Nitric Acid → HCID 20304550, compound

Participants

Reaction Steps

Ethyl 6,7,8,9-tetrahydro-4-oxo-10-propyl-4H-naphtho[2,3-b]pyran-2-carboxylate (9.4 g) was dissolved in concentrated sulphuric acid (100 ml) and cooled to room temperature, and fuming nitric acid (3 ml) was added dropwise, with stirring. The resulting mixture was stirred for a further 3 hours and then poured into water (2 l). The resulting yellow semi-solid was extracted into ether. The organic layer was washed with water, dried (sodium sulphate) and evaporated to give a yellow solid of moderately pure ethyl 6,7,8,9-tetrahydro-5-nitro-4-oxo-10-propyl-4H-naphtho[2,3-b]pyran-2-carboxylate (3.5 g; 79%). An analytically pure sample (5 g) was obtained on recrystallisation from cyclohexane, mp 140°-2°.

Provenance & Evidence