The Dow Chemical Company

Dowelanco

Dow Agrosciences LLC

Zeneca Limited

Alexander P Fung

Charles A Wilson

Thomas J Dietsche

M Moklesur Rahman

James M Renga

Gary A Roth

Ronald Ross, Jr

Raymond Vincent Jones

Jon A Orvik

Douglas Bland

Alan John Whitton

George S Fujioka

Jennifer Ann White

Jim Love

David D Friese

Mark A Van Dort

Janice E Gatlin

Alastair Lain Stewart

Erwin Michael Seidel

John Desmond Hunt

Clark S Davis

Douglas C Bland

3-substituted-6-trifluoromethyl pyridines are useful synthetic intermediates in the preparation of the N-substituted (6-haloalkylpyridin-3-yl)alkyl sulfoximines, which are useful in forming potent insecticides. Methods of forming such 3-substituted-6-trifluoromethyl pyridines are disclosed. Also disclosed are methods of using 6-trichloromethyl halogenated pyridines to form 3-substituted-6-trifluoromethyl pyridines are disclosed.

Methods for preparing 3-substituted-6-trifluoromethyl pyridines and methods for using 6-trichloromethyl halogenated pyridines

A process for the preparation of 2-hydroxy-6-trifluoromethylpyridine which comprises reacting 2-fluoro-6-trifluomethylpyridine or a mixture of 2-fluoro-6-trifluoromethylpyridine and 2-chloro-6-trifluoromethylpyridine with an alkali metal hydroxide at a temperature of from 50.degree. C. to 160.degree. C. and acidifying the product so formed.

Chemical process

Chloro and bromophenols and N-acylanilines are fluorinated in an ortho or para position with an N-fluoropyridinium salt to obtain fluorohalophenols and N-acylfluorohaloanilines, which can be further converted to fluorophenols and N-acylfluoroanilines by reduction. Thus, o-fluorophenol is obtained by fluorination of p-bromophenol with 2-chloro-6-(trichloromethyl)pyridinium fluoroborate and reduction of the product obtained with sodium formate and a palladium catalyst. N-Fluoropyridinium salts having trichloromethyl substituents are disclosed.

Preparation of fluorohalophenols and N-acylfluorohaloanilines

Chloro and bromophenols and N-acylanilines are fluorinated in an ortho or para position with an N-fluoropyridinium salt to obtain fluorohalophenols and N-acylfluorohaloanilines, which can be further converted to fluorophenols and N-acylfluoroanilines by reduction. Thus, o-fluorophenol is obtained by fluorination of p-bromophenol with 2-chloro-6-(trichloromethyl)-pyridinium fluoroborate and reduction of the product obtained with sodium formate and a palladium catalyst. N-fluoropyridinium salts having trichloromethyl substituents are disclosed.

Preparation of fluorohalophenols and N-acyfluorohaloanilines

Novel methods for preparing 2-cyano-6-chloropyridines are disclosed. The compounds are useful as intermediates in preparing other intermediates or as intermediates directly used in making pesticides, especially herbicides.

Preparation of 2-cyano-6-chloropyridine compounds

The preparation of 3,5-dichloro-2,4,6-trifluoropyridine from pentachloropyridine and potassium fluoride was found to proceed in high yield and at a rapid rate with little tar formation when the reaction is conducted under essentially anhydrous conditions in N-methylpyrrolidone solvent at temperatures below 170.degree. C. High yields of this intermediate for herbicides are obtained.

Method of preparation of 3,5-dichloro-2,4,6-trifluoropyridine

(Trifluoromethyl)pyridine compounds are prepared by contacting (trichloromethyl)pyridine compounds with hydrogen fluoride in the presence of a catalytic amount of a catalyst selected from the group consisting of FeCl.sub.2, FeF.sub.2 and mixtures thereof under liquid phase conditions. The (trifluoromethyl)pyridine compounds are useful as intermediates for the preparation of agricultural chemicals.

Preparation of (trifluoromethyl)pyridines under liquid phase conditions

A method of exchanging a chlorine atom for a fluorine atom at the 2-position of a 2-fluoropyridine compound which comprises contacting a 2-fluoropyridine compound with a substituted or unsubstituted trichloromethyl or dichlorofluoromethyl alpha, beta or gamma picoline compound at a temperature of 50.degree.-250.degree. C. and a pressure of atmospheric to about 100 psig.

Chlorine exchange for fluorine in 2-fluoropyridine compounds

(Trifluoromethyl)pyridine compounds are prepared in high yields and with a high selectivity by using a mercury or silver fluorinating agent, i.e., HgF.sub.2, AgF, AgF.sub.2, in a liquid phase halogen exchange process.

Liquid phase halogen exchange of (trichloromethyl) pyridines to

Ring-fluorinated pyridine compounds are contacted with a chlorinating agent, preferably in the presence of a catalyst, under favorable conditions to yield pyridine compounds having a chlorine substituted in the ring-fluorine position(s).

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Martinez, CA, United States of America

Alexander P Fung