Example 113
Stilbene derivative 156. Aldehyde 153 (0.235 g, 0.73 mmol), 4-methoxycarbonyl-2-nitro methylenetriphenylphosphonium bromide (0.587 g, 1.09 mmol), and K2CO3 (0.252 g, 1.83 mmol) in DMF (5 mL) were stirred at 95-100° C. for 20 h, cooled to rt and poured into 200 mL H2O. An aqueous 1N HCl was added to pH 3.0, and the mixture was extracted with CHCl3 (7×25 mL). Extract was washed with brine, filtered through paper filter, and evaporated. The residue was purified by chromatography on a silica gel column (2×40 cm bed, packed with CHCl3), eluant: CHCl3 to get compound 156 (0.290 g, 79%) as a yellow oil, solidified upon standing.
INDO PH-sensor 157. Stilbene 156 (0.280 g, 0.56 mmol) was heated with P(OEt)3 at 130° C. for 4 h, cooled to rt, and evaporated at 3 mm Hg vacuum. The residue was purified by chromatography on a silica gel column (2×40 cm bed, packed with EtOAc/hexanes (1:2)), eluant: EtOAc/hexanes (1:2) to get compound 157 (0.160 g, 61%) as a greenish-yellow oil.
