2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 6-(4-Chloro-1-butenyl)carbostyril

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Reaction Steps

2.5 Grams of 6-(4-chloro-1-butenyl)-3,4-dihydrocarbostyril and 2.3 g of DDQ (2,3-dichloro-5,6-dicyanobenzoquinone) were mixed in 160 ml of dioxane and the mixture was refluxed by heating for 6 hours. Further, 1.1 of DDQ was added to the reaction mixture and the mixture was refluxed by heating for 3 hours. The reaction mixture was cooled and the precipitates thus formed were removed by filtration and the mother liquor was concentrated under a reduced pressure to obtain a residue. The residue was dissolved in a mixture of 100 ml of chloroform with 5 ml of methanol and the solution was padded through a silica gel column for removing the unreacted DDQ. The residue was recrystallized from methanol to obtain 1.6 g of 6-(4-chloro-1-butenyl)carbostyril in yellow needle-like crystals. Melting point: 215°-128° C.

Provenance & Evidence