tert-Butyl acrylate → HCID 20825944, compound

Participants

Reaction Steps

Tri-tert-butylphosphine (3.0 g, 15.28 mmol) was added to a solution of tris(dibenzylideneacetone)dipalladium (4.2 g, 4.63 mmol) in 1,4-dioxane (45 ml), under argon, and the solution stirred for 30 minutes at room temperature. This solution was then added to a mixture of 6-benzyl-2-chloro-5,6,7,8-tetrahydro[1,6]naphthyridine (WO 9830560 Example 33b) (12 g, 46.3 mmol) and tert-butylacrylate (20.3 ml, 139 mmol) in triethylamine (45 ml), and the reaction was stirred under reflux for 17 hours. The cooled mixture was concentrated under reduced pressure and the residue partitioned between ethyl acetate (300 ml) and water (300 ml) and this mixture filtered through Arbocel®. The pH of the mixture was adjusted to 8 using sodium bicarbonate, the phases separated, and the aqueous layer re-extracted with ethyl acetate (2×100 ml). The combined organic solutions were dried over magnesium sulphate and evaporated under reduced pressure. The crude product was pre-adsorbed onto silica gel, and purified by column chromatography using an elution gradient of cyclohexane: ethyl acetate (84:16 to 66:34) to afford the title compound as an orange-red oil, (15.8 g).

Provenance & Evidence