US3461128A - Process for producing n:n'-dilower alkyl-4:4'-bipyridylium salts - Google Patents

Process for producing n:n'-dilower alkyl-4:4'-bipyridylium salts Download PDF

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US3461128A
US3461128A US550965A US3461128DA US3461128A US 3461128 A US3461128 A US 3461128A US 550965 A US550965 A US 550965A US 3461128D A US3461128D A US 3461128DA US 3461128 A US3461128 A US 3461128A
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carbon
halogen atom
tetrahydrobipyridyl
salts
reaction
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John Edward Colchester
John Hubert Entwisle
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Imperial Chemical Industries Ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/06—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom containing only hydrogen and carbon atoms in addition to the ring nitrogen atom
    • C07D213/22—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom containing only hydrogen and carbon atoms in addition to the ring nitrogen atom containing two or more pyridine rings directly linked together, e.g. bipyridyl

Definitions

  • This invention relates to the production of bipyridylium salts and particularly to the production of bis-quaternary salts of 4:4-bipyridyl.
  • N:N'-dibenzyl tetrahydrobipyridyl can be oxidised to an N:N'-dibenzyl bipyridylium salt by the action of iodine, but this process gives only poor yields of the bipyridylium salt, and much of the starting material is converted into benzyl pyridinium salts by fission of the bond connecting the two pyridine rings.
  • N:N'-disubstit-utedtetrahydro-4:4-bipyridyls may be converted in good yield into N:N-disubstituted 4:4-bipyridylium salts by the action of compounds containing a labile halogen atom.
  • tetrahydrobipyridyls which may conveniently be used in our process are those more fully described in the above mentioned U.K. applications, for example tetrahydrobipyridyls which carry alkyl or carbamyl alkyl, and particularly methyl or N:N-disubstituted carbamyl methyl substituents on the nitrogen atoms.
  • tetrahydrobipyridyls which carry alkyl or carbamyl alkyl, and particularly methyl or N:N-disubstituted carbamyl methyl substituents on the nitrogen atoms.
  • Other suitable N:N-disubstituted-tetrahydro-4:4 bipyridyls are those carrying inert substituents, for example alkyl groups, on the carbon atoms of the pyridine nuclei.
  • the carbon compound containing a labile halogen atom may be any such compound which is capable of nited States Patent 3,461,128 Patented Aug. 12, 1969 removing hydrogen from the tetrahydrobipyridyl, for example a compound containing a carbon-to-halogen bond of dissociation energy less than about kcals./mole.
  • Bromine and iodine atoms tend to be more labile than chlorine atoms when attached to carbon and compounds containing bromine and iodine will therefore tend to be more effective than those containing chlorine only.
  • compounds containing bromine and iodine are relatively expensive and it is therefore economically desirable to use the cheaper compounds containing chlorine.
  • a carbon tetrahalide which does not contain fluorine for example carbon tetrachloride, carbon tetrabromide, bromotrichloromethane or dichlorodibromo m e t h a n e.
  • Other compounds which may be used in our invention are bromoform, iodoform, methylene iodide, hexachloroethane, hexachloropropene, 1:1:1 trifiuoro 2:2 dibromo-Z-chloroethane and hexachloroacetone.
  • chloroform, methylene dichloride, benzotrichloride and monochlorobenzene tends to yield very little of the desired product.
  • tetrahydrobipyridyl and the carbon compound containing the labile halogen atom may be interacted simply by mixing the two components, but this procedure tends to give rise to a vigorous reaction which may be difficult to control. We have therefore found it useful to moderate this reaction by carrying it out in solution in an inert solvent. Suitable solvents are those which will dissolve the N:N'-disubstituted-tetrahydro4:4-bipyridyl and also the carbon compound containing the labile halogen atom.
  • solvents examples include ethers for example diethyl ether, tetrahydrofuran, 1:2 dimethoxyethane, bis (2- methoxyethyl) ether and 1:4-dioxane; ketones, for example acetone; hydrocarbons, for example benzene and hexane; organic bases, for example pyridine; halogenated hydrocarbons, other than those used to interact with the tetrahydrobipyridyl, particularly chlorinated hydrocarbons, for example chlorobenzene, chloroform and methylene dichloride; amides, particularly tertiary alkylamides, for example formamide; sulphoxides, for example dimethyl sulphoxide or nitriles, for example acetonitrile.
  • ethers for example diethyl ether, tetrahydrofuran, 1:2 dimethoxyethane, bis (2- methoxyethyl) ether and 1:4-di
  • the concentration of the tetrahydrobipyridyl may conveniently be above about 0.75 mole per litre and the concentration of the carbon compound containing a labile halogen atom, for example carbon tetrachloride, may be above about 0.25 mole per litre. Lower concentrations of either reagent necessitates the recovery of the N:N-disubstituted bipyridylium salts from large quantities of solvent and therefore tend to be inconvenient.
  • Either reagent may if desired be used undiluted, the other reagent being dissolved in the chosen solvent, but if the reagents are Q used in high concentration care should be taken that the reaction does not become too vigorous and lead to some destruction of the desired product or to the production of unwanted by-products.
  • Methylene iodide 200 200 35 1 13 Carbon tetrabromide 200 200 35 1 22 Hexachloropropene. 450 600 20 1. 30
  • the temperature at which reaction is carried out will depend on the concentration of the reagents and on the particular reagents used. We have found that suitable temperatures are from about 55 C. to 70 C. and preferably from 0 C. to 50 C.; higher temperatures tend to cause decomposition of the tetrahydrobipyridyls and lower temperatures will necessitate cooling of the reactants.
  • the most suitable time of reaction can be found by simple experiment and will depend on the reagents used and the temperature at which the reaction is earned out; we have however found that a minimum time of 20 to 30 minutes is generally necessary.
  • the N:N-disubstituted bipyridylium salt may be recovered from the reaction mixture by conventional processes for example by extraction of the reaction mixture with water or with a dilute aqueous solution of a mineral acid such as sulphuric, hydrochloric or phosphoric acid.
  • the N:N-bipyridylium salt may then be recovered from the aqueous phase, which has previously been separated from the organic phase, by evaporation of the water and crystallisation of the salt.
  • a process for the production of an N:N-dilower alkyl-4:4-bipyridylium salt which comprises reacting in an inert solvent a N:N-dilower alkyl tetrahydro-4:4-bipyridyl with a linear alkyl or linear alkenyl carbon compound having less than 4 carbon atoms and containing a labile halogen atom selected from chlorine, bromine and iodine and the labile halogen atom is attached to carbon by a bond of dissociation energy less than about 70 kcal./mole.
  • a process as claimed in claim 2 wherein the electron withdrawing group is a carbonyl group, a CHal group (where Hal represents chlorine, bromine or iodine), or a fluorine, chlorine or bromine atom.
  • carbon compound is bromotrichloromethane, dichlorodibromomethane, bromoform, iododform, methylene iodide, hexachloropropene, hexachloroacetone or 1:1:1-trifiuoro-2:2- dibromo-Z-chloroethane.
  • ether is diethyl ether, tetrahydrofuran or bis-(Z-methoxy ethyl) ether.
  • a process as claimed in claim 9 wherein the solvent comprises diethyl ether, tetrayhdrofuran, 1:2-dimethoxyethane, bis-(Z-methoxyethyl) ether, 1:4-dioxane, acetone, benzene, hexane, pyridine, chlorobenzene, chloroform, methylene dichloride, formamide, dimethyl sulphoxide and acetonitrile.
  • a process as claimed in claim 9 wherein the initial concentration of carbon compound in the reaction mixture is more than about 0.25 mole per litre.
  • a process as claimed in claim 1 wherein the pro- 3,461,128 5 6 portion of carbon compound used is such that substanpyridyliurn salt is extracted from the reaction mixture by tially two labile halogen atoms are available for each water. molecule of tetrahydrobipyridyl. References Cited 16.
  • a process as claimed in claim 1 wherein the inter- UNITED STATES PATENTS action is carried out at a temperature in the range 55 C to C 5 3,227,723 1/1966 Baines e1: a1. 260-296 17.
  • a process as claimed in claim 1 wherein the inter- 3272835 9/1966 Dransfi 61d et 260296 action is carried out at a temperature in the range of 0 HENRY R. JILES Primary Examiner C. to 50 C.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Pyridine Compounds (AREA)
  • Plural Heterocyclic Compounds (AREA)

Description

US. Cl. 260296 18 Claims ABSTRACT OF THE DISCLOSURE There is provided a process for the production of an N:Ndisubstituted 4:4-bipyridylium salts by the interaction of an N:N-disubstituted tetrahydro-4:4-bipyridyl with a carbon compound containing a labile halogen atom wherein the labile halogen atom is attached to carbon by a bond of dissociation energy less than about 70 kcaL/mole. The process will produce salts which are useful as herbicides.
This invention relates to the production of bipyridylium salts and particularly to the production of bis-quaternary salts of 4:4-bipyridyl.
It is known that bis-quaternary salts of 4:4-bipyridyl are useful herbicides and these compounds are usually made by a quaternisation reaction from 4:4-bipyridyl. It is also known that N:N'-dibenzyl tetrahydrobipyridyl can be oxidised to an N:N'-dibenzyl bipyridylium salt by the action of iodine, but this process gives only poor yields of the bipyridylium salt, and much of the starting material is converted into benzyl pyridinium salts by fission of the bond connecting the two pyridine rings.
In UK. applications Nos. 14,720/64 and 36,729/64, certified copy of which is in the file of US. application Ser. No. 445,770, filed on Apr. 5, 1965, we have described processes whereby N:N'-disubstituted tetrahydro-4:4-bipyridyls may be oxidised to N:N-disubstituted-4:4-bi pyridylium salts by organic oxidants particularly quinones. We have now found that the N:N'-disubstit-utedtetrahydro-4:4-bipyridyls may be converted in good yield into N:N-disubstituted 4:4-bipyridylium salts by the action of compounds containing a labile halogen atom.
Thus according to our invention we provide a process for the conversion N:N-disubstituted tetrahydro-4:4'-bipyridyls to N:N'-disubstituted 4:4 bipyridylium salts which comprises treating the tetrahydrobipyridyl with one or more carbon compounds which each contains a labile halogen atom. We do not include fluorine in the term halogen atom.
The tetrahydrobipyridyls which may conveniently be used in our process are those more fully described in the above mentioned U.K. applications, for example tetrahydrobipyridyls which carry alkyl or carbamyl alkyl, and particularly methyl or N:N-disubstituted carbamyl methyl substituents on the nitrogen atoms. Other suitable N:N-disubstituted-tetrahydro-4:4 bipyridyls are those carrying inert substituents, for example alkyl groups, on the carbon atoms of the pyridine nuclei.
The carbon compound containing a labile halogen atom may be any such compound which is capable of nited States Patent 3,461,128 Patented Aug. 12, 1969 removing hydrogen from the tetrahydrobipyridyl, for example a compound containing a carbon-to-halogen bond of dissociation energy less than about kcals./mole. Such carbon compounds include those in which the halogen is attached to an electron withdrawing group for example a CHal (where Hal=Cl, Br or 1), CO, F, Br or Cl group. We have found that it is convenient to use liquid or solid carbon compounds and particularly liquid or solid compounds containing less than 4 carbon atoms per molecule. Bromine and iodine atoms tend to be more labile than chlorine atoms when attached to carbon and compounds containing bromine and iodine will therefore tend to be more effective than those containing chlorine only. However compounds containing bromine and iodine are relatively expensive and it is therefore economically desirable to use the cheaper compounds containing chlorine. We also prefer to use highly halogenated compounds and in particular fully halogenated compounds such as carbon tetrahalides (other than carbon tetrafiuoride). In particular there may be used a carbon tetrahalide which does not contain fluorine, for example carbon tetrachloride, carbon tetrabromide, bromotrichloromethane or dichlorodibromo m e t h a n e. Other compounds which may be used in our invention are bromoform, iodoform, methylene iodide, hexachloroethane, hexachloropropene, 1:1:1 trifiuoro 2:2 dibromo-Z-chloroethane and hexachloroacetone. We have found that use of chloroform, methylene dichloride, benzotrichloride and monochlorobenzene tends to yield very little of the desired product.
The tetrahydrobipyridyl and the carbon compound containing the labile halogen atom may be interacted simply by mixing the two components, but this procedure tends to give rise to a vigorous reaction which may be difficult to control. We have therefore found it useful to moderate this reaction by carrying it out in solution in an inert solvent. Suitable solvents are those which will dissolve the N:N'-disubstituted-tetrahydro4:4-bipyridyl and also the carbon compound containing the labile halogen atom. Examples of such solvents are ethers for example diethyl ether, tetrahydrofuran, 1:2 dimethoxyethane, bis (2- methoxyethyl) ether and 1:4-dioxane; ketones, for example acetone; hydrocarbons, for example benzene and hexane; organic bases, for example pyridine; halogenated hydrocarbons, other than those used to interact with the tetrahydrobipyridyl, particularly chlorinated hydrocarbons, for example chlorobenzene, chloroform and methylene dichloride; amides, particularly tertiary alkylamides, for example formamide; sulphoxides, for example dimethyl sulphoxide or nitriles, for example acetonitrile. We prefer that the tetrahydrobipyridyl and the carbon compound containing a labile halogen atom be dissolved in the same solvent as this avoids difficulties inherent in the use of mixed solvents.
The concentration of the tetrahydrobipyridyl may conveniently be above about 0.75 mole per litre and the concentration of the carbon compound containing a labile halogen atom, for example carbon tetrachloride, may be above about 0.25 mole per litre. Lower concentrations of either reagent necessitates the recovery of the N:N-disubstituted bipyridylium salts from large quantities of solvent and therefore tend to be inconvenient. Either reagent may if desired be used undiluted, the other reagent being dissolved in the chosen solvent, but if the reagents are Q used in high concentration care should be taken that the reaction does not become too vigorous and lead to some destruction of the desired product or to the production of unwanted by-products.
halogen atom, the solvent, the concentration of the reagents in the solvent, the reaction temperature and the time of the reaction. These variations and their effects on the yield of bipyridylium salts calculated on the tetra- We prefer to use such a proportion of carbon com- 5 hydrobipyridyl used are set out in the following table.
TABLE Carbon Compound (A) eon- Volume of tetra- Yield of bipyritammg a labile halogen Weight of (A) Volume of (A) hydrobipyridyl Temperature, Reaction time, dylium salt, per
atom gms. Solvent solution, ml. solution, ml. 0. hrs. cent of theory 27 Diethyl other. 600 450 55 24 79 Dibutyl car tol 100 100 35 24 17 Dicthyl other 100 100 35 14 16 Hexachloroethane 200 200 35 1 :21
Methylene iodide 200 200 35 1 13 Carbon tetrabromide 200 200 35 1 22 Hexachloropropene. 450 600 20 1. 30
Hexachloroaeetone 450 200 25 0. 5 14 Bromolorm 450 200 25 1 11 CF3CBI'201 250 600 35 1 Ildol'orm 500 500 35 1 17 pound containing a labile halogen atom that two labile halogen atoms are available for each molecule of tetrahydrobipyridyl; thus about, or rather more than, 2 moles of a carbon compound containing one labile halogen atom per molecule should be used to interact with 1 mole of tetrahydrobipyridyl. A smaller proportion of carbon compound containing a labile halogen atom will tend to leave some of the tetrahydrobipyridyl unreacted and a larger proportion will leave an excess of the halogen containing carbon compound.
The temperature at which reaction is carried out will depend on the concentration of the reagents and on the particular reagents used. We have found that suitable temperatures are from about 55 C. to 70 C. and preferably from 0 C. to 50 C.; higher temperatures tend to cause decomposition of the tetrahydrobipyridyls and lower temperatures will necessitate cooling of the reactants. The most suitable time of reaction can be found by simple experiment and will depend on the reagents used and the temperature at which the reaction is earned out; we have however found that a minimum time of 20 to 30 minutes is generally necessary. The mechanism of the reaction is at present obscure but it appears that the labile halogen atom from the carbon compound is replaced by one of the hydrogen atoms from the tetrahydrob1pyr1dyl. Thus when carbon tetrachloride is used in the reaction chloroform as well as the N:N-disubstituted bipyridylium salt is found in the reaction product.
The N:N-disubstituted bipyridylium salt may be recovered from the reaction mixture by conventional processes for example by extraction of the reaction mixture with water or with a dilute aqueous solution of a mineral acid such as sulphuric, hydrochloric or phosphoric acid. The N:N-bipyridylium salt may then be recovered from the aqueous phase, which has previously been separated from the organic phase, by evaporation of the water and crystallisation of the salt.
The invention is illustrated but not limited by the following example in which the parts and percentages are by weight.
EXAMPLE A solution of 1:1 dimethyl-1:1:4:4-tetrahydrobipyridyl (16.55 gms.) in an inert solvent was mixed with a solution of a carbon compound containing a labile halogen atom in the same solvent. The mixture was heated to the required temperature and maintained at the temperature for a given time. The mixture was then treated with aqueous hydrochloric acid (7.3 gms. in 200 mls.), and the aqueous phase separated and analysed polarographically for N:N-dimethyl-4:4'-dipyridylium salts. The procedure set out above was repeated, variations being made in the carbon compound containing a labile What we claim is:
1. A process for the production of an N:N-dilower alkyl-4:4-bipyridylium salt which comprises reacting in an inert solvent a N:N-dilower alkyl tetrahydro-4:4-bipyridyl with a linear alkyl or linear alkenyl carbon compound having less than 4 carbon atoms and containing a labile halogen atom selected from chlorine, bromine and iodine and the labile halogen atom is attached to carbon by a bond of dissociation energy less than about 70 kcal./mole.
2. A process as claimed in claim 1 wherein the labile halogen atom is attached to a carbon atom which is attached to an electron Withdrawing group.
3. A process as claimed in claim 2 wherein the electron withdrawing group is a carbonyl group, a CHal group (where Hal represents chlorine, bromine or iodine), or a fluorine, chlorine or bromine atom.
4. A process as claimed in claim 1 wherein the labile halogen atom is chlorine.
5. A process as claimed in claim 1 wherein the carbon compound is fully halogenated.
6. A process as claimed in claim 1 wherein the carbon compound is a carbon tetrahalide not containing fluorine.
7. A process as claimed in claim 6 wherein the carbon tetrahalide is carbon tetrachloride or carbon tetrabromide.
8. A process as claimed in claim 1 wherein the carbon compound is bromotrichloromethane, dichlorodibromomethane, bromoform, iododform, methylene iodide, hexachloropropene, hexachloroacetone or 1:1:1-trifiuoro-2:2- dibromo-Z-chloroethane.
9. A process as claimed in claim 1 wherein the interaction of the tetrahydrobipyridyl and the carbon compound containing a labile halogen atom is carried out in an inert solvent.
10. A process as claimed in claim 9 wherein the solvent comprises an ether.
11. A process as claimed in claim 10 wherein the ether is diethyl ether, tetrahydrofuran or bis-(Z-methoxy ethyl) ether.
12. A process as claimed in claim 9 wherein the solvent comprises diethyl ether, tetrayhdrofuran, 1:2-dimethoxyethane, bis-(Z-methoxyethyl) ether, 1:4-dioxane, acetone, benzene, hexane, pyridine, chlorobenzene, chloroform, methylene dichloride, formamide, dimethyl sulphoxide and acetonitrile.
13. A process as claimed in claim 9 wherein the initial concentration of tetrahydrobipyridyl in the reaction mixture is more than about 0.75 mole per litre.
14. A process as claimed in claim 9 wherein the initial concentration of carbon compound in the reaction mixture is more than about 0.25 mole per litre.
15. A process as claimed in claim 1 wherein the pro- 3,461,128 5 6 portion of carbon compound used is such that substanpyridyliurn salt is extracted from the reaction mixture by tially two labile halogen atoms are available for each water. molecule of tetrahydrobipyridyl. References Cited 16. A process as claimed in claim 1 wherein the inter- UNITED STATES PATENTS action is carried out at a temperature in the range 55 C to C 5 3,227,723 1/1966 Baines e1: a1. 260-296 17. A process as claimed in claim 1 wherein the inter- 3272835 9/1966 Dransfi 61d et 260296 action is carried out at a temperature in the range of 0 HENRY R. JILES Primary Examiner C. to 50 C.
18. A process as claimed in claim 1 wherein the bi- 10 ALAN ROTMANI Assistant Examiner
US550965A 1965-05-28 1966-05-18 Process for producing n:n'-dilower alkyl-4:4'-bipyridylium salts Expired - Lifetime US3461128A (en)

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US20080160084A1 (en) * 2004-12-22 2008-07-03 Colarome, Inc. Natural Water-Insoluble Encapsulation Compositions and Processes for Preparing Same

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3227723A (en) * 1966-01-04 Process for preparing bipykibyils
US3272835A (en) * 1966-09-13 Process for the manufacture of bipyridyls

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3227723A (en) * 1966-01-04 Process for preparing bipykibyils
US3272835A (en) * 1966-09-13 Process for the manufacture of bipyridyls

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080160084A1 (en) * 2004-12-22 2008-07-03 Colarome, Inc. Natural Water-Insoluble Encapsulation Compositions and Processes for Preparing Same
US9687807B2 (en) 2004-12-22 2017-06-27 Colarome, Inc. Natural water-insoluble encapsulation compositions and processes for preparing same
US10981136B2 (en) 2004-12-22 2021-04-20 Capol Inc. Natural water-insoluble encapsulation compositions and processes for preparing same

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NL6607290A (en) 1966-11-29
CH487153A (en) 1970-03-15
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IL25837A (en) 1970-02-19
ES327222A1 (en) 1967-08-01

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