Hydrogen Bromide → 2-Bromo-5-tert-butyl-1,3,4-thiadiazole

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Reaction Conditions

Reaction Steps

To a solution of crude 5-tert-butyl-1,3,4-thiadiazol-2-amine (120.8 g) in glacial acetic acid (800 ml) was added aqueous hydrobromic acid (≧40%, 218 ml) at room temperature. The resulting solution was heated to 65° C., and a solution of sodium nitrite (167 g, 2.42 mol) in water (300 ml) was added dropwise such that the internal temperature was maintained at 65˜75° C. After addition was complete, the resulting yellow solution was cooled to room temperature, poured into ice and then extracted with ethyl acetate. The combined organic layer was washed with saturated aqueous sodium carbonate solution until the pH was neutral, dried over magnesium sulfate, filtered and concentrated. The resulting oil was purified via flash column chromatography (ethyl acetate/petroleum ether) to obtain 2-bromo-5-tert-butyl-1,3,4-thiadiazole.

Provenance & Evidence