Hydrochloric Acid → Diethyl {2-[(3-phenoxybenzyl)thio]-4,5,6,7-tetrahydro-1,3-benzothiazol-7-yl}malonate

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Reaction Steps

A mixture of 2-[(3-phenoxybenzyl)thio]-4,5,6,7-tetrahydro-1,3-benzothiazol-7-ol (2.00 g, 5.41 mmol), thionyl chloride (0.723 mL) and toluene (10 mL) was stirred at room temperature for 3 hr. The reaction mixture was concentrated, and the residue was dissolved in tetrahydrofuran (10 mL). The solution was added to a mixture of diethyl malonate (1.60 g, 10 mmol), sodium hydride (60% in oil, 400 mg) and tetrahydrofuran (20 mL) at room temperature, and the mixture was stirred at the same temperature for 3 hr. The reaction mixture was neutralized with 1 M hydrochloric acid and extracted with ethyl acetate. The organic layer was washed successively with water and saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was purified by silica gel column chromatography (AcOEt:hexane=1:19-2:1) to give the title compound (2.73 g, quantitative) as a pale-yellow oil.

Provenance & Evidence