Sulfuric Acid → HCID 22490527, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-tolylhydrazine hydrochloride (1 g), levulinic acid (1.3 g) and 10% aqueous sulfuric acid (20 ml) was stirred for 6 hours under a nitrogen atmosphere at 80° C. The reaction mixture was allowed to cool, water was added, and then extraction was performed with ethyl acetate and the organic layer was concentrated under reduced pressure. Saturated sodium bicarbonate was added to the obtained residue and vigorously stirred therewith, and then dichloromethane was added and the mixture was again vigorously stirred. The aqueous layer was collected, rendered acidic with concentrated aqueous hydrochloric acid, and then extracted with ethyl acetate. The organic layer was dried over sodium sulfate and concentrated under reduced pressure. Methanol (20 ml) and concentrated sulfuric acid (1 ml) were added to the obtained residue, and the mixture was heated to reflux for 2 hours. The reaction mixture was allowed to cool, water was added, and then extraction was performed with dichloromethane. The organic layer was collected and dried over sodium sulfate, and then concentrated under reduced pressure. A 2-(2,6-dimethyl-1H-indol-3-yl)acetic acid methyl ester component was purified from the obtained residue by silica gel column chromatography using a mixed solvent of hexane and ethyl acetate. A 2 N sodium hydroxide aqueous solution (10 ml) and methanol (10 ml) were added to the obtained 2-(2,6-dimethyl-1H-indol-3-yl)acetic acid methyl ester, and the mixture was heated to reflux for one hour. The reaction mixture was allowed to cool, water was added, and then the mixture was rendered acidic with concentrated aqueous hydrochloric acid and extracted with ethyl acetate. The organic layer was collected and dried over sodium sulfate, and then concentrated under reduced pressure to obtain 0.13 g of the title compound as a colorless powder (13% yield).

Provenance & Evidence