Abstract
The synthesis of polymer‐bound thiol reagents, supported on macroporous 4% divinylbenzene co‐polymer (Amberlite XE‐305), via three synthetic approaches is described: (i) Alkylation or acylation of XE‐305 with 3‐nitro‐4‐halogen‐substituted benzyl chloride or benzoyl halide yielding 3‐nitro‐4‐halobenzene‐bound species, followed by substitution of the activated polymeric halogen atom with sulfur (see Scheme 1). (ii) Formation of a thiol ether by a direct substitution of an active polymeric halogen by reaction with benzylthiol, followed by chlorination, thiolation, and reduction (see Scheme 2). (iii) Attachment of a prepared tailor‐made disulfide to aminomethyl function of a polymeric support, followed by reduction (see Scheme 3). The polymers were tested for their free‐thiol content by 5, 5′‐dithiobis(2‐nitrobenzoic acid) (Ellman's reagent^12^) in DMF. Their thiolytic activity was investigated in the removal of 2‐nitrophenylsulphenyl (Nps) group from Nps‐protected amino acid (Scheme 4). Site‐site interaction between the polymer‐bound thiol with its activated halide precursor to yield polymeric sulfide during displacement reaction, and the interconversion of the polymeric thiols into polymeric disulfides at equilibrium or during reaction with Nps‐amino acids, observed, and is attributed to the flexibility of the polymeric matrices.