- Catalytic synthesis method of tert-butyl alpha-bromoisobutyrate by using cation exchange resin
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The invention relates to a catalytic synthesis method of tert-butyl alpha-bromoisobutyrate by using cation exchange resin, and belongs to the technical field of synthetic organic chemistry synthesis. The method use alpha-bromoisobutyrate and isobutylene as raw materials; the raw materials are supplemented with a solvent and a polymerization inhibitor and subjected to an esterification reaction by using a cation exchange resin as a catalyst, so as to obtain the tert-butyl alpha-bromoisobutyrate. The cation exchange resin is one or more selected from D001, D003, CH-A, CH-B, 732, and CHR-06. The invention solves the problems of large amount of wastewater, serious equipment corrosion and high content of polymer in the prior art; the prepared product has yield of 80-90% and purity higher than 98%; and the selected cation exchange resin has the characteristics of high catalytic activity, good selectivity, small equipment corrosion, long service life, easiness to recycle and reuse, low energy consumption and less wastewater generation, and has high economic values for reducing production costs, safety and environmental protection.
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Paragraph 0032; 0033; 0034
(2016/12/01)
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- Spin trapping of superoxide, alkyl- and lipid-derived radicals with derivatives of the spin trap EPPN
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The N-t-butyl-α-phenylnitrone derivative N-2-(2-ethoxycarbonyl-propyl)-α-phenylnitrone (EPPN) has recently been reported to form a superoxide spin adduct (t1/2=5.25min at pH 7.0), which is considerably more stable than the respective N-t-butyl-α -phenylnitrone or 5,5-dimethylpyrroline N-oxide adducts (t1/2 ～10 and 45s, respectively). In continuation of our previous studies on structure optimization of 5-(ethoxycarbonyl)-5-methyl-1-pyrroline N-oxide derivatives, a series of six different EPPN derivatives was synthesized and characterized by 1H NMR, 13C NMR and IR spectroscopy. The ethoxy group of EPPN was replaced by a propoxy, iso-propoxy, n-butoxy, sec-butoxy, and tert-butoxy moiety, as well as the phenyl by a pyridyl ring. Electron spin resonance spectra and stabilities of the superoxide adducts of the propoxy derivatives were found to be similar to those of the respective EPPN adduct, whereas the electron spin resonance spectra of the superoxide adducts of N-2-(2-ethoxycarbonyl-propyl)-α-(4-pyridyl) nitrone and the butoxy derivatives were accompanied by decomposition products. In contrast to the 5-(ethoxycarbonyl)-5-methyl-1-pyrroline N-oxide series, no significant improvement of the superoxide adduct stability could be obtained when the ethoxy group was replaced by other substituents. Carbon centered radical adducts derived from methanol, ethanol, formic acid and linoleic acid hydroperoxide were more stable than those of 5,5-dimethylpyrroline N-oxide, whereas among the alkoxyl radicals only the methoxyl radical adduct could be detected.
- Stolze, Klaus,Udilova, Natascha,Rosenau, Thomas,Hofinger, Andreas,Nohl, Hans
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p. 1717 - 1726
(2007/10/03)
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- Prodrugs activated by targeted catalytic proteins
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Prodrugs that are activated by and conjugated to a catalytic antibody conjugated to a moiety that binds to a tumor cell population are provided.
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