Propanal → HCID 86586360, compound

Participants

Reaction Steps

To a mixture of 1.00 g (2.5 mmole) of [(2R)-8-formyl-7-nitro-2,3-dihydro-1,4-benzodioxin -2-yl]methyl 4-methylbenzenesulfonate, 0.35 g (2.5 mmole) of potassium carbonate and 0.31 g (1.7 mmole) of benzyltrimethylammonium chloride in 5 mL of methylene chloride was added 0.145 g (2.5 mmole) of propionaldehyde. The mixture was stirred at room temperature under nitrogen for 15 hours, then diluted with 100 mL of water and extracted twice with 100 mL portions of methylene chloride. The combined organic extracts were washed with 100 mL of saturated brine, dried over sodium sulfate, filtered and concentrated in vacuum. The crude residue was column chromatographed on silica gel with methylene chloride as eluant to give 0.50 g of the (R)-enantiomer of toluene-4-sulfonic acid 8-(2-methyl-3-oxo-propenyl)-7-nitro-2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl ester as a yellow oil. This was dissolved in a mixture of 12 mL of acetic acid and 8 mL of ethanol and 0.32 g (5.7 mmole) of iron powder was added. The mixture was refluxed for eight hours under nitrogen. The solvent was then removed in vacuum and replaced with 250 mL of ethyl acetate. This mixture was washed with 250 mL portions of saturated aqueous sodium bicarbonate and saturated brine, dried over sodium sulfate, filtered and concentrated in vacuum. Column chromatography on silica gel with chloroform as eluant gave 0.22 g of the (R)-enantiomer of the title compound as a yellow oil. 1H-NMR (CDCl3): doublet (m-coupling) 8.6 δ (1 H); doublet (m-coupling) 8.0 δ (1 H); doublet 7.76 8 (2 H); doublet 7.57 δ (1 H); doublet 7.24 δ (1 H); doublet 7.20 δ (2 H); multiplet 4.55 δ (1 H); doublet of doublets 4.3 δ (1 H); multiplet 4.2 δ (2 H); doublet of doublets 4.15 δ (1 H); singlet 2.5 δ (3H); singlet 2.4 δ (3 H).

Provenance & Evidence