1,4-Naphthoquinone (Sigma Aldrich)

Hydrogen Peroxide 30% (Sigma Aldrich)

Into a boiling tube (A) was placed either 1,4-naphthoquinone (0.91 g, 5.8 mmol) and ethanol (10 mL) and the tube was heated in a water bath until the entire solid dissolved. Into a second boiling tube (B) was added sodium carbonate (0.2 g), distilled water (5 mL) and cold 30% hydrogen peroxide (2 mL). Boiling tube A was placed under a cold tap until very slight crystallization occurred, then boiling tube B was added to A in one go. With swirling, boiling tube A was cooled in ice water which produced a white solid. The solid was isolated at the pump and washed with water (3 × 10 ml).  The solid was dried at the pump to yield 2,3-epoxy-1,4-naphthoquinone (0.39 g, 39%) as white crystals.

Should a yellow colour still be present upon addition of the hydrogen peroxide, stir the reaction mixture until the colour subsides.  Its recommended that 1,4-naphthoquinone is purified by column chromatography before use on a silica column using chloroform as eluent.

 ¹H NMR δ: 7.97–7.94 (m, 2H, Ar-H) 7.75–7.73 (m, 2H, Ar-H); 4.00 (s, 2H, C–H),  ¹³C NMR δ: 55.24, 127.16, 131.69, 134.67, 190.68. LCMS – ESI (mz) 174 [M-H].

Lucy Lee, Maria Marti Villalba, Robert B.Smith and JamesDavis Epoxide–quinone transformations: Multi-parametric indicators for assessing animal welfare, Electrochemistry Communications 11 (2009) 1555–1558.  https://doi.org/10.1016/j.elecom.2009.05.056