Hydrochloric Acid → (RS)-3,4-dihydroxy-6-methoxy-7-methyl-1,3-dihydro-isobenzofuran-1-one

HRID 1377841Notes

Reaction equation

[OH-].[K+].C[O:4][C:5](=[O:18])[C:6]1[C:11]([CH3:12])=[C:10]([O:13][CH3:14])[CH:9]=[C:8]([OH:15])[C:7]=1[CH:16]=[O:17].Cl>O>[OH:17][CH:16]1[C:7]2[C:6](=[C:11]([CH3:12])[C:10]([O:13][CH3:14])=[CH:9][C:8]=2[OH:15])[C:5](=[O:18])[O:4]1

Participants

Conditions

Temperature: 75 °C

Procedure

A solution of 28 g of potassium hydroxide in 0.2 l of water was added to 44.8 g of 2-formyl-3-hydroxy-5-methoxy-6-methylbenzoic acid methyl ester. The mixture was warmed to 75° C. within 30 min and subsequently cooled to 5° C. Upon addition of 50 ml of 10N hydrochloric acid, a precipitate was formed immediately. The mixture was stirred at 0° C. for 30 min and then filtered. The solid material was washed with water and dried in vacuo. The crude product was triturated with 160 ml of hot ethyl acetate. The mixture was cooled and 0.9 l of hexane were added. The solid was isolated by filtration to yield 41.2 g of (RS)-3,4-dihydroxy-6-methoxy-7-methyl-1,3-dihydro-iso-benzofuran-1-one, m.p. >255° C. (dec.).

Workup

temperaturesubsequently cooled to 5° C
customa precipitate was formed immediately
filtrationfiltered
washThe solid material was washed with water
customdried in vacuo
customThe crude product was triturated with 160 ml of hot ethyl acetate
temperatureThe mixture was cooled
addition0.9 l of hexane were added
customThe solid was isolated by filtration

Sources & evidence

ORD record: ord-85697394bdbe4b84b86006fd0d1c2cf7
Source dataset: uspto-grants-1997_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05665746

Reaction notes

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