1,3-Propanediol → 2-(3-Ethyl-4-nitrophenyl)-2-phenyl-1,3-dioxane

Participants

Reaction Steps

A suspension of 3-ethyl-4-nitro-benzophenone (11f) (20.0 g, 78.4 mmol), 1,3-propandiol (7.15 g, 94.0 mmol), p-toluenesulfonic acid monohydrate (50 mg) in toluene (300 mL) was refluxed using a Dean-Stark-trap for 24 hours. The Dean-Stark-trap was then replaced by a Soxhlet-extractor filled with molecular sieve and the mixture was refluxed for an additional 48 hours to achieve complete conversion. The reaction mixture was then cooled to ambient temperature, washed with an aqueous, saturated solution of NaHCO3 and concentrated in vacuo until crystallization started. The suspension was cooled for 0.5 hours in an ice bath and after which the crystalline product was filtered, washed with a small volume of hexane and air dried to give 22.48 g (72 mmol, 91.5%) compound 17 as yellow crystals.

Provenance & Evidence