
TY  - JOUR
A1  - Teitei, T 
T1  - The Synthesis of (3'-Oxo-3',4'-Dihydro-2'h-1',4'-Benzothiazin-2'-Yl)Acetic Acid and (3'-Oxo-3',4'-Dihydro-2'h-1',4'-Benzoxazin-2'-Yl)Acetic Acid-Derivatives
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1986
VL  - 39
IS  - 3
SP  - 503
EP  - 510
KW  - 
UR  - https://doi.org/10.1071/CH9860503 
N2  - Reaction of o-aminophenol with various maleic anhydrides gave first 2-hydroxymaleanilic acids (4-(2&#8242;-hydroxyphenylamino)-4-oxobut-2-enoic acids) (1), which were then converted into the 3-oxo-1,4-benzoxazines (2d-h) and (3f-1) under mild basic conditions; similarly the reaction of o- aminothiophenol with the maleic anhydrides gave the 3-oxo-1,4-benzothiazines (2a), (3a) and (3d) in one step. The facile cycloaddition and esterification of 2-hydroxymaleanilic acids to form the benzoxazines observed in this work is discussed in terms of the formation of the isomaleimide type intermediate (7). 
ER  -

