| 摘要 |
PURPOSE:To obtain the titled compound useful as a vasodilator, etc., safely and selectively, in high yield, by reacting a specific compound with a halogen or a hypohalous acid salt in the presence of an alkali. CONSTITUTION:The 2,4(1H,3H)-quinazolinedione derivative of formula II can be prepared by reacting the compound of formula I (R1 and R2 are lower alkyl; R3 is straight or branched-chain alkoxycarbonyl; R4-R6 are H, halogen, alkyl, alkoxy, trifluoromethyl, etc.) with a halogen (e.g. Cl, Br, etc.) or a hypohalous acid salt in the presence of an alkali (e.g. KOH, NaOH, etc.). The compound of formula II is useful as a vasodilator and an intermediate for a compound having similar use.
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