Maleic Anhydride → 191014-72-9

Temperature

0 °C

Aluminum chloride anhydrous (32.6 g, 0.245 mol.) was added at room temperature and under dry nitrogen atmosphere, to a solution of maleic anhydride (9.6 g, 0.098 mol.) and difluorobenzene (20 ml, 0.195 mol.) in dry dichloromethane. The reaction mixture was heated to reflux for 4 hours; then cooled and quenched with ice/37% hydrochloric acid (100 g/100 mL). Dichloromethane (200 mL) was added, the phases separated and the aqueous layer was extracted twice with dichloromethane (50 mL), the collected organic extracts were washed with 2N HCl and then with brine. The resulting solution was dried (Na2SO4) and evaporated in vacuo to provide the crude product, as deep yellow oily material, which was dissolved in diethyl ether (60 mL). The organic phase was extracted with saturated sodium bicarbonate solution (150 mL), the collected aqueous layers were washed with diethyl ether and cooled at 0° C., then to the alkaline aqueous solution, 37% hydrochloric acid was added on stirring until the pH was 2. The obtained suspension was extracted with ethyl acetate (3×100 mL); the collected organic extracts were washed with brine, dried (Na2SO4) and evaporated in vacuo to provide a yellow solid (11 g). Crystallisation from toluene provided the pure titled compound (7.6 g, 40%) melting at 107-108° C.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 4 hours
3. temperaturethen cooled
4. customquenched with ice/37% hydrochloric acid (100 g/100 mL)
5. additionDichloromethane (200 mL) was added
6. customthe phases separated
7. extractionthe aqueous layer was extracted twice with dichloromethane (50 mL)
8. washthe collected organic extracts were washed with 2N HCl
9. dry with materialThe resulting solution was dried (Na2SO4)
10. customevaporated in vacuo
11. customto provide the crude product
12. extractionThe organic phase was extracted with saturated sodium bicarbonate solution (150 mL)
13. washthe collected aqueous layers were washed with diethyl ether
14. additionto the alkaline aqueous solution, 37% hydrochloric acid was added
15. extractionThe obtained suspension was extracted with ethyl acetate (3×100 mL)
16. washthe collected organic extracts were washed with brine
17. dry with materialdried (Na2SO4)
18. customevaporated in vacuo

ORD record

ord-f3e11f8d97204756be014d410204d905

Source dataset

uspto-grants-2000_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06048896