Abstract:A new method has been designed to prepare the known benzoxazinone derivative 2-(N-phthaloylmethyl)-4H-3,1-benzoxazin-4-one (4). The acyl chloride derivative N-phthaloylglycine reacts with anthranilic acid in chloroform, in the presence of triethylamine, to give an intermediate that is then reacted with cyanuric chloride, used as a cyclization agent, to produce the benzoxazinone derivative.
Circularly polarized luminescence (CPL) and total luminescence of Tb(III) and Eu(III) as substitutional replacements for iron in a series of Fe binding transferrins are reported. The measurement of the total emission intensity is a direct measure of binding of the lanthanide ions and illustrates that approximately 2 equiv of Tb(III) and Eu(III) is bound to these proteins. In agreement with previous work, circularly polarized luminescence from Tb(III) bound to the transferrins is quite large. Additional measurements show that the net CPL displays no dependence on concentration of the metal ion and shows little variation between the two binding sites. CPL from lactoferrin is very similar to serum transferrin, however, ovotransferrin shows differences in line shape and magnitude. These results are discussed in the context of the previously published crystal structure of the binding sites of the three proteins.
The vanadium phosphorous oxide (VPO) catalysts, supported on mesoporous hexagonal molecular sieves (HMS) with different vanadium loadings, were prepared by precipitation method on organic phase. Techniques such as XRD, BET and SEM, were used for characterization of the catalyst. The bulk VPO catalyst contains vanadyl pyrophosphate phase ((VO) 2 P 2 O 7 ), and a small amount of VOPO 4 . The high surface area, large pore volume and pore size of HMS in VPO/HMS samples, provide an excellent dispersion of same phase of VPO compound on the support surface. Oxidation of various alcohols was studied in the liquid phase over VPO/HMS catalyst, using tert-butylhydroperoxide (TBHP) as an oxidant. The activity of VPO/HMS samples were considerably increased with respect to bulk VPO catalyst. At 90°C, the obtained activities were 0.567 and 6.545 g pro . g -1 VPO ·h -1 over the bulk VPO and 20 wt% VPO/HMS catalysts, respectively. The effects of substrates, reaction time, reaction temperature, solvents, catalyst recycling and leaching of VPO in liquid phase reaction were also investigated. The following order has been observed for the percentage of conversions of alcohols: Benzylic alcohol > Secondary alcohol~Primary alcohol.The kinetic of benzyl alcohol oxidation using excess TBHP over VPO/HMS catalyst was investigated at temperatures of 27, 60 and 90°C, and followed a pseudo-first order with respect to benzyl alcohol.
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