Acetic Anhydride → Dihydro-4-(2-methylpropyl)-2H-pyran-2,6(3H)-dione

HRID 269409Notes

Reaction equation

[CH2:1]([CH:5]([CH2:10][C:11]([OH:13])=[O:12])[CH2:6][C:7]([OH:9])=O)[CH:2]([CH3:4])[CH3:3].C(OC(=O)C)(=O)C>>[CH2:1]([CH:5]1[CH2:6][C:7](=[O:9])[O:13][C:11](=[O:12])[CH2:10]1)[CH:2]([CH3:3])[CH3:4]

Participants

Reactant 2

HCID 7918Acetic Anhydride

HCID 10976240Isobutylglutaric acid

Product 1

HCID 11480690Dihydro-4-(2-methylpropyl)-2H-pyran-2,6(3H)-dioneYield 98.4%

Procedure

A 1 l, four-necked flask equipped with a mechanical stirrer, thermometer pocket and condenser, was charged with 3-isobutyl glutaric acid (500 g) and acetic anhydride (326 g). The reaction mixture was refluxed at 135°-1450° C. for 2.5-3 hours, followed by distilling out the unreacted acetic anhydride at 147°-155° C., and then the distillation was continued under vacuum to ensure removal of traces of unreacted acetic anhydride. The residue was cooled to 25°-30° C. to obtain 445 g of 3-isobutylglutaric anhydride.

Workup

customA 1 l, four-necked flask equipped with a mechanical stirrer
temperatureThe reaction mixture was refluxed at 135°-1450° C. for 2.5-3 hours
distillationby distilling out the unreacted acetic anhydride at 147°-155° C.
distillationthe distillation
customremoval of traces of unreacted acetic anhydride
temperatureThe residue was cooled to 25°-30° C.

Sources & evidence

ORD record: ord-9bdbdc51939f4cd6ae1681b476d143af
Source dataset: uspto-grants-2008_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07446220B2

Reaction notes

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