Phosphoric Acid → 5-chloro-2-methyl-2,3-dihydro-1H-dibenzo[2,3:6,7]oxepino[4,5-c]pyrrol-1-one

P2O5 (90 grams) was added in portions to H3PO4 (90 grams) while maintaining the temperature below 140° C. The mixture was heated at 115° C. for 1.5 hour, whereupon 3-[2-(4-chloro-phenoxy)-phenyl]-1-methyl-pyrrolidine-2,4-dione (XI) (30 grams; 95 mmol) was added. The resulting mixture was stirred for 4 days at 115° C. to 130° C. with extra P2O5 (in total 5 portions of 5 grams each were added). The mixture was poured into water (200 ml) and the resulting precipitate was stirred overnight. The mixture was extracted with dichloromethane (250 ml) and washed with sat. NaHCO3 (pH=7). After drying on magnesium sulphate the solvent was removed under vacuum. The resulting crude product was dissolved in methanol (520 ml) at 70° C. Following removal of part of the methanol by evaporation the product crystallized. The mixture was stirred overnight at −12° C. The crystals were filtered and dried to provide 5-chloro-2,3-dihydro-2-methyl-1H-dibenz [2,3;6,7]oxepino[4,5-c]pyrrol-1-one (VI) (16.4 grams, 55 mmol; 58%), purity according to GC 92%. 1H-NMR (400 MHz, CDCl3): 3.2 (s, 3H), 4.3 (s, 1H), 3.8 (m, 1H), 7.2-7.4 (m, 6H), 8.2 (dd, 1H).

1. temperaturewhile maintaining the temperature below 140° C
2. additionwas added
3. extractionThe mixture was extracted with dichloromethane (250 ml)
4. washwashed with sat. NaHCO3 (pH=7)
5. customAfter drying on magnesium sulphate the solvent
6. customwas removed under vacuum
7. dissolutionThe resulting crude product was dissolved in methanol (520 ml) at 70° C
8. customremoval of part of the methanol
9. customby evaporation the product
10. customcrystallized
11. stirringThe mixture was stirred overnight at −12° C
12. filtrationThe crystals were filtered
13. customdried

ORD record

ord-8d7d0bb7d7bf40bfb7da87fae4698599

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08426610B2