Hydrochloric Acid → 1-Methylisatin

Participants

Reaction Conditions

Reaction Steps

A dimethylformamide (hereinafter referred to as DMF) (500 ml) solution of isatin (14.70 g, 100 mmol, purity 98%; manufactured by SIGMA-ALDRICH) was cooled to 0° C. in an ice bath, and sodium hydride (4.73 g, 118 mmol, 60% in oil; manufactured by Tokyo Chemical Industry Co., Ltd.) was added by portions with a spatula over a period of 10 min. After stirring for 15 min, methyl iodide (7.5 mL, 120 mmol) was added by portions with a Komagome pipette over a period of 10 min. The mixture was stirred at 0° C. for 1 hr and was then poured into 1 L of an aqueous hydrochloric acid solution. The mixture was extracted with ethyl acetate, and an ethyl acetate phase was washed twice with water. The ethyl acetate phase was concentrated to obtain 13.6 g of a crude product of N-methylisatin (HPLC assay: 79 area %). The HPLC assay was carried out in the same manner as described above.

Provenance & Evidence