175217-20-6Relevant articles and documents
Process research on the synthesis of silthiofam: A novel fungicide for wheat
Phillips, Gary,Fevig, Thomas L.,Lau, Patrick H.,Klemm, George H.,Mao, Michael K.,Ma, Chun,Gloeckner, James A.,Clark, Art S.
, p. 357 - 366 (2002)
The development of an efficient, low-cost synthesis of the novel wheat fungicide silthiofam (1) is described. Improvements to the original Discovery route allowed 300 kg of material to be prepared in two, overlapping pilot-plant campaigns. Thereafter, efforts were focused on further optimizing the pilot-plant route, and on devising alternate, lower cost routes to silthiofam. One potential new route involved a cydoaddition reaction between 3-mereapto-2-butanone and N-(2-propenyl)-3-trimethylsilyl-propynamide. The cyclic product could be directly dehydrated to silthiofam, however the overall yield was modest, raw material costs were high, and there were purification problems. The route ultimately selected for development proceeds in 6 chemical steps and about 60% yield from the inexpensive precursors 3-chloro-2-butanone and methyl 3-methoxyacrylate. Key features of the route are a novel thiophene-3-carboxylate synthesis involving cycloaddition of 3-mercapto-2-butanone with the acrylate followed by acid catalyzed aromatization, the room temperature formation and silylation of a thiophene-3-carboxylate dianion, and conversion of the resulting carboxylic acid into silthiofam with negligible loss of the silyl group. The process involves isolation of just two intermediates, only one of which is purified, and uses only three organic solvents, all of which are recycled. It can be run safely on large scale to give highpurity silthiofam.
A silicon saisai fungus amine synthesis method
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Paragraph 0026; 0031-0034; 0035; 0040-0042; 0043; 0048-0050, (2019/04/02)
The invention provides a synthetic method for silthiopham, which belongs to the technical field of organic synthesis. The objective of the invention is to overcome the problems of complicated synthesis process, a great number of byproducts and severe environmental pollution of conventional synthetic methods for silthiopham. The synthetic method provided by the invention comprises the following steps: (1) with trimethylsilylacetylene as a raw material, under the protection of inert gas, reacting trimethylsilylacetylene with methyl chloroformate under the action of organic base so as to obtain methyl (trimethylsilyl)propiolate; (2) reacting methyl (trimethylsilyl)propiolate with allyl amine in a solvent under the action of a catalyst so as to obtain N-allyl-3-(trimethylsilyl)propiolamide; and (3) subjecting N-allyl-3-(trimethylsilyl)propiolamide with 3-mercapto-2-butanone to a heating reflux reaction under the action of an alkali catalyst and carrying out dehydration so as to obtain the final product silthiopham. The method has the advantages of usage of cheap and easily available raw materials, simple route, high yield and no usage of reagents severely polluting the environment, e.g., t-butyl nitrous acid and thionyl chloride.
