- Preparation method of trans-3-chloro-2-propenyl hydroxylamine
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The invention belongs to the technical field of organic synthesis, and relates to a preparation method of trans-3-chloro-2-propenyl hydroxylamine for producing clethodim technical intermediates and other pesticide important intermediates, which specifically comprises the following steps: hydrolyzing trans-1, 3-dichloropropene serving as a raw material to obtain 3-chloropropenol; and reacting the obtained 3-chloropropenol with hydroxylamine salt under the catalysis of an acidic catalyst to generate the trans-3-chloro-2-propenyl hydroxylamine. By adopting the technical scheme, the preparation method disclosed by the invention has the beneficial effects that the raw materials are easy to purchase, the operation is simple and convenient, the yield is high, no pollution is caused, and industrial production is easy.
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Paragraph 0041-0057
(2021/02/13)
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- Dechlorination of chloropicrin and 1,3-dichloropropene by hydrogen sulfide species: Redox and nucleophilic substitution reactions
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The chlorinated fumigants chloropicrin (trichloronitromethane) and 1,3-dichloropropene (1,3-D) are extensively used in agricultural production for the control of soilborne pests. The reaction of these two fumigants with hydrogen sulfide species (H2S and HS-) was examined in well-defined anoxic aqueous solutions. Chloropicrin underwent an extremely rapid redox reaction in the hydrogen sulfide solution. Transformation products indicated reductive dechlorination of chloropicrin by hydrogen sulfide species to produce dichloro- and chloronitromethane. The transformation of chloropicrin in hydrogen sulfide solution significantly increased with increasing pH, indicating that H2S is less reactive toward chloropicrin than HS - is. For both 1,3-D isomers, kinetics and transformation products analysis revealed that the reaction between 1,3-D and hydrogen sulfide species is an SN2 nucleophilic substitution process, in which the chlorine at C3 of 1,3-D is substituted by the sulfur nucleophile to form corresponding mercaptans. The 50% disappearance time (DT50) of 1,3-D decreased with increasing hydrogen sulfide species concentration at a constant pH. Transformation of 1,3-D was more rapid at high pH, suggesting that the reactivity of hydrogen sulfide species in the experimental system stems primarily from HS-. Because of the relatively low smell threshold values and potential environmental persistence of organic sulfur products yielded by the reaction of 1,3-D and HS-, the effects of reduced sulfide species should be considered in the development of alternative fumigation practices, especially in the integrated application of sulfur-containing fertilizers.
- Zheng, Wei,Yates, Scott R.,Papiernik, Sharon K.,Guo, Mingxin,Gan, Jianying
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p. 2280 - 2287
(2007/10/03)
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- Weakly ligated palladium complexes PdCl2(RCN)2 in piperidine: Versatile catalysts for Sonogashira reaction of vinyl chlorides at room temperature
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Copper iodide and weakly ligated palladium complexes PdCl2(RCN)2 (R = Ph, Me) catalyzed efficiently the coupling reaction of vinyl chlorides with 1-alkynes in the presence of piperidine to give the corresponding conjugated enynes in good to excellent yields. The reaction takes place rapidly and cleanly at room temperature. Application to the synthesis of terbinafine which exhibits strong antimycotic activity has been realized.
- Alami, Mouad,Crousse, Benoit,Ferri, Fabiola
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p. 114 - 123
(2007/10/03)
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- Total synthesis of the callipeltoside Aglycon
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Following macrolactonization, a Sonogashira coupling leads efficiently from 1 and 2 to the aglycon of the structurally unique cytotoxic macrolide callipeltoside A, isolated in tiny quantities from the lithistid sponge Callipelta sp. Key steps in the prepa
- Paterson, Ian,Davies, Robert D. M.,Marquez, Rodolfo
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p. 603 - 607
(2007/10/03)
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