Chlorosulfonic acid → Ralfuranone A

HRID 1584241Notes

Reaction equation

HRID 1584241 reaction equation
ClS(O)(=O)=O.C1([C:12]2[C:13](=[O:23])[O:14][CH2:15][C:16]=2[C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)C=CC=CC=1>ClCCl>[C:17]1([C:16]2[CH2:15][O:14][C:13](=[O:23])[CH:12]=2)[CH:18]=[CH:19][CH:20]=[CH:21][CH:22]=1

Participants

4

Reactant 2

HCID 24638Chlorosulfonic acidHCID 3440493,4-diphenyl-5H-furan-2-one

Product 1

HCID 267373Ralfuranone AYield 98.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To 20 mL of stirring chlorosulfonic acid cooled to -5° C. was added 3,4-diphenyl-2-(5H)-furanone (Step 1) (3.160 g, 13.4 mmol) portionwise over 30 minutes. The solution was warmed to room temperature and maintained at that temperature for 16 hours. The reaction mixture was diluted with dichloromethane and quenched into ice water. The phases were separated and the aqueous phase extracted with dichloromethane, the combined dichloromethane extract was dried over anhydrous MgSO4, filtered and concentrated in vacuo. The residue was diluted with dichloromethane and added to excess concentrated NH4OH. The mixture was stirred for 1 hour. The phases were separated and the aqueous phase was extracted with dichloromethane. The organic extract was dried over anhydrous MgSO4, filtered and concentrated in vacuo to give a white solid that was crystallized from aqueous ethanol to afford pure 3-[(4-aminosulfonyl)phenyl)]-4-phenyl-2-(5H)-furanone (2.110 g, 50%): mp 225.5-226.5° C. 1H NMR (CDCl3 /300 MHz) 7.79 (d, 2H, J=8.4 Hz), 7.41 (d, 2H, J=8.4 Hz), 6.38 (brs, 2H), 5.09 (s, 2H). FABLRMS m/z 316 (m+H). Anal. Calc'd for C16H13NO4S: C, 60.94; H, 4.16; N, 4.44. Found: C, 60.86; H, 4.18; N, 4.40.

Workup

  1. temperaturemaintained at that temperature for 16 hours
  2. customquenched into ice water
  3. customThe phases were separated
  4. extractionthe aqueous phase extracted with dichloromethane
  5. extractionthe combined dichloromethane extract
  6. dry with materialwas dried over anhydrous MgSO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. additionThe residue was diluted with dichloromethane
  10. additionadded to excess concentrated NH4OH
  11. customThe phases were separated
  12. extractionthe aqueous phase was extracted with dichloromethane
  13. extractionThe organic extract
  14. dry with materialwas dried over anhydrous MgSO4
  15. filtrationfiltered
  16. concentrationconcentrated in vacuo
  17. customto give a white solid
  18. customthat was crystallized from aqueous ethanol

Sources & evidence

ORD record
ord-c933f0df17c44f92b5a9b38e3ca2904a
Source dataset
uspto-grants-1999_08
Patent number
US05932598

Reaction notes

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