| abstract |
NEW MATERIAL:A compound expressed by formula I [ring A may be substituted by halogen, nitro, alkyl or butadienylene group (-CH=CH-CH=CH-) forming benzene ring with two adjacent carbon atoms at the 6-, 7-, 8- and 9-positions; R is H, alkyl, phenyl, amino, carboxy or OH]. EXAMPLE:Ethyl 7-ethyl-2-methyl-2-azaxanthone-3-carboxylate. USE:An antiallergic agent. The salt thereof has good solubility in water, and the aqueous solution thereof has improved stability and is convenient for injection, solution, etc. 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 acetylenecarboxylic acid derivative, and the resultant product is then hydrolyzed. |