A series of 2,3-dihydro-7-nitroimidazo[5,1-b]oxazoles has been prepared in one-pot reaction. The proposed new method of their synthesis requires a treatment of 4,5-dinitroimidazole or 2-methyl-4,5-dinitroimidazole with oxiranes. Some of the obtained compounds have been tested in vitro for antimycobacterial activity and the spatial structure of them has been also discussed.