Dimethylformamide → 3-[4,4-Dimethylthiochroman-6-yl]-3-chloro-2-propene-1-al

Participants

Reaction Steps

In a 500 ml 4-necked round bottom flask fitted with a mechanical stirrer and a reflux condenser, 6-acetyl-4,4-dimethylthio-chroman (22 g) and dimethylformamide (38 ml) are added at a temperature in the range of from about 35° C. to about 95° C. under stirring. The reaction mixture is then cooled to a temperature in the range of from about −5° C. to about 0° C. Phosphorus oxychloride (17.2 g) is added to the reaction mixture dropwise over about 30 minutes. Following the addition of the phosphorous oxychloride, the reaction mixture is maintained at a temperature in the range of from about 10° C. to about 15° C. for about 8 hours to about 10 hours. After completion of the reaction as determined by TLC, the reaction mixture is added to cold water (100 ml) at a temperature of from about 0° C. to about 5° C. containing sodium acetate (25 g). The aqueous layer is extracted with dichloromethane (200 ml×3). The organic layer is washed with demineralized water (100 ml×3) until it becomes neutral.

Provenance & Evidence