6-iodo-8-methyl-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione → 6-cyano-8-methyl-1H-benzo[d][1,3]oxazine-2,4-dione

Participants

Reaction Steps

600 mg (1.98 mmol) 6-iodo-8-methyl-1H-benzo[d][1,3]oxa zine-2,4-dione (prepared according to known procedures, see G. M. Coppola, Synthesis, 1980, 505), 212 mg (2.37 mmol) CuCN, 377 mg (1.98 mmol) Cul and 114 mg tetrakis(triphenylphosphine) palladium in 60 ml THF are heated 5 h at reflux. After cooling down, the mixture is filtered on Hyflo. The organic phase is washed with water and evaporated. The residue is crystallized from a mixture of dichloromethane, ethyl acetate and hexane to afford 245 mg 8-methyl-2,4-dioxo-1,4-dihydro-2H-benzo[d][1,3]oxazine-6-carbonitrile, which is directly used in the next step.

Provenance & Evidence