Dimethylformamide → 6-Chloro-5-nitro-1H-isochromen-1-one
Reaction equation
[Cl:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[C:4]([CH3:12])[C:3]=1[N+:13]([O-:15])=[O:14].CN(C)C=O.COC(OC)N(C)C.C(OCC)(=O)C>>[Cl:1][C:2]1[C:3]([N+:13]([O-:15])=[O:14])=[C:4]2[C:5](=[CH:10][CH:11]=1)[C:6](=[O:7])[O:8][CH:9]=[CH:12]2Participants
Conditions
- Temperature
- 120 °C
Procedure
A pressure tube was charged with methyl 4-chloro-2-methyl-3-nitrobenzoate (13 g, 57 mmol), N,N-dimethylformamide (10 mL, 200 mmol) and 1,1-dimethoxy-N,N-dimethylmethanamine (26.5 mL, 200 mmol) and the reaction heated to 120° C. for 20 h. The solvents were removed and the resultant brown residue was redissolved in ethyl acetate (600 mL, 6000 mmol) and 130-270 mesh 60A silica gel (500 g, 6000 mmol) was added and the reaction stirred with a mechanical stirrer for 8 h. The silica gel was filtered off, washed with ethyl acetate (400 mL) and the organics were removed under vacuum and the residue purified by flash chromatography (330 g, 2-50% ethyl acetate/hexane) to obtain the two isomers in 14% yields each in almost 98% purity. MS m/z=226.2 (M+H). 1H NMR (400 MHz; DMSO-d6) δ 8.35 (d, J=8.63 Hz, 1H), 7.95 (d, J=8.63 Hz, 1H), 7.76 (d, J=5.91 Hz, 1H), 6.61 (d, J=6.04 Hz, 1H).
Workup
- customThe solvents were removed
- filtrationThe silica gel was filtered off
- washwashed with ethyl acetate (400 mL)
- customthe organics were removed under vacuum
- customthe residue purified by flash chromatography (330 g, 2-50% ethyl acetate/hexane)
- customto obtain the two isomers in 14%
- customyields each in almost 98% purity
Sources & evidence
- ORD record
- ord-e659516bb4864d4f90fb4357fb133b94
- Source dataset
- uspto-grants-2010_10
- Patent number
- US07816371B2
Reaction notes
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