Hydrochloric Acid → 2-Chloro-4,5-bis-(p-methoxyphenyl)-thiazole

HRID 544651Notes

Reaction equation

HRID 544651 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9](=O)[CH:10]([C:14]2[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=2)[N:11]=[C:12]=[S:13])=[CH:5][CH:4]=1.[ClH:23]>C(OCC)C>[Cl:23][C:12]1[S:13][C:9]([C:6]2[CH:7]=[CH:8][C:3]([O:2][CH3:1])=[CH:4][CH:5]=2)=[C:10]([C:14]2[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=2)[N:11]=1

Participants

4

Reactant 2

HCID 313Hydrochloric Acid2×HCID 204583321,2-Bis-(p-methoxyphenyl)-2-isothiocyanoethanone

Product 1

HCID 197579572-Chloro-4,5-bis-(p-methoxyphenyl)-thiazole

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

10 g of the 1,2-bis-(p-methoxyphenyl)-2-isothiocyanoethanone so obtained are suspended in 150 ml of diethyl ether and, while stirring, the suspension is cooled to 15°-20°. Gaseous hydrogen chloride is then introduced slowly at such a rate that the reaction temperature does not exceed 20°. After about 45 minutes a clear, yellowish solution is obtained. It is maintained at 15° and a little hydrogen chloride is introduced for a further 7 hours, the solution is left to stand overnight at 15°, poured onto 300 ml of ice, the diethyl ether is removed by distillation, and the crystalline precipitate is filtered with suction, then washed twice with water and sucked dry on a suction filter. The crude product is recrystallised from 100 ml of hexane. 2-Chloro-4,5-bis-(p-methoxyphenyl)-thiazole having a melting point of 92°-94° is obtained.

Workup

  1. temperaturethe suspension is cooled to 15°-20°
  2. customdoes not exceed 20°
  3. customAfter about 45 minutes a clear, yellowish solution is obtained
  4. temperatureIt is maintained at 15°
  5. waitthe solution is left
  6. customthe diethyl ether is removed by distillation
  7. filtrationthe crystalline precipitate is filtered with suction
  8. washwashed twice with water
  9. customsucked dry on a suction
  10. filtrationfilter
  11. customThe crude product is recrystallised from 100 ml of hexane

Sources & evidence

ORD record
ord-b430873a3a6340bca85bb05b3042bd6f
Source dataset
uspto-grants-1984_05
Patent number
US04451471

Reaction notes

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