Tristriazolotriazines (TTTs) with a threefold alkoxyphenyl substitution were prepared and studied by DSC, polarized optical microscopy (POM) and X-ray scattering. Six pentyloxy chains are sufficient to induce liquid-crystalline behavior in these star-shaped compounds. Thermotropic properties of TTTs with varying substitution patterns and a periphery of linear chains of different lengths, branching in the chain and swallow-tails, are compared. Generally, these disks display broad and stable thermotropic mesophases, with the tangential TTT being superior to the radial isomer. The structure–property relationships of the number of alkyl chains, their position, length and structure were studied.
Dedicated to the memory of Prof. Dr. Helmut Bönnemann Suzuki-Miyaura-couplings to aryl-nitropyridines followed by Cadogan reactions is a straight-forward method for the synthesis of d-and b-carbolines. Microwave irradiation of the nitrobiaryls in triethyl phosphite solutions conveniently gives moderate to very good yields of the carbolines. Reduction to the amines without cyclization occurs on certain substrates, and alkylation of the products is observed as a follow-up reaction. Instead of a-carbolines, naphthonitriles are generated by phosphite reduction and ring transformation.
Dedicated to Prof. Gerhard Wenz on the occasion of his retirementπ-Conjugated molecules with the shape of St. Andrew's cross have been synthesized via fourfold Huisgen reaction. Four 2,5diaryl-1,3,4-oxadiazol arms are attached to a central pyrazine nucleus. These fluorescent stars, when decorated with a rim of eight alkoxy side chains are discotic liquid crystals. Depending on the substitution pattern, the width of the liquid phase varies within a broad range of 25°C to 250°C. In their liquid crystalline phase, the molecules assemble in a typical hexagonal columnar supramolecular arrangement.
The title compound, C12H9BrN2O3, was prepared in two steps from 2-chloro-3-nitropyridine. The nitrobiaryl unit is twisted, with dihedral angles of 35.4 (5)° between the nitro substituent and the pyridine ring to which it is bound, and 51.0 (5)° between the nitro group and the benzene ring. In the crystal, the molecules are connectedviaC—H...O hydrogen bonds, forming strands along theb-axis direction.
Three very similar and nearly planar molecules are present in the asymmetric unit of the title compound, C6Cl3N9. Whereas the threefold 1,5-annulation of the chlorotriazole moieties is obvious, all of the C and N atoms in the central triazine ring are equally disordered on the same site, approachingD3hsymmetry for each of the molecules.
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