Triphenylphosphine → Orlistat

참여 물질

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반응 단계

166 g of (3S,4S)-3-hexyl-4-((R)-2-hydroxy tridecyl)-2-oxetanone obtained from Reference Example 1 was dissolved in 830 mL of tetrahydrofuran. After the addition of 160 g of triphenylphosphine (PPh3) and 86 g of N-formyl-L-leucine, the reaction mixture was cooled to 0° C. A mixed solution where 120 mL of diisopropylazodicarboxylate (DIAD) was diluted in 332 mL of tetrahydrofuran, was continuously added thereto over 1.5 hours. After stirring for further 30 minutes, the reaction mixture was stirred for 4 hours while slowly raising its temperature. After removing the solvent, 832 mL of hexane was added thereto, and the reaction mixture was stirred for 5 hours. The formed solid was removed therefrom by filtration, and the hexane layer thereof was washed with 499 mL of 55% methanol/distilled water three times. The remaining organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed under a reduced pressure. Then, 2.5 L of hexane was added thereto, and the reaction mixture was cooled to 10° C. and stirred for 1 hour, followed by addition of a seed of orlistat solid. The reaction mixture was slowly cooled to 0° C. again, and stirred overnight. The obtained solid was filtered, washed with 500 mL of cold hexane, and dried, to obtain 192.5 g of the title compound (yield: 83%) as a white solid.

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