Abstract
Cephalexin (1) was acylated using N-acylbenzotriazoles (3a-k ') derived from various carboxylic acids including aromatic, heterocyclic and N-Pg-alpha-amino acid to afford N-acylcephalexins in excellent yields (82%-96%). Antibacterial screening of the novel cephalosporins revealed that all targets (4a-j) retained the antibacterial activity of cephalexin against Staphylococcus aureus (ATCC 6538). N-Nicotinylcephalexin (4c) and N-(3,4,5-trimethoxybenzoyl) cephalexin (4g) exhibited a broader spectrum of antibacterial activity towards standard strains of Staphylococcus aureus (ATCC 6538), Paenibacillus polymyxa (ATCC 842), and Escherichia coli (ATCC 10536) as well as a resistant strain of Pseudomonas aeruginosa (ATCC 27853).