Baker's yeast catalyzed synthesis of 1,4-benzothiazines, performed under ultrasonication

▶ Baker's yeast catalyzes the cyclocondensation leading to 1, 4-benzothiazines. ▶ Baker's yeast accelerates the cyclocondensation of 2-aminothiophenols and 1, 3-dicarbonyls. ▶ Synthesis of 1, 4-benzothiazines expedited by baker's yeast and ultrasound.