Developing Efficient Nucleophilic Fluorination Methods and Application to Substituted Picolinate Esters
摘要:
This report describes nucleophilic fluorination of 3 and 5-substituted picolinate ester substrates using potassium fluoride in combination with additive promoters. Agents such as tributylmethylammonium or tetraphenylphosphonium chloride were among the best additives investigated giving improved fluorination yields. Additionally, the choice of additive promoters could influence the potential formation of new impurities such as alkyl ester exchange. Other parameters explored in this study include additive stoichiometry, temperature influence on additive degradation, solvent selection, product isolation by solvent extraction, and demonstration of additive recycling.
Mild Fluorination of Chloropyridines with in Situ Generated Anhydrous Tetrabutylammonium Fluoride
作者:Laura J. Allen、Joseck M. Muhuhi、Douglas C. Bland、Rachel Merzel、Melanie S. Sanford
DOI:10.1021/jo5003054
日期:2014.6.20
This paper describes the fluorination of nitrogen heterocycles usinganhydrous NBu4F. Quinoline derivatives as well as a number of 3- and 5-substituted pyridines undergo high-yielding fluorination at room temperature using this reagent. These results with anhydrous NBu4F compare favorably to traditional halex fluorinationsusing alkali metal fluorides, which generally require temperatures of ≥100 °C
[EN] PROCESS FOR FLUORINATING COMPOUNDS<br/>[FR] PROCÉDÉ DE FLUORATION DE COMPOSÉS
申请人:DOW AGROSCIENCES LLC
公开号:WO2015073525A1
公开(公告)日:2015-05-21
Methods of preparing a fluorinated substrate by combining potassium fluoride, a quaternary ammonium salt, and a substrate substituted with at least one chloro, bromo, sulfonyl, or nitro group to thereby provide the fluorinated substrate are disclosed.