Butanoic acid, 4-chloro-4-oxo-, ethyl ester → Ethyl 3-[5-(2,3-dihydro-1-benzofuran-5-yl)-1,3,4-oxadiazol-2-yl]propionate

HRID 452707Notes

Reaction equation

[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([C:10]3[NH:14][N:13]=NN=3)=[CH:9][C:4]=2[CH2:3][CH2:2]1.Cl[C:16](=[O:24])[CH2:17][CH2:18][C:19]([O:21][CH2:22][CH3:23])=[O:20]>N1C=CC=CC=1.C(OCC)(=O)C>[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([C:10]3[O:24][C:16]([CH2:17][CH2:18][C:19]([O:21][CH2:22][CH3:23])=[O:20])=[N:13][N:14]=3)=[CH:9][C:4]=2[CH2:3][CH2:2]1

Participants

Conditions

Temperature: 100 °C

Procedure

To a solution of 5-(2,3-dihydro-1-benzofuran-5-yl)-1H-tetrazole (4.40 g, 23.38 mmol) in pyridine (50 mL) was added ethyl 4-chloro-4-oxobutyrate (4.62 g, 28.06 mmol), and the resulting mixture was stirred at room temperature for 30 min and at 100° C. for 3.5 hr. After cooling, the reaction mixture was diluted with ethyl acetate, washed with water, 1M hydrochloric acid, 1M aqueous sodium hydroxide solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by basic silica gel column chromatography (hexane/ethyl acetate=95/5-0/100) and recrystallized from hexane/ethyl acetate to give the title compound (5.27 g, yield 78%) as pale-yellow crystals.

Workup

temperatureAfter cooling
washwashed with water, 1M hydrochloric acid, 1M aqueous sodium hydroxide solution and saturated brine
dry with materialdried over anhydrous magnesium sulfate
concentrationconcentrated under reduced pressure
customThe residue was purified by basic silica gel column chromatography (hexane/ethyl acetate=95/5-0/100)
customrecrystallized from hexane/ethyl acetate

Sources & evidence

ORD record: ord-da56a99d1e994698986b97684f31b8c9
Source dataset: uspto-grants-2013_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08492378B2

Reaction notes

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