The application belongs to the field of
pharmacy, and discloses a
crystal form I of an oxazolidinone antibacterial candidate new
drug OTB-658, a preparation method of the
crystal form I, and a composition and application of the
crystal form I. Specifically, the application relates to a crystal form I of N-(((3S,3aS)-8-fluoro-1-oxo-7-thiomorpholinyl-3a,4-dihydro-1H,3H-benzo[b]oxazol[3,4-d][1,4]oxazin-3-yl)methyl)
acetamide, i.e. OTB-658, and a preparation method of the crystal form I. The crystal form I of OTB-658 is used as a pharmaceutical
active ingredient to prepare a
drug for treating and / or preventing a bacterial, in particular
Mycobacterium tuberculosis, infectious
disease.