Facile Synthesis of Natural Alkoxynaphthalene Analogues from Plant Alkoxybenzenes

Analogues of the bioactive natural alkoxynaphthalene pycnanthulignene D were synthesized by an efficient method. The starting plant allylalkoxybenzenes (<b>1</b>) are easily available from the plant essential oils of sassafras, dill, and parsley. The target 1-arylalkoxynaphthalenes (<b>5</b>) exhibited antiproliferative activity in a phenotypic sea urchin embryo assay

Synthesis, Structure, and Properties of Supramolecular Photoswitches Based on Ammonioalkyl Derivatives of Crown Ether Styryl Dyes

The synthesis of new styryl dyes derived from 4-pyridine and 4-quinoline and having an ammonioalkyl <i>N</i>-substituent and benzocrown ether moieties of different sizes and with different sets of heteroatoms was developed. Spontaneous “head-to-tail” dimerization of these dyes via the formation of numerous hydrogen bonds between the terminal NH₃⁺ groups and crown ether moieties was detected in MeCN solutions. The stability constants of the dimeric complexes having pseudocyclic structure were studied by ¹H NMR titration. The most stable complexes (log <i>K</i>_d up to 8.2) were found in the case of dyes with the 18-crown-6 ether moiety, which is most complementary for binding a primary ammonium group. Stacking interaction of the conjugated systems in the dimeric complexes contributes to their stability to a much lesser extent. In dimeric complexes, the ethylene bonds of the dyes are preorganized for stereospecific [2 + 2] photocycloaddition (PCA) induced by visible light. PCA yields only <i>rctt</i> isomers of bis-crown-containing cyclobutane derivatives. The dyes were studied by X-ray diffraction; it was found that the dimeric arrangement is also retained in the crystalline state. The possibility of topochemical PCA of the dyes in single crystals without their destruction was demonstrated. The possibility of retro-PCA of the obtained cyclobutane derivatives to give the starting dyes was shown. The elucidated regularities of PCA can be used to fabricate optical data recording systems based on ammonioalkyl derivatives of crown ether styryl dyes

<i>cis</i>-Restricted 3‑Aminopyrazole Analogues of Combretastatins: Synthesis from Plant Polyalkoxybenzenes and Biological Evaluation in the Cytotoxicity and Phenotypic Sea Urchin Embryo Assays

We have synthesized a series of novel <i>cis</i>-restricted 4,5-polyalkoxydiaryl-3-aminopyrazole analogues of combretastatins via short synthetic sequences using building blocks isolated from dill and parsley seed extracts. The resulting compounds were tested in vivo in the phenotypic sea urchin embryo assay to reveal their antimitotic and antitubulin effects. The most potent aminopyrazole, <b>14a</b>, altered embryonic cell division at 10 nM concentration, exhibiting microtubule-destabilizing properties. Compounds <b>12a</b> and <b>14a</b> displayed pronounced cytotoxicity in the NCI60 anticancer drug screen, with the ability to inhibit growth of multi-drug-resistant cancer cells

Synthesis, Structure, and Characterization of Chromo(fluoro)ionophores with Cation-Triggered Emission Based on <i>N</i>‑Methylaza-Crown-Ether Styryl Dyes

Novel 2-benzothiazole-, 4-pyridine-, and 2- and 4-quinoline-based styryl dyes containing an <i>N</i>-methylbenzoaza-15­(18)-crown-5­(6)-ether moiety were synthesized. A detailed electronic spectroscopy study revealed high performance of these compounds as optical molecular sensors for alkali and alkaline-earth metal cations. They were shown to considerably surpass analogous chromoionophores based on <i>N</i>-phenylaza-crown ethers regarding both the ionochromism and the cation-binding ability. In addition, they act as fluorescent sensors for the metal cations by demonstrating cation-triggered emission. Upon complexation with Ba²⁺, the fluorescence enhancement factor reaches 61. The structural features of dyes and their metal complexes were studied by NMR spectroscopy and X-ray diffraction. The high degree of macrocycle preorganization was found to be one of the factors determining the high cation-binding ability of the sensor molecules based on <i>N</i>-methylbenzoaza-crown ethers