No abstract

No abstract

No abstract

Summary The antibacterial activity in vitro of dihydro‐1,3‐oxazine derivatives with aromatic rings condensed in positions 5, 6 was examined. Of more than thirty compounds examined, two (T 615 and T 638) showed marked activity against various strains of Mycobacterium tuberculosis at concentrations below 2 μg/ml. These two compounds also showed marked activity against Escherichia coli, Clostridium pneumoniae and Salmonella typhi. Both showed marked activity in vivo against tuberculosis produced in mice and guinea‐pigs by various strains of Mycobacterium such as human strain ‘Sz’, bovine ‘An 5’ and H37Rv non‐resistant and resistant to isonicotinic acid hydrazide (INH), streptomycin (SM) and p‐aminosalicylic acid (PAS).