| 摘要 |
<p>NEW MATERIAL:The compound of formula I (R<1> is H or carboxyl-protecting group: R<2> is halogen, alkoxy, etc.; R<3> is H, lower alkylamino, etc.; R<4> is lower alkyl, lower alkenyl, cycloalkyl or aryl; X1 and X<2> are halogen) and its salt. EXAMPLE:1,7-Dicyclopropyl-5,6,8-trifluoro-1,4-dihydro-4-oxo-3-quinolin ecarboxylic acid ethyl ester. USE:An antibacterial agent. PREPARATION:The objective compound of formula Ia can be produced, accord ing to the reaction formula, by ketoesterifying a compound of formula II (R<2a>=R<1>) and its salt to form a compound of formula III (R<1a>=R<1>) and its salt, reacting the product with methyl orthoformate or ethyl orthoformate in acetic anhydride. reacting with a compound of formula IV and its salt to form a compound of formula V and its salt and finally subjecting the compound to cyclization reaction in the presence or absence of a fluoride, etc.</p> |
