Ethanol → HCID 54720025, compound

Participants

Reaction Steps

5,7-Dimethyl-3-methoxyoxalylamino-4-oxo-4H-1-benzopyrane with a melting point of 186°-187° (from ethanol) can be prepared in a manner analogous to that described in Example 1, using 3-amino-5,7-dimethyl-4-oxo-4H-1-benzopyrane as the starting material. The starting material can be obtained, for example, using 5,7-dimethyl-4-hydroxy-coumarin as the starting material, by reacting the latter with nitric acid in acetic acid at 80° to give 5,7-dimethyl-4-hydroxy-3-nitro-coumarin, treating this compound for 24 hours with sodium hydroxide solution and subsequently acidifying, with decarboxylation, to give 4,6-dimethyl-2-hydroxy-β-nitro-acetophenone, analogously to the process described in J. Am. Chem. Soc. 67, 99 (1945), and also reacting the latter compound with the mixed anhydride of formic acid and acetic acid to give 5,7-dimethyl-3-nitro-4-oxo-4H-1-benzopyrane with a melting point of 120°-125° and reducing this compound with sodium dithionite to give 3-amino-5,7-dimethyl-4-oxo-4H-1-benzopyrane (melting point 120°-121°), analogously to the process described in Tetrahedron Letters 1976, 719, and purifying this product via the hydrochloride.

Provenance & Evidence