Dimethylformamide → 2,3-Dihydro-8-methoxy-4H-1-benzothiopyran-4-one

HRID 1521815Notes

Reaction equation

[CH3:1][O:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[S:9][CH2:10][CH2:11][C:12]([OH:14])=O.C(Cl)(=O)C(Cl)=O.CN(C=O)C.[Sn](Cl)(Cl)(Cl)Cl>C(Cl)Cl>[CH3:1][O:2][C:3]1[CH:8]=[CH:7][CH:6]=[C:5]2[C:4]=1[S:9][CH2:10][CH2:11][C:12]2=[O:14]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 3-[(2-methoxyphenyl)thio]propanoic acid (5.0 g, 23.6 mmol) in dry DCM (50 mL) at 0° C. is added oxalyl chloride (6.01 g, 4.09 mL, 47.2 mmol, 2 Eq) followed by few drops of DMF. The reaction mixture is stirred at 0° C. for 30 minutes. After 30 minutes, the solvent is removed under reduced pressure. To a solution of the acid chloride in DCM (150 mL) at 0° C. is added a solution of tin (IV) chloride in DCM (26 mL, 1 M, 26.0 mmol, 1.1 Eq) and the reaction mixture is stirred for 2 h. The reaction is quenched by addition of water and the product is extracted with DCM. The organic layer is dried over MgSO4, concentrated under reduced pressure. The crude residue is purified by flash chromatography (eluent: ethyl acetate/hexane 4/6) to afford 3.2 g of the title compound as a white solid.1H NMR (DMSO-d6, 400 MHz): δ 7.59-7.57 (m, 1H), 7.18 (m, 2H), 3.84 (s, 3H), 3.24-3.21 (m, 2H), 2.84-2.81 (m, 2H). MS (ESI+): 196.0. HPLC (max plot) 89.4%; Rt 3.36 min.

Workup

waitAfter 30 minutes
customthe solvent is removed under reduced pressure
stirringthe reaction mixture is stirred for 2 h
customThe reaction is quenched by addition of water
extractionthe product is extracted with DCM
dry with materialThe organic layer is dried over MgSO4
concentrationconcentrated under reduced pressure
customThe crude residue is purified by flash chromatography (eluent: ethyl acetate/hexane 4/6)

Sources & evidence

ORD record: ord-e5c3b7c42fc449cf82588feddb651833
Source dataset: uspto-grants-2015_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09073940B2

Reaction notes

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