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A palladium-catalyzed domino cyclization/ring-opening reaction between 8

A palladium-catalyzed enantioselective ring-opening/carbonylation of cyclic diarylsulfonium salts is reported. In comparison to thioethers, the sulfonium salts displayed high reactivity and enabled the reaction to be performed under mild conditions (room temperature). The steric repulsion of the two non-hydrogen substituents adjacent to the axis led cyclic diarylsulfonium salts to be distorted, which enabled the ring-opening reaction to proceed with significant preference for breaking the exocyclic C-S bond.

A direct cross-coupling between 9H-fluoren-9-ols and organic azides for the synthesis of steric hindered 2-amino-2'-ketonyl biaryls was reported. The reaction featured an acid-mediated azidation/ring-expansion/hydrolysis cascade, which formally realized the C-N bond coupling reaction via cleavage of a C-C single bond. This method was applicable to chiral helical structure to give bulky axially chiral biaryls with full stereospecificity.

An alternative metal-free amination for the synthesis of 3-trifluoromethyl aniline derivatives under Kröhnke pyridine synthesis conditions has been developed.

Nitrenes and nitrenoids are highly reactive species and the proposed key intermediates in nitrogen-containing heterocyclic compound synthesis. In this work, we developed a practical method for the synthesis of phenanthridines by the reaction of oximes and Grignard reagents (with or without diethylzinc) via ring-expansion of magnesium coordinated nitrenoid complex as the key step. The method has been used to synthesize optically active planar chiral ferrocenyl phenanthridines.

A direct cross-coupling between 9

A palladium-catalyzed ring-opening reaction of optically active ferrocenyl tertiary alcohols for the construction of planar chiral ketones is reported. The stereochemistry of the hydroxyl group in ferrocenyl alcohols markedly affects reaction: ferrocenyl alcohols with a β-hydroxyl group show better reactivity and chemoselectivity than the corresponding α-hydroxyl analogues. The treatment of α-hydroxyl substrates with trifluoroacetic acid successfully realizes the inversion of the orientation of hydroxyl group to the corresponding β-analogues.

By reacting acyl chloride-MWCNTs with gallic amino derivative containing three long alkyl chains, novel gallic-MWCNTs 4 was prepared in good yield. Its structure was characterized by Fourier translation infrared spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The gallic derivative content of gallic-MWCNTs was 14.5 wt%. Its adsorption experiments for four cationic and anionic dyes [Orange G sodium salt (OG), Brilliant ponceau 5R (BP), Neutral red (NR), and Methylene blue (MB)] were investigated. The adsorption process attained to adsorption equilibrium in 2.5 h under the condition of 5.0 mg of sorbent in dye solutions (10 mL, 2.0 × 10−3 M) in the thermostatic shaker bath with a shaking of 200 rpm at 25°C. The saturated adsorption capabilities were 0.642 mmol/g (289 mg/g), 0.537 mmol/g (324 mg/g), 0.891 mmol/g (256 mg/g), and 0.823 mmol/g (310 mg/g), respectively. The adsorption processes were exothermic and spontaneous, and obeyed p...

The novel calixarene-linked discotic triphenylene 5a and 5b were synthesized in good yields via click chemistry. Structural and conformational characterization of new compounds had been achieved by NMR, MS, and elemental analysis. Their liquid crystalline behaviors before and after complexation were studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction. The neat compounds 5a and 5b showed mesophase but the complexes of 5a and 5b with metallic salts exhibited no liquid crystal behaviors.

By formylation of 1,3-bisubstituted calix[4]arene anthraquinone derivative 1 in hexamethylenetetramine/trifluoroacetic acid system, the corresponding formylated gecalix[4]arene anthraquinone derivative 2 was synthesized in yield of 63%. By further reacting compound 2 with salicylic hydrazide, 2,4-dinitrophenyl hydrazine, nicotinyl hydrazine or phenyl thiosemicarhazide, novel calix[4]arene derivatives with anthraquinone and hydrazone groups 3a–3d were obtained in yields of 74–83%. The extracting experiments for series of metallic cations showed that compounds 3a–3d possessed high extracting abilities and extracting selectivity for tested cations. The complexation UV-Vis spectra for a series of anions indicated compounds 3a–3d exhibited the strong complexation abilities for tested anions. The 1H-NMR titration study showed that compound 3d possessed excellent complexation abilities for ion-pair of NaH2PO4 in 1:1 host-guest complex with the association constant of 4.6 × 104 M−1.

The first examples of lariat calix[4]-1,3-aza-crowns with chiral amino acid groups as branched chains (5a and 5b) were designed and synthesized via a 1 + 1 addition reaction of calix[4]-1,3-substituted benzaldehyde derivative (4) and amino acid hydrazide derivatives (3a and 3b) in yields of 70% and 75%, respectively. The preliminary extraction experiments suggested that hosts 5a and 5b possessed good complexation abilities for α-amino acids.

By reacting calix[4]arene 1,3-bi-hydrazide derivative (2) with formacylferrocene in “1 + 2” condensation mode, novel calix[4]arene derivative bearing two conjugated ferrocene groups (3) was obtained in yield of 88%. By reacting 1,3-bi-substituted [2-(p-formylphenyloxy)ethyloxy]-p-tert-butylcalix[4]arene (5) with 1,1′-diacetylferrocene hydrazone (4) in “1 + 1” condensation mode, novel calix[4]arene derivative with 1,3-substituted large conjugated ferrocene bridge (6) was synthesized in yield of 83%. The structures and conformations of new compounds were confirmed by elemental analyses, IR spectra, ESI-MS, 1H NMR, etc. The electrochemical cyclic voltammetry experiments revealed that compounds 3 and 6 possessed excellent reversible electrochemical properties. The 1H NMR titration study showed that compound 6 possessed excellent complexation abilities for NaH2PO4 and glycine in 1:1 host–guest complex with the association constants of 3,850 and 2,460 M−1, respectively.

By reacting mono-substituted or 1,3-bi-substituted [2-(p-formylphenyloxy)ethyloxy]-p-tert-butylcalix[4]arene (3 or 4) with hydrazine hydrate in ‘1+2’ or ‘2+2’ condensation mode, novel benzalazine-bridging biscalix[4]arenes 5 and 7 were conveniently obtained in the yields of 76 and 81%, respectively. Condensation of compound 4 and salicylide hydrazone gave a novel calix[4]arene benzalazine derivative 6 in the yield of 85%. The structures and conformations of all new compounds were characterised by elemental analyses, ESI-MS, 1H NMR and 1H–1H COSY techniques. Biscalix[4]arene 7 adopts a symmetrical cone conformation with tube cavity. The liquid–liquid extraction experiment showed that all new hosts possessed excellent complexation abilities towards soft metal cations. Compound 7 exhibited high complexation selectivity towards Ag+. The Ag+/Na+ and Ag+/Hg2+ extraction percentages of host 7 were as high as 73.1 and 54.9, respectively. The UV–vis spectra complexation experiments revealed that the complexation c...

By reacting calix[4]-1,3-aza-crown 2 with 1,4-phenyl diisothiocyanate in “1 + 2” condensation mode, the novel dumbbell shaped biscalix[4]-1,3-aza-crown 3 with rigid thiourea-bridge was conveniently prepared in yield of 85%. Its structure and conformation were characterized by elemental analyses, ESI-MS, 1H NMR and 1H–1H COSY techniques. The complexation properties of compound 3 were investigated by liquid–liquid extraction experiments and 1H NMR titration experiments. The results showed that compound 3 has excellent complexation abilities for soft cations and outstanding extraction selectivity for Ag+. The Ag+/Na+ and Ag+/Hg2+ extraction percentage of host 7 were as high as 43.2 and 16.9, respectively. 1H NMR titration experiments revealed the 1:2 stoichiometry of receptor 3-Ag+ complex was formed.

The novel calixarene-linked discotic triphenylene 5a and 5b were synthesized in good yields via click chemistry. Structural and conformational characterization of new compounds had been achieved by NMR, MS, and elemental analysis. Their liquid crystalline behaviors before and after complexation were studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction. The neat compounds 5a and 5b showed mesophase but the complexes of 5a and 5b with metallic salts exhibited no liquid crystal behaviors.