Nitric Acid → HCID 13406828, compound

Participants

Reaction Conditions

Reaction Steps

3-Ethoxycarbonyl-1,2,3,4-tetrahydroisoquinoline hydrochloride (50 g.) is added in small portions, at -20° C., whilst stirring, to concentrated sulphuric acid (d = 1.83; 325 cc.). After 10 minutes, a limpid solution is obtained. The mixture is cooled to -30° C., and concentrated nitric acid (d = 1.49; 10 cc.) is then added over the course of 15 minutes. The reaction mixture is left, whilst being stirred, at -40° C., for 30 minutes and is then poured onto ice (1 kg.) and rendered alkaline by adding sodium hydroxide solution (d = 1.33; 1,000 cc.) whilst maintaining the temperature at between 15° and 20° C. The batch is extracted with methylene chloride (3 × 500 cc.). The organic extracts are combined, dried over potassium carbonate, filtered and evaporated under reduced pressure (30 mm.Hg) at 40° C. A pinkish solid (34 g.) is obtained, which is recrystallised from diisopropyl ether (300 cc.). (S)-3-Ethoxycarbonyl-7-nitro-1,2,3,4-tetrahydroisoquinoline is thus obtained in the form of pale pink crystals (17.5 g.) melting at 94°-95° C. are thus obtained.

Provenance & Evidence