Novel synthesis of symmetrical 3,3′-allyl dithioethers as photoplastic monomer precursors by equal molar rate addition of reactants and solvent controlled oligomerization

An alternative method has been developed whereby novel 3,3 0 -allyl dithioethers, for monomers used in photoplastic polymers, have been synthesized from a syn- chronized, rapid addition of a concentrated mixture of 2 mol equiv alkyl halide and 1 mol equiv 3-mercapto-2- mercaptomethyl-1-propene (A) in MeOH in one syringe and an equi-volume two mol equivalent sodium methoxide in MeOH in another syringe. Thus, two-fold excess 3-chloro-2- chloromethyl-1-propene (B) with A gave B-A-B and B-A-B- A-B as the main products but no B-A or B-A-B-A due to the mechanism involved and the low solubility of the longer oligomer in MeOH. When the reaction of 2 9 A with B was carried out, the main product was A-B-A-B-A-B-A.