- Campestarenes: New building blocks with 5-fold symmetry
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Campestarene is a planar, shape-persistent macrocycle with 5-fold symmetry. A range of derivatives bearing peripheral functional groups suitable for generating supramolecular interactions has been designed and synthesised for potential applications in creating 2D quasicrystal molecular assemblies. The new campestarene derivatives bear ester, carboxylic acid, methoxy, bromo, 4-pyridyl, 4-cyanophenyl and 4-phenyl carboxylic acid groups, including further derivatives of the latter two bearing alkyl chains on the phenyl groups to improve solubility. The campestarene derivatives were prepared by reductive condensation of phenol precursors bearing nitro and formyl groups using Na2S2O4. The target functional groups were installed either by pre-cyclisation derivatisation or by synthesis of methoxy-substituted campestarene and subsequent derivatisation. The cyclisation reaction is tolerant of the functional groups introduced. The ten new campestarene derivatives were characterised by NMR spectroscopy and MALDI-TOF MS, although the poor solubility of some examples precluded their detailed characterisation.
- Nam, Seong,Ware, David C.,Brothers, Penelope J.
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p. 6460 - 6469
(2018/10/02)
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- Discrimination and identification of the six aromatic positional isomers of trimethoxyamphetamine (TMA) by gas chromatography-mass spectrometry (GC-MS)
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A reliable and accurate GC-MS method was developed that allows both mass spectrometric and chromatographic discrimination of the six aromatic positional isomers of trimethoxyamphetamine (TMA). Regardless of the trifluoroacetyl (TFA) derivatization, chromatographic separation of all the investigated isomers was achieved by using DB-5ms capillary columns (30 m x 0.32 mm i.d.), with run times less than 15 min. However, the mass spectra of the nonderivatized TMAs, except 2,4,6-trimethoxyamphetmine (TMA-6), showed insufficient difference for unambiguous discrimination. On the other hand, the mass spectra of the TFA derivatives of the six isomers exhibited fragments with significant intensity differences, which allowed the unequivocal identification of all the aromatic positional isomers investigated in the present study. This GC-MS technique in combination with TFA derivatization, therefore, is a powerful method to discriminate these isomers, especially useful to distinguish the currently controlled 3,4,5-trimethoxyamphetmine (TMA-1) and 2,4,5-trimethoxyamphetmine (TMA-2) from other uncontrolled TMAs. Copyright
- Zaitsu, Kei,Katagi, Munehiro,Kamata, Hiroe,Kamata, Tooru,Shima, Noriaki,Miki, Akihiro,Iwamura, Tatsunori,Tsuchihashi, Hitoshi
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p. 528 - 534
(2008/09/20)
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- Quinazoline derivatives with anti-tumour activity
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The invention concerns quinazoline derivatives of Formula I wherein each of m, R1, n, R2 and R3 have any of the meanings defined in the description; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use as an anti-invasive agent in the containment and/or treatment of solid tumour disease.
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- Nitration of electron-rich aromatic compounds by cerium ammonium nitrate coated on silica
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Treatment of electron-rich aromatic derivatives with cerium (IV) ammonium nitrate coated on silica (CANSio2) affords nitro aromatic compounds. The scope and the limitation of this reaction are discussed.
- Grenier, Jean-Luc,Catteau, Jean-Pierre,Cotelle, Philippe
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p. 1201 - 1208
(2007/10/03)
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- Nitrodecarboxylation and nitrodeformylation of some electron-rich benzoic acids and benzaldehydes
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The nitration ipso to a carboxylic or formyl group of disubstituted and trisubstituted benzoic acids and benzaldehydes using nitric acid in acetic acid is described.
- Cotelle, Philippe,Catteau, Jeanpierre
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p. 4105 - 4112
(2007/10/03)
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- Total Synthesis of (+)-Macbecin I
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The first total enantiospecific synthesis of (+)-macbecin I has been performed in a convergent manner by coupling the epoxide (3) with a higher order cyanocuprate derived from the vinyl iodide (46).The required absolute stereochemistries at C(20)-C(21) and C(12)-C(13) were accessible by enantioselective aldol condensations while that at C(16)-C(17) was achieved by Sharpless epoxidation of a secondary (E)-allylic alcohol (39), efficiently prepared by reaction of the aldehyde (37) with CrCl2-CH3CHI2.The remaining stereocentre at C-18 was introduced by an asymmetric hydroxylation of an enolate.Macrocyclization of the amino acid (59) to give the lactam (60) was successfully achieved by its reaction with either 2-mesitylenesulphonyl chloride or bis(2-oxo-3-oxazolidinyl)phosphinic chloride.Incorporation of the carbamate functionality was achieved by reaction of the parent hydroxy derivative with sodium cyanate and trifluoroacetic acid.The final oxidation to the quinone was accomplished with cerium(IV) ammonium nitrate.
- Baker, Raymond,Castro, Jose L.
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- Light Absorption and Emission Properties of Cyanovinyl-substituted Dimethoxybenzenes
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Synthetic routes to a range of dyes based on cyanovinyl-substituted dimethoxybenzenes are described.The light absorption and fluorescence properties of these compounds in fluid solution at room temperature are discussed.
- Chu, Kwong Yung,Griffiths, John,Ward, David
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p. 3701 - 3721
(2007/10/02)
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