- Efficient solid phase synthesis of benzo[1,2,3]thiadiazoles and related structures
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The first solid-phase synthesis of benzo[1,2,3]thiadiazoles was achieved by starting from resin bound ortho bromo or iodo triazenes and using a functionalization on cleavage. Two different synergistic methods including an anionic approach and a cross-coupling approach were used for the synthesis. The resulting diazonium compounds readily underwent electrophilic cyclization yielding benzothiadiazoles, when cleaving the arenethiol resins. Cleavage from the resin with diluted trifluoroacetic acid resulted spontaneously in the desired cyclization reaction.
- Kreis, Michael,Nising, Carl F.,Schroen, Maarten,Knepper, Kerstin,Braese, Stefan
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- One- And Two-Proton Transfer Mechanisms Coexist in One Active Site
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Acibenzolar-S-methyl (ASM) is one of the most successfully commercialized plant activators of the systemic acquired resistance (SAR). However, its activation (hydrolysis) mechanism catalyzed by the salicylic acid binding protein 2 (SABP2) remains elusive. The fundamental catalytic mechanism of the SABP2-catalyzed hydrolysis of the ASM had been investigated by extensive computational and experimental studies, including QM/MM simulations, charge transfer analysis, small-molecule synthesis, and biochemical assays. Here we report that the promiscuous SABP2 shows different catalytic mechanisms toward different substrates. To catalyze the ASM hydrolysis, the SABP2 uses a two-proton transfer mechanism, and the key intermediate is stabilized by the charge transfer effect; to catalyze the ethyl 1,2,3-benzothiadiazole-7-carboxylate (BTM, an ASM analogue) hydrolysis, the SABP2 applies the one-proton transfer mechanism, and the classic tetrahedral intermediate is stabilized by the electrostatic effect. The HPLC analyses of the SABP2 esterase activities toward the ASM and the BTM show comparable results with our computaional results, suggesting that the obtained computational mechanism insights are reasonable. The obtained mechanism is not only an important supplement to the theory of enzymes' catalytic promiscuity, but it also contributes a possible strategy for the design of next generation plant SAR activators.
- Dong, Huaikun,Gao, Juan,Jiang, Cheng-Shi,Ren, Jing,Song, Jiali,Wang, Xia,Yao, Jianzhuang,Zhao, Yueqi
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- Novel benzo-1,2,3-thiadiazole-7-carboxylate derivatives as plant activators and the development of their agricultural applications
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Plant activators are a novel kind of agrochemicals that could induce resistance in many plants against a broad spectrum of diseases. To date, only few plant activators have been commercialized. In order to develop novel plant activators, a series of benzo-1,2,3-thiadiazole-7-carboxylate derivatives were synthesized, and the structures were characterized by 1H NMR, IR, elemental analyses, and HRMS or MS. Their potential systemic acquired resistance as plant activators was evaluated as well. Most of them showed good activity, especially, fluoro-containing compounds 3d and 3e, which displayed excellent SAR-inducing activity against cucumber Erysiphe cichoracearum and Colletotrichum lagenarium in assay screening. Field test results illustrated that compounds 3d and 3e were more potent than the commercial plant activator, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH) toward these pathogens. Further, the preparation of compound 3d is more facile than BTH with lower cost, which will be helpful for further applications in agricultural plant protection.
- Du, Qingshan,Zhu, Weiping,Zhao, Zhenjiang,Qian, Xuhong,Xu, Yufang
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scheme or table
p. 346 - 353
(2012/04/10)
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- BICYCLIC COMPOUND AND PHARMACEUTICAL USE THEREOF
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The present invention provides a compound represented by the formula wherein R1 is a hydrocarbon group optionally having substituent(s), amino optionally having substituent(s), hydroxy optionally having a substituent or a heterocyclic group optionally having substituent(s); R2 is a hydrogen atom or a hydrocarbon group optionally having substituent(s); Xa and Xb are each C, N, O or S; Xc and Xd are each C or N; m is 0-2; n is 1-3; ring A is a 5-membered ring optionally having substituent(s); ring B is a 6-membered ring optionally having substituent(s); and ring C is a 3- to 5-membered ring optionally having substituent(s), provided that when Xa, Xc and Xd are each C, then Xb is N or S, or a salt thereof, which is useful as an agent for the prophylaxis or treatment of a disease relating to an action of melatonin, and the like.
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Page/Page column 111
(2010/01/29)
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- Derivatives of benzothiadiazole-7-carboxylates: Synthesis and biological activity
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Salicylic acid (SA) and methyl jasmonate (MJ) are important plant signal molecules to cause systemic acquired resistance (SAR), while it's reported that they also have wide spectrum antitumor activities. Benzothiadiazole-7- carboxylates are plant activators which can cause SAR just like SA and MJ. To investigate whether the benzothiadiazole-7-carboxylate family is endowed with anticancer activities, several benzothiadiazole-7-carboxylate derivatives are synthesized and their inhibition to P388 murine leukemia cell and A549 human lung cancer cell compared with MJ are evaluated. The data indicated that benzo-1,2,3-thiadiazole-7-carboxylic acid 2-benzoyloxyethyl ester has a higher inhibition ability to the cancer cell P388 and A549, compared with MJ.
- Zhu, Weiping,Zhao, Zhenjiang,Xu, Yufang
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scheme or table
p. 1067 - 1071
(2009/12/02)
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- The chemistry of benzothiadiazole plant activators
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Systemic Acquired Resistance (SAR) is an inducible resistance mechanism in plants that, together with other defence mechanisms, provides broadspectrum and long-lasting disease control. With novel screening techniques the benzo[1,2,3]thiadiazole-7-carboxylic acid derivatives have been identified as a new class of chemicals which stimulate the plant's own defence mechanisms. The synthesis and biological activities of various benzo[1,2,3]thiadiazoles and related structures are described. S-Methyl benzo[1,2,3]thiadiazole-7-carbothioate is the first synthetic chemical 'plant activator' that has been developed for this novel disease control concept.
- Kunz,Schurter,Maetzke
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p. 275 - 282
(2007/10/03)
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- Process and a composition for immunizing plants against diseases
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A method and composition for the immunization of healthy useful plants against plant diseases containing as active ingredients compounds of formula STR1 in which: X is hydrogen, halogen, hydroxy, methyl, methoxy, HOOC or MOOC; Y is hydrogen, halogen, SO3 H, SO3 M, nitro, hydroxy or amino, M being the molar equivalent of an alkali metal or alkaline earth metal ion that is formed from a corresponding base or basic compound; and Z is cyano or --CO--A; A represents either --OH or --SH, the hydrogen atom of which may also be replaced by the molar equivalent of an inorganic or organic cationic residue, or wherein A represents any other organic residue which has a molecular weight of less than 900 and which may also contain one, or more than one, hetero atom, including the salts of the phytophysiologically tolerable 7-carboxylic acid or 7-thiocarboxylic acid with primary, secondary or tertiary amines or with inorganic bases.
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