Yu-Ying Huang

Chemoselective synthesis, antiproliferative activities, and SAR study of 1H-pyrazol-5-yl-N,N-dimethylformamidines and pyrazolyl-2-azadienes

Chemoselective microwave-assisted amidination was successfully developed to synthesize 1H-pyrazol-5-yl-N,N-dimethylformamidines and pyrazolyl-2-azadienes. All of the starting materials and resulting products were tested against NCI-H226, NPC-TW01, and Jurkat cancer cells to evaluate their antiproliferative activities. 1H-Pyrazol-5-yl-N,N-dimethylformamidines 2b, 2c, and 2d were most potent with IC50 values in low micromolar range. The formyl group at C-4 position and the grafted amidinyl group in the main core of pyrazolic molecule were necessary for the inhibitory activity.Graphical Abstract

Evaluation of electrophilic heteroaromatic substitution: synthesis of heteroaromatic-fused pyrimidine derivatives via sequential three-component heterocyclization.

A new sequential three-component heterocyclization was developed by reacting aromatic and heterocyclic substrates, including aminobenzenes, 1-aminonaphthalene, 2-aminopyrazines, 5-aminopyrazoles, 3-aminopyridine, 5-aminopyrimidine, 5-aminoquinoline, and 8-aminoquinoline, with formamide in the presence of PBr(3). The reaction gave the corresponding pyrazolo[3,4-d]pyrimidines in good yields (59-96%), except for aminobenzenes and 3-aminopyridine. A plausible reaction mechanism involving amidination, electrophilic substitution imination, and oxidative cyclization in three steps was proposed to account for the heterocyclization. The reactivity of the reaction was found proportional to the electrophilicity of the aromatic or heterocyclic substrate.

Synthesis and Characterization of Soluble Conjugated Poly(p-phenylenevinylene) Derivatives Constituted of Alternating Pyrazole and 1,3,4-Oxadiazole Moieties

New soluble poly(p-phenylenevinylene) derivatives with 1,3,4-oxadiazole and pyrazole rings along the main chain were synthesized by Heck coupling. The new conjugated polymers are soluble in common organic solvents as a result of the fully conjugated backbone with dodecyloxy side groups. The polymers show relatively high glass-transition temperatures (up to 160°C) and good satisfactory thermal stability. Solutions of the polymers emit blue-greenish light with photoluminescence (PL) emission maxima around 490–500 nm. The PL spectrum of the polymer’s thin films, with a maximum at 515 nm, shows a red-shift (~20 nm), with respect to the solution spectrum. Cyclic voltammetry reveals that both conjugated polymers have reversible oxidation and irreversible reduction, making them n-type electroluminescent materials. The electron affinity of the new polymers was estimated as 2.73–2.74 eV. The weight-average molecular weights (M w) of the new soluble polymers were in the range of 4790–4950.