Categories: Synthesis of N-Heterocycles, Synthesis of O-Heterocycles > benzo-fused N-Heterocycles, benzo-fused O-Heterocycles >
Synthesis of 4H-1,3-benzoxazines
Recent Literature
Unprecedented catalyst-controlled divergent cyclizations of
Morita-Baylis-Hillman carbonates provide 1,2-dihydroquinolines in the presence
of Cs2CO3 or 4H-3,1-benzoxazines in the presence of
quinuclidine.
W. Cai, Y. He, Y. Zhou, Y. Huang, J. Org. Chem., 2021, 86,
12267-12276.
Treatment of various 2-amino-arylalkyl alcohols with isothiocyanates afforded
thiourea intermediates, which were reacted in situ with molecular iodine in the
presence of triethylamine to give 2-amino-4H-1,3-benzoxazines. The
reaction of the thiourea intermediates with T3P as mild cyclodehydrating reagent
and triethylamine as the base provides 2-amino-4H-1,3-benzothiazines.
V. P. R. K. Putta, N. Vodnala, R. Gujjarappa, U. Tyagi, A. Garg, S. Gupta, P. P.
Pujar, C. C. Malakar, J. Org. Chem., 2020, 85, 380-396.