Hydrochloric Acid → 2-Chloro-5-phenyl-1,3,4-thiadiazole

HRID 878428Notes

Reaction equation

HRID 878428 reaction equation
N[C:2]1[S:3][C:4]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[N:5][N:6]=1.N([O-])=O.[Na+].[ClH:17]>C(O)(=O)C.O.[Cu]>[Cl:17][C:2]1[S:3][C:4]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[N:5][N:6]=1

Participants

7

Reactant 3

HCID 313Hydrochloric AcidHCID 2194082-Amino-5-phenyl-1,3,4-thiadiazoleHCID 23668193Sodium Nitrite

Product 1

HCID 2531452-Chloro-5-phenyl-1,3,4-thiadiazole

Reagents, catalysts & solvents 3

HCID 23978CopperCatalystHCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

A stirred suspension of 2-amino-5-phenyl-[1,3,4]thiadiazole (6.45 g, 36.4 mmol; Aldrich) and copper (230 mg, 3.6 mmol; Aldrich) in hydrochloric acid (36 mL, 12 M) and glacial acetic acid (180 mL) was chilled to 0° C. and treated with a solution of sodium nitrite (2.64 g, 38.2 mmol; Aldrich) in water (12 mL), added dropwise over 40 minutes. After stirring at room temperature for 4 hours, the mixture was poured into ice water. The aqueous solution was extracted with chloroform (3×), and the combined extracts were washed sequentially with 5% sodium bicarbonate and brine, and dried over sodium sulfate. The crude product was filtered through a short silica gel plug with chloroform to afford the title product: 1H NMR (300 MHz, CDCl3) δ ppm 7.46-7.55 (m, 3H), 7.85-7.93 (m, 2H). MS (DCI/NH3) m/e 197/199 (M+H)+.

Workup

  1. additionadded dropwise over 40 minutes
  2. extractionThe aqueous solution was extracted with chloroform (3×)
  3. washthe combined extracts were washed sequentially with 5% sodium bicarbonate and brine
  4. dry with materialdried over sodium sulfate
  5. filtrationThe crude product was filtered through a short silica gel plug with chloroform

Sources & evidence

ORD record
ord-8e4a22c8b17949d694bd4c6123376d79
Source dataset
uspto-grants-2015_03
Patent number
US08987453B2

Reaction notes

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