Synthesis of Benzoxazinones
Solvent-assisted grinding enables a mild and convenient synthesis of 2-substituted 4H-3,1-benzoxazin-4-ones, 2-aminobenzoxazin-4-ones, and 2-amino-4H-3,1-benzothiazin-4-ones from N-substituted anthranilic acid derivatives in the presence of 2,4,6-trichloro-1,3,5-triazine and catalytic triphenylphosphine via a rapid cyclodehydration.
M. Pattarawarapan, S. Wet-osot, D. Yamano, W. Phakhodee, Synlett, 2017, 28, 589-592.
A facile and efficient copper-catalyzed method for the synthesis of 4H-3,1-benzoxazin-4-one derivatives is based on a tandem intramolecular C-N coupling/rearrangement process. This method provides a new and useful strategy for construction of N-heterocycles.
Z.-Y. Ge, Q.-M. Xu, X.-D. Fei, T. Tang, Y.-M. Zhu, S.-J. Ji, J. Org. Chem., 2013, 78, 4524-4529.
A series of substituted benzoxazinones were synthesized from N-(o-bromoaryl)amides by palladium-catalyzed carbonylation with paraformaldehyde as the carbonyl source, which is inexpensive, stable, and easy to use.
W. Li, X.-F. Wu, J. Org. Chem., 2014, 79, 10410-10416.
A palladium-catalyzed carbonylation of 1-azido-2-iodobenzenes in the presence of amines provides a broad range of 2-aminobenzoxazinone derivatives in good yields. By using organic azides as the substrates, external oxidant usage can be successfully avoided and only N2 is formed as byproduct.
Y. Zhang, Z. Yin, H. Wang, X.-F. Wu, Org. Lett., 2019, 21, 3242-3246.