Lithium Hexamethyldisilazide → diethyl ((1-(triphenylmethyl)-1H-imidazol-4-yl)methyl)phosphonate

関与物質

反応手順

To a solution of diethylphosphite (4.30 g, 31.2 mmol) in dry tetrahydrofuran (hereinafter abbreviated to THF) (10 ml) was added 1M THF solution of lithium bis-(trimethylsilyl)amide (31.2 ml, 31.2 mmol) dropwise over 1 hour at −72° C. under argon flow, followed by adding dropwise (1-triphenylmethylimidazol-4-yl)methyl chloride (9.30 g, 26.0 mmol) in THF (80 ml) over 30 minutes. The reaction mixture was stirred for 15 minutes at the same temperature, and then was heated to room temperature and stirred for additional 3 hours at room temperature. After the reaction was quenched by addition of saturated aqueous ammonium chloride (150 ml), the THF was removed and the residue was extracted four times with ethyl acetate (100 ml). The organic layers were dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The obtained crude pale yellow solid product was purified by chromatography on silica gel column using methanol-ethyl acetate (1:20) to give diethyl(1-triphenylmethylimidazol-4-yl)methylphosphonate (10.30 g, 86%) as a white powder. This powder was recrystallized from a mixture of ethyl acetate and hexane to provide the titled compound as white small needles (m.p. 141-144° C.).

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