Triethylamine → 1,1-Dimethylethyl 1-[2-(butyloxy)-2-oxoethyl]-6-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-5-methyl-3,4-dihydro-2(1H)-isoquinolinecarboxylate

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Reaction Steps

To a solution of 1,1-dimethylethyl 1-[2-(butyloxy)-2-oxoethyl]-6-[(hydroxyamino)(imino)methyl]-5-methyl-3,4-dihydro-2(1H)-isoquinolinecarboxylate (Preparation 19; 264 mg, 0.629 mmol) in dioxane (4 ml) was added triethylamine (0.263 ml, 1.89 mmol) followed by dropwise addition of 3-chloro-4-[(1-methylethyl)oxy]benzoyl chloride (Preparation 33; 176 mg, 0.755 mmol) in dioxane (2 ml). The resulting mixture was stirred at room temperature for 90 min, followed by heating at 100° C. for 24 h. The mixture was cooled to room temperature, most of the solvent was removed in vacuo, and the residue was partitioned between ethyl acetate and saturated sodium bicarbonate. The layers were separated and the aqueous layer further extracted with ethyl acetate. The combined organic phases were washed with brine, dried over MgSO4 and concentrated in vacuo. Purification by flash chromatography, eluting with 5-25% ethyl acetate in cyclohexane, gave the title compound as a pale yellow oil (80 mg).

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