Potassium Carbonate → 1,2-Dihydro-2-(3-hydroxypropyl)-1-oxo-4-isoquinolinecarboxylic acid

Temperature

100 °C

A mixture of 21.6 g of 4-ethoxycarbonyl-1(2H)-isoquinolone, 25 g of anhydrous potassium carbonate and 100 ml of dimethylformamide was heated at 100° C. for 2 hours. Then, 14 ml of 3-chloropropanol was added thereto and the mixture was heated at 110° C. for 4 hours. The solvent was distilled off and the residue was extracted with dichloromethane. The extract was washed with water, dried and the solvent was distilled off. 120 ml of an ethanolic solution of 5.5 g of potassium hydroxide was added to the residue, and the mixture was warmed. After cooling, the reaction mixture was poured into ice-water and then filtered. The filtrate was rendered neutral with dilute acetic acid, and the precipitated crystals were filtered and recrystallized from a mixture of ethanol and petroleum ether to obtain 12.5 g of 4-carboxy-2-(3-hydroxypropyl)-1(2H)-isoquinolone having a melting point of 205° C. as colorless prisms.

1. temperaturethe mixture was heated at 110° C. for 4 hours
2. distillationThe solvent was distilled off
3. extractionthe residue was extracted with dichloromethane
4. washThe extract was washed with water
5. customdried
6. distillationthe solvent was distilled off
7. addition120 ml of an ethanolic solution of 5.5 g of potassium hydroxide was added to the residue
8. temperaturethe mixture was warmed
9. temperatureAfter cooling
10. additionthe reaction mixture was poured into ice-water
11. filtrationfiltered
12. filtrationthe precipitated crystals were filtered
13. customrecrystallized from a mixture of ethanol and petroleum ether

ORD record

ord-fbb60830492149c29e4a52bc8d9d9b9e

Source dataset

uspto-grants-1983_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04393210