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The reaction between isatin and 2,5-dimethoxyaniline is described. The main product was identified as 3,3-bis(4-amino-2,5-dimethoxyphenyl)-1,3-dihydroindol-2-one. The antioxidant activity of the compounds isolated was evaluated with two methods. Three published antitumor E-3-(2-chloro-3-indolylmethylene)1,3-dihydroindol-2-ones entered the same tests to search whether they are endowed with antioxidant activity too. 3,3-Bis(4-amino-2,5-dimethoxyphenyl)-1,3-dihydroindol-2-one and the three antitumor agents showed a good chemical antioxidant activity.

Many different ways have been devised over the years for analysing phospholipids in solution by 31P NMR. One promising method entails the use of the so-called CUBO solvent, a ternary mixture of dimethylformamide, triethylamine and guanidinium hydrochloride. As this interesting system seems to have been overlooked in the literature, we present here a study on the quantification of phospholipids and lysophospholipids contained in 10 samples of commercial lecithin using the CUBO/31P NMR method. Cluster analysis and principal component analysis of the NMR data showed clear differences among the samples according to the actual lecithin producer. Multivariate analysis of the chemical and physical parameters of the samples confirmed these differences. Copyright © 2004 Society of Chemical Industry

The title compounds (EtOS−SNR2) display diastereotopic OCH2 hydrogens below room-temperature owing to the existence of two stereolabile enantiomers brought about by the restricted S−S rotation in the adopted gauche conformer. A second dynamic process, which makes the N-bonded alkyl groups diastereotopic, was also observed at a much lower temperature (below −80 °C). On the basis of experimental observations and of ab initio calculations, the latter has been interpreted as due to the restricted rotation about the S−N bond. Line shape analysis of the variable temperature 1H and 13C NMR spectra allowed the free energies of activation to be determined for both motions in the case of R = Me, Et, Pri.

The authors studied the addition of alkylthio and alkoxy radicals to C{sub 60} fullerene. The reactions were driven by photoactivation using the emission from a xenon or mercury lamp. ESR was used evaluate the progress and the products of the reactions. 18 refs., 3 figs., 1 tab.

Photolysis of alkyl thiols (RSH) in alkaline solutions yields the corresponding disulfide radical anions (RSSR .- ) whine EPR spectra can be detected over a large temperature range. When mixtures of two different thiols are photolyzed (RSH and R'SH) each of the three possible disulfide radical anions are observed, i.e., RSSR .- , R'SSR .- , and R'SSR' .- . In the case of the allylthiol (CH 2 =CH 2 -SH) both the corresponding disulfide radical anion and the thioaldehyde radical anion (CH 2 =CHCH=S .- ) are simultaneously obtained, the latter exhibiting two rotational conformers due to the restricted rotation about the C-CS bond

Low-temperature photolysis of ArCH 2 OH derivatives (Ar=2- and 3-furyl and -thienyl) in the presence of Bu t OOBu t yields the corresponding ArCHOH radicals which can be observed by means of EPR spectroscopy. Each radical displays E and Z rotational conformers due to restricted a Ar-C α rotation. The study of ArCHOMe radicals, as well as of 2-furyl- and 2-thienylhydroxymethyl radicals having a methyl group in position 3 of the ring, allowed us to identify the most stable of the two conformers

The effect of exocyclic conjugation on the inversion of a saturated six-membered ring is shown in a dynamic nmr study of a series of N-substituted morpholines where the substituents have similar shapes but different conjugating ability. As conjugation increases the ring inversion barrier decreases in contrast to previous observations of an unsaturated ring with conjugating substituents.

The 8-oxoguanosine derivative 1 and the 8-oxoinosine derivative 2 b, with appropriate substituents on their ribose moieties, form hexagonal lyotropic mesophases in hydrocarbon solvents. Small-angle X-ray scattering analysis of a film of 1 and of the mesophase of 2 b, and NMR and CD spectra of isotropic solutions of 2 b, indicate that in both cases the supramolecular structures adopted are continuous helices formed by a hydrogen-bond network between the heterocyclic bases. Notably, while derivative 2 b, which bears large substituents on its ribose moiety, undergoes self-assembly and mesophase formation, oxoinosine 2 a, with only decanoyl groups on its ribose moiety, does not. This may be ascribed to the reduced amphiphilic properties of the latter and the absence of aromatic groups.

The most effective remedy for iron deficiency is the use of synthetic iron chelates, specifically chelates derived from polyamine-carboxylic acids as EDDHSA (N,N'-ethylenediamine-di-(2-hidroxy-5-sulfophenylacetic) acid). A gradient ion-pair chromatographic method was developed to quantify the total amount of chelated iron in EDDHSA/Fe-3divided by fertilizers. Two mobile phases were used containing. respectively, 35 and 75% acetonitrile in a 0.005 M tetrabutylammonium hydroxide aqueous solution at pH 6.0. The stationary phase was a reverse phase C-18 column (150 mm x 3.9 mm i.d., dp = 5 mum). Two chromatographic peaks appeared and were identified by Electrospray Mass Spectrometry. The first peak corresponds to the monomer of EDDHSA/Fe-3divided by and the second peak has been assigned to condensation molecules. Quality parameters indicate that the method is suitable for the quantification of iron chelate by EDDHSA fertilizers.

Some properties of hydroxylating enzymes able to add the two oxygen atoms of molecular oxygen into aromatic substrates such as benzene and phthalate are reviewed. In particular the non-haem single iron dioxygenases capable of incorporating two hydroxyl groups are presented as well as their up-to-date biophysical characterization.