Sodium Chloride → Methyl 2-chloro-4-methylbenzo[d]thiazole-5-carboxylate

HRID 1071905Notes

Reaction equation

HRID 1071905 reaction equation
N[C:2]1[S:3][C:4]2[CH:10]=[CH:9][C:8]([C:11]([O:13][CH3:14])=[O:12])=[C:7]([CH3:15])[C:5]=2[N:6]=1.[Cl-:16].[Na+].C1OCCOCCOCCOCCOC1.N(OC(C)(C)C)=O>C(#N)C.[Cu]Cl.O>[Cl:16][C:2]1[S:3][C:4]2[CH:10]=[CH:9][C:8]([C:11]([O:13][CH3:14])=[O:12])=[C:7]([CH3:15])[C:5]=2[N:6]=1

Participants

8

Reactant 4

HCID 5234Sodium ChlorideHCID 10906Tert-Butyl nitriteHCID 3633615-Crown-5HCID 22390084Methyl 2-amino-4-methylbenzo[d]thiazole-5-carboxylate

Product 1

HCID 22390080Methyl 2-chloro-4-methylbenzo[d]thiazole-5-carboxylateYield 77.3%

Reagents, catalysts & solvents 3

HCID 62652Cuprous chlorideCatalystHCID 962WaterSolventHCID 6342AcetonitrileSolvent

Procedure

A solution of 5 g (22.5 mmol) of methyl 2-amino-4-methyl-benzothiazole-5-carboxylate in 2 l of acetonitrile was admixed with 10 ml of water, 4.5 g (44.8 mmol) of copper(I) chloride, 6.6 g of sodium chloride (110 mmol) and 2 ml of 15-crown-5. A solution of 3 g (29 mmol) of tert-butyl nitrite was then added dropwise with stirring, the solution was heated at reflux for 15 h, the resulting precipitate was filtered off and the solution was concentrated under reduced pressure. The residue was then extracted three times with in each case 500 ml of ethyl acetate. To this end, the solvent was heated to boiling point and the solution was filtered whilst hot. The extracts were concentrated under reduced pressure. The residue was purified by trituration with n-hexane/diethyl ether. This gave 4.2 g (17.4 mmol, 77% yield) of methyl 2-chloro-4-methylbenzothiazole-5-carboxylate of m.p. 112° C.

Workup

  1. temperaturethe solution was heated
  2. temperatureat reflux for 15 h
  3. filtrationthe resulting precipitate was filtered off
  4. concentrationthe solution was concentrated under reduced pressure
  5. extractionThe residue was then extracted three times with in each case 500 ml of ethyl acetate
  6. temperatureTo this end, the solvent was heated
  7. filtrationthe solution was filtered whilst hot
  8. concentrationThe extracts were concentrated under reduced pressure
  9. customThe residue was purified by trituration with n-hexane/diethyl ether

Sources & evidence

ORD record
ord-3aa97c414aa54f4ab25150730a167a30
Source dataset
uspto-grants-2005_06
Patent number
US06908884B2

Reaction notes

Loading…