Odorless thiols for permanent waving, straightening and depilatory applications

An odorless thiol compound comprising a pyridinium ring of the following structure of formula Xa or:

• wherein R1a is:
• a linear, branched, cyclo alkyl, aminoalkyl, hydroxyalkyl or alkenyl group,
• or a linker group L which connects to another moiety of Xa forming a dimeric structure;
• wherein the linker group Lis a linear, branched or cyclo alkyl, aminoalkyl,
• hydroxyalkyl or alkenyl group;
• wherein R1b, R1c, and R1e are each independently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, hydroxyalkyl, aminoalkyl, acyl, or a heterocyclic moiety;
• wherein W and Z are different and are hydrogen or a group T;
• or W and Z are the same and are the group T represented by the structure:
• wherein the group T is attached to the pyridinium ring through X;
• wherein, R1f, R1g, R1h, R1j and R1k are each independently selected from hydrogen, alkyl, alkenyl, hydroxyalkyl, thioalkyl, or aminoalkyl;
• wherein m and n are independently whole numbers ranging from O to 5;
• wherein X is selected from N;
• wherein Y is SR;
• wherein R comprises H or a protected thiol group selected from the group consisting of isothiouronium, thioacetyl, thiotetrahydropyranyl, —C(NH2)═NH2+A−, a mercapto radical connected to another mercapto radical (Xa) to form a disulfide structure, and combinations thereof;
• wherein A− is selected from the group consisting of bromide, chloride, iodide, sulfate, methanesulfonate, carbonate, phosphate, acetate, and combinations thereof.