Dimethyl Sulfide → Methyl 2-hydroxy-7-nitro-2,3-dihydrobenzofuran-4-carboxylate

HRID 354052Notes

Reaction equation

[CH3:1][O:2][C:3](=[O:17])[C:4]1[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[C:6]([OH:13])[C:5]=1[CH2:14][CH:15]=C.[O:18]=[O+][O-].CSC>ClCCl.CO>[CH3:1][O:2][C:3]([C:4]1[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[C:6]2[O:13][CH:15]([OH:18])[CH2:14][C:5]=12)=[O:17]

Participants

Conditions

Temperature: -70 °C

Procedure

Into a solution of 2-allyl-3-hydroxy-4-nitro-benzoic acid methyl ester (6.11 g 25.6 mmol) in dichloromethane (100 mL) and methanol (10 mL) at −78° C. was bubbled with ozone for 40 minutes. After stirring for another 20 min at −70° C., a stream of nitrogen gas was passed through the reaction mixture. Dimethyl sulfide (5 mL, 68.1 mmol) was added at −78° C. The reaction solution was allowed to warm up gradually to room temperature overnight. The reaction mixture was partitioned between dichloromethane and water. The aqueous layer was further extracted twice with dichloromethane. The organic extract was washed with brine, dried (anhydrous sodium sulfate), and concentrated under reduced pressure to give 2-hydroxy-7-nitro-2,3-dihydro-benzofuran-4-carboxylic acid methyl ester as a yellow solid (6.0 g). 1H NMR (CDCl3) δ: 3.51-3.74 (m, 2H), 3.96 (s, 3H), 6.43 (dd, 1H, J=6.4 Hz, 2.6 Hz), 7.63 (d, 1H, J=8.8), 8.01 (d, 1H, J=8.9 Hz).

Workup

temperatureto warm up gradually to room temperature overnight
customThe reaction mixture was partitioned between dichloromethane and water
extractionThe aqueous layer was further extracted twice with dichloromethane
extractionThe organic extract
washwas washed with brine
dry with materialdried (anhydrous sodium sulfate)
concentrationconcentrated under reduced pressure

Sources & evidence

ORD record: ord-ea4e5a4680974f7da94754d1a6747285
Source dataset: uspto-grants-2004_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06756395B2

Reaction notes

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