3,4-Dichloroaniline → Ethyl 4-[(3,4-dichlorophenyl)amino]-5,8-dihydropyrido[4',3':4,5]furo[2,3-d]pyrimidine-7(6H)carboxylate

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Reaction Steps

Ethyl 3-cyano-2-{[(1E)-(dimethylamino)methylidene]amino}-4,7-dihydrofuro[2,3-c]pyridine-6(5H)-carboxylate from Example 37A (1.00 g, 4.14 mmol) and 3,4-dichloroaniline (1.12 g, 6.89 mmol) were heated in a mixture of acetonitrile (20 mL) and acetic acid (2 mL) for 20 h under reflux. The mixture was then half-concentrated in vacuo and heated for further 20 h. Subsequently, it was diluted with water, basified with aqueous sodium hydroxide solution and extracted with ethyl acetate. The organic layer was dried over sodium sulfate, and the solvent was evaporated. The residue was triturated with methanol. The precipitate was collected by suction filtration to yield 542 mg (34%) of the title compound. A second batch of 50 mg (4%) was obtained from the mother liquor after purification by preparative HPLC.

Provenance & Evidence