Lawesson's reagent → ethyl 1-[4-(1H-pyrazol-1-yl)benzyl]-4-thioxo-1,4-dihydrocinnoline-3-carboxylate

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Reaction Conditions

Reaction Steps

Ethyl 4-oxo-1-{[4-(1H-pyrazol-1-yl)phenyl]methyl}-1,4-dihydrocinnoline-3-carboxylate (253 mg, 0.676 mmol) was suspended in toluene (3 mL) and treated with 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide (Lawesson's Reagent, 164 mg, 0.405 mmol, 0.6 equiv). The mixture was heated at 105° C. for 1 hour, cooled to ambient temperature, and concentrated in vacuo. The residue was purified by silica gel chromatography (90:10 to 60:40; hexanes:ethyl acetate), providing the titled compound.

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