| 摘要 |
Intermediates for preparing an antibacterial 1-dethia-1-oxacephalosporins which are represented by the following formula: <IMAGE> wherein R is a monovalent group (minus the carbonyl) from an acyl group derived from a carboxylic or carbonic acid; Y1 is a divalent group of the following formula: <IMAGE> +TR <IMAGE> wherein COB is carboxy or protected carboxy; X is hydrogen or a nucleophilic group; and Z is a leaving group are prepared from a compound of the following formula: <IMAGE> wherein R and Y1 are as defined above by the action of an acid. The new compounds of this invention shown by the following formula: <IMAGE> wherein A is amino or substituted amino; E is hydrogen or methoxy; and Y is a divalent group of the following formula: <IMAGE> in which COB, X, and Z are as defined above are convertible into other compounds of the same formula by applying conventional methods in beta -lactam chemistry. |
