Used Chemicals

• Methyl 3-Amino-4-hydroxybenzoate [M3498]
• Potassium Ethylxanthate [E0194]
• Methanol (= MeOH)

Procedure

Potassium ethylxanthate (1.00 g, 6.28 mmol) was added to methyl 3-amino-4-hydroxybenzoate (700 mg, 4.19 mmol) in methanol (10 mL) and stirred at reflux for 2 hours. Then potassium ethylxanthate (1.00 g, 6.28 mmol) was added to the solution and stirred at reflux for 1 hour. After cooling to room temperature, acetic acid (3 mL) and water (30 mL) were added to the solution. The resulting precipitate was collected by filtration and dried to afford 1 as a white solid (842 mg, 96% yield).

Experimenter’s Comments

The reaction mixture was monitored by UPLC.
All the procedures were conducted in a fume hood due to a slightly rotten smell.

Analytical Data

Methyl 2-Mercaptobenzo[d]oxazole-5-carboxylate (1)

¹H NMR (270 MHz, CDCl₃); δ 14.13 (brs, 1H), 7.89 (dd, J = 6.4, 2.2 Hz, 1H), 7.69 (d, J = 1.62 Hz, 1H), 7.63 (d, J = 8.4 Hz, 1H), 3.88 (s, 3H).

Lead Reference

• The discovery and optimization of a series of 2-aminobenzoxazole derivatives as ChemR23 inhibitors
  • T. Imaizumi, A. Kobayashi, S. Otsubo, M. Komai, M. Magara, N. Otsubo, Bioorg. Med. Chem. 2019, 27, 115091.

References

• Potassium isopropyl xanthate (PIX): an ultra-efficient palladium scavenger
  • H. Ren, C. A. Strulson, G. Humphrey, R. Xiang, G. Li, D. R. Gauthiera, K. M. Maloney, Green Chem. 2017, 19, 4002.