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

HRID 615815Notes

Reaction equation

HRID 615815 reaction equation
[BrH:1].N[C:3]1[S:4][C:5]([C:8]([CH3:11])([CH3:10])[CH3:9])=[N:6][N:7]=1.N([O-])=O.[Na+]>C(O)(=O)C.O>[Br:1][C:3]1[S:4][C:5]([C:8]([CH3:11])([CH3:10])[CH3:9])=[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-thiadiazoleYield 78%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent2×

Conditions

Temperature
65 °C

Procedure

48% Aqueous hydrobromic acid (67.5 ml) was added to a solution of 2-amino-5-t-butyl-1,3,4-thiadiazole (43 g) in glacial acetic acid (300 ml) the mixture was warmed to 65° C. and a solution of sodium nitrite (56 g) in water (80 ml) was added dropwise with stirring over 60 minutes at 65°-75° C. The mixture was cooled to 20° C. and was poured into water. The organic layer was extracted into ether (2×300 ml) and the extracts were combined, washed with sodium bicarbonate solution until neutral and dried over magnesium sulphate. The drying agent was filtered off and the solvent was evaporated to give a yellow oil which was distilled under reduced pressure to give 2-bromo-5-t-butyl-1,3,4-thiadiazole (47 g, 78%) as a colourless liquid, bp 134°-136° C. at 23 mm Hg.

Workup

  1. temperatureThe mixture was cooled to 20° C.
  2. extractionThe organic layer was extracted into ether (2×300 ml)
  3. washwashed with sodium bicarbonate solution until neutral and
  4. dry with materialdried over magnesium sulphate
  5. filtrationThe drying agent was filtered off
  6. customthe solvent was evaporated
  7. customto give a yellow oil which
  8. distillationwas distilled under reduced pressure

Sources & evidence

ORD record
ord-e024c29c45a747289667d74530b9d874
Source dataset
uspto-grants-1985_02
Patent number
US04501605

Reaction notes

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