Sulfuric Acid → 6,7-Dimethoxy-1-oxo-1,2-dihydroisoquinoline-4-carbonitrile

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Reaction Conditions

Reaction Steps

Concentrated sulfuric acid (0.4 mL) was added the the mixture of [2-cyano-2-(3,4-dimethoxy-phenyl)-vinyl]-carbamic acid ethyl ester (33.5 g, 121 mmol) and diphenyl ether (230 mL). The mixture was heated to 230° C. for 6 hr. After cooling, ether was added to precipitate the solid. The resulting solid was collected by filtration, washed with ether and dried to afford 6,7-dimethoxy-1-oxo-1,2-dihydro-isoquinoline-4-carbonitrile (20.7 g, 74.1%) as a brown solid which was used without further purification. LC-MS m/e calcd for C12H10N2O3 (MH+) 231. found 231.

Provenance & Evidence