Note: Descriptions are shown in the official language in which they were submitted.
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
R2 I
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 -
0 11
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
- 10 -
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
- 11 -
