Hydrochloric Acid → 4-Methyl-2,1,3-benzothiadiazole

HRID 843242Notes

Reaction equation

HRID 843242 reaction equation
[S:1](Cl)(Cl)=O.[NH2:5][C:6]1[C:11]([NH2:12])=[CH:10][CH:9]=[CH:8][C:7]=1[CH3:13].Cl>N1C=CC=CC=1>[CH3:13][C:7]1[C:6]2[C:11](=[N:12][S:1][N:5]=2)[CH:10]=[CH:9][CH:8]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 175932,3-DiaminotolueneHCID 24386Thionyl Chloride

Product 1

HCID 27812624-Methyl-2,1,3-benzothiadiazole

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

Thionyl chloride (166 g, 1.4 mol) was added to a solution of 2,3-diaminotoluene (71 g, 0.58 mol) in pyridine (430 mL) dropwise at a temperature below 45° C. Concentrated HCl (300 mL) was then added dropwise while care was taken to ensure that the reaction temperature did not exceed 65° C. After cooling to room temperature, the reaction mixture was subjected to a steam distillation. The light-yellow oil suspension in the water layer was extracted with diethyl ether. The combined extracts were washed with brine and dried over Na2SO4. After removal of the solvent by rotary evaporation, 4-methyl-2,1,3-benzothiadiazole was obtained as a light-yellow liquid in 92% (80.6 g) of yield. Rf=0.62 (hexane/ethyl acetate=3:1); 1H NMR (200 MHz, CDCl3) δ2.74 (s, 3H), 7.34 (m, 1H), 7.48 (d,J1=8.7 Hz, J2=6.7 Hz, 1H), 7.83 (m, 1H).

Workup

  1. customdid not exceed 65° C
  2. distillationthe reaction mixture was subjected to a steam distillation
  3. extractionThe light-yellow oil suspension in the water layer was extracted with diethyl ether
  4. washThe combined extracts were washed with brine
  5. dry with materialdried over Na2SO4
  6. customAfter removal of the solvent
  7. customby rotary evaporation

Sources & evidence

ORD record
ord-3bb5f70f18b64333b497bae5379fc504
Source dataset
uspto-grants-2002_04
Patent number
US06376664B1

Reaction notes

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