ENHANCED REACTIVITY AND AFFINITY OF POLYMERIC 3 - CARBAMOYLPYRIDINIUM TOWARD CYANIDE ION.

Synthetic polymers containing functional groups of biological cofactors are of major significance, since they often produce catalytic activities superior to monomeric compounds or cofactors themselves. Additionally, these phenomena are interesting from the standpoint of elucidating the effect of apoenzymes on the activity of coenzymes. Nicotinamide-containing polymers as a NAD coenzyme model were synthesized by several workers from poly(p-chloromethylstyrene) and nicotinamide. In order to assess the polymer effect on the reactivity of nicotinamide, the authors synthesized poly-1-(p-vinylbenzyl)-3-carbamoylpyridinium chloride (PVCC) from the corresponding monomer (VCC), and studied the reactivity and affinity of PVCC toward cyanide ion in aqueous media. 1-Benzyl-3-carbamoylpyridinium chloride (NBzN) was employed as the corresponding monomeric compound. Results of the kinetic measurements are tabulated. It is seen that the rate constant of cyanide addition toward PVCC is greater by 22-fold and the corresponding association constant by about 65-fold, when compared with those of NBzN. Experimental data are discussed in terms of reaction mechanisms. It is concluded that the VCC unit in the polymer serves as an excellent electrophile and the reactivity is markedly affected by the reaction conditions employed. The assessment of the behavior of PVCC should be useful as a model study of NAD coenzyme, since the reactivity of NAD(P) is known to be greatly affected by the nature of apoenzymes.