DE2023687C - Process for the preparation of 2-alkylidene-norbornane compounds - Google Patents

Description

in which R ^{1 is} a hydrogen atom or a C; _ _G alkyl and R ² is a hydrogen atom, a C ₁ _ ₆ alkyl or C ₁ _ ₆ acyl, as characterized by reacting a 1-alkenyl-nortricycIen of the general formula II (II)

R "-C = CH ₂

in which R ^{1 has} the above meaning, with a proton donor of the general formula R ² OH, in which R ^{2 has} the above meaning, in the presence of an inorganic acid or its aqueous solution, an organic sulfonic acid or palladium-on-carbon as catalysts implements.

The above procedure can be illustrated by the reaction scheme below:

(H)

R ¹ - C = CH ₇

R ¹ - C = CH ₂

in which R ^{1 has} the above meaning, with a proton donor of the general formula

R ² OH

in which R ^{2 has} the above meaning, in the presence of an inorganic acid or its aqueous solution, an organic sulfonic acid or of palladium-on-carbon as catalysts.

2. The method according to claim 1, characterized in that the proton donor is water, Methanol, ethanol, propanols, butanols, formic acid, acetic acid or propionic acid are used.

3. The method according to claim 1, characterized in that the reaction is carried out at temperatures carried out from -20 ° C to the boiling point of the reaction mixture for 10 minutes to several hours.

4. The method according to claim 1, characterized in that that the reaction is carried out in the presence of 5-alkylidene-2-norbornene and 5-alkenyl-2-norbornene performs and the 2-alkylidene-norbornane derivative produced separated from the unreacted norbornenes.

The invention relates to a process for the preparation of 2-alkylidene-norbornane compounds of the general Formula I.

R ² O

R ¹
C-CH ₃

(I)

55

60

in which R ¹ is a hydrogen atom or a C ₁ _ ₈ alkyl and R ² is a hydrogen atom, a C, _ ₆ alkyl or C j _ ₆ is acyl, the characterized ge-R ² OH

Catalyst RO

The process according to the invention is preferably carried out in such a way that the l-AJkenyl-nortricyclen in a mixture with the proton donor, such as water, a lower aliphatic alcohol or a lower one Carboxylic acid, in the presence of a catalyst at temperatures from -20 ° C to the boiling point stirs.

The reaction seems to proceed as follows: The rearrangement of the side chain takes place with the opening of the cyclopropane ring. A carbonium ion is obtained which combines with the anion of the proton donor.

The proton donor can be water, an alcohol such as methanol, ethanol, propanols or butanols, or use a carboxylic acid such as formic acid, acetic acid, or propionic acid.

As catalysts in the process according to the invention, for. B. palladium-aut-charcoal, which is generally used as a hydrogenation catalyst, also inorganic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid or their aqueous solutions, or organic sulfonic acid, such as p-toluenesulfonic acid or naphthalenesulfonic acid, are used. The amount of catalyst to be used is not critical. In the case of palladium-on-charcoal, however, a lot of ₁₀ V b ^'s is preferred V100 equivalent.

The reaction proceeds within 10 minutes to several hours under vigorous stirring of the reactants at temperatures of from - 20 ⁰ C to the boiling point of the reaction mixture and at any desired pressures quantitatively. The end product can be isolated in the usual way.

The inventive method can also be carried out when the compound (II) in Mixture with its isomers 5-alkylidene-2-norbornene and 5-alkenyl-2-norbornene is present, which by fract-

tioning distillation cannot be separated from one another. In this case only the reacts Compound (II) to the desired norbornane compounds (I). The method according to the invention enables hence the separation of the isomer mixture mentioned. Since only the 1-alkenyl-nortricyclen reacts to the higher-boiling norbornane compounds, the lower-boiling isomers can be easily detach.

The new 2-alkylidene-norbornane derivatives are as starting compounds for the production of organic intermediates. Medicinal and agricultural Chemicals suitable. They can also be used for the production and purification of 5-alkylidene-2-norhornenes are used, in turn as a diene component of ethylene-propylene-diene terpolymers are suitable.

The examples illustrate the invention.

example 1

3.0 g are placed in a 3 ml glass vessel 1-Isopropenyinortricyclen, 1.41 g of 10% palladium on charcoal and 30 ml of glacial acetic acid. The mixture is stirred vigorously at room temperature in a nitrogen atmosphere. After 10 hours, the catalyst is filtered off, and 90 ml of water are added to the filtrate then extracted with ether. The ether extract is neutralized with sodium carbonate, dried and steamed the ether off and receives 4.2 g of 6-acetoxy-2-isopropylidene-norbornane.

Bp ₁₆ Hf ° C; nV ^J 1.4830.

The structure of the product is confirmed by the IR, mass and NMR spectra.

C ₁₂ H ₁₈ O ₂ :

Calculated ... C 74.19, H 9.34;
found .... C 73.88, H 9.55.

Example 2

1.0 g of 1-isopropenyl-nortricyclene and 0.5 g of 10% palladium-on-charcoal are placed in the 20 ml glass vessel and 10 ml of ethanol. The mixture is stirred vigorously at room temperature in a nitrogen atmosphere. The reaction mixture is analyzed by gas chromatography. It has the following composition:

C _n H _3n O:

Calculated
found .

reaction time
Min. Starting
material
% End product
% 30th
360 60.0
2.0 40.0
98.0

Yield of 6-ethoxy-2-isopropylidene-norbornane: 1.3 g.

Bp ₁₄ 92 ° C; n9 1.4790,

The structure of the final product is confirmed by the infrared, mass and NMR spectra.

C 79.94, H 11.18;
C 80.05, H 11.31.

Example 3

2.0 g are placed in a 30 ml Erlenmeyer flask equipped with a magnetic stirrer l-isopropenyl-nortricyclen, 20ml ethanol and 0.1g concentrated sulfuric acid. The mixture is stirred vigorously at room temperature in a nitrogen atmosphere. After 3 hours, the reaction mixture is mixed with water, neutralized and extracted with Ether. The ether extract is washed with water, dried and the ether is evaporated. You get 2.5 g of o-ethoxy ^ -isopropylidene-norbornane.

Example 4

2.0 g are placed in a 30 ml Erlenmeyer flask equipped with a magnetic stirrer l-isopropenyl-nortricyclen, 15 g glacial acetic acid and 0.1 g concentrated sulfuric acid. The mixture is stirred briskly at room temperature in a nitrogen atmosphere. After 30 minutes, it is added to the reaction mixture Ice water, neutralized and extracted with ether. The ether extract was washed with water, dries it and steams off the ether. 2.60 g of 6-acetoxy-2-isopropylidene-norbornane are obtained.

B e i s ρ i e 1 5

A mixture of 275 g of 5-isopropylidene-2-norbornene and 24 g of 1-isopropenyl-nortricyclene, 240 g of ethanol and 18 g of 50% strength sulfuric acid are placed in a 1 liter Erlenmeyer flask equipped with a magnetic stirrer. The mixture is stirred vigorously for 5 hours at room temperature in a nitrogen atmosphere. The reaction mixture is poured into ice water, neutralized and extracted with ether. The ether extract is washed with water, dried and the ether is evaporated. This gives 260 g of 5-isopropylidene-2-norbornene, bp ₁₆₀ 90 ⁰ C and 32 g of 6-ethoxy-2-isopropylidene-norbornane, bp. ₁₇ 104 ⁰ C.

Example 6

A mixture of 4.0 g of 5-isopropylidene-2-norbornene and 1.0 g of l-isopropenyl-nortricyclene and 14 ml of 20% strength aqueous sulfuric acid are placed in a 50 ml separating funnel. The mixture is stirred vigorously at room temperature in a nitrogen atmosphere. After 5 hours, the mixture is neutralized and extracted with ether. The ether extract is washed with water, dried and the ether is evaporated. 4.1 g of a mixture with a boiling point of ₁₅₀ 85 ° to 87 ° C., 95% of 5-isopropylidene-2-norbornene and 5% 1-isopropenyl-nortricyclene and 0.7 g of 6-hydroxy-2 are obtained -isopropylidene-norbornane of bp ₁₉ 118'C;n'i 1.5060, consists.

C ₁₀ H ₁₆ O:

-Calculated ... C 78.89, H 10.59;
found .... C 78.23, H 10.95.

Claims (1)

Patent claims: 1. Process for the preparation of 2-alkylidene norbornane compounds of the general formula I. is characterized by a 1-Alker.yl-nortricyclen of the general formula II (I)