Ch15 : Preparation of Thiols

Chapter 15: Alcohols, Diols and Thiols

Preparation of Thiols

Reaction type: Nucleophilic substitution (S_N2)

Summary

A convienient source of S is thiourea.
Reaction of the S system as a nucleophile with an alkyl halide, R-X, in an S_N2 fashion gives an intermediate isothiouronium salt.
Hydrolysis of the intermediate provides the thiol, R-SH.
These steps can be carried out without isolating the intermediate.
Overall, this is equivalent to treating the alkyl halide, R-X, with H₂S or HS^- (note: H₂S is a toxic gas with a very strong odour).