A new synthetic route was designed to significantly increase the content of triazine structure in benzoxazine resin. 2,4,6-Tri(4-hydroxylphenyl)-13,5-s-triazine (TP) was synthesized by cyclotrimerization of 4-cyanolphenol and then benzoxazine monomercontaining triazine [2,4,6-tri(3-phenyl-3,4-dihydro-2H-1,3-benzoxazin-6-yl)-1,3,5-s-triazine (BZ-ta)] was synthesized via Mannich reaction from TP. Finally, the cross-linked polymer P(BZ-ta) was produced by thermal polymerization of BZ-ta. BZ-ta was characterized by nuclear magnetic resonance spectroscopy (NMR), fourier transform infrared spectroscopy (FTIR), mass spectrum, elemental analysis, and viscosity measurement. Curing behavior of BZ-ta was studied by differential scanning calorimetry, FTIR, and gel permeation chromatography. The structure and properties of P(BZ-ta) were investigated by powder X-ray diffraction, dynamic mechanical analysis, and thermogravimetric analysis. The results showed that the P(BZ-ta) had high glass temperature (T g ¼ 322 C), excellent thermal oxidation stability (5 and 10% weight loss temperatures in air up to 403 and 453 C, respectively), high char yield (64%, 800 C in nitrogen), and high flame-retardance (limiting oxygen index, 39.7).

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Synthesis of Planar Chiral [2.2]Paracyclophanyl Imidazo[1,5-a]pyridinium Salts for the Rhodium-Catalyzed Asymmetric Arylation. -A series of novel planar--chiral NHC precursors are synthesized and applied in the Rh-catalyzed asymmetric 1,2-addition of arylboronic acids to aromatic aldehydes. Moderate enantioselectivities and yields are obtained. -(WANG, D.; MA*, Y.; HE, F.; DUAN, W.; ZHAO, L.; SONG, C.; Synth. Commun. 43 (2013) 6, 810-825, http://dx.