Sulfuric Acid → Ethyl 2-chlorothiazole-4-carboxylate

HRID 2261299Notes

Reaction equation

N[C:2]1[S:3][CH:4]=[C:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[N:6]=1.S(=O)(=O)(O)O.[Cl-:17].[Na+].N([O-])=O.[Na+]>O.S([O-])([O-])(=O)=O.[Cu+2]>[Cl:17][C:2]1[S:3][CH:4]=[C:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[N:6]=1

Participants

Conditions

Temperature: -10 °C

Procedure

15.0 g of ethyl 2-amino-1,3-thiazole-4-carboxylate was added to 400 ml of water, and 500 g of concentrated sulfuric acid, 29.2 g of copper sulfate and 23.0 g of sodium chloride were then added. The mixture was cooled to −10° C. Thereto a solution of 14.8 g of sodium nitrite in 55 ml of water was added dropwise while the internal temperature was kept at 0° C. or lower. After completion of the addition, the mixture was stirred at 0° C. for 30 minutes, heated to an internal temperature of room temperature, and then further stirred for 30 minutes. The reaction mixture was extracted with ethyl acetate. The organic layer was washed with 30% aqueous ammonia, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The resulting residue was subjected to silica gel column chromatography to obtain 9.0 g of ethyl 2-chloro-1,3-thiazole-4-carboxylate.

Workup

additionwere then added
customwas kept at 0° C.
additionAfter completion of the addition
temperatureheated to an internal temperature of room temperature
stirringfurther stirred for 30 minutes
extractionThe reaction mixture was extracted with ethyl acetate
washThe organic layer was washed with 30% aqueous ammonia
dry with materialdried over anhydrous sodium sulfate
concentrationconcentrated under reduced pressure

Sources & evidence

ORD record: ord-5e6d32cb764e467b8c6285cc831f351b
Source dataset: uspto-grants-2010_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07846956B2

Reaction notes

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