| abstract |
NEW MATERIAL:A compound expressed by formula I [ring A is substituted by halogen, nitro, alkyl, alkoxyl or butadienylene group (-CH=CH-CH=CH-) forming benzene ring with the two adjacent carbon atoms at the 6-, 7-, 8- and 9-positions; R1 is H, alkyl, phenyl, amino, alkoxycarbonyl or OH; R2 is cyano, alkoxycarbonyl or -CONH2]. EXAMPLE:Ethyl 7-ethyl-2-methyl-1-azaxanthone-3-carboxylate. USE:An antiallergic agent. PREPARATION:A compound expressed by formula II, e.g. 2-amino-6-ethyl-4-oxo- 4H-1-benzopyran-3-carboxaldehyde, is reacted with an active methylene compound, e.g. ethyl acetoacetate, or an acetylenecarboxylic acid derivative. |