The synthetic access to 2-sec-amino-4H-3,1-benzothiazin-4-ones 2 was explored. Compounds 2 were available from methyl 2-thioureidobenzoates 1, 2-thioureidobenzoic acids 3, and novel 2-thioureidobenzamides 6, respectively, under different conditions. 2-Alkylthio-4H3,1-benzothiazin-4-ones 5 have been prepared from anthranilic acid following a two step route. Both, benzothiazinones 2 and 5 underwe...