N,N'-Dimethylthiourea → 5-Methanesulfonyl-3-methyl-2-methylimino-2,3,8,8a-tetrahydroindeno[1,2-d]thiazol-3a-ol

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Reaction Steps

1.45 g of 2-bromo-6-methanesulfonyl-1-indanone are dissolved in 15 ml of acetone and, while stirring, 0.65 g of N,N′-dimethylthiourea in 10 ml of acetone is added. The solution is initially clear but, after about 10 min, the hydrobromide of 5-methanesulfonyl-3-methyl-2-methylimino-2,3,8,8a-tetrahydroindeno[1,2-d]thiazol-3a-ol crystallizes out. Stirring at room temperature for 1 h is followed by filtration with suction and washing with a little acetone. 2.1 g of hydrobromide (melting point 265° C.) are suspended in 10 ml of methanol, and 1 ml of triethylamine is added. After 15 min, 150 ml of water is added, and the mixture is stirred while cooling in ice for 1 h. The product which is formed is filtered off with suction and washed with a little cold water. 5-Methanesulfonyl-3-methyl-2-methylimino-2,3,8,8a-tetrahydroindeno[1,2-d]thiazol-3a-ol is obtained with a melting point of 158° C.

Provenance & Evidence