Ammonium Chloride → 2-(3,5-dichloropyridine-4-yl)-1-(7-methoxy-2',3',5',6'-tetrahydro-spiro[1,3-benzodioxole-2,4'-(4H)-pyran]-4-yl)ethanone

Participants

Reaction Steps

A solution of methyl 7-methoxy-2′,3′,5′,6′-tetrahydro-spiro[1,3-benzodioxole-2,4′-(4H)-pyran]-4-carboxylate (1.80 g, 6.42 mmol) and 3,5-dichloro-4-picoline (1.46 g, 8.99 mmol) in tetrahydrofuran (33 mL) was cooled to 0° C. A 1.0 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran (19.3 mL, 19.3 mmol) was added and the reaction mixture was allowed to reach room temperature overnight. Saturated aqueous NH4Cl (70 mL) was added. The aqueous phase was extracted with dichloromethane (3×100 mL). The combined organic phase was washed with water (50 mL), dried over MgSO4 and evaporated to dryness under reduced pressure. Standard silica gel column chromatography followed by recrystallization from isopropanol afforded 2-(3,5-dichloropyridine-4-yl)-1-(7-methoxy-2′,3′,5′,6′-tetrahydro-spiro[1,3-benzodioxole-2,4′-(4H)-pyran]-4-yl)ethanone (1.90 g, 71%). 13C NMR (DMSO) δ 189.1, 148.2, 147.7, 147.0, 141.2, 134.5, 132.8, 122.0, 118.0, 113.0, 107.8, 64.4, 56.3, 43.5, 35.2.

Provenance & Evidence