Resins Amberlyst 15 and Amberlyst XN 1010 are used in the synthesis of 3,4-dihydro-1H-2,3 -benzothiazines 2,2-dioxide. Advantages of this new procedure are simple work-up, high yield and selectivity, easy recovery of the catalyst and no waste problems. ... Resins Amberlyst 15 and Amberlyst XN 1010 are used in the synthesis of 3,4-dihydro-1H-2,3-benzothiazines 2,2-dioxide. Advantages of this new procedure are simple work-up, high yield and ...