FOERFARANDE FOER FRAMSTAELLNING AV PYRIDO/1,2,3-DE/(1,4)BENZOXAZIN-6-KARBOXYL-SYRA-BF2-KELATDERIVAT.

摘要

The invention relates to a process for the preparation of pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid-BF2- chelate derivatives of the formula <IMAGE> wherein X1 and X2 are halogen and R1 is C1-6 alkyl. According to the process, 1,4-benzoxazine derivative of the formula <IMAGE> wherein X1, X2 and R1 are as defined above, is reacted with diethyl ethoxymethylene malonate and the compound thus obtained is treated with boron trifluoride or a complex thereof. Compounds with the structural formula II are useful intermediates in the preparation of antibacterial agents.