Methanol → 2-(5-(tert-Butoxycarbonylamino)pentyloxy)-4-fluorobenzoic acid

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Reaction Steps

Methanol (500 ml) and water (500 ml) were added to the crude reaction mixture obtained in Example 24. LiOH hydrate (1.4 mol) was added and the reaction mixture was stirred at room temperature for 16 h. Then, water (500 ml) was added and the organic solvent was evaporated under vacuum. The mixture was extracted with methyl tert-butyl ether to remove impurities. The water layer was adjusted to pH 8-9 and extracted again with ethyl acetate (3×500 ml). The water layer was adjusted to pH 4-5 and ethyl acetate was added. The organic layer was separated, washed with brine, dried and concentrated in vacuo. Yield: 120 g (purity 80%, 75% yield over 2 steps).

Provenance & Evidence