Oblon, Fisher, Spivak, McClelland & Maier
KA-6643-Series antibiotics, process for producing same and medical composition containing same
 A-KA-6643-series antibiotic comprising at least one substance represented by any of the following formulae, or a salt or ester thereof: ##STR1## is effectively useful as an antibacterial and .beta.-lactamase inhibiting agent. 
Kowa Co., Ltd.
C C C C
C07D C12R C12P C12N
inventional additional inventional inventional
Sohei Akira Toshihito Hisakatsu Masahito Masao Shigeru Toshimi Akio
Tanabe Murakami Mori Ito Nakayama Okuchi Kimura Mizoguchi Iwasaki