Abstract: A suspension of 4H-2-acetyl-3-amino furo [3, 2-c] benzopyran 4-one 5a-d in aqueous sodium hydroxide is treated with acetyl chloride to give 4H-2-acetyl-3-acetylamido furo [3, 2-c] benzopyran 4-one 6a-d. The compounds 6a-d and hydrazine hydrate in absolute alcohol is refluxed to give 11H-2, 4-dimethyl-3, 4-dihydro-3-amino-4-hydroxy- pyrimido [3, 2-d] furo [3, 2-c] benzopyran-11-one 7a-d which in formic acid is refluxed for 5 ...