RU2504532C1 - Method of producing norbornane derivatives - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing norbornane derivatives of general formula

, where R₁=H, R₂=CN; or R₁R₂=CH₂-CH₂-CH₂-, which can be used in organic synthesis as semi-products, e.g. for synthesis of adamantane. The method involves hydrogenating a norbornene derivative with hydrogen gas at atmospheric pressure on a catalyst. The norbornene derivative used is dicyclopentadiene or 2-cyanonorbornene-5, and the catalyst used is nickel nanoparticles, obtained by reducing nickel (II) chloride with sodium borohydride in an isopropanol medium in situ. The process is carried out in an isopropanol medium at temperature of 40-50°C for 6-8 hours, followed by separation of the end product.

EFFECT: method simplifies production of compounds of said general formula.

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Description

The invention relates to a method for producing norbornane derivatives, in particular, to a new method for the hydrogenation of norbornene derivatives, which is applicable in the laboratory and allows to obtain saturated hydrocarbons and their derivatives of the general formula

R ₁ = H, R ₂ = CN;

or R ₁ R ₂ = —CH ₂ —CH ₂ —CH ₂ -,

which are used in organic synthesis as intermediates, for example, for the synthesis of adamantane.

A known method of producing norbornane by heterogeneous catalytic hydrogenation of norbornene on iron nanoparticles [At the frontier between heterogeneous and homogeneous catalysis: hydrogenation of olefins and alkynes with soluble iron nanoparticles / C. Rangheard, C. de Julian Fernandez, Pim-Huat Phua, J. Hoorn , L. Lefort, JG de Vries // Dalton Trans., 2010, 39, 8464-8471].

The disadvantage of this method is the need to use an autoclave to create the required hydrogen pressure (20 atm). There are also certain difficulties with the preparation of a catalyst solution, which is prepared in a box with a nitrogen atmosphere for half an hour. In this way, compounds of the claimed structural formula were not obtained.

A known method of producing norbornane by hydrogenation of norbornene with hydrogen under mild conditions on a polyaluminazane stabilized magnesium oxide platinum complex [Hydrogenation of norbornene catalyzed by magnesium oxide-supported polyalumazane-platinum complexes / Tie-Jun Wang, Zhao-Hui Ma, Mei-Yu Huang, Ying-Yian Jiang // Polymers for advanced Technologies. - Vol.7, Issue 2. - P.84-87, February, 1996]. The disadvantages of this method are the difficulty of obtaining and the high cost of the catalyst. In this way, substances of the claimed structural formula were not obtained.

A known method of producing tetrahydrodicyclopentadiene by hydrogenation of dicyclopentadiene on a platinum oxide catalyst at a pressure of about 4 atm with hydrogen gas [Adamantane // P. Schleyer, M.M. Donaldson, R.D. Nicholas, C. Cupas // Organic Syntheses. - Vol. 5. - P.16]. The disadvantage of this method is the use of an expensive platinum catalyst and high hydrogen pressure.

The closest is a method of hydrogenating dicyclopentadiene to tricyclodecane with gaseous hydrogen at atmospheric pressure in the presence of a catalyst representing a mixture of nickel or cobalt chloride hexahydrate and sodium borohydride in a ratio of 1: 2-6 in a medium of dimethylformamide or dimethylacetamide at 15-35 ° C [SU 1066976 C07C 1307 1307 / 61, B01J 23/78 L.I. Gwinter, V.M. Ignatov, G.D. Kharach, L.Kh. Freudlin].

The disadvantages of the method are the need to use fairly hard-to-reach solvents and the difficulty of separating the reaction mixture due to the proximity of the boiling points of the solvent and the product, which makes it difficult to scale the method to large amounts of hydrogenated sutstrate. In addition, the composition of the products and their yield were analyzed by gas-liquid chromatography, without isolation.

The objective of the proposed method is to develop a technologically advanced method for producing norbornane derivatives that does not require the use of expensive catalysts and complex technological conditions, which will allow to achieve high yield values for the initial norbornene derivatives using available reagents.

The technical result is a simplification of the method for producing compounds of the claimed structural formula.

The set result is achieved in a method for producing norbornane derivatives of the general formula

R ₁ = H, R ₂ = CN;

or R ₁ R ₂ = —CH ₂ —CH ₂ —CH ₂ -,

consisting in hydrogenation of the norbornene derivative with gaseous hydrogen at atmospheric pressure on a catalyst, characterized in that dicyclopentadiene or 2-cyanonorbornene-5 is used as the norbornene derivative, and nickel nanoparticles obtained by the reduction of nickel (II) chloride with sodium borohydride in isopropanol are used as the catalyst in situ and the process is carried out in isopropanol at a temperature of 40-50 ° C for 6-8 hours, followed by isolation of the target product.

The essence of the method is the hydrogenation reaction of norbornene derivatives from the series: dicyclopentadiene, 2-cyanonorbornene-5 with gaseous hydrogen in isopropanol medium in the presence of nickel nanoparticles.

The method is as follows.

Sodium borohydride, isopropanol and anhydrous nickel (II) chloride in a molar ratio of sodium borohydride: nickel (II) chloride equal to 2: 1 were charged into a flat-bottomed flask, and a catalyst was obtained by the reaction

The amount of sodium borohydride is calculated based on the amount of catalyst obtained with a slight excess, and therefore, the effect of boron hydrides on the hydrogenation of olefin does not occur. After obtaining a black, transparent in a thin layer of a colloidal metal solution, a norbornene derivative from the series: dicyclopentadiene, 2-cyanonorbornene-5 is loaded and hydrogen gas is bubbled through the reaction mass, which is previously passed through a layer of concentrated sulfuric acid to remove any traces of moisture at atmospheric pressure in for 6-8 hours at a temperature of 40-50 ° C. At the end of the reaction, a few drops of water are added to the reaction mixture to coagulate the catalyst particles. The desired product is isolated from the filtrate by distillation at atmospheric pressure or in vacuum. The properties of the synthesized tetrahydrocyclopentadiene and 2-cyanonorbornane are consistent with published data.

Stabilization of colloidal solutions of metal nanoparticles is not required, this greatly simplifies and cheapens the proposed method of hydrogenation. Since the same conditions are used for the synthesis of the catalyst and the reduction of the claimed compounds, the whole process is reduced to a single-stage synthesis, in which the catalyst is formed in situ from available nickel chloride.

The invention is illustrated by the following examples:

Example 1

Tetrahydrodicyclopentadiene

In a flat-bottomed flask equipped with a bubbler and reflux condenser, a suspension of 1 g (0.028 mol) of sodium borohydride in 30 ml of isopropanol is charged, after which 1.8 g (0.014 mol) of anhydrous nickel (II) chloride are gradually added, and the formation of a black colloidal solution is observed. After that, hydrogen bubbling is started and 26.4 g (0.2 mol) of dicyclopentadiene are added. The reaction is carried out at a temperature of 40 ° C for 6 hours. At the beginning of the reaction, an exothermic effect is observed. At the end of the reaction, 3-4 drops of water are added, the precipitate of the catalyst is filtered off, isopropanol is distilled off from the filtrate using a reflux condenser. The residue was distilled at atmospheric pressure to obtain 24.85 g (0.19 mol, 95%) of tetrahydrodicyclopentadiene] a colorless crystalline substance, because 192-193 ° C. ¹ H NMR spectrum, δ, ppm: 1.20 t (2H, CH ₂ ); 1.24-1.58 m (10H, 5 CH ₂ ); 2.03 s (2H, 2 CH); 2.26 s (2H, 2 CH).

Example 2

2-cyanonorbornan

In a flat-bottomed flask equipped with a bubbler and reflux condenser, a suspension of 1 g (0.028 mol) of sodium borohydride in 30 ml of isopropanol is charged, after which 1.8 g (0.014 mol) of anhydrous nickel (II) chloride are gradually added, and the formation of a black colloidal solution is observed. After that, hydrogen bubbling is started and 15.75 g (0.15 mol) of 2-cyanonorbornene-5 is added. The reaction is carried out by heating to 50 ° C for 8 hours. At the end of the reaction, the mixture is cooled, add 3 ml of water to accelerate the coagulation of the catalyst. The precipitated precipitate is filtered off, isopropanol is distilled off from the filtrate using a reflux condenser. The residue is distilled at atmospheric pressure,) 11.2 g (0.105 mol, 70%) of 2-cyanonorbornane are obtained, a colorless liquid with a characteristic smell of nitrile, crystallizes upon standing, because 192-193 ° C. ¹ H NMR spectrum, δ, ppm: 0.92-1.04 m (2H, CH ₂ ); 1.17-1.52 m (6H, 3CH ₂ ); 2.24-2.40 m (2H, 2CH); 2.50-2.68 m (1H, CHCN).

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:

- a tool embodying the claimed invention in its implementation, is intended for use in laboratory conditions;

- for the claimed invention in the form described in the independent clause of the claims below, the possibility of its implementation using the means and methods described above or known prior to the priority date is confirmed;

- a tool embodying the claimed invention in its implementation is able to ensure the achievement of a technical result.

findings

A new method has been developed for the synthesis of norbornane derivatives, which proceeds with a high yield according to the starting materials, which consists in hydrogenating the norbornene derivative with hydrogen gas in the presence of nickel nanoparticles obtained from their nickel (II) chloride in situ and the process proceeds at a temperature of 40-50 ° C for 6-8 hours.

Claims (1)

A method of obtaining derivatives of norbornane of the General formula

R_one= H, R₂= CN;
or R_oneR₂= -CH₂-CH₂-CH₂- consisting in the hydrogenation of a norbornene derivative with hydrogen gas at atmospheric pressure on a catalyst, characterized in that dicyclopentadiene or 2-cyanonorbornene-5 is used as a norbornene derivative, and nickel nanoparticles obtained by reducing nickel (II) chloride with sodium borohydride are used as a catalyst in situ isopropanol medium, and the process is carried out in isopropanol at a temperature of 40-50 ° C for 6-8 hours, followed by isolation of the target product.