Dimethylformamide → 4-[(Dimethylamino)methylidene]-1H-2-benzopyran-1,3(4H)-dione

Participants

Reaction Steps

100 ml of anhydrous DMF in a 1 liter round-bottomed, three necked flask (fitted with a drying tube containing drierite, and a 125 ml dropping funnel) is cooled in an ice-salt bath, and 31 ml of POCl3 is subsequently added over a period of half an hour while stirring the DMF. The 125 ml dropping funnel is replaced with a 150 ml dropping funnel, and a solution of 54 g of homopthalic acid in 100 ml of DMF is added to the flask over a period of one hour at <10° C. The reaction mixture is then stirred at room temperature until a yellow paste was formed, and then poured into ice water. The solid is collected by filtration, washed with water and dried to give 54 g of the title compound as a yellow solid, m.p. 137-40° C.

Provenance & Evidence