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

HRID 1253513Notes

Reaction equation

HRID 1253513 reaction equation
[C:1]([C:5]1[S:9][C:8](N)=[N:7][N:6]=1)([CH3:4])([CH3:3])[CH3:2].[BrH:11].N([O-])=O.[Na+]>C(O)(=O)C.O>[Br:11][C:8]1[S:9][C:5]([C:1]([CH3:4])([CH3:3])[CH3:2])=[N:6][N:7]=1

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 170170ButhidazolamineHCID 23668193Sodium Nitrite

Product 1

HCID 204065272-Bromo-5-tert-butyl-1,3,4-thiadiazole

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
65 °C

Procedure

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.

Workup

  1. temperaturewas maintained at 65˜75° C
  2. additionAfter addition
  3. temperaturethe resulting yellow solution was cooled to room temperature
  4. additionpoured into ice
  5. extractionextracted with ethyl acetate
  6. washThe combined organic layer was washed with saturated aqueous sodium carbonate solution until the pH
  7. dry with materialdried over magnesium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customThe resulting oil was purified via flash column chromatography (ethyl acetate/petroleum ether)

Sources & evidence

ORD record
ord-c799a20b45474747a09e71fa4309cb70
Source dataset
uspto-grants-2013_06
Patent number
US08455477B2

Reaction notes

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