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Phosphate groups are naturally present in starch at C3- or C6-position of the glucose residues and impact the structure of starch granules. Their precise quantification is necessary for understanding starch physicochemical properties and metabolism. Nevertheless, reliable quantification of Glc-3-P remains laborious and time consuming. Here we describe a capillary electrophoresis method for simultaneous measurement of both Glc-6-P and Glc-3-P after acid hydrolysis of starch. The sensitivity threshold was estimated at the fg scale, which is compatible with the analysis of less than a μg of sample. The method was validated by analyzing antisense potato lines deficient in SBEs, GWD or GBSS. We show that Glc-3-P content is altered in the latter and that these variations do not correlate with modifications in Glc-6-P content. We anticipate the method reported here to be an efficient tool for high throughput study of starch phosphorylation at both C3- and C6-position. [ABSTRACT FROM AUTHOR]

Examines the conversion of polyfunctional enones into cyclic imines. Synthesis of enones; Protection of amino group as a benzylcarbamate and obtaining the Z-aminoesters; Reduction of Z-protected amino esters 5a-c to aldehydes 6a-c; Hydrogenation and hydrogenolysis of the enones; Application of analytical apparatus in conducting the experiment.

Describes the synthesis suitable for a undergraduate organic chemistry laboratory class consisting of fourth-year organic chemistry students. Use of the efficiency glycosyl donor; Interpretation of 2D-NMR spectra; Physical and chemical properties of chemicals.

This study deals with the synthesis and evaluation of salen based derivatives as fire retardants in thermoplastic polyurethane. Salens, hydroxysalens and their first row transition metal complexes (salen-M) were synthesized (Copper, Manganese, Nickel and Zinc). They were then incorporated in thermoplastic polyurethane (TPU) with a loading as low as 10:1 weight ratio. The thermal stability as well as the fire properties of the formulations were evaluated. Thermogravimetric analysis (TGA) showed that different coordination metals on the salen could induce different decomposition pathways when mixed with TPU. The Pyrolysis Combustion Flow Calorimetry (PCFC) results showed that some M-salen have the ability to significantly decrease the peak heat release rate (􀀀61% compared to neat TPU) and total heat released (􀀀63% compared to neat TPU) when formulated at 10:1 wt % ratio in TPU. Mass Loss Cone Calorimetry (MLC) results have shown that some additives (salen-Cu and salen-Mn) exhibit very promising performance and they are good candidates as flame-retardants for TPU. [ABSTRACT FROM AUTHOR]

Seven new antioxidants derived from natural or synthetic phenols have been designed as alternatives to BHT and BHA antioxidants. Influence of various substituents at the ortho , meta and para positions of the aromatic core of phenols on the bond dissociation enthalpy of the ArO–H bond was evaluated using a DFT method B3LYP/6-311++G(2d,2p)//B3LYP/6-311G(d,p). This prediction highlighted the ortho -propenyl group as the best substituent to decrease the bond dissociation enthalpy (BDE) value. The rate constants of hydrogen transfer from these phenols to DPPH radical in a non-polar and non-protic solvent have been measured and were found to be in agreement with the BDE calculations. For o -propenyl derivatives from 2- tert -butyl-4-methylphenol, BHA, creosol, isoeugenol and di- o -propenyl p -cresol, fewer radicals were trapped by a single phenol molecule, i.e. a lower stoichiometric number. Reaction mechanisms involving the evolution of the primary phenoxyl radical ArO are proposed to rationalise these effects. [ABSTRACT FROM AUTHOR]

A new Schiff base namely 1,13-bis-[(2-hydroxynaphtaldehyde) 4,7,10-trioxatridecane diimine] (HNTTD) was synthesized and its corrosion behavior in 1 M hydrochloric acid solution on mild steel (MS) X48 was studied by using weight loss, polarization curves, electrochemical impedance spectroscopy (EIS) and quantum chemical calculations. All measurements showed that, inhibition efficiency increases with increasing inhibitor concentration. Polarization curves indicate that the studied compound was acting as mixed type inhibitor. The adsorption of HNTTD on steel surface followed Langmuir’s adsorption isotherm. The molecular structure effect on the corrosion inhibition efficiency was investigated by using DFT calculations. The structural and electronic parameters were calculated and discussed. The results of AFM studies further confirmed the inhibition action of HNTTD. [ABSTRACT FROM AUTHOR]