N-Methylcarbazole → 7-tert-butyl-5-methyl-3-(9-methyl-9H-carbazol-3-yl)-3H-benzofuran-2-one
Reaction equation
[C:1]([C:5]1[C:13]2[O:12][C:11](=[O:14])[CH:10](O)[C:9]=2[CH:8]=[C:7]([CH3:16])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2].[CH3:17][N:18]1[C:30]2[CH:29]=[CH:28][CH:27]=[CH:26][C:25]=2[C:24]2[C:19]1=[CH:20][CH:21]=[CH:22][CH:23]=2>CCCCCCCC>[C:1]([C:5]1[C:13]2[O:12][C:11](=[O:14])[CH:10]([C:22]3[CH:21]=[CH:20][C:19]4[N:18]([CH3:17])[C:30]5[C:25]([C:24]=4[CH:23]=3)=[CH:26][CH:27]=[CH:28][CH:29]=5)[C:9]=2[CH:8]=[C:7]([CH3:16])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2]Participants
Procedure
A mixture of 2.2 g (10.0 mmol) of 7-tert-butyl-3-hydroxy-5-methyl-3H-benzofuran-2-one (compound (202), Example 1a, Table 2), 1.8 g (10.0 mmol) of N-methylcarbazole and 0.2 g of Fulcat 22B and 20 ml of n-octane is refluxed for 5 hours under nitrogen. The Fulcat 22B catalyst is subsequently removed by filtration and excess n-octane is distilled off on a vacuum rotary evaporator. Chromatography of the residue on silica gel with the solvent system dichloromethan/hexane=1:2 to 1:1 and subsequent crystallisation of the pure fractions from methanol yields 0.70 g (10%) of 7-tert-butyl-5-methyl-3-(9-methyl-9H-carbazol-3-yl)-3H-benzofuran-2-one, m.p. 84°-90° C. (compound (120), Table 1). The product may additionally contain minor amounts of other structural isomers in accordance with the substitution at the carbazole ring.
Workup
- temperatureis refluxed for 5 hours under nitrogen
- customThe Fulcat 22B catalyst is subsequently removed by filtration and excess n-octane
- distillationis distilled off on a vacuum rotary evaporator
- customChromatography of the residue on silica gel with the solvent system dichloromethan/hexane=1:2 to 1:1 and subsequent crystallisation of the pure fractions from methanol
Sources & evidence
- ORD record
- ord-026bb30894f14c2cb93708135774f5f3
- Source dataset
- uspto-grants-1996_05
- Patent number
- US05516920
Reaction notes
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