Triphenylphosphine → 4'-Ethoxycarbonyl-methoxy-3',5'-dimethoxyacetophenone

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Reaktionsschritte

Ex-61A: 3′,5′-Dimethoxy-4′-hydroxyacetophenone (6.03 g, 31 mmol) and triphenylphosphine (8.05 g, 31 mmol) were stirred in 124 mL of tetrahydrofuran (THF). The mixture was treated with ethyl glycolate (3.2 g, 31 mmol) and diethylazodicarboxylate (4.83 mL, 31 mmol). The reaction mixture was stirred under reflux for about 3.5 h and then evaporated. The residue was crystallized from hexane/ethyl acetate. The mother liquor was concentrated to give a crude product which was purified by recrystallization from EtOH twice to give 3.14 g of 4′-ethoxycarbonyl-methoxy-3′,5′-dimethoxyacetophenone. Solvent removal from the mother liquor provided additional crude product which was purified by silica gel chromatography (hexane/ethyl acetate, 1:1) to give additional product (4.2 g). The total amount of pure material isolated was 7.34 g (90% yield). mp. 81-83° C.; Anal. Calcd. for C14H18O6: C, 59.57; H, 6.43; Found: C, 59.60; H, 6.34; MS (direct probe): Calcd for C14H18O6: m/z=282, found: m/z=282.

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