Hydrochloric Acid → 1-methyl-1H-pyrrole-3-carboxylic acid

Temperature

0 °C

7.66 g (50 mmole) of ethyl 1-methyl-3-pyrrolecarboxylate prepared in Example 1 and 37.5 ml (75 mmole) of 2N sodium hydroxide aqueous solution were charged into a reaction vessel and refluxed for two hours. The reaction mixture was cooled to 0° C. and about 7 ml of 6N hydrochloric acid solution was added while stirring. After the addition of 15 g of sodium chloride, the mixture was stirred for one hour over an ice-acetone bath to collect precipitated crystals. The crystals were washed with cold water and dried under reduced pressure to obtain 5.77 g (yield 92.2%) of colorless or light-yellow powdery crystals of 1-methyl-3-pyrrolecarboxylic acid.

1. temperaturerefluxed for two hours
2. stirringthe mixture was stirred for one hour over an ice-acetone bath
3. customto collect
4. customprecipitated crystals
5. washThe crystals were washed with cold water
6. customdried under reduced pressure

ORD record

ord-747b45be66664507851ea84f0a5ecd59

Source dataset

uspto-grants-1997_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05684161