Process for the synthesis of 2-thiohistidine and similar

The present invention relates to a method of synthesizing 2-thiohistidine or one of its derivatives of formula (I): or a physiologically acceptable salt, a tautomer, a stereoisomer or a mixture of stereoisomers in any proportion thereof, from a compound of formula (II): or a physiologically acceptable salt, a tautomer, a stereoisomer or a mixture of stereoisomers in any proportion of thereof, by reaction with an organic or inorganic reducing agent. The present invention also relates to compounds of formula (II) and their synthesis method.