Sodium Carbonate → 6-o-chlorophenyl-8-ethyl-4H-tetrazolo[5,1-c]thieno[2,3-e] [1,4]diazepine

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Reaktionsschritte

[f] 10 g of 2-hydrazino-5-o-chlorophenyl-7-ethyl-3H-thieno[2,3-e][1,4]diazepine prepared in the above example [d] is suspended in 54 ml of 2N hydrochloric acid. A solution of 2.4 g of sodium nitrite in 20 ml of water is added to the suspension at -5°C with stirring. The mixture is stirred at room temperature for 30 minutes, and then alkalified with sodium carbonate. The precipitated crystals are filtered off and dissolved in chloroform, and the solution is washed with water. The chloroform layer is dried over anhydrous magnesium sulfate, and the chloroform is distilled off under reduced pressure. The reddish brown jellylike residue thus obtained is crystallized from a mixture of ligroin and ethanol to give 8.2 g of 6-o-chlorophenyl-8-ethyl-4H-tetrazolo[5,1-c]thieno[2,3-e] [1,4]diazepine as white crystals. The product, when recrystallized from ethanol, melts at 135° - 136°C.

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