Sulfuric Acid → 1,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acid

HRID 48533

Reaction equation

HRID 48533 reaction equation
S(=O)(=O)(O)O.[C:6]([OH:17])(=[O:16])[C:7]1[CH:15]=[CH:14][C:10]([C:11]([OH:13])=[O:12])=[CH:9][CH:8]=1.O1COCO[CH2:19]1>CC(OCC1C2C(=CC=CC=2)C(COC(C)=O)=C2C=1C=CC=C2)=O>[C:11]([C:10]1[CH:14]=[C:15]2[C:7](=[CH:8][CH:9]=1)[C:6](=[O:17])[O:16][CH2:19]2)([OH:13])=[O:12]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 7489Terephthalic AcidHCID 80811,3,5-Trioxane

Product 1

HCID 785171,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acidYield 70.4%

Reagents, catalysts & solvents 1

HCID 613145Acetic acid 10-acetoxymethyl-anthracen-9-ylmethyl esterSolvent

Procedure

To 153 ml of fuming sulfuric acid, containing about 27% of SO3, 50 g (0.3 m) of terephthalic acid are added, under stirring, at room temperature, then 23 g (0.25 m) of 1,3,5-trioxane are added thereinto in two portions, by cooling to a temperature of 15-18° C. after any addition. At the end of the addition, the mixture is left 30 minutes under stirring at room temperature, then it is heated at 135-145° C. and let under stirring for 2-2.5 hours at this temperature until the end of the reaction. The reaction mixture is cooled to a temperature lower than 3° C., then 100 ml of glacial acetic are added thereto by keeping the temperature at about 25° C. At the end of the addition, the mixture is let to stand 60 minutes under stirring at 20-25° C. and filtered. The wet product is suspended in 1900 ml of water. The suspension is heated up to 25-30° C. under stirring, its pH is adjusted to about 8 by gradual addition of 175 g of sodium bicarbonate. The solid is filtered off on Celite® by washing with hot water (40-45° C.). The pH of the mother liquors is brought to 1.5 by addition of about 125 ml of 37% hydrochloric acid and the obtained precipitate is filtered at 20-25° C. by washing with water until the filtrate reaches a neutral pH. Thus, 32 g of 5-carboxyphthalide with a titer (HPLC)>93% are obtained.

Workup

  1. additionare added
  2. temperaturein two portions, by cooling to a temperature of 15-18° C.
  3. additionafter any addition
  4. additionAt the end of the addition
  5. stirringunder stirring at room temperature
  6. temperatureit is heated at 135-145° C.
  7. stirringunder stirring for 2-2.5 hours at this temperature until the end of the reaction
  8. temperatureThe reaction mixture is cooled to a temperature lower than 3° C.
  9. customat about 25° C
  10. additionAt the end of the addition
  11. waitto stand 60 minutes
  12. stirringunder stirring at 20-25° C.
  13. filtrationfiltered
  14. temperatureThe suspension is heated up to 25-30° C.
  15. stirringunder stirring
  16. additionits pH is adjusted to about 8 by gradual addition of 175 g of sodium bicarbonate
  17. filtrationThe solid is filtered off on Celite®
  18. washby washing with hot water (40-45° C.)
  19. additionThe pH of the mother liquors is brought to 1.5 by addition of about 125 ml of 37% hydrochloric acid
  20. filtrationthe obtained precipitate is filtered at 20-25° C.
  21. washby washing with water until the filtrate

Sources & evidence

ORD record
ord-dc45d70a88db4445bdbe6860ec86d276
Source dataset
uspto-grants-2004_03
Patent number
US06703516B2

Linked notes

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