2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 2-Formyl-5-methoxy-3-methoxycarbonyl-1-methylindole

Temperature

30 °C

24.7 g (100 mmol) of 5-methoxy-3-methoxycarbonyl-2-methoxymethyl -1-methylindole obtained in Example 2 or 4 was dissolved in 494 ml of methylene chloride and 27.4 ml of water, followed by the addition of 25.0 g (110 mmol) of DDQ and subsequent 8 hours of stirring at 30° C. The reaction mixture was filtered and the thus collected insoluble materials were washed with 120 ml of methylene chloride. The filtrate and the washings were combined and applied to a column packed with 123.5 g of alumina. The eluate was combined with another eluate obtained by further elution of the alumina column with 2,260 ml of methylene chloride, and the thus combined eluates were concentrated under reduced pressure. The thus obtained residue was recrystallized from 111 ml of ethyl acetate, and the precipitated crystals were collected by filtration and dried under reduced pressure to obtain 11.8 g of the title compound with a yield of 80.1%. The compound thus obtained showed the same properties as those of the compound obtained in Example 5 in terms of NMR, IR and TLC data.

1. filtrationThe reaction mixture was filtered
2. washthe thus collected insoluble materials were washed with 120 ml of methylene chloride
3. customanother eluate obtained by further elution of the alumina column with 2,260 ml of methylene chloride
4. concentrationthe thus combined eluates were concentrated under reduced pressure
5. customThe thus obtained residue was recrystallized from 111 ml of ethyl acetate
6. filtrationthe precipitated crystals were collected by filtration
7. customdried under reduced pressure

ORD record

ord-14e9b939f1664c808329a72a75ffcd93

Source dataset

uspto-grants-1994_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05344938