Potassium Acetate → Methyl 4-(acetyloxy)-2-methyl-1-benzofuran-6-carboxylate

HRID 2233361Notes

Reaction equation

[CH3:1][O:2][C:3](/[C:5](=[CH:10]/[C:11]1[O:12][C:13]([CH3:16])=[CH:14][CH:15]=1)/[CH2:6][C:7]([OH:9])=O)=[O:4].[C:17]([O-])(=[O:19])[CH3:18].[K+].O.C(OCC)(=O)C>C(OC(=O)C)(=O)C>[CH3:16][C:13]1[O:12][C:11]2[CH:10]=[C:5]([C:3]([O:2][CH3:1])=[O:4])[CH:6]=[C:7]([O:9][C:17](=[O:19])[CH3:18])[C:15]=2[CH:14]=1

Participants

Conditions

Temperature: 140 °C

Procedure

A mixture of E-3-methoxycarbonyl-4-(5-methylfur-2-yl)-but-3-enoic acid (Method 15; 1.39 g, 6.2 mmol) and potassium acetate (620 mg, 6.3 mmol) in acetic anhydride (12.5 ml) was heated at 140° C. for 15 mins. The reaction mixture was cooled and poured on to a water/ethyl acetate mixture; the aqueous layer was separated and the organic layer washed sequentially with saturated sodium bicarbonate solution and brine, dried (MgSO4) and evaporated in vacuo to yield the crude product as a dark crystalline mass. This was chromatographed (50 g Bondelut, eluting with hexane containing ethyl acetate, 0-100%) to give the title compound as a pale yellow solid, 1.42 g (92%). NMR: 2.36 (s, 3H), 3.34 (s, 3H), 3.87 (s, 3H), 6.68 (s, 1H), 7.56 (s, 1H), 7.96 (s, 1H); m/z 247 (M−H)−, 97.1% by LC-MS.

Workup

temperatureThe reaction mixture was cooled
customthe aqueous layer was separated
washthe organic layer washed sequentially with saturated sodium bicarbonate solution and brine
dry with materialdried (MgSO4)
customevaporated in vacuo
customto yield the crude product as a dark crystalline mass
customThis was chromatographed
wash(50 g Bondelut, eluting with hexane containing ethyl acetate, 0-100%)

Sources & evidence

ORD record: ord-6cca5735a1ac41599c822c4cb0f4dad8
Source dataset: uspto-grants-2010_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07709505B2

Reaction notes

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