Sodium Chloride → 2,7-dichloro-4-methyl-1,3-benzothiazole

HRID 1865490Notes

Reaction equation

HRID 1865490 reaction equation
N[C:2]1[S:3][C:4]2[C:10]([Cl:11])=[CH:9][CH:8]=[C:7]([CH3:12])[C:5]=2[N:6]=1.N([O-])=O.[Na+].[Na+].[Cl-:18]>OP(O)(O)=O.O>[Cl:18][C:2]1[S:3][C:4]2[C:10]([Cl:11])=[CH:9][CH:8]=[C:7]([CH3:12])[C:5]=2[N:6]=1

Participants

6

Reactant 3

HCID 5234Sodium ChlorideHCID 20498937-chloro-4-methyl-benzothiazol-2-ylamineHCID 23668193Sodium Nitrite

Product 1

HCID 20498762,7-dichloro-4-methyl-1,3-benzothiazoleYield 64.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 1004Phosphoric AcidSolvent

Procedure

To a slurry of 2-amino-4-methyl-7-chlorobenzothiazole (77.2) (6.37 g) in H3PO4 (85%, 213 ml) in a 500 ml 3-necked flask with mechanical stirring and an internal temperature of <−10° C., was added dropwise a solution of NaNO2 (6.87 g) in water (11 ml). The mixture was warmed to 0° for 30 minutes and then recooled. The slurry was then slowly added to a cold (˜−5° C.) solution of CuSO4.5H2O (32 g) and NaCl (40 g) in water (128 ml) with vigorous mechanical stirring. After the foaming subsides and warming to RT, the solids were collected by filtration and rinsed with water. The solids were dissolved in ether leaving some insoluble residue. The ether solution was washed with water, and sodium bicarbonate solution. After the organic layer was concentrated, the residue was purified by flash chromatography with 10% methylene chloride in hexane to afford 2-chloro-4-methyl-7-chlorobenzothiazole (77.3) (4.48 g).

Workup

  1. temperatureThe mixture was warmed to 0° for 30 minutes
  2. filtrationthe solids were collected by filtration
  3. washrinsed with water
  4. dissolutionThe solids were dissolved in ether leaving some insoluble residue
  5. washThe ether solution was washed with water, and sodium bicarbonate solution
  6. concentrationAfter the organic layer was concentrated
  7. customthe residue was purified by flash chromatography with 10% methylene chloride in hexane

Sources & evidence

ORD record
ord-3bfe21375e0746d08f5038aa9dced3bc
Source dataset
uspto-grants-2009_12
Patent number
US07626033B2

Reaction notes

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