PROCESS FOR THE PREPARATION OF 8-AMINO-4-OXO-2-(TETRAZOLE-5-YL)-4H-1-BENZOPYRAN AND PRANULKAST

A 8-amino-4-oxo-2-(tetrazole-5-yl)-4h-1-benzopyran and a preparation process of pranulkast using the same are provided to be economic by inducing an imine group which can introduce a blocking group easily. A manufacturing method 8-amino-4-oxo-2-(tetrazole-5-yl)-4h-1-benzopyran and its salt comprise a first step for reacting 3- amino -2- hydroxyacetophenone with an aldehyde compound to obtain a compound; a second step for reacting the compound with 1H- tetrazole -5- carboxylate to obtain a compound; and a third step for reacting the compound obtained from the second step under the presence of acid to manufacture -amino-4-oxo-2-(tetrazole-5-yl)-4h-1-benzopyran and their salt.