5-Nitro-1,3-dihydroisobenzofuran synthesis

Yield:52771-99-0 58%

Reaction Conditions:

with caesium carbonate;bis(tri-tert-butylphosphine)palladium⁽⁰⁾ in 1,4-dioxane;water at 20 - 100;

Steps:

15 Synthesis of 5-nitro-1,3-dihydro-isobenzofuran

[Example 15] Synthesis of 5-nitro-1,3-dihydro-isobenzofuran To the mixture of sodium 2-chloro-5-nitrobenzyloxymethyl trifluoroborate (30 mg, 0.10 mmol) synthesised in Example 14 and 1,4-dioxane (1.5 ml), water (0.15 ml), cesium carbonate (100 mg, 0.31 mmol), and bis(tri-t-butylphosphine)palladium(0) (11 mg, 0.021 mmol) were added at room temperature, and the obtained reaction mixture was then stirred at 100°C (an outer temperature) overnight. The reaction mixture was cooled to room temperature, and then water and ethyl acetate were added thereto, followed by filtration with Celite. The organic layer of the filtrate was separated and washed with saturated saline. The solvents were evaporated under reduced pressure from the organic layer, and then the obtained residue was purified with silica gel column chromatography (heptane: ethyl acetate = 6:1), thereby obtaining the entitled compound (9.9 mg, 58%). ¹H-NMR Spectrum (CDCl₃) δ(ppm): 5.18(4H, s), 7.39(1H, d, J=8.2Hz), 8.11(1H, d, J=2.0Hz), 8.18(1H, dd, J=2.0, 8.2Hz)

References:

EP2062901,2009,A1 Location in patent:Page/Page column 19