Pyridine → 4-methoxy-3-trichloroacetyl-1H-indole

온도

0 °C

To a solution of 4-methoxy-1H-indole (7.15 g, 49 mmol) and pyridine (19.7 mL, 243 mmol) in dichloromethane (50 mL) at 0° C. under Nitrogen was added dropwise a solution of trichloroacetyl chloride (27.1 mL, 243 mmol) in dichloromethane (50 mL). After stirring at 0° C. for an additional 1.5 h, the mixture was concentrated in vacuo. The residue was taken up in the minimal volume of methanol necessary and placed in a freezer overnight. The precipitate was filtered, rinsed well with methanol, and dried to yield 4-methoxy-3-trichloroacetyl-1H-indole. To a stirring solution of sodium methoxide (3.5 mL of a 25 weight % solution in methanol) in methanol (200 mL) at ambient temperature was added 4-methoxy-3-trichloroacetyl-1H-indole (9.07 g, 31.0 mmol) in portions over 0.75 h. After stirring an additional 0.75 h, the mixture was cooled in an ice bath, diluted with ice water, acidified with concentrated hydrochloric acid, and the methanol removed in vacuo. The resulting heterogeneous mixture was cooled in an ice bath, the precipitate filtered, rinsed with water, and dried to afford methyl 4-methoxy-1H-indole-3-carboxylic ester. A slurry of this ester (5.6 g 27 mmol) in 50% aqueous sodium hydroxide (50 mL) and methanol (50 mL) was stirred at ambient temperature for 19 h. The mixture was cooled in an ice bath, acidified with concentrated hydrochloric acid, the precipitate filtered, rinsed with ice water, and dried to afford 4-methoxy-1H-indole-3-carboxylic acid.

1. concentrationthe mixture was concentrated in vacuo
2. waitplaced in a freezer overnight
3. filtrationThe precipitate was filtered
4. washrinsed well with methanol
5. customdried

ORD 기록

ord-3570fc7fe22d43718b4815f8a36fa54d

출처 데이터셋

uspto-grants-1996_01

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US05484944