Synthesis and chiral recognition abilities of new calix[6]arenes bearing amino alcohol moieties

Herein the synthesis and recognition abilities towards amino acids and amino alcohols of new d-/l-phenylalaninol substituted p-tert-butylcalix[6]arenas are reported. These compounds, 6 and 7 have been synthesized via nucleophilic substitution reactions involving 5,11,17,23,29,35-tert-butyl-37,38-dimethoxy-39,40,41,42-(p-tosylethoxy)calix[6]arene 5 with d-/l-phenylalaninol in dry THF. The extraction properties of 6 and 7 towards some selected amino acid methylesters and amino alcohols have been studied by liquid–liquid extraction. These results show that chiral calix[6]arene derivatives exhibit a good affinity towards all amino acids and amino alcohols.     

Synthesis and electrochromism of novel organosoluble polyarylates bearing triphenylamine moieties

A series of novel aromatic polyarylates with triphenylamine units in the main chain and as the pendent group were prepared from the dicarboxylic acid monomer, N,N‐bis(4‐carboxyphenyl)‐N′, N′‐diphenyl‐1,4‐phenylenediamine (1), and various bisphenols. These polyarylates were amorphous and readily soluble in common organic solvents. They had excellent levels of thermal stability associated with moderately high T_g values (182–263 °C). These polymers exhibited strong UV–vis absorption bands at 357–360 nm in toluene solution and the photoluminescence spectra showed maximum bands around 493–503 nm in the green region. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyarylates exhibited two reversible oxidation redox couples in acetonitrile solution at E_onset 0.77–0.79 V and 1.12–1.14 V, respectively. The typical polymer 3b film revealed good stability of electrochromic characteristics, with color change from colorless to green and blue at applied potentials ranging from 0.00 to 1.24 V. These anodically polymeric electrochromic materials not only showed excellent reversible electrochromic stability with good green coloration efficiency (CE = 159 cm²/C) and blue coloration efficiency (CE = 154 cm²/C) but also exhibited high contrast of optical transmittance change (ΔT%), 54% in 895 nm for green color and up to 84% in 595 nm for blue color. After over 100 cyclic switches, the polymer films still exhibited excellent stability of electrochromic characteristics. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2004–2014, 2007     

Synthesis of chiral calix[4]arenes bearing tartaric ester moieties

The synthesis of chiral calix[4]arenes with tartaric acid ester moieties has been achieved by the reactions of tartaric ester chloroacetates with calix[4]arenes in moderate yields. All the chiral calix[4]arene derivatives are in a cone conformation according to the ¹H NMR doublet–doublet pattern of the protons of the methylene groups between the phenol rings. The results of NMR and specific rotations indicate that the molecules have C₂ symmetry with asymmetric features.     

Synthesis of chiral calix[4]arenes bearing aminonaphthol moieties and their use in the enantiomeric recognition of carboxylic acids

Two armed chiral calix[4]arenes 8-16 functionalized at the lower rim with chiral aminonaphthol units have been prepared and the structures of these receptors characterized by FTIR, (1)H, and (13)C, DEPT and COSY NMR spectroscopy and elemental analysis. The enantioselective recognition of these receptors with various carboxylic acids has been studied by (1)H NMR and UV/Vis spectroscopy. The receptors exhibited different chiral recognition abilities towards the enantiomers of racemic materials and formed 2 : 1 or 1 : 1 complexes between host and guest. It was also demonstrated that chiral calix[4]arenes 9 and 16 could be used as chiral NMR solvating agents to determine the enantiomeric purity of mandelic acid.     

Enantioselective recognition by optically active chiral fluorescence sensors bearing amino acid units

Chiral fluorescence receptors 1 and 2 were synthesized and their structures characterized by IR, ¹H NMR, ¹³C NMR, MS spectra, and elemental analysis. The chiral recognition abilities of 1 and 2 were studied by ¹H NMR and fluorescence spectra. The results demonstrate that receptors 1 and 2 with bis(tetrabutylammonium) dibenzoyl tartrate formed a 1:1 complex. Receptor 2 exhibits an excellent enantioselective recognition ability toward the enantiomers of bis(tetrabutylammonium) dibenzoyl tartrate.     

Selective recognition of dihydrogen phosphate by receptors bearing pyridyl moieties as hydrogen bond acceptors

Dihydrogen phosphate anion is selectively recognized by amide-based receptors bearing pyridyl moieties as hydrogen bond acceptors in 0.5% DMSO-acetonitrile.     

Synthesis of novel chiral bis-N-substituted-hydrazinecarboxamide receptors and probing their solution-phase recognition to chiral carboxylic guests by ESI-TOF/MS and tandem ESI-MS

Seven novel bis-N-substituted-hydrazinecarboxamide receptors were synthesized in good to excellent yields by reacting chiral dicarbohydrazides, obtained from commercially available tartaric acid, with substituted aromatic isocyanates. The newly synthesized hydrazinecarboxamides formed structurally unique supramolecular aggregates, which have been confirmed by ESI-TOF/MS and tandem ESI-MS. They also showed molecular recognition to a selection of chiral carboxylic guests and oligopeptides, which mimic the backbone structure of the bacterial cell wall. The structures of the novel compounds were verified by various spectroscopic techniques including FTIR, ¹H NMR, ¹³C NMR, ESI-TOF/MS, tandem ESI-MS, 2D ROESY NMR, and CD spectroscopy.     

Synthesis of novel thiazoles bearing hydrazine,thiosemicarbazide, thiazole,and thiazolidinone moieties

Thiazolecarboxylate esters (I) and (II) react with hydrazine hydrate to give the acid hydrazides (III) and (IV), which then react with KSCN and PhNCS to give high yields of the thiosemicarbazides (V)-(VIII). Cyclocondensation of the thiosemicarbazide (V) with 3-phenyl-3-chloro-2-oxopropionic acid derivatives gives compounds with two thiazole moieties (IX)-(XIV). The reaction of the phenylthiosemicarbazides (VII) and (VIII) with chloroacetyl chloride and (or) chloroacetic acid affords the thiazolidinonethiazoles (XV) and (XVI).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2832–2836, December, 1991.     

Synthesis of novel chlorophyll a derivatives bearing glucose moieties and estimation of their photocytotoxic activity

A series of chlorophyll a derivatives bearing glucose moieties linked to the porphyrin macrocycle via ester bonds were synthesized. The dark cytotoxicity and photocytotoxicity of new chlorin-glucose conjugates were competitively evaluated in comparison with those of structurally similar chlorin-galactose derivatives synthesized previously. It was revealed that the introduction of the glucose moiety into the molecule of chlorophyll a derivative facilitates a decrease in the dark cytotoxicity relative to chlorin-galactose conjugates.

     

Diastereomeric recognition of chiral foldamer receptors for chiral glucoses

[reaction: see text] Three chiral aromatic hydrazide foldamers have been designed and synthesized, in which two R- or S-proline units were incorporated at the terminals of their backbones. The 1H NMR, circular dichroism (CD), and fluorescent experiments and molecular dynamics simulations revealed that the foldamers adopted a chiral helical conformation and complexed alkylated glucoses in chloroform with a good diastereomeric selectivity.     

Synthesis and chiral recognition properties of two novel chiral calix[4]arene tartaric ester derivatives

Two new chiral calix[4]arene derivatives containing tartaric acid ester moieties were synthesized. The chiral calix[4]arenes are in a ‘cone’ conformation according to NMR spectroscopy. The chiral recognition capabilities of 1–4 toward the guests, 1,2-propanediol and serine methyl ester hydrochloride (SerOMe), were investigated (¹H NMR spectroscopy). The extraction properties of compounds 1 and 2 toward selected α-amino acid methyl esters were also studied.     

Synthesis and chiral recognition of novel amylose derivatives containing regioselectively benzoate and phenylcarbamate groups

A new class of regioselectively substituted amylose derivatives bearing three different substituents at 2-, 3- and 6-positions, and two different substituents at 2-position and 3-, 6-positions were synthesized by a sequential process based on the esterification of 2-position of a glucose unit. Their chiral recognition abilities were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). Each derivative had its own characteristic recognition ability depending on the arrangement of side chains at the three positions. Among the derivatives, amylose 2-(4-t-butylbenzoate) and amylose 2-(4-chlorobenzoate) series exhibited high chiral recognition. Some racemates can be efficiently separated on these derivatives as well as on the amylose tris-3,5-dimethylphenylcarbamate, which is commercially available as Chiralpak AD and one of the most powerful CSPs. The structures of the amylose derivatives were also investigated by circular dichroism spectroscopy.     

Anomalous disproportionation of 9-benzoylanthracene and 9-anthryl styryl ketone

9-Benzoylanthracene and 9-anthryl styryl ketone disproportionate to anthracene and the corresponding 9,10-diacylanthracene when warmed in carbon disulphide or nitrobenzene with an excess of aluminium chloride. The reactions are co-catalysed by hydrogen chloride. Comparison is made with other 9-anthryl ketones and with 1-naphthyl styryl ketone, which undergo different reactions under similar conditions. The results are interpreted in terms of steric requirements.     

Macrocyclic chiral receptors toward enantioselective recognition of naproxen

[structure: see text] A macrocyclic receptor based on a bischromenylurea and an alpha,alpha'-(o,o'-dialkyl)diphenyl-p-xylylenediamine spacer provides a C(2) chiral cavity to associate carboxylates by H-bonds. The extent of the selectivity obtained for the racemic receptor 2 and enantiomerically pure (S)-naproxen is 7.2:1. Steric repulsions close to the cavity are decisive for the chiral selectivity.     

Synthesis and properties of novel macrocyclic compounds bearing thiourea moieties by use of chemical feature of hypervalent sulfur

Macrocyclic compounds 5a‐i bearing two tetraazathiapentalene frameworks were synthesized by the reaction of 10‐S‐3 tetraazathiapentalene derivatives 3a‐f with compounds having various diisothiocyanate functions 4a‐e. The reduction of the macrocyclic compounds with NaBH₄ afforded the ring‐opened macrocyclic compounds 11a‐b and 11e‐h by elimination of the hypervalent sulfur. The structures of these compounds were established by their spectral data and also by the X‐ray crystallographic analysis of lla. The other ring‐opened macrocyclic compounds 14a and 14e‐h that bear four thiourea groups were synthesized by alkaline hydrolysis of 5a and 5e‐h in that elimination of the C=S^IV moiety in the tetraazathiapentalene rings occurred.     

Synthesis and radical polymerization of styrene derivative bearing kojic acid moieties

A styrene derivative ( 1 ) bearing kojic acid moieties was prepared by the base-catalyzed reaction of p-formylstyrene with kojic acid. Hydroxyl groups in 1 were subjected to acetylation. Although 1 did not undergo radical polymerization, the acetylated styrene derivative ( 2 ) showed good radical homo- and copolymerizability. For instance, a polymer having the number average molecular weight (M_n) of 60,000 was obtained in almost quantitative yield (97%) by the polymerization of 2 in chloroform (1.5 M) at 60°C for 36 h using α,α′-azobis(isobutyronitrile) (AIBN, 5 mol %) as an initiator. Under similar conditions, copolymers of 2 with styrene were also obtained in high yield. By partial deacetylation of the copolymer with a triethylamine catalyst, a copolymer containing α-hydroxyketone structures originated from kojic acid moieties was successfully regenerated. The deacetylated copolymer can be crosslinked by complexation with metal salts such as Al³⁺. © 1996 John Wiley & Sons, Inc.     

Synthesis and properties of wholly aromatic polymers bearing cardo fluorene moieties

Three series of aromatic polyamides, polyesters, and poly(1,3,4‐oxadiazole)s containing bulky fluorene structures were prepared from 9,9‐bis(4‐carboxyphenyl) fluorene. All of the polymers were readily soluble in many organic solvents and showed useful thermal stability associated with high glass‐transition temperatures in the range of 220–366 °C. These wholly aromatic polymer films were colorless, with high optical transparency, and exhibited UV‐vis absorption bands at 266–348 nm and photoluminescence maximum bands at 368–457 nm within the purple to green region in N,N‐dimethylacetamide (DMAc) solutions. The poly(amine‐amide) Ic exhibited excellent electrochromic contrast and coloration efficiency, changing color from the colorless neutral form to green and then to the dark blue oxidized forms with good stability of electrochromic characteristics. Almost all of these wholly aromatic polymer films were colorless and showed high optical transparency. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4352–4363, 2007     

Synthesis and properties of thermally stable polyimides bearing pendent fluorene moieties

A new diamine monomer containing fluorene unit, 3,5‐diamino‐N‐(9H‐fluoren‐2‐yl)benzamide was successfully synthesized via the condensation of 2‐aminofluorene and 3,5‐dinitrobenzoyl chloride and subsequent reduction of the dinitro compound. A series of novel aromatic polyimides having pendent fluorenamide moieties were prepared from the reaction of the diamine monomer and various tetracarboxylic dianhydrides by a conventional two‐step polymerization process. The polyimides were obtained in quantitative yields with inherent viscosities of 0.33–0.44 dl/g. The resulting polymers dissolved in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The glass transition temperature of these polymers was in the range of 261–289°C. They were fairly stable up to a temperature around 450°C and lost 10% weight in the range of 498–556°C in nitrogen. The UV–vis absorption spectra showed that all of the polymers had absorption maxima around 320 nm. Cyclic voltammograms of the polyimides revealed an oxidation wave with a peak around 1.3 V. Copyright © 2014 John Wiley & Sons, Ltd.     

去氢枞酸异丙醇胺衍生物的合成及其细胞毒性评价

为了寻找高效的抗肿瘤活性化合物,设计合成了一系列去氢枞酸异丙醇胺类化合物,利用IR、NMR和MS对其结构进行表征。采用噻唑蓝(MTT)法评价了目标化合物对四种不同肿瘤细胞T24(人膀胱移行癌细胞)、HepG2(人肝癌细胞)、SK-OV-3(人卵巢癌细胞)、A549(人肺癌细胞)和LO2(人正常肝细胞)的抗增殖活性。结果表明,部分化合物对肿瘤细胞的抑制作用优于阳性对照顺铂。其中,化合物3d对四种细胞株表现出最好的抗增殖效果,IC₅₀值分为8.10±0.28,8.65±0.10,13.21±0.35和8.24±0.42 μmol.L_-1^{。初步机理研究表明},化合物3d使A549细胞周期阻滞在G1/G0期,并诱导A549细胞凋亡,且呈浓度依赖性。     

Molecular recognition on supramolecular systems (XXXV)-- Synthesis of novel b-cyclodextrin derivative bearing pyridinio group and its chiral discrimination of amino acids

A novel b-cyclodextrin derivative 4 bearing a pyridinio group on the primary side was synthesized by the reaction of 2-aminopyridine with 6-b-cyclodextrin monoaldehyde 3, and its complexation stability constants with several aliphatic amino acids have been determined in phosphate buffer solution ( pH = 7.2, 0.1 mol·L-1) at 25 ℃ by using spectrofluormetric titrations. The stoichiometry is 1︰1 for the inclusion complexation of amino acids with compound 4. Circular dichroism study indicates that the aromatic moiety was embedded shallowly into the cyclodextrin cavity. As a spectral probe, the pyridinio group in the modified cyclodextrin can recognize not only differences of the size and shape of amino acid molecules, but also the L/D-amino acid chiral isomer. As com-pared with mono-[6-(1-pyridinio)-6-deoxy]-b-cyclodextrin 5, compound 4 switched the enantiomer preference for L- to D-isomer, and showed the highest enantioselectivity of 5.4 for D/L-serine. The-se results are discussed from the viewpoints of geometric compensation, induced-fit concept and cooperation of several weak interactions.