| abstract |
NEW MATERIAL:Compounds of formula I (R 1 , R 3 are lower alkyl; R 2 is alkoxycarbonyl; R 1 WR 3 bond with the 5W7 or 6W8 positions in the quinazoline ring; R 4 is straight-chain, branched-chain or cyclic alkyl). n EXAMPLE: 6-Ethoxycarbonyl-3,5,7-trimethyl-2,4-(1H,3H)-quinazolinedione. n USE: A synthetic intermediate of 1-substituted 2,4(1H,3H)-quinazolinedione derivatives used as vasodilator, blood stream improver, hypotensor or antiarteriosclerotic. n PREPARATION: The reaction of a compound of formula III with an isocyanate of formula IV affords a compound of formula II, which is subjected to ring-closing condensation reaction in the presence of an acid or alkali under heating at 50W 100°C to produce the compound of formula I. n COPYRIGHT: (C)1982,JPO&Japio |