Pyruvic Acid → 6-Chloro-5-(ethoxycarbonyl)-1H-indole-2-carboxylic acid

Temperature

100 °C

A solution of ethyl 4-amino-2-chloro-5-iodobenzoate (1.82 g, 5.59 mmol) in N,N-dimethylformamide (18 ml) under argon was admixed with pyruvic acid (1.27 ml, 18.2 mmol) and 1,4-diazabicyclo[2.2.2]octane, evacuated and flushed with argon. Then argon was passed through the solution for 5 min and then palladium(II) acetate (68 mg, 0.30 mmol) was added and the mixture was heated to 100° C. for 2 h. The cooled solution was filterd through Celite and the filtercake was rinsed with ethyl acetate (100 ml). The filtrate (suspension) was washed with hydrochloric acid (2 M; 2×25 ml) and with water (2×25 ml), dried over sodium sulphate and filtered. The filtrate was concentrated to dryness under reduced pressure and gave a red-brown solid (1.93 g, approx. 51% product), which was used for the next step without further purification.

1. customevacuated
2. customflushed with argon
3. washthe filtercake was rinsed with ethyl acetate (100 ml)
4. washThe filtrate (suspension) was washed with hydrochloric acid (2 M; 2×25 ml) and with water (2×25 ml)
5. dry with materialdried over sodium sulphate
6. filtrationfiltered
7. concentrationThe filtrate was concentrated to dryness under reduced pressure

ORD record

ord-5b69fc19fd3d40b48b7200ad64efd53d

Source dataset

uspto-grants-2015_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09107411B2