Thiolation

We use a wide range of thiolating agents for introducing sulphur into a molecule including:

• sulphur chlorides (S₂Cl₂, SO₂Cl₂, SOCl₂)
• phosphorus pentasulphide (P₂S₅ )
• thioacetic acid and potassium thioacetate (KTAA)

Potassum thioacetate is particularly useful for converting chiral alcohols to chiral thiols with inversion of chirality:

Long chain and branched thiols

Using our proprietary chemistry, we have produced long chain alkanethiols, such as octadecanethiol and eicosanethiol, starting from the corresponding olefin or from the bromoalkane and proceeding via the isothiuronium salt:

We have also produced branched thiols, such as DPHTG, from reaction of pentaerythritol derivatives with thioglycollic acid.

Sulphur Redox Reactions

Using hydrogen peroxide and transition metal catalysis, we have produced disulphides from thiols and oxidised the sulphide to the sulphoxide and on to the sulphone. As such, we have oxidised alkyl thiobenzoic acid through to alkyl sulphonyl benzoic acid.

We have also developed in-house knowledge to reduce aromatic sulphino-acids or sulphonyl chlorides to disulphides and on to the aromatic thiol. This route has been used for the development of 3-mercaptobenzoic acid.

These sulphur redox reactions have found particular importance in the manufacture of pharmaceutical intermediates and effect chemicals for digital and medical imaging.