 6.74 g (66.6 mmol) of triethylamine in 10 ml of acetone followed by 7.83 g (72.2 mmol) of ethyl chloroformate. After stirring for 2 h at 0 to 5° C., a solution of 4.0 g (61.1 mmol) of sodium azide in 9.5 ml of water was added. After stirring for 1 additional h the reaction mixture was poured onto 200 ml of ice water and extracted twice with chloroform. The organic phase was dried over magnesium sulfate, 40 ml diphenylether were added and the chloroform was cautiously removed in vacuo. The residue was then added dropwise into 50 ml of diphenylether, which had been preheated to 245° C. After complete addition it was stirred for another 1 h at 230-250° C. After cooling down to 150° C. the reaction mixture was poured into 270 ml of heptane and after further cooling in an ice bath the precipitated product was filtered by suction and 4.1 g 6-fluoro-7-methyl-2H-isoquinolin-1-one were obtained.

Provenance & Evidence