CA1219600A - 5-haloalkyl-pyridines - Google Patents

Abstract

ABSTRACT
Novel chlorobutyraldehydes of the general formula R-CCl2-CHO, in which R is chosen from -CH2CH2Cl, -CH2CHCl2 or -CH2-CCl3 are described to-gether with a process for their preparation. These compounds find use in the preparation of pesticidally active compounds of the formula

Description

I
21489-615G~
This application is a divisional appLicatioll from application 413,692 filed October Thea, 1982.
This invention relates to novel chlorobutyraldehydes, and to processes for their preparation.
In application 413,692 are described 5-haloaLkylpyridines anal to processes for producing them, which correspond to the formula I

Of X - R (I) wherein R is a C2-C10-alkyl group which is uniformly or nonuniformly substituted by 1 to 21 halogen atoms, and X is halogen.
By halogen atoms or halogen is meant preferably fluorine, chlorine or bromide.
Preferred compounds in application 413,692 are those compounds of the formula I wherein R is an ethyl group which is uniformly or nonuniformly substituted by 1 to 5 fluorine or chlorine atoms, and X is fluorine or chlorine;
particularly those compounds wherein R is a radical from the group comprising:
-C1}2-CF3, -CF2-CF2Cl, -CF2-CFC12, -CC12-CC13, -CF2-CC13, -CF2-CH3, -CC12-C113,

2 3' C~12-CI12Cl' -Cll2-c~lcl2 or -Oil -Cal Compounds of the formula I especially preferred are those wherein X
is chlorine.
Ire compounds of the formula I can be used as starting products to produce, by way of one or more intermediate stages, various active substances, in particular active substances for plant protection, for example insecticides, herbicides or f~mgicides.

It is e.g. possible to obtain, starting with compounds of the for-mute I, valuable insecticides of the formula Al R3 R5 CO-NI-I-CO-NII--~ O R

in which Al and R2 are hydrogen, methyl or halogen, R3 and R4 are hydrogen or halogen, R5 is chlorine, and R has the meanirlg defined under the formula I.
Chloropyridines substituted by trichloromethyl or trifluoromethyl groups could hitherto be produced only by complicated, multistage processes.
On chlorination of 3-methylpyridine, there are in general formed several isomers in addition to the desired compound. By chlorination of 2,3-dichloro-5-methylpyridine is obtained 2,3-dichloro-5-trichlorolllethylpyridine, which can be converted, by exchange of the chlorine atoms of the trichloromethyl group for fluorine atoms, into 2,3-dichloro-5-trifluoromethylpyridine (see, for example, European Patent Publication No. 004414). There are produced in a similar manner, according to the German Offenlegungsschrift No. 2,~12,607, 2-halo-5-trifluoromethylpyridines and 2,3-dichloro-5-trifluoromethylpyridine. Halogen-substituted 5-trifluoromethyl- and 5-difluoromethylpyriclines and the production thereof are known moreover from the published British Patent Application No.
2,002,368.
The compounds of the formula I are produced according to application 413,692 by reaction of an alluded of the formula II with acrylonitrile, where-by there is firstly formed, by an addition reaction, an intermediate of the formula III, which is then cyclised - optionally in situ - to a pardon compound of the formula I.

~l21'3~;(~() / \ Cal / Swahili Cyclisat-i-on~ I R
11 C-N I! C-N (-I-i20) N -IT (III) (I) I = Of + I-IX I (-ill, -~12) cyclisation Cal X - R
I) As is seen from the above reaction scheme, there are obtained, when the procedure is carried out in situ, that is, without isolation of the inter-mediate owe the formula III wherein X is chlorine, compo~mds of the formula I
in which X is chlorine. In case whelp an intermediate of the formula III is isolated, there is the possibility of reacting it with a hydrogen halide ill to obtain a compound of the formula I wherein X can not only be chlorine but also fluorine or bromide. Furthermore, a resulting compound of the formula I can be optionally further halogenated, preferably chlorinated, in the radical R, or halogen atoms present in the radical R can be exchanged for other halogen atoms, preferably chlorine or fluorine atoms, in order to obtain corresponding further compounds of the formula I. In the above formulae II and III, the symbol R has the monologue given under the formula I.
This application is concerned with aldehydes of the formula II where-in R is any one of the radicals -Sulks, -Cil2-CilC12 or -Soullessly Of The pardons of the formulcl I, obtailled from these preferred aLdehydes by an addition re~actioll Whitehall acrylonitrile and cyclisation of the addition product of the formula TIP) can be chlorinated in a particularly advantageous manner to 2,3-dichloro-5-(pentachloroet}lyl)-pyridille, whereupon, in the case of the last-mentioned compound, chlorine atoms present in the pentachloroethyl side chain can be exchangecL preferably for fluorine atoms by means of customary fluorine-lion methods. Ike number of fluorine atoms introduced by exchange depends on the selected fluorination conditiolls.
Jo structurally similar reaction sequence of trichloroformylbutyro-nitrite to 2,3,5-trichloropyridille is clescribeci in the European Patent Publication No. 12117. The cyclisation according to the invention with format lion of an aromatic ring to give pardons of the formula I was however not to be expected. Rather would the formation of a pardon derivative have been expected. The course of reaction according to the invention is thus to be described as being to a very great extellt surprising.
Novel aldehydes of the formula II can be obtained by reaction of in-chloroacetaldehycle with corresponding ethylenically unsaturated compounds, for example y 2 13C-C\ ----I O

wherein Y is hydrogen or halogen, preferably chlorine.
Thus in a first embodiment this invention provides chlorobutyral-duds of the general formula R-CC12-CH0 wherein R is chosen from -CH2CH2Cl;
-CH2-CI-IC12; or -Sulks.
In a second embodiment this invention provides a process for the preparation of the aforementioned chlorobutyraldehydes which comprises either L9~it~V

chlorillati.ng in the cl-posit:i.on tile corresponclillg chlorobutyraldellycle of the formula R-C112-CII0, or reacting trichloroacetalclehyde with a compound of the Eormllla Y2C=C1l2 wherein each Y independently is hydrogen or chlor:ille.
The addition reactions with the Formation of a compound of the formula III can be performed in an open or closed system, preferably at a temperature of 70-160C. Tile addition reaction is preferably carried Owlet in a dosed system under a pressure corresponding to the applied reaction temperature, the pressure being for example within the range of 1-30 bar.
Catalysts used for the addition reactions can be, according to the invention, metals of the main group VIII and of the subgroups Via Viva, IT and jib of the periodic system, for example iron, cobalt, nickel, ruthenium, palladium, chromium, molybden~n, manganese, copper and zinc. These metals can be employed in the elementary form or in the form of suitable compounds, for example oxides and salts, such as halides, sulfates, solutes, sulfides, nit-rates, acetates, struts, citrates, carbonates, cyanides and redounds, as well as complexes with ligands, such as pllosphines, phosphates, bouncily and acetylacetonates, nitrites, :isonitriles and carbon monoxide.
Examples which may be mentioned are: Cooper) oxide or iron) oxide; copper-, Cooper)-, iron!- and iron(III)-bromides, -iodizes and particularly -chlorides, zinc chloride, as well as the chlorides owe ruthenium, rhodium, palladium, cobalt and nickel; Cooper) sulfate, iron)- and iron(III)-sul:Eate; Cooper) nitrate and iron) nitrate; manganese) acetate, Cooper) acetate, Cooper) Stewart, iron) citrate and copper (I) cyanide; ruthenium) dichloro-tris-triphenylphosphine, rhodium dichloro-tris-triphenylpilosphine; chromium- and nickel-acetylacetonate, Cooper) acetylacetonate, iron) acetylacetonate, cobalt)- and cobalt)-Jo acetyl(lceto11;1te~ manganese) acetylclcetollatc and Cooper) benzoylacetonclte;
iron carbonyl-cyclopenta-diellyl complex molybdenum carbonylcyclopenta{licny.L
complex, chromium tricarbonylaryl complexes, rutheniu111(tI) acetate complex, chromium-a11d molybdenum hexacarbonyl, nickel tetracarbonyl, iron pentacarbonyl and cobalt-and manganese-carbonyl.
I-t is also possible to use mixtures of the stated metals with metal compounds and/or other additives, such as copper powder in combi1lation with one of the afore-mentionec1 copper compo-1ncls; mixtures of copper powder with lithium halides, such as Lithuania chloride, or isocyanides, such as tert-butyliso-lo cyanide; mixtures of iron powder with iron(lII) chloride, optionally with the addition of carbon monoxide; mixtures of iron) chloride with Bunsen; mix-lures or iron)- or iron) chloride White trialkylphosphites; and mixtures o-E iron pentacarbo11yl and iodine.
The catalysts are in general used in amounts of about Oily to lo mow %, preferably Owl to 5 mow I, relative to the alluded.
Tile addi-tio11 Rex o-E the aldehydes of the formula II with acrylo-nitrite is advantageously performed in the presence of an inert organic solvent.
Suitable solvents are those in which the catalysts are sufficie1ltly soluble, or -those which can form complexes with the catalysts, which solvents are how-I ever inert to the reactants.
Preferred solvents for the addition reaction are alkanecarboxylicacid nitrites having 2-5 carbon atoms, and 3-alkoxypropionitriles having 1-2 carbon atoms in the alkoxy group, especially acetonitrile, butyronitrile and 3-met11oxypropiollitrile, or the acrylonitrile used as reactant.
The cyclisation o-f the compoullds of the formula III can be performed in an open or dosed system at temperatures of between about 0 and 220C, in lo o particular between about 100 isles 200C. Ire cyclisation is perforllled preferably I'll .111 Opaquely system Which case it is advclntageous to carry out the reaction in the presence of a hydrogen halide, or in the presence of substances which form hydrogen ilalides under the reaction conditiolls, such as phosgc?ne, boron trichloride, alumilliulll chloride, trialkyl<munonium chlorides having 1-4 carbon atoms in each of the alkyd groups, phosphorus pentclchloride, phosphorus ox-chloride or phosphorus trichloride, or the corresponding bromide or floral compounds. Tile cyclisation reaction is preferably performed in the priceless of hydrogen chloride, hydrogen bromide or hydrogen fluoride.
The cyclisation reaction is preferably performed witllo~lt the addition of a solvent, in tile liquid or gas phase, by merely heating the compou]lcls of the formula III. The reaction can however also be performed in the presence of an organic solvent.
Preferred solvents err the cyclisation reaction are chloroform, ethylene chloride, cyclic ethers and dialkyl ethers having 1-4 carbon atoms in each owe the alkyd groups, especially Dixon and deathly ether, as well as NUN-dialkylamides of alkanecarboxylic acids having 1-3 carbon atoms, particularly N,N-dimethyl:Eormamide.
Tile process described in application 413,692 can be advantageously performed by firstly isolating the compounds of the formula III formed by the addition reaction, and subsequently cyclising them in a second stage of the process.
It is possible however, when is chlorine, -to advantageously dispense with the isolation of the addition product of the formula III, and to perform the addition and cyclisation reactions in one operation. In this case, the reaction of the alluded of the formula II with acrylonitrile to a pardon of I

the formula [ is carried out preferably at a temperature of between 70 and 220C, especially between 130 and 200C. [Nile process can be performed in an open or closed system. When the reaction is carried out in an open system, it can be advantageous to carry it out in the presence of hydrogen chloride, or of substances which form hydrogen chloride under the reaction conditions. These substances are for example phosgene, boron trichloride, aluminum chloride, trialkylammonium chloride having 1-4 carbon atoms in each of the ~lkyl groups, phosphorus pentachloride, phosphorus oxychloride or phosphorus trichloride. The single-stage production of pardons owe the formula I is preferably performed however in a closed system under a pressure corresponding to the applied reaction temperature, the pressure being for example within the range of 1-50 bar, depending on the reaction temperature. The single-stage synthesis of compoullds of the formukl I in a closed system at a pressure of 1-30 bar is especially preferred.
The said single-stage synthesis can likewise be carried out in the presence of a catalyst, and advantageously in the presence of an inert organic solvent. Suitable catalysts and solvents are those of the type described ear-tier in the text, and with regard to preferred catalysts and amounts of catalyst, that applies which was stated in the foregoing in this connection.
Preferred solvents for carrying out the process in a single-stage are alkanecarboxylic acid nitrites having 2-5 carbon atoms and 3-alkoxypro-pionitriles having 1-2 carbon atoms in the alkoxy group. Particularly suitable solvents are acetonitrile, butyronitrile and 3-methoxypropionitrile, or an excess of the acylonitrile used as reactant. After completion of the reaction, the chloro-pyridines of the formula I can be isolated in the customary manner, for example by removal of the solvent by evaporation, and purification of the go crude product by distillation o-r by steam distillation.
\ further advalltageoLIs emboclimellt of the process according to the involution comprises reactirlg the alkaloids of the formula II and tile acylollit-rile directly to the pardons of the formula I, the reaction being performed at 130-200C in acetollitrile, butyronitrile or 3-metho~yprol)ionitrile as sol-vent, in the presence of 0.1 to 6 mow JO of copper powder, copper bronze, copperware copper(II)-chloride or -bromide or copper iodide, or of a mixture of these substances, and in a closed system under a pressure correspond-in to tile applied reaction temperature.
Example 1:
Production of 2,2,L?,4?4-pentacilloIobutyraldehyde a) Into 200 ml of dimetilylEormamide are introduced "with cooling, 10 g of luckily gas and afterwards, at 60-65C, 10 g of chlorine. There is tllell added drops to the slightly yellow solution, likewise at 60-65C, the solution of 210 g of 2,4,4,4-tetrachlorobutyraldellyde in 300 ml of climethylformamide, and Somali--tonsil an approximately aliquotic amount of chlorine as introduced until tile reaction solution reunions slightly yellow. The temperature is maintained for 1 hour at 65C, and the reaction mixture is subsequently subjected to steam disk tillation. The organic phase of the distillate is separated, and rectified in vacua and the light-yellow oil, b.p.l5 mm 95-99C, is collected-b) 145.3 g of vinylldene chloride, 148.0 g of trichloroacetaldehyde, 3.0 g of copper chloride and 300 ml of acetonitrile are heated in an enameled auto-crave at 125C for 12 hours. The solvent is thereupon distilled of-E in a water-jet vacuum, and the residue is taken up in 500 ml of deathly ether. After removal of precipitated copper sludge by filtration, the deathly ether is distilled off, and the residue is rectified in a water-jet vacuum to thus obtain the title compound, b.p.15 95-99C.

Exhume 2:
Proc1uctioll of 2,2,~ 4-tetrachlo~obutyraldehyde 125.0 g of vinyl chloride, 1~18.0 g of trichloroacetaldehyde, 3 g of copper chloride aloud 300 ml of acetonitrile are heated in an enameled auto-crave for 4 flours at 140C. after cooling, the salivate is distilled of at room temperature in a water-jet vacuum. Tao residue is taken up in 500 ml of deathly ether, and filtered off from the precipitated copper chloride. the deathly ether is distilled off, and the residue is rectified in a water-jet vacuum. The product thus obtained is a colorless Lockwood, by lo mm 78-80C.
lo Example 3:
Production of 2,2,4-trichlorobutyraldehyde .
56.1 g of ethylene, 1'18.0 g of trichloroacetaldehyde, 3.0 g of copper (I) chloride and 300 ml of acetonitrile are heated in an enameled autoclclve at 140~C for 4 hours. After cooling, the solvent is distilled off at room them-portray in a water-jet vacuum. The residue is taken up in 500 ml of deathly ether, and filtered off from the precipitated copper chloride. After the deathly eater has been distilled off, the residue is rectified in a water-jet vacuum. There is obtained a colorless liquid, by 15 mm 64-66C.
Example 4.
Production of 2,3-c1ichloro-5-(2,_2,2-trichloroethyl?-pyridine . . .
244.3 g of the 2,2,4,4,4-pentachlorobutyraldehyde produced according to Example l, lo g of acrylonitrile, 400 ml of acetonitrile and 5 g of Curl are heated in a tantalum autoclave at 180C for 4 hours. After cooling, the ace-tonitrile and the excess of acrylonitrile are distilled off in vacua. The dark oil remaining is extracted with deathly ether; the ether is then dried with Nazi, and evaporated off in vacua, and the residue is subjected to steam SO

cl:istillrLt:iorl. 'Icky 2,3-clichloro-5-(2,2,2-tr;chloroetilyl)-yyridine precipitates, in tile distillate, in the form of almost white flilkes. after a single retry-stylization from ctharlol diluted with water, tile product has a meltillg pullout of 98-99C

Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A compound of the formula II

(II) wherein R is any one of the radicals -CH2-CCl3, -CH2-CHCl2 and -CH2-CH2Cl.

2. 2,2,4,4,4-Pentachlorobutyraldehyde.

3. 2,2,4,4-Tetrachlorobutyraldehyde.

4. 2,2,4-Trichlorobutyraldehyde.

5. A process for producing a compound of the formula II according to Claim 1, which comprises either reacting trichloroacetaldehyde with a compound of the formula IV

(IV) wherein each Y independently is hydrogen or chlorine, or .alpha.-chlorinating the corresponding butyraldehyde.