Computational and Experimental Studies of Regioselective S<sub>N</sub>Ar Halide Exchange (Halex) Reactions of Pentachloropyridine
作者:Robert D. J. Froese、Gregory T. Whiteker、Thomas H. Peterson、Daniel J. Arriola、James M. Renga、Justin W. Shearer
DOI:10.1021/acs.joc.6b01656
日期:2016.11.18
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.
Exchanging fluorine for chlorine in a chlorinated pyridine with an
申请人:The Dow Chemical Company
公开号:US04542221A1
公开(公告)日:1985-09-17
A process for preparing a fluoropyridine compound by reacting a chlorinated pyridine compound with a molar excess of an alkali metal fluoride, especially potassium fluoride, in the presence of a catalytic amount of a catalyst selected from halides of organometals and halides of metals of the iron, nickel and copper groups, and which is preferably FeCl.sub.3, whereby at least one chlorine atom of the chlorinated pyridine compound is replaced by a fluorine atom. Of special interest is the preparation of 3,5-dichloro-2,4,6-trichloropyridine from pentachloropyridine. The compounds prepared by such a process are useful for the preparation of agriculturally-useful fluoropyridines.
Herbicidal halogenomethyl--pyridyloxy-phenoxy-alkanecarboxylic acids and derivatives, and processes of controlling unwanted plants therewith
申请人:IMPERIAL CHEMICAL INDUSTRIES PLC
公开号:EP0001473A2
公开(公告)日:1979-04-18
Herbicidal pyridine compounds of the formula
wherein Z and Y each represent a fluorine, chlorine, bromine, iodidine, or hydrogen atom, or a trifluoromethyl, difluoromethyl, or chlorodifluoromethyl radical. provided that at least one of Z and Y is a halogenomethyl radical; R1 represents hydrogen or an alkyl radical of 1 to 4 carbon atoms; and R2 is a cyano group; a carboxyl group; one of a specified range of carboxamide or alkoxycarbonyl groups; a cyclohexyloxycarbonyl radical optionally substituted by one or more halogen atoms or methyl radicals; an alkenyloxycarbonyl radical in which the alkenyl group contains from 3 to 6 carbon atoms; a phenoxycarbonyl radical optionally bearing one or more halogen or methyi substituents; or a benzyloxycarbonyl radical, the phenyl group of which optionally bears one or more halogen or methyl substituents; and in the case of compounds wherein R2 is a carboxyl group, salts thereof. The compounds are useful as selective herbicides for grass weeds in broad-leaved crops, intermediates of formula
with Y = hydrogen or chlorine.
式中的除草吡啶化合物
其中 Z 和 Y 分别代表氟、氯、溴、碘、氢原子或三氟甲基、二氟甲基或氯二氟甲基基。条件是 Z 和 Y 中至少有一个是卤代甲基基;R1 代表氢或 1 至 4 个碳原子的烷基;R2 是氰基;羧基;指定范围的羧酰胺基或烷氧基羰基之一;任选被一个或多个卤原子或甲基基取代的环己氧羰基;烯氧羰基,其中烯基含有 3 至 6 个碳原子; 苯氧羰基,可选择带有一个或多个卤素或甲基取代基;或苄氧羰基,其中苯基可选择带有一个或多个卤素或甲基取代基;以及 R2 为羧基的化合物的盐。这些化合物可用作阔叶作物禾本科杂草的选择性除草剂,其中间体式为
其中 Y = 氢或氯。
2-Chloro-5-trichloromethylpyridine
申请人:IMPERIAL CHEMICAL INDUSTRIES PLC
公开号:EP0021453A2
公开(公告)日:1981-01-07
A compound which is 2-chloro-5-trichloromethyl- pyridine and a composition consisting essentially of 2-chloro-5-trifluoromethylpyridine. The compound and the composition are useful in the preparation of 2-[4-(5-trifluoromethylpyridyl- 2-oxy)phenoxy} propionic acid and its derivatives, which are useful as herbicides.
A compound which is 5-trifluoromethyl-2-p-hydroxy- phenoxypyridine or a metal salt. The compound and salts are useful in the preparation of 2-[4-(5-trifluoromethyl- pyridyl-2-oxy) phenoxy]propionic acid and its derivatives, which are useful as herbicides.