Hydrochloric Acid → Coumarin

Dimethyl acetonedicarboxylate (13.9 g), 13.6 grams of the product from the previous step, 3.0 grams of anhydrous zinc chloride and 35 mL of methanol were refluxed for 23.5 hours. After cooling, the solution was poured over 60 g of ice, 20 mL of water and 3 mL of concentrated hydrochloric acid. The purple oil which separated was extracted into methylene chloride. The methylene chloride solution was washed once with cold water, dried over sodium sulfate, filtered and evaporated (yield 13.6 g of semi-solid). After 2 days at room temperature the solid was filtered from the liquid, washed twice with -20° C. methanol, and dried. Yield 1.34 g, MP 150°-154° C. This material was then recrystallized from methanol to give yellow-orange plates, MP 158.5°-160° C. The 1H NMR spectrum for this compound was consistent with that expected formethyl 7-[N-methyl-N-(2-hydroxyethyl)amino]coumarin-4-acetate. Elemental analysis for nitrogen: for C15H17NO5, %N expected: 4.81; found: 4.93.

1. temperatureAfter cooling
2. customThe purple oil which separated
3. extractionwas extracted into methylene chloride
4. washThe methylene chloride solution was washed once with cold water
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. customevaporated (yield 13.6 g of semi-solid)
8. filtrationAfter 2 days at room temperature the solid was filtered from the liquid
9. washwashed twice with -20° C. methanol
10. customdried
11. customThis material was then recrystallized from methanol
12. customto give yellow-orange plates, MP 158.5°-160° C

ORD record

ord-b72e04ad2286418b8fb3540aac050cd7

Source dataset

uspto-grants-1993_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05212269