Hydrochloric Acid → 1,1-Dimethylethyl 4-[5-(methoxycarbonyl)-2-thiazolyl]-1-piperazinecarboxylate

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Reaction Steps

1,1-Dimethylethyl 1-piperazinecarboxylate (1.86 g, 10 mmol), methyl 2-bromo-5-thiazolecarboxylate (2.0 g, 9.0 mmol), diazabicycloundecene (1.5 mL, 10 mmol) and a catalytic amount of potassium iodide (2 mg) were dissolved in 10 mL of dry dimethylsulfoxide and stirred at ambient temperature for 1 h to give a precipitate. An additional 10 mL of dimethylsulfoxide was added, the mixture was heated briefly to dissolve the solids, and the mixture was stirred at ambient temperature for 40 minutes and then at 50° C. for 2 h. The warm solution was added dropwise with stirring to 200 mL of cold water containing 10 mL of 1 N aqueous hydrochloric acid, and the resulting precipitate was filtered, dissolved in ether, dried over MgSO4 and concentrated under reduced pressure to give 2.62 g of the title compound as a light yellow solid.

Provenance & Evidence