Thiols can be made from haloalkanes by nucleophilic substitution of the halide ion by the sulfhydryl ion (HS⁻), which is an excellent nucleophile. Because thiolate ions are also excellent nucleophiles, thioethers can react again to give a thioether.

Where does thiol come from?

Aliphatic thiols are commonly prepared from alkyl halides and sodium hydrosulfide or from olefins and hydrogen sulfide. Aromatic thiols can be made from the amino compounds by way of the diazonium salts.

Where are thiols found in nature?

A number of thiols are found in nature, such as cysteine and glutathione. In addition, 2-butenethiol is found in the defensive spray of the skunk, 2-propanethiol (allyl mercaptan) is found in the breath of people who have eaten garlic, and furfurylthiol contributes to the aroma of fresh coffee.