Syntheses for 2‐amino and 2‐mercapto‐2 H ‐1,4‐benzoxazin‐3(4 H )‐one and 2 H ‐1,4‐benzothiazin‐3(4 H )‐one as aza and thio analogues of the natural product blepharigenin

2‐Amino‐2 H ‐1,4‐benzoxazin‐3(4 H )‐one 3 , 2‐amino‐2 H ‐1,4‐benzothiazin‐3(4 H )‐one 4 , 2‐mercapto‐2 H ‐1,4‐benzoxazin‐3(4 H )‐one 7 , and 2‐mercapto‐2 H ‐1,4‐benzothiazin‐3(4 H )‐one 8 representing aza and thio analogues of the natural product's aglucone Blepharigenin (2‐hydroxy‐2 H ‐1,4‐benzoxazin‐3(4 H )‐one) from Gramineae and Acantnaceae species have been synthesized for the first time from their 2‐bromo precursors 1 and 2 . Attempts to similarly prepare the 4‐hydroxy derivatives of 7 and 8 , which would represent new thio analogues of the naturally occurring cyclic hydroxamic acid, 2,4‐dihydroxy‐2 H ‐1,4‐benzoxazin‐3(4 H )‐one, have failed.