Selenium Dioxide → 6-Phenanthridinecarboxaldehyde

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Reaction Steps

In the next step, a mixture of 6-(2-hydroxy-1-hydroxymethyl)-phenanthridine (24) (6 g, 31 mmoles) and finely powdered selenium dioxide (3.8 g, 34 mmoles) is refluxed in ethyl acetate (125 ml) for 10 hours. The deep red solution that form is then filtered while hot through celite, before evaporating to dryness. The resulting solid is digested in warm 1M hydrochloric acid (125 ml), filtered and partially neutralized with sodium bicarbonate. The initial red precipitate is filtered off before completely neutralizing the solution. The resulting pale yellow solid is filtered off and recrystallized from acetone/petroleum ether to give 2.7 g of 6-formylphenanthridine (yield=42%).

Provenance & Evidence