2-Aminobenzo[b]thiophencarbonsäureester aus 3-Hydroxy-2-nitro-1-thiochromon

2-Aminobenzo[b]thiophenecarboxylic esters from 3-Hydroxy-2-nitro-1-thiochromone 3-Hydroxy-2-nitro-1-thiochromone (1b) , when mixed with bases in alcoholic solution, yields the 2-nitro-benzothiophene-3-carboxylates 4a and 4b as well as the 2-amino-3-benzothiophene-3-carboxylates 11a and 11b . Under the same conditions, 3-methoxy-2-nitro-1-thiochromone (1c) yields 3-amino-2-nitro-1-thiochromone (12) . Compound 1b reacts with morpholine in dioxane to give 2-nitro-benzothiophene-3-carboxamide (10) .