WO2008084086A1 - Method for the production of o-vinylcarbamates and vinylcarbonates - Google Patents

Abstract

The present invention relates to a method for the production of o-vinylcarbamates or vinylcarbonates, wherein a secondary amine or an alcohol is reacted with an alkyne compound in the presence of a catalyst selected from among carbonyl complexes of rhenium, manganese, tungsten, molybdenum, chromium, and iron, at a temperature of = 250°C.

Description

 Process for the preparation of O-vinyl carbamates and vinyl carbonates

The present invention relates to a process for the preparation of vinyl carbonates and O-vinyl carbamates, in which alcohols or secondary amines with Acetylenverbin- fertilize and CO ₂ are reacted in the presence of certain catalysts.

O-vinyl carbamates are valuable intermediates in the manufacture of, for example, insecticides, herbicides and fungicides. Vinyl carbonates are used inter alia as starting material for contact lenses. The vinyl carbamates are frequently prepared by dehydrohalogenation of haloalkyl carbamates (EP 104 984) or by the addition of amines to vinyl chloroformate (Olofson et al .: Tetrahedron Letters 18 (1977), 1563-1566). Vinyl carbonates are accessible by reaction of vinyl chloroformate with alcohols (EP 0 757 033).

Two variants of phosgene are known for the preparation of vinyl chloroformate: on the one hand, the reaction with mercury enolate (Olofson et al., J. Org. Chem. 43 (1978), 752) and, on the other hand, the reaction with ethylene glycol to form ethylene glycol bis-chloroformate which is subsequently thermally cleaved to vinyl chloroformate (Lee, J. Org. Chem. 30 (1965), 3943, US 2,377,085). The thermal elimination of the ethylene glycol bis-chloroformate succeeds only with poor selectivity. A further problem with these processes is the use of phosgene or organomercury compounds.

There have therefore been many attempts to replace phosgene with the less hazardous carbon dioxide. Mäh discusses the synthesis of vinyl carbamates from secondary amines, carbon dioxide and acetylene in the presence of a ruthenium catalyst (J. Org. Chem. 54, (1989), 1518-1523). The yield is only moderate. WO 9 602 498 A1 describes a process for the preparation of vinyl carbamates by means of a ruthenium catalyst from secondary amines, carbon dioxide and acetylenically unsaturated compounds in the presence of a tertiary amine. However, the yields vary greatly in this process. Jiang and Hua report the regioselective, re-catalyzed coupling of terminal alkynes with diethylamine and CO ₂ with high yields of vinyl carbamates (Tetrahedron Letters 47 (2006), 953-955). The reaction time is 24 hours and more.

It is therefore an object of the present invention to provide a simple process for the preparation of vinyl carbamates and vinyl carbonates which provides the desired products with a short reaction time.

Another object is to provide a process which provides these products with short reaction time and satisfactory yield. Surprisingly, it has now been found that this object is achieved by a process for the preparation of vinyl carbamates and vinyl carbonates from the reaction of secondary amines or of alcohols with alkynes and carbon dioxide, if the catalyst used is a carbonyl complex, halide or oxide of rhenium, ruthenium, Manganese, tungsten or iron is used.

The present invention therefore provides a process for the preparation of O-vinylcarbamates or vinylcarbonates of the general formula I.

wherein

R ^{1 is} dC ₂ o-alkyl optionally having 1, 2 or 3 substituents independently selected from phenyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ monoalkylamino, di-C 1 -C ₄ alkylamino ; or

R ^{1 is} C ₂ -C ₂ o-alkenyl optionally having 1, 2 or 3 substituents independently selected from phenyl, halogen, hydroxy, C ₁ -C ₄ alkoxy, amino, C ₁ -C ₄ monoalkylamino, diCrC _4- alkylamino; or

R ¹ is C ₃ -C ₇ cycloalkyl having optionally 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, -C ₄ - alkoxy, amino, CrC ₄ alkyl, _Ci-C4- Monoalkylamino, di-C 1 -C ₄ -alkylamino; or

R ^{1 is} phenyl optionally having 1, 2, 3 or 4 substituents independently selected from C 1 -C ₄ alkyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ monoalkylamino, diCrC _4- alkylamino;

R ² is H, d-Cβ-alkyl, phenyl-C _r C ₄ alkyl, phenyl which is optionally substituted with 1 or 2 C _r C ₄ alkyl groups, or C ₃ -C ₇ cycloalkyl;

X is O or NR ³ ;

R ^{3 is} H; or

R ^{3 is} dC ₂ o-alkyl, wherein R ³ optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ monoalkylamino, diCrC ₄ alkylamino; or R ^{3 is} C ₂ -C ₂ o-alkenyl, wherein R ³ optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C ₁ -C ₄ -alkoxy, amino, C 1 -C ₄ -monoalkylamino , Di-C 1 -C ₄ -alkylamino; or

R ^{3 is} C ₃ -C ₇ -cycloalkyl, where R ³ optionally has 1, 2 or 3 substituents which are selected independently of one another from phenyl, halogen, hydroxyl, C 1 -C ₄ -alkoxy, amino, C 1 -C ₄ -alkyl, dC ₄ monoalkylamino, di-C 1 -C ₄ alkylamino; or

R ^{3 is} phenyl, wherein R ³ optionally has 1, 2, 3 or 4 substituents which are independently selected from C 1 -C ₄ alkyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ monoalkylamino, diCrC _4- alkylamino; or

R ¹ and R ³ together represent a 5- or θ-membered saturated heterocycle having one or two heteroatoms independently selected from N and O,

comprising the reaction of a secondary amine or an alcohol of the general formula II

R ⁱ -XH (II)

wherein R ¹ and X have the meanings given above, with carbon dioxide and an alkyne of the general formula III

H-C≡C-R2 (IN)

wherein R ^{2 has} the meanings given above, in the presence of a catalyst which is selected from a carbonyl complex, a halide or oxide of rhenium, manganese, tungsten, molybdenum, chromium, iron or rhenium metal.

The preparation of the vinyl carbonates can be illustrated by the following reaction equation:

Cat. = Catalyst The preparation of vinyl carbamates can be illustrated by the following reaction equation:

Cat. = Catalyst

The dC ₂ o-alkyl groups may be straight-chain or branched groups having the stated carbon number. Examples are methyl, ethyl, i-propyl, n-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, n-dodecyl, etc.

Examples of C ₃ -C ₇ -cycloalkyl are cyclopropyl, cyclobutyl, cycloheptyl and in particular cyclopentyl and cyclohexyl.

Examples of C ₂ -C ₂ o-alkenyl groups are vinyl, 1- or 2-propenyl, butene-1-yl, butene-2-yl and isobutenyl.

Halogen is fluorine, chlorine, bromine or iodine.

R ¹ is preferably C ¹ -C 10 -alkyl, in particular C ¹ -C 6 -alkyl. Preference is given to methyl, ethyl, n-propyl, n-butyl, isobutyl and t-butyl.

R ² is preferably H or C ¹ -C 8 -alkyl, particularly preferably H.

R ³ preferably represents Ci-Ci _o alkyl, in particular _Ci-C6 alkyl. Preference is given to methyl, ethyl, n-propyl, n-butyl, isobutyl and t-butyl.

Suitable alcohols of the formula II are aliphatic, alicyclic and aromatic alcohols, such as methanol, ethanol, i-propanol, n-propanol, n-butanol, tert-butanol, 2-ethylhexanol, 2-propylheptanol, cyclobutanol, cyclohexanol, benzyl alcohol, o-cresol , p-cresol or phenol. Aliphatic alcohols such as methanol, ethanol, n-propanol, n-butanol, n-hexanol, 2-ethylhexanol or 2-propylheptanol are preferred.

Suitable amines of the formula II are secondary aliphatic and aromatic amines such as dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diphenylamine, methylethylamine, methylpropylamine, N, N-dibenzylamine, N-methylaniline, piperidine etc. Preferred amines are aliphatic amines such as dibutylamine , Dipentylamine and dihexylamine.

Suitable alkynes are aliphatic compounds having a terminal triple bond. Preference is given to acetylene. The catalyst used is the carbonyl complexes, oxides or halides of rhenium, manganese, tungsten, molybdenum, chromium and iron. Carbonyl complexes are compounds which have at least one carbonyl group as ligand. The remaining coordination sites may be occupied by other ligands, as exemplified in the following paragraph. Oxides and halides are also compounds in which one or more coordination sites and / or valencies are occupied by a Ci-Cs-alkyl group, and oxyhalides. Examples of these are CH ₃ ReO ₃ , ReO ₃ Cl, or ReOCl ₄ .

The catalysts can be present in all oxidation states, in the case of carbonyl complexes they are preferably present in the oxidation state 0 or I. Preferred catalysts are the carbonyl complexes, oxides or halides of rhenium, manganese or molybdenum and in particular of rhenium, wherein the carbonyl complexes of rhenium or manganese have proven to be particularly suitable.

Particularly effective are the carbonyl complexes of the above-mentioned metals. One or more of the carbonyl groups may be replaced by suitable ligands such as halogens, especially chlorine or bromine, phosphine ligands such as triphenylphosphine, trimethylphosphine, triethylphosphine, tri-n-butylphosphine, etc., amine ligands such as NH ₃ , ethylenediamine, etc., alcohol ligands such as Phenol, methanol, ethanol, etc., or H ₂ O. Examples of suitable catalysts are Mn ₂ (CO) i ₀ , Fe (CO) ₅ , Fe ₂ (CO) ₉ , Mo (CO) ₆ , W (CO) ₆ and Cr (CO) ₆ .

The rhenium catalysts have proven to be particularly suitable. Examples include Re ₂ (CO) _I0, Re (CO) ₅ Cl, Re (CO) ₅ Br, ReBr (CO) ₃ (CH ₃ CN) _2, recp (CO) _3, Re (penta-methyl-Cp) (CO) _3, ReCl (CO) ₃ (CH ₃ CN) _2, ReBr (CO) ₃ (THF) _2, recp _2, ReCl (CO) ₃ (THF) _2, Re ₂ (penta-methyl-Cp) ₂ (CO) ₃ , Re ₂ (penta-methyl-Cp) ₂ O ₄ , Re (pentamethyl-Cp) OCI ₂ (Cp = cyclopentadiene, THF = tetrahydrofuran), Re ₂ O ₇ , Re, ReCl ₃ , ReBr ₃ and ReCH ₃ O ₃ . A particularly preferred catalyst is Re ₂ (CO) i ₀ .

The reaction can be carried out in homogeneous or heterogeneous liquid phase. If a homogeneous liquid phase is desired, a catalyst is used which is soluble in the reaction medium under the given reaction conditions or goes into solution during the reaction. Such catalysts are in particular the carbonyl complexes of the metals in question here. Heterogeneous catalysts are the halides and oxides of these metals as well as the rhenium metal. The heterogeneous catalysts can be directly, for example in powder form, or on a support applied applied. Suitable carriers are carbon powder, zeolites, aluminum oxides, silicon oxides, etc.

In general, the catalyst is used in an amount of 0.000,005 to 5 mol%, preferably 0.000,005 to 0.5 mol%, more preferably 0.0001 to 0.1 mol%, and especially 0.0005 to 0.05 mol%. , 0.0001 to 0.05 mol%, 0.0005 to 0.01 mol% or 0.001 to 0.01 mol%, each based on equivalents of the compound of formula II.

The reaction is generally carried out in a suitable inert solvent. Suitable inert solvents are aliphatic and aromatic hydrocarbons, such as pentane, hexane, heptane, decalin, paraffin oil, toluene, xylene, etc., ethers, such as tetrahydrofuran, dioxane or diphenyl ether, chlorinated hydrocarbons, such as methylene chloride, 1, 2-dichloroethane or chlorobenzene, esters such as ethyl acetate, n-butyl acetate or butyrolactone, acetonitrile, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone or polyethylene glycols or mixtures thereof. The reaction can also be carried out in a compound of the formula II as a solvent, if this is liquid at the chosen reaction temperature.

The reaction temperature is freely selectable over a wide range. It is generally chosen to be rapidly reacted without degrading parent compounds or the product. In general, the temperature is in the range of 70 to 250 ^° C., in particular 100 to 210 ^° C., preferably 120 to 180 ^° C., 130 to 170 ^° C., 140 to 160 ^° C. and in particular 140 to 150 ^° C.

The reaction pressure is between 1 and 300 bar, for the proportion of the alkyne in the mixture preferably between 1 and 20 bar, for the proportion of carbon dioxide in the mixture preferably between 1 and 250 bar. The pressure can be adjusted, for example, with the compound of the formula III used and / or an inert gas such as nitrogen. The reaction time is generally in the range of 0.5 to 72 hours, especially 1 to 48 hours.

Optionally, it is also possible to add reaction-promoting additives, such as zinc acetate, lithium salts, for example LiCl, Lewis acids, such as BF ₃ , etc., Lewis bases, such as triethylamine, pyridine, 1,5-diazabicyclo [4.3.0] non-5- en etc., substances that react with the catalyst at the CO and thereby can create free coordination sites, such as trimethylamino-N-oxide. The reaction can be carried out batchwise, continuously or in the sem / -öafc /? - process. The workup is carried out in the usual way, expediently by distilling off the desired vinyl carbonate / vinyl carbamate. The catalyst remains in the sump and can optionally be reused. Expediently, the reaction and the work-up, in particular the purifying distillation, can be carried out in the presence of a polymerization inhibitor. Examples of suitable polymerization inhibitors are hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, nitroso compounds such as iso-acrylonitrate, nitrosodiphenylamine, N-nitroso-cyclohexylhydroxylamine, Methylene blue, phenothiazine, tannic acid or diphenylamine can be used. The polymerization inhibitors are generally used in amounts of from 1 to 10,000 ppm, in particular from 100 to 1000 ppm, in each case based on the entire batch.

In a particularly preferred embodiment of the invention, secondary amines of the formula II are reacted with carbon dioxide and acetylene. The catalyst used is Re ₂ (CO) 10. Preferably, the reaction is carried out under a pressure of 15 to 25 bar, in particular 18 to 22 bar, wherein the pressure can be adjusted by nitrogen, carbon dioxide and / or acetylene. The pressure is kept substantially constant by repressing acetylene.

Examples

The following examples illustrate the invention without limiting it. GC analyzes were performed on a capillary column, with a Carbowax (polyethylene glycol) film, e.g. DB Wax from J & W Scientific.

GC = gas chromatography

GCMS = gas chromatography / mass spectroscopy

example 1

A mixture of 8.60 g (46 mmol) of dihexylamine, 0.26 g (0.4 mmol) of Re ₂ (CO) i ₀ and 50 ml of toluene were at 160 ° C a nitrogen pressure of 2 bar, a carbon dioxide pressure of 13 bar and a Acetylene pressure of 5 bar for 6 h subjected to the vinylation. The total pressure was maintained by repressing the acetylene. The formed O-vinylcarbamate could be detected by GC and GCMS as the main product. Example 2

A mixture of 8.60 g (46 mmol) of dihexylamine, 0.26 g (0.4 mmol) Re ₂ (CO) i ₀ and 50 ml of toluene were at 160 ° C a nitrogen pressure of 2 bar, a carbon dioxide pressure of 8 bar and a Acetylene pressure of 10 bar for 6 h subjected to the vinylation. The total pressure was maintained by repressing the acetylene. The formed O-vinylcarbamate could be detected by GC and GCMS as the main product.

Example 3

A mixture of 8.60 g (46 mmol) of dihexylamine, 0.26 g (0.4 mmol) of Re ₂ (CO) _I o and 50 ml of divinyl ether were at 160 ° C a nitrogen pressure of 2 bar, a carbon dioxide pressure of 13 bar and a Acetylene pressure of 5 bar for 6 h of vinylation. The total pressure was maintained by repressing the acetylene. The formed O-vinylcarbamate could be detected by GC and GCMS as the main product.

Claims

claims 1. A process for the preparation of O-vinylcarbamates or vinyl carbonates of the general formula I.

wherein R ^{1 is} dC ₂ o-alkyl which optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C 1 -C ₄ -alkoxy, amino, C 1 -C ₄ -monoalkylamino, C 1 -C ₄ -alkylamino; or R ^{1 is} C ₂ -C ₂ o-alkenyl which optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C ₁ -C ₄ -alkoxy, amino, C ₁ -C ₄ -monoalkylamino, di-C ₁ -C _{4 4-} alkylamino; or R ¹ is C ₃ -C ₇ cycloalkyl having optionally 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, -C ₄ alkoxy, amino, -C ₄ alkyl, -C ₄ monoalkylamino , Di-CrC ₄ -alkylamino; or R ^{1 is} phenyl which optionally has 1, 2, 3 or 4 substituents which are independently selected from C 1 -C ₄ -alkyl, halogen, hydroxy, C 1 -C ₄ -alkoxy, amino, C 1 -C ₄ -monoalkylamino, di-C 1 -C _{4 4-} alkylamino; R ^{2 is} H, C 1 -C ₈ alkyl, phenylCrC ₄ alkyl, phenyl optionally substituted with 1 or 2 dC ₄ alkyl groups, or C ₃ -C ₇ cycloalkyl; X is O or NR ³ ; R ^{3 is} H; or R ^{3 is} dC ₂ o-alkyl, wherein R ³ optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ -monoalkylamino, diCrC ₄ alkylamino; or R ^{3 is} C ₂ -C ₂ o-alkenyl, wherein R ³ optionally has 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, C ₁ -C ₄ -alkoxy, amino, C ₁ -C ₄ -monoalkylamino, di -CrC ₄ -alkylamino; or R ³ is C ₃ -C ₇ -cycloalkyl, where R ³ has optionally 1, 2 or 3 substituents which are independently selected from phenyl, halogen, hydroxy, -C ₄ -alkoxy, amino, CrC ₄ alkyl, dC ₄ Monoalkylamino, di-CrC ₄ -alkylamino; or R ^{3 is} phenyl wherein R ³ optionally has 1, 2, 3 or 4 substituents independently selected from C 1 -C ₄ alkyl, halogen, hydroxy, C 1 -C ₄ alkoxy, amino, C 1 -C ₄ monoalkylamino, diCrC _4- alkylamino; or R ¹ and R ³ together represent a 5- or θ-membered saturated heterocycle having one or two heteroatoms independently selected from N and O, comprising the reaction of a secondary amine or an alcohol of the general formula II R ¹ -XH (II) wherein R ¹ and X have the meanings given above, with carbon dioxide and an alkyne of the general formula III H-C≡C-R2 wherein R ^{2 has} the meanings given above, in the presence of a catalyst which is selected from a carbonyl complex, a halide or oxide of rhenium, manganese, tungsten, molybdenum, chromium, iron or rhenium metal. 2. The method according to claim 1, characterized in that the reaction is carried out in a temperature range from 70 ⁰ C to 250 ⁰ C; 3. The method according to the preceding claims, characterized in that the reaction is carried out at a reaction pressure between 1 bar and 300 bar; 4. The method according to the preceding claims, characterized in that the amount of catalyst is 0.000 005 to 5 mol%, based on equivalents of the compound of formula II; 5. The method according to the preceding claims, characterized in that is carried out with a 2- to 10-fold excess of alkyne based on the compound of formula II; A process according to the preceding claims, characterized in that a ratio of carbon dioxide to alkyne is from 1: 1 to 5: 1; 7. The method according to the preceding claims, characterized in that acetylene is used as the alkyne; 8. The method according to the preceding claims, characterized in that is used as the catalyst Re ₂ (CO) i ₀ .