反应 #2173451
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openreactiondata ↗doi:10.6084/m9.figshare.5104873.v1; patent:US05807891
反应条件: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.
实验步骤: 880 ml of a 1M solution of lithium bis(trimethylsilyl)amide in THF are added dropwise, at -70° C., under an argon atmosphere and within the space of 20 min, to 130 g (400 mmol) of 5(S)-[1(S)-(Boc-amino)-2-cyclohexylethyl]dihydrofuran-2-(3H)-one which is dissolved in 1000 ml of abs. THF and 108 ml of DMPU. After 20 min, a solution of 110 g (443 mmol) of p-methoxybenzyl iodide [preparation, see Example 7e)] in 60 ml of abs. THF is added dropwise, and this mixture is thoroughly stirred at -75° C. for 2 h. The mixture is subsequently protonated at -70° C. with 152 ml of propionic acid followed by 250 ml of water (temperature rises to -20° C.); 1 l of ethyl acetate is then added and the reaction mixture is poured onto 2 l of 15% NaHCO3 solution. The aqueous phase is separated off and extracted with 1 l of ethyl acetate. The organic phases are washed 2× with sat. NaHCO3 solution, water and saline, dried with Na2SO4 and evaporated. Column chromatography (SiO2, hexane/ethyl acetate, 9:1) and crystallization from hexane yields the pure title compound: TLC Rf (E)=0.45; tRet (II)=8.6 min; FAB-MS (M+H)+ =432. is dissolved in 1000 ml of abs The aqueous phase is separated off extracted with 1 l of ethyl acetate The organic phases are washed 2× with sat. NaHCO3 solution, water and saline dried with Na2SO4 evaporated Column chromatography (SiO2, hexane/ethyl acetate, 9:1) and crystallization from hexane
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