57153-18-1Relevant academic research and scientific papers
Nickel-Mediated Alkoxycarbonylation for Complete Carbon Isotope Replacement
Ton, Stephanie J.,Neumann, Karoline T.,N?rby, Peter,Skrydstrup, Troels
supporting information, p. 17816 - 17824 (2021/11/04)
Many commercial drugs, as well as upcoming pharmaceutically active compounds in the pipeline, display aliphatic carboxylic acids or derivatives thereof as key structural entities. Synthetic methods for rapidly accessing isotopologues of such compounds are highly relevant for undertaking critical pharmacological studies. In this paper, we disclose a direct synthetic route allowing for full carbon isotope replacement via a nickel-mediated alkoxycarbonylation. Employing a nickelII pincer complex ([(N2N)Ni-Cl]) in combination with carbon-13 labeled CO, alkyl iodide, sodium methoxide, photocatalyst, and blue LED light, it was possible to generate the corresponding isotopically labeled aliphatic carboxylates in good yields. Furthermore, the developed methodology was applied to the carbon isotope substitution of several pharmaceutically active compounds, whereby complete carbon-13 labeling was successfully accomplished. It was initially proposed that the carboxylation step would proceed via the in situ formation of a nickellacarboxylate, generated by CO insertion into the Ni-alkoxide bond. However, preliminary mechanistic investigations suggest an alternative pathway involving attack of an open shell species generated from the alkyl halide to a metal ligated CO to generate an acyl NiIII species. Subsequent reductive elimination involving the alkoxide eventually leads to carboxylate formation. An excess of the alkoxide was essential for obtaining a high yield of the product. In general, the presented methodology provides a simple and convenient setup for the synthesis and carbon isotope labeling of aliphatic carboxylates, while providing new insights about the reactivity of the N2N nickel pincer complex applied.
A phenoxy carboxylic acid ester herbicide preparation method (by machine translation)
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Paragraph 0098; 0100; 0102; 0104, (2019/01/08)
The invention provides a phenoxy carboxylic acid ester herbicide preparation method, including: S1, phenol in the presence of alkaline substance with the chlorinated carboxylic acid ester condensation reaction, phenoxy carboxylic acid ester obtained; the ClR states the chloro- carboxylic acid ester of the general formula1 COOR, R1 Is C1 - 3 alkylene or alkylidene, R is C1 - 10 alkyl or C3 - 10 cycloalkyl; S2, the [...] ester in the 1st and 2nd catalyst the presence of a catalyst, with the chlorinating agent to carry out the selective chlorination of, get [...] ester; the Lewis acid catalyst is selected from the 1st, the 2nd catalyst is C5 - 22 of the thioether, thiazole, thiophene compounds or different benzisothiazoles; S3, will the [...] ester with an alcohol reaction, as shown in formula I phenoxy carboxylic acid ester herbicide; R3 Is H, Cl or CH3 , R ' is a C4 - 20 alkyl or cycloalkyl. This invention can improve the product quality and the production environment, three waste low. (by machine translation)
