| 摘要 |
NEW MATERIAL:A compound of formulaI(R1 is H or lower alkyl; X1 and X2 are halogen). EXAMPLE:9,10-Difluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-d,e][ 1,4]-benzoxazine-6-carboxylic acid-BF2-chelate. USE:A synthetic intermediate for compounds of formula II useful as an antimicrobial agent. PROCESS:A compound of formula III is reacted with a dialkyl ethoxymethylenemalonate to give a compound of formula IV (R is lower alkyl), which is then cyclized and condensed with boron trifluoride or its complex, e.g. THF complex of boron trifluoride, to afford the aimed compound of formulaI. A compound of formula V is obtained from the compound of formulaIand then reacted with a compound of formula IV (R2 is H or lower alkyl) to give a useful compound of formula II. |
