Furan-2-ylmethanethiol

Furan-2-ylmethanethiol (2-Furanmethanethiol) is an organic compound containing a furan substituted with a sulfanylmethyl group. It is a clear colourless liquid when pure, but it becomes yellow coloured upon prolonged standing. It possesses a strong odour of roasted coffee and a bitter taste. It is a key component of the aroma of roasted coffee. It has been identified as a trigger molecule for parosmia following COVID-19 infection.

Synthesis
Furan-2-ylmethanethiol is easily prepared by reacting furfuryl alcohol with thiourea in hydrochloric acid via an intermediate isothiouronium salt which is hydrolized to the thiol by heating with sodium hydroxide.