Hydrochloric Acid → HCID 178439731, compound

Participants

Reaction Steps

Propionaldehyde (RCHO, R=propyl, 5.0 mL, 69.3 mmol) was added to a solution of concentrated HCl (2 mL) and lawsone (2.00 g, 11.5 mmol) in acetic acid (35 mL) at 60° C. After stirring for 1.25 hours, another portion of propionaldehyde was added (5.0 mL, 69.3 mmol). The solution was then stirred for an additional 1 hour. The solution was allowed to cool to room temperature, and then ice water (200 mL) was added to quench the reaction. The solution was extracted with diethyl ether (3×200 mL) and the organic fractions pooled. The combined organic layers were re-extracted with 5% Na2CO3 (8×150 mL). The aqueous extracts were also pooled and acidified with concentrated HCl. A precipitate formed which was collected by filtration to afford (20) as an orange solid. 2-Hydroxy-3-propenyl-1,4-naphthoquinone (20) (983 mg, 40%): mp 133-134° C.; 1H NMR (CDCl3, 300 MHZ) δ 8.13 (d, J=7.7 Hz, 1H), 8.06 (d, J =7.5 Hz, 1H), 7.80-7.62 (m, 3H), 7.15-6.95 (m, 1H), 6.63 (d, J=16.1 Hz, 1H), 1.99 (d, J=6.8 Hz, 3H).

Provenance & Evidence