Abstract
The reaction of 7-chloro-l-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (7) with each of sarcosine and (+/-)-pipecolinic acid afforded the corresponding N-(4oxoquinolin-7 -yl)-alpha- amino acids 8 and 9. Reductive lactarnization of the latter with sodium dithionite gave hexahydropyrido[2,3-f]quinoxaline (10) and octahydrodipyrido[1,2-a: 2,3-f]quinoxaline (11) derivatives, respectively. Compounds 8 - 11 and their homologs I - 6, accessible from (S)-proline, (2S, 4R)-4-hydroxyproline and (S)-tetrahydroisoquinoline-3-carboxylic acid exhibit good to excellent antibacterial activities against E coli and S. aureus.