A Facile Synthesis of Novel Dihydroindeno[1,2-e][1,2,4]triazolo[3,4-b][1,3,4]thiadiazines Using HTIB

The synthesis of a series of 21 novel 3-alkyl/aryl-7/9-methyl-10,10a-dihydroindeno[1,2-e][1,2,4]triazolo[3,4-b][1,3,4]thiadiazines (4) has been achieved by the cyclocondensation between 4/6-methyl-2-tosyloxy-1-indanones (2) and 3-alkyl/aryl-4-amino-5-mercapto-1,2,4-s-triazoles (3). 4/6-Methyl-2-tosyloxy-1-indanones (2) were readily accessible through hypervalent iodine oxidation of 4/6-methyl-1-indanones using [(hydroxy)tosyloxyiodo]benzene (HTIB, Koser's reagent) in acetonitrile.