- Copper-catalyzed intramolecular cross dehydrogenative coupling approach to coumestans from 2′-hydroxyl-3-arylcoumarins
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A copper-catalyzed intramolecular cross dehydrogenative C-O coupling reaction of 2′-hydroxyl-3-arylcoumarins was developed. This protocol provided a facile and efficient strategy for the construction of natural coumestans and derivatives in moderate to high yields. This transformation exhibited good functional group compatibility and was amenable to substrates with free phenolic hydroxyl groups.
- Song, Xianheng,Luo, Xiang,Sheng, Jianfei,Li, Jianheng,Zhu, Zefeng,Du, Zhibo,Miao, Hui,Yan, Meng,Li, Mingkang,Zou, Yong
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p. 17391 - 17398
(2019/06/24)
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- Preparation method of 2,4-dihydroxyphenyl acetic acid
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The invention discloses a preparation method of 2,4-dihydroxyphenyl acetic acid, which comprises the following steps: by using m-bromophenol and glyoxalic acid as raw materials, carrying out condensation reaction and acidification to obtain hydroxy o-bromomandelic acid, reducing the hydroxy o-bromomandelic acid to obtain p-hydroxy o-bromophenyl acetic acid, carrying out bromine hydroxylation reaction on the p-hydroxy o-bromophenyl acetic acid in the presence of a catalyst under alkaline conditions, and carrying out acidification to obtain the 2,4-dihydroxyphenyl acetic acid. The method has the advantages of simple and accessible raw materials, simple reaction treatment and higher yield. The obtained intermediate also has important applications.
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- Syntheses and biological activities of joro spider toxin analogs to spidamine and joramine
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In order to study the structure-activity relationships of spidamine and joramine found in the venom of Joro spider, Nephila clavata, we attempted to synthesize various analogs. Six analogs were convergently synthesized according to our previous method for the synthesis of spidamine, N-(3- aminopropyl-β-alanyl)-N'-(2,4-dihydroxyphenylacetyl-L-asparaginyl)-1,5- pentanediamine and joramine, N-(3-aminopropyl-β-alanyl)-N'-(4- hydroxyphenylacetyl-L-asparaginyl)-1,5-pentanediamine. The biological activities of the analogs and four intermediates were compared with those of synthetic spidamine and joramine in three bioassay systems, lobster neuromuscular synapse, cockroaches and mosquito larvae. The glutamate receptors in these systems were inhibited by some analogs, and the D- asparagine- or indoleacetyl-containing analogs were found to be strong inhibitors. These compounds have potential application as insecticides.
- Chiba, Tadashige,Akizawa, Toshifumi,Matsukawa, Motomi,Kawai, Nobufumi,Kono, Yoshiaki,Yoshioka, Masanori
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