1737-93-5Relevant articles and documents
Computational and Experimental Studies of Regioselective SNAr Halide Exchange (Halex) Reactions of Pentachloropyridine
Froese, Robert D.J.,Whiteker, Gregory T.,Peterson, Thomas H.,Arriola, Daniel J.,Renga, James M.,Shearer, Justin W.
, p. 10672 - 10682 (2016)
The Halex reaction of pentachloropyridine with fluoride ion was studied experimentally and computationally with a modified ab initio G3MP2B3 method. The G3 procedure was altered, as the anionic transition state optimizations failed due to the lack of diffuse functions in the small 6-31G? basis set. Experimental Halex regioselectivities were consistent with kinetic control at the 4-position. The reverse Halex reaction of fluoropyridines with chloride sources was demonstrated using precipitation of LiF in DMSO as a driving force. Reverse Halex regioselectivity at the 4-position was predicted by computations and was consistent with kinetic control. Scrambling of halide ions between chlorofluoropyridines was catalyzed by n-Bu4PCl, and the products of these reactions were shown to result from a combination of kinetic and thermodynamic control. Comparison of the C-F and C-Cl homolytic bond dissociation energies suggests that an important thermodynamic factor which controls regioselectivity in this system is the weak C2-Cl bond. The differences between ΔH° values of chlorofluoropyridines can be explained by a combination of three factors: (1) the number of fluorine atoms in the molecule, (2) the number of fluorine atoms at the C2 and C6 positions, and (3) the number of pairs of fluorine atoms which are ortho to one another.
A kind of boron-containing compounds and their use in catalytic fluorination reaction (by machine translation)
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Paragraph 0042-0045, (2019/05/28)
The invention relates to the field of fine chemical engineering, in particular to boron-containing compounds and application thereof in catalytic fluorination reaction. The boron-containing compoundsprovided by the invention are used as a catalyst and can be fluorinated by further mild reaction. Compared with the prior art, the boron-containing compounds have the advantages of mild conditions andhigh efficiency of the fluorination reaction, novel catalysis principle, simplicity and convenience in operation, less pollution, low solvent cost and suitability for industrial production.
Medicament intermediate and preparation method of fluroxypyr 1-methylheptyl ester
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Paragraph 0042-0046; 0048-0052; 0054-0058, (2017/11/18)
The invention discloses a medicament intermediate and a preparation method of fluroxypyr 1-methylheptyl ester, and relates to the field of organic synthesis. The preparation method of the medicament intermediate has the advantages that a molecular sieve is added, a fluoridation reaction and next amination reaction of pentachloropyridine can be realized through one-pot reaction, complex separation steps are saved, product loss caused by the separation process is avoided, and the key medicament intermediate for preparing herbicide can be prepared at high yield. The preparation method is easy to operate, is low in equipment demand, contributes to lowering production cost, and is suitable for large-scale industrial production. The preparation method is characterized in that low-cost and readily-available pentachloropyridine is taken as an initial raw material, the fluoridation reaction and next amination reaction are implemented by adopting the one-pot method to obtain key medicament intermediate; on the basis of the medicament intermediate, a hydroxylation reaction and a condensation reaction are implemented to obtain efficient high-yield fluroxypyr 1-methylheptyl ester. The preparation method is reasonable in route design, is simple in steps, is convenient to operate, is low in cost, is low in pollution, and is suitable for industrial large-scale production.
