Ethyl oxoacetate → 2-Hydroxy-3-methyl-4-oxo-4-(2-phenyl-thiazol-5-yl)-butyric Acid Ethyl Ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a −78° C. solution of 0.26 g (1.2 mmol) of the above-prepared 1-(2-phenyl-thiazol-5-yl)-propan-1-one was added 0.24 g (1.4 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran. The mixture was allowed to stir for 0.5 hours and then 0.38 g (1.5 mmol) of 1M chlorotitanium triisopropoxide in hexanes was added. The reaction was allowed to warm to −20° C. and stirred for 15 minutes. The reaction was recooled to. −78° C. and 0.25 g (0.24 mmol) of ethyl glyoxalate in toluene(50%) was added. The solution was warmed to room temperature and allowed to stir for 0.5 hours. The reaction was quenched with aqueous potassium sodium tartrate tetrahydrate and partitioned with ethyl acetate. The organic phase was twice washed with aqueous potassium sodium tartrate tetrahydrate, once with water, once with brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by chromatography on silica gel using 1:9 ethyl acetate:hexanes to give 0.15 g of the title compound (40%). 1H NMR (500 MHz, CDCl3) δ 8.42 (s, 1H) 8.01 (d, 2H) 7.48 (m, 3H) 5.8 (m, 1H) 4.27 (q, 2H) 3.75 (m, 1H) 3.28 (m, 1H) 1.37 (d, 3H) 1.26 (t, 3H).

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