Used Chemicals

• 1-Naphthalenemethanol [N0633]
• 2,2,6,6-Tetramethylpiperidine 1-Oxyl Free Radical (= TEMPO) [T1560]
• Iodobenzene Diacetate (= PhI(OAc)₂) [I0330]
• Dichloromethane

Procedure

To a solution of 1-naphthalenemethanol (306 mg, 2.0 mmol) in dichloromethane (2 mL, 1.0 mol/L) was added TEMPO (31.2 mg, 0.20 mmol), PhI(OAc)₂ (709mg, 2.2 mmol) and the mixture was stirred at room temperature for 4 hours. Dichloromethane (12.5 mL), saturated aqueous sodium thiosulfate solution (12.5 mL) was added and the mixture was stirred for 30 minutes. The organic layer was washed with saturated aqueous sodium bicarbonate solution (10 mL), brine (10 mL) and the organic layer was dried over sodium sulfate and filtered. The solvent was removed under reduced pressure and the residue was purified by column chromatography (ethyl acetate:hexane = 0:100 - 3:97 on silica gel) to give 1-naphthaldehyde as a yellow liquid (291 mg, 93%).

Experimenter’s Comments

The reaction mixture was monitored by TLC (ethyl acetate:hexane = 1:9, Rf = 0.50).

Analytical Data

1-Naphthaldehyde

¹H NMR (400 MHz, CDCl₃); δ 10.41 (s, 1H), 9.26 (d, J = 8.9 Hz, 1H), 8.11 (d, J = 8.4 Hz, 1H), 8.01 (d, J = 6.8 Hz, 1H), 7.93 (d, J = 8.9 Hz, 1H), 7.74-7.57 (m, 3H).

Lead Reference

• 2-(Hydroxyimino)aldehydes: Photo- and Physicochemical Properties of a Versatile Functional Group for Monomer Design
• P. Gentili, M. Nardi, I. Antignano, P. Cambise, M. D’Abramo, F. D’Acunzo, A. Pinna, E. Ussia Chem. Eur. J. 2018, 54, 5410.

Used Chemicals

• 2-Phenylimidazoline [P0685]
• Iodobenzene Diacetate (= PIDA) [I0330]
• Potassium Carbonate [P1748]
• Dimethyl Sulfoxide

Procedure

To a solution of 2-phenylimidazoline (500 mg, 3.4 mmol), potassium carbonate (520 mg, 3.8 mmol, 1.1 equiv) in DMSO (17 mL) was added iodobenzene diacetate (1.21 g, 3.8 mmol, 1.1 equiv) and stirred at rt for 18 hours. The residue was diluted with ethyl acetate (75 mL) and washed with saturated aqueous sodium bicarbonate solution (50 mL, twice) dried over sodium sulfate and filtered. The solvent was removed under reduced pressure and the residue was purified by column chromatography (on aminosilica gel, ethyl acetate:hexane = 0:1 - 1:0), giving 2-phenylimidazole as a white solid (340 mg，y. 69%).

Experimenter’s Comments

The reaction mixture was monitored by NH-TLC (ethyl acetate, Rf = 0.30).

Analytical Data

2-phenylimidazole

¹H NMR (270 MHz, DMSO-d6); δ 12.5 (dr, 1H), 7.95-7.91 (m, 2H), 7.44 (t, 2H, J = 7.3 Hz), 7.33 (t, 1H, J = 7.3 Hz), 7.24 (s, 1H), 7.02 (s, 1H)

Lead Reference

• Expanded applicability of iridium(I) NHC/phosphine catalysts in hydrogen isotope exchange processes with pharmaceutically-relevant heterocycles
• J. Atzrodt, V. Derdau, W. J. Kerr, M. Reid, P. Rojahn, R. Wecka, Tetrahedron 2015, 71, 1924.

References

• G. Piancatelli, F. Leonelli, Org. Synth. 2006, 83, 18.