Imidazole → tert-Butyl-[2-chloro-5-(2-nitro-vinyl)-benzyloxy]-dimethyl-silane

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Reaction Steps

A mixture of 3-(tert-butyl-dimethyl-silanyloxymethyl)-4-chloro-benzaldehyde (14.0 g, 49.1 mmol) and ammonium acetate (3.79 g, 49.1 mmol) in nitromethane (8.19 mL, 152 mmol) and AcOH (39 mL) was heated to reflux for 3 h. The mixture was allowed to cool to rt, and was poured onto water. The resulting mixture was extracted several times with EtOAc. The combined org. extracts were washed with water and aq. sat. NaHCO3 several times. The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure. The residue was dried under high vacuum overnight, and was dissolved in DMF (217 mL). The sol. was cooled to 0° C., and imidazole (8.36 g, 123 mmol) and TBDMS-Cl (8.84 g, 58.6 mmol) were added. The mixture was stirred for 2 h at 0° C., and was poured onto aq. sat. NH4Cl. The resulting mixture was extracted with EtOAc several times. The combined org. extracts were washed with water and brine. The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the crude by FC (EtOAc/heptane 2:8) yielded the title compound (9.50 g, 59%). LC-MS: tR=1.18 min.

Provenance & Evidence