Preparation of Poly(arylene ether pyrimidine)s by Aromatic Nucleophilic Substitution Reactions

Synthesis and characterization of novel pyrimidine-containing poly(arylene ether)s

Two novel thermally stable high-performance polymers, poly(arylene ether pyrimidine)s have been prepared with 2,4-dichloropyrimidine and 4,4′-(hexafluoroisopropylidene)diphenol and bisphenol A by nucleophilic displacement reaction, respectively. Gel permeation chromatography results show that the obtained polymers exhibited 20,000 g mol−1 weight-average molecular weight. Thermal analysis studies indicate glass transition temperature values up to 156°C in differential scanning calorimetry and thermogravimetric analysis results revealed outstanding thermal stability up to 430 and 427°C for 5% weight loss under nitrogen and in air atmospheres, respectively. The polymers are soluble in a wide range of organic solvents, such as tetrahydrofuran, chloroform, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, and toluene at room temperature. The cutoff wavelengths of the resulting polymers were in the range of 278–283 nm.

SuFEx-based synthesis of polysulfates

High-molecular-weight polysulfates are readily formed from aromatic bis(silyl ethers) and bis(fluorosulfates) in the presence of a base catalyst. The reaction is fast and proceeds well under neat conditions or in solvents, such as dimethyl formamide or N-methylpyrrolidone, to provide the desired polymers in nearly quantitative yield. These polymers are more resistant to chemical degradation than their polycarbonate analogues and exhibit excellent mechanical, optical, and oxygen-barrier properties.

Design, Synthesis, and Evaluation of Novel Biarylpyrimidines: A New Class of Ligand for Unusual Nucleic Acid Structures

Biarylpyrimidines are characterized as selective ligands for higher-order nucleic acid structures. A concise and efficient synthesis has been devised incorporating Suzuki biaryl cross-coupling of dihalopyrimidines. Two ligand series are described based on the parent thioether 4,6-bis[4-[[2-(dimethylamino)ethyl]mercapto]phenyl]pyrimidine (1a) and amide 4,6-bis(4[(2-(dimethylamino)ethyl)carboxamido]phenyl)pyrimidine (2a) compounds. In UV thermal denaturation studies with the poly(dA) x [poly(dT)]2 triplex structure, thioethers showed stabilization of the triplex form (Delta Tm < or = 20 degrees C). In contrast, amides showed duplex stabilization (Delta Tm < or = 15 degrees C) and either negligible stabilization or specific destabilization (Delta Tm = -5 degrees C) of the triplex structure. Full spectra of nucleic acid binding preferences were determined by competition dialysis. The strongest interacting thioether bound preferentially to the poly(dA) x [poly(dT)]2 triplex, K(app) = 1.6 x 10(5) M(-1) (40 x K(app) for CT DNA duplex). In contrast, the strongest binding amide selected the (T2G20T2)4 quadruplex structure, K(app) = 0.31 x 10(5) M(-1) (6.5 x K(app) for CT DNA duplex).