Polymerization of Cyclic Monomers Containing Phosphorus

Abstract

The mechanism of polymerization is discussed, in which cyclic esters of phosphoric acid, and related compounds are converted into linear macromolecules, modelling nucleic and teichoic acid backbones. Structures like deoxyribose polyphosphate and glycerol polyphosphate were prepared from the corresponding cyclic compounds.These polymerizations involve heterolytic breaking of the P-0 bond in the corresponding cyclic monomer and proceed by ionic mechanisms. Both 5-and 6-membered monomers have been polymerized. The thermodynamic parameters of the ring-chain interconversion were determined; the 5-membered ring polymerization is driven by the exothermicity of the ring-opening, whereas polymerization of several 6-membered rings is endothermic and allowed because of the positive change of entropy.Anionic polymerization, and particularly the coordinate-anionic polymerization provides, in contrast to the cationic processes, high-molecular weight polymers with more uniform structure. Anionic polymerization proceeds mostly (in the applied conditions) on the macroion-pairs. The elementary reactions consist of the nucleophilic attack of the paired macroanions on the phosphorus atom in the cyclic monomer molecule. Rate constants of the elementary reactions for the model monomers are discussed.

Backbone-modified oligonucleotides containing a butanediol-1,3 moiety as a ‘vicarious segment’ for the deoxyribosyl moiety—synthesis and enzyme studies

“…In the course of studies on the synthesis of biopolymers bearing a carbon-phosphate skeleton vicarious to the natural deoxyribose-phosphate fragment we2, and others3, have used different approaches, which rely upon the phosphite-triester method of oligonucleotide synthesis originally designed by Letsinger4 and elegantly developed by Caruthers5. Instead of the routinely used 5'-DMT-nucleoside 3'-(0-2-cyanoethyl-N,N-diisopropyl)phosphoramidites (1), the corresponding 1-0-DMT-butane-3-0-(-2-cyanoethyl-N,Ndiisopropyl)phosphoramidite (2) was employed. Reagent 2 was prepared by dimethoxytritylation of (i) butanediol-1,3 and subsequent phosphitylation of 1-O-dimethoxytrityl-butane-3-ol with [(N,N,N',N'-tetraisopropyl)2-cyanoethyl] phosphordiamidite.…”

Thermodynamics and kinetics of ring‐opening polymerization of cyclic alkylene phosphates

“…In our earlier papers (Refs.10,23) and reviews (Refs. 24,25) we have shown that polymerization of the six-membered esters of phosphoric acid proceeds with enthalpy (A%) positive and/or close to zero: the six-membered rings are virtually strainless. However, the thermodynamics of propagation does depend on the structure of the exocyclic groups: Let us imagine that the interaction of a given solvent with the polymer unit is more exothermic than it is with the parent monomer.…”