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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence