5-chloro-4-nitro-1H-pyrrole-2-carboxylic acid → 2-chloro-3-nitro-1H-pyrrole

A stirred solution of 0.34 gram (0.0018 mole) of 5-chloro-4-nitropyrrole-2-carboxylic acid in about 5 mL of ethylene glycol was heated to 190° C. where it was maintained during a one-hour period. After this time the reaction mixture was cooled and diluted with 20 mL of water and 25 mL of ethyl acetate. The organic layer was separated and washed with 25 mL of a solution of 12.5 mL of water and 12.5 mL of an aqueous solution saturated with sodium bicarbonate. The organic layer was then dried with sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to a residue. The residue was purified with column chromatography on silica gel. Elution was accomplished using diethyl ether as an eluant. The appropriate fractions were combined and concentrated under reduced pressure, yielding 0.21 gram of the subject compound. The NMR spectrum was consistent with the proposed structure.

1. temperaturewas maintained during a one-hour period
2. temperatureAfter this time the reaction mixture was cooled
3. customThe organic layer was separated
4. washwashed with 25 mL of a solution of 12.5 mL of water and 12.5 mL of an aqueous solution saturated with sodium bicarbonate
5. dry with materialThe organic layer was then dried with sodium sulfate
6. filtrationfiltered
7. concentrationthe filtrate was concentrated under reduced pressure to a residue
8. customThe residue was purified with column chromatography on silica gel
9. washElution
10. concentrationconcentrated under reduced pressure

ORD record

ord-0183d854a98b4ffa8ec4cfe099682f6c

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07943642B2