Phosphorus oxychloride → 2-Chloro-4-phenyl-5-thiazolecarboxylic acid ethyl ester

HRID 1156594Notes

Reaction equation

HRID 1156594 reaction equation
O=[C:2]1[NH:6][C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[C:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[S:3]1.P(Cl)(Cl)([Cl:20])=O>>[Cl:20][C:2]1[S:3][C:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:6]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 13041815Ethyl 2,3-dihydro-2-oxo-4-phenyl-5-thiazolecarboxylate

Product 1

HCID 130418162-Chloro-4-phenyl-5-thiazolecarboxylic acid ethyl esterYield 68%

Procedure

To a solution of 20.0 g (0.105 mole) of ethyl β-amino-cinnamate in 40 ml. of chlorobenzene under ice cooling was added a solution of 11.6 g (0.112 mole) of chorocarbonylsulfenyl chloride in 10 ml. of chlorobenzene. The reaction mixture was heated at 110° C. for 2 hours, cooled to triturated with petroleum ether. The precipitate was heated with hot benzene, cooled and filtered to give 14.4 g (55%) of ethyl 2,3-dihydro-2-oxo-4-phenyl-5-thiazolecarboxylate as yellow needles. A mixture of 3.0 g (0.012 mole) of ethyl 2,3-dihydro-2-oxo-4-phenyl-5-thiazolecarboxylate and 14 ml. of phosphorus oxychloride was held at reflux for 24 hours and cooled. The reaction mixture was poured into ice water. The solid precipitate was extracted into ether. The ether solution was dried and concentrated under reduced pressure. The residue was recrystallized from hexane to give 2.2 g (68%) of ethyl 2-chloro-4-phenyl-5-thiazolecarboxylate, m.p. 56°-57° C.

Workup

  1. temperatureat reflux for 24 hours
  2. temperaturecooled
  3. extractionThe solid precipitate was extracted into ether
  4. dry with materialThe ether solution was dried
  5. concentrationconcentrated under reduced pressure
  6. customThe residue was recrystallized from hexane

Sources & evidence

ORD record
ord-1d9caf51ec7f40219bc0aa16eebc46db
Source dataset
uspto-grants-1982_06
Patent number
US04336389

Reaction notes

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