Phosphorus oxychloride → HCID 19604217, compound

Temperature

75 °C

A suspension of 37 g (152 mmol) of methyl 4-(5-chloro-1,6-dihydro-6-oxopyridin-3-yl)-4-oxobutyrate in 230 ml of phosphorus oxychloride was heated at 75° C. for 25 hours. The phosphorus oxychloride was subsequently distilled off in vacuo. The pale red residue was taken up in 200 ml of dichloromethane, 100 ml of water was added, and the pH of the aqueous phase was brought to 8.5 using 30 percent sodium hydroxide solution. After phase separation, the aqueous phase was extracted using 100 ml of dichloromethane. The combined organic phases were treated with active charcoal and evaporated. The residue was recrystallized from 300 ml of diisopropyl ether and filtered at 2° C. The yield was 32.83 g of pale pink crystals. A further 1.76 g of product was obtained from the mother liquor in the form of crystals. The total product yield was 87 percent. The melting point of the product was 85.2° to 86° C. Other data concerning the product was:

1. distillationThe phosphorus oxychloride was subsequently distilled off in vacuo
2. addition100 ml of water was added
3. customAfter phase separation
4. extractionthe aqueous phase was extracted
5. additionThe combined organic phases were treated with active charcoal
6. customevaporated
7. customThe residue was recrystallized from 300 ml of diisopropyl ether
8. filtrationfiltered at 2° C

ORD record

ord-f3dc4dfea0ee488c865435da5a8e3ac9

Source dataset

uspto-grants-1999_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05994540