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

HRID 253187Notes

Reaction equation

HRID 253187 reaction equation
S(O)(O)(=O)=O.N[C:7]1[S:8][C:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)=[N:10][N:11]=1.[BrH:18].N([O-])=O.[Na+]>C(Cl)Cl.O>[Br:18][C:7]1[S:8][C:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)=[N:10][N:11]=1

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 162130872-amino-5-phenyl-1,3,4-thiadiazole sulfate saltHCID 23668193Sodium Nitrite

Product 1

HCID 131041172-Bromo-5-phenyl-1,3,4-thiadiazoleYield 74%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
5 °C

Procedure

A mixture of 2-amino-5-phenyl-1,3,4-thiadiazole sulfate (Aldrich, 2.5 g, 9.08 mmol) and 48% aqueous HBr (10 mL) was cooled to 5° C. and a solution of NaNO2 (0.69 g, 9.99 mmol) H2O (10 mL) was added dropwise at a rate so the internal temperature is maintained at approximately 5° C. The mixture was stirred for 15 min after the addition, then CuBr (0.69 g, 4.8 mmol) was added portion-wise so as to maintain the temperature at approximately 5° C. After the addition was complete, the mixture was allowed to warm to ambient temperature and stirred for 16 h. The mixture was diluted with 20 mL CH2Cl2 and 10 mL H2O. The organic layer was separated and concentrated under reduced pressure to provide the title compound (1.63 g, 6.76 mmol, 74% yield). MS (DCl/NH3) m/z 241, 243 (M+H)+.

Workup

  1. temperatureis maintained at approximately 5° C
  2. additionafter the addition
  3. temperatureto maintain the temperature at approximately 5° C
  4. additionAfter the addition
  5. temperatureto warm to ambient temperature
  6. stirringstirred for 16 h
  7. customThe organic layer was separated
  8. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-1742f78049334d6885a6f18a49f66fd4
Source dataset
uspto-grants-2011_01
Patent number
US07872010B2

Reaction notes

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