The main reason for selecting oxazines over oxazoles for anti tubercular drug progress by PathoGenesis was probably driven by the requirement to patent ingredients different from those produced by contact us Hindustan Ciba Geigy. Anaerobes and microaerophilic bacteria but growth stopped as a result of mutagenicity of the ring. 22 nitroimidazoles were the very first class of nitroimidazoles with reported anti tubercular activity. A large array of materials owned by this type tried at 5 and 1 positions was tested against Gram positive and Gram negative bacteria, as well as fungi. The antitubercular activity of a selected set of ingredients understanding the SAR with this collection is represented in Table 3. amide, halide and alkyl replacement at the 1 along with 5 position showed poor activity, although vinyl substituents at the 5 position showed increased effectiveness. One of the most active compound inside the original collection, minimal inhibitory concentration 29. 93 uM had an ethyl at N1 and an unsubstituted vinyl at the 5 position. Subsequently, further vinyl replaced 2 nitroimidazoles were made out of only marginal improvement in antimycobacterial Gene expression action 1H imidazole. Further probing of the replacement at the 5 position with larger substituents produced a little improvement in anti tubercular activity with the most active ingredient being d decyl tried oxime at the vinylic position. It is significant that 2 amino imidazoles, which are believed to be the end product of intracellular nitroimidazole bioreduction, were also examined for antimicrobial activity with similar alterations in the 5 position producing compounds with moderate anti tubercular as well as generalized antimicrobial activity. Generally speaking, increase in the lipophilicity at the 5 position of the two nitroimidazoles increased the antimicrobial activity of Gram positive bacteria, including Mtb. Framework order Avagacestat activity relationships of imidazo oxazoles were investigated on finding that substance 35 demonstrated anti tubercular activity. Substitution of the two position of the oxazole ring with different alkyl and alkyl halides resulted in compounds with mainly increased in vitro anti tubercular action as represented in Table 4. While activity was marginally improved by substitution with a phenyl group only, substitution of the methyl of 35 with ethyl triggered the lead compound in this study, CGI 17341 with 35 fold improved activity above 35. Alkyl mono halide substitutions 36 and 38 had considerably improved activity, although the trichloromethyl group triggered a tenfold reduction in activity. It’s not clear if the materials that were tried were enantiomerically natural or not, since the R enantiomer was later shown to be the active enantiomer for the 4 nitro imidazo oxazole series, although the S enantiomer was the active enantiomer in the 4 nitro imidazo oxazine series. Hence, screening of racemic mixtures could have underestimated the true potency of those substances.