TWI773190B - Diamine compound and method of preparing the same - Google Patents

Abstract

A diamine compound and a method for preparing the diamine compound are provided. The method has steps of: mixing N-alkyl-2-(4-nitrophenyl)ethylamine hydrochloride and a solvent to form a reaction solution; adding a basic substance in the reaction solution to allow the reaction solution to be alkaline; adding triphosgene in the reaction solution to form a dinitro compound; and performing a reduction reaction on the dinitro compound to form a diamine compound. The diamine compound has a structural formula as shown in formula (I).

Description

Diamine compound and preparation method thereof

The present invention relates to a diamine compound and its preparation method, in particular to a structurally stable diamine compound and its preparation method.

In the Republic of China Patent Publication No. TW201030059A, Nissan Chemical Nakahara Shoichiro et al. applied for a liquid crystal alignment treatment agent in 2006. During the rubbing treatment, the treatment agent causes less scratches or scratches on the film surface and has good orientation. This treating agent is a diamine containing the following structural components.

In the above-mentioned patent, utilize carbonic acid bis(4-nitrophenyl) to import urea group, and import triethylamine and 4-dimethylaminopyridine (DMAP) as basic substance, successfully obtain the urea group with dinitro group. Intermediate. The intermediate is mixed with 5% Pd/C and 1,4-dioxane, and then filled with hydrogen to carry out a reduction reaction, thereby obtaining a diamine compound.

However, when the diamine compound is used as an alignment treatment agent, the -N-CO-N- contained in the compound is easily destroyed during the reaction process, resulting in a variety of by-products, and the existence of these by-products will also affect the LCD panel. quality affects.

Therefore, it is necessary to provide a diamine compound and a preparation method thereof. The diamine compound has better structural stability and reduces the generation of by-products when the alignment reaction occurs, so as to solve the problems existing in the conventional technology.

The main purpose of the present invention is to provide a diamine compound and a preparation method thereof, which can obtain a diamine compound with an alkyl group, and use the alkyl group to protect the -N-CO-N- link in the diamine compound to make it in the diamine compound. The alignment reaction process is not destroyed, which can reduce the generation of different kinds of by-products. At the same time, the preparation method of the diamine compound also has quite good yield.

……(I)， 其中R是甲基或乙基。 To achieve the above purpose, an embodiment of the present invention provides a method for preparing a diamine compound, which comprises the steps of: (1) mixing NR-2-(4-nitrophenyl)ethanamine hydrochloride and a solvent, forming a reaction solution; (2) adding an alkaline substance to the reaction solution to make the reaction solution alkaline; (3) adding triphosgene to the reaction solution to synthesize dinitro compounds; and (4) adding The dinitro compound undergoes a reduction reaction to form a diamine compound, wherein the diamine compound has the structure shown in the following formula (I):

...(I), wherein R is methyl or ethyl.

In one embodiment of the present invention, the solvent is dichloromethane, toluene, xylene, tetrahydrofuran or 1,4-dioxane.

In one embodiment of the invention, R is methyl.

In one embodiment of the present invention, the basic substance is sodium hydroxide, potassium carbonate, diisopropylethylamine, 4-dimethylaminopyridine, triethylamine or a mixture thereof.

…….式(II)。 In one embodiment of the present invention, the dinitro compound has the structure shown in the following formula (II):

.... formula (II).

In an embodiment of the present invention, the reduction reaction uses a catalyst and a reducing agent to reduce the nitro group (-NO ₂ ) of the dinitro compound to an amine group (-NH ₂ ).

In one embodiment of the present invention, the catalyst is Pd/C, platinum oxide, iron powder or tin chloride.

In one embodiment of the present invention, the reducing agent is hydrogen, hydrazine, hydrogen chloride or ammonium chloride.

……(I)， 其中R是甲基或乙基。 Another embodiment of the present invention provides a diamine compound having the structure shown in the following formula (I):

...(I), wherein R is methyl or ethyl.

In one embodiment of the invention, R is methyl.

In order to make the above-mentioned and other objects, features and advantages of the present invention more clearly understood, the preferred embodiments of the present invention will be exemplified below, and will be described in detail as follows. References herein to the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include multiple compounds, including mixtures thereof; the "%" mentioned in the present invention refers to "weight percent (wt%)" unless otherwise specified; the numerical range ( For example, 10% to 11% of A) includes upper and lower limits unless otherwise specified (ie 10%≦A≦11%); if the value range does not define the lower limit (such as B below 0.2%, or 0.2 % below B), it means that the lower limit may be 0 (ie 0%≦B≦0.2%); the proportional relationship of “weight percent” of each component can also be replaced by the proportional relationship of “weight part”. The above terms are used to describe and understand the present invention, but not to limit the present invention.

An embodiment of the present invention provides a method for preparing a diamine compound, which comprises the steps of: (S1) mixing N-R-2-(4-nitrophenyl)ethylamine hydrochloride and a solvent to form a reaction solution; ( S2) adding a basic substance to the reaction solution to make the reaction solution alkaline; (S3) adding triphosgene to the reaction solution to synthesize a dinitro compound; and (S4) carrying out the dinitro compound A reduction reaction forms a diamine compound.

The present invention will hereinafter describe in detail the implementation details and principles of the above steps one by one.

The preparation method of the diamine compound according to an embodiment of the present invention is firstly: (S1) mixing N-R-2-(4-nitrophenyl)ethylamine hydrochloride and a solvent to form a reaction solution. In this step, the solvent is dichloromethane, toluene, xylene, tetrahydrofuran or 1,4-dioxane. Preferably, R is an alkyl group, which can be, for example, methyl or ethyl.

The preparation method of the diamine compound according to an embodiment of the present invention is followed by: (S2) adding a basic substance to the reaction solution to make the reaction solution alkaline. In this step, the basic substance is sodium hydroxide, potassium carbonate, diisopropylethylamine, 4-dimethylaminopyridine, triethylamine or a mixture thereof. For example, triethylamine and 4-dimethylaminopyridine can be mixed in an appropriate ratio to form an alkaline environment suitable for the reaction, but it is not limited to these two substances.

……(II) The preparation method of the diamine compound according to an embodiment of the present invention is as follows: (S3) adding triphosgene to the reaction solution to synthesize a dinitro compound. In this step, the dinitro compound has the structure shown in the following formula (II):

...(II)

……(I) The method for preparing a diamine compound according to an embodiment of the present invention is followed by: (S4) performing a reduction reaction on the dinitro compound to form a diamine compound. The diamine compound has the structure shown in the following formula (I):

...(I)

In the above formula (I), R is a methyl group or an ethyl group. Preferably, R is methyl. Through the protection of the methyl group, the N-C-N bond in the diamine compound is not easily destroyed, the overall molecular structure can be stabilized, and the generation of by-products can be reduced when used as an alignment reactant.

In this step, the reduction reaction can use a catalyst and a reducing agent to reduce the nitro group (-NO ₂ ) of the dinitro compound to an amine group (-NH ₂ ). In one embodiment, the catalyst may be, for example, Pd/C, platinum oxide, iron powder, or tin chloride, and the reducing agent may be, for example, hydrogen, hydrazine, hydrogen chloride, or ammonium chloride. Preferably, the catalyst is Pd/C and the reducing agent is hydrogen. Preferably, the catalyst is Pd/C and the reducing agent is hydrazine.

……(I)， 其中R是甲基或乙基。較佳的，R是甲基。 Another embodiment of the present invention provides a diamine compound having the structure shown in the following formula (I):

...(I), wherein R is methyl or ethyl. Preferably, R is methyl.

In order to make the diamine compound of the present invention and the preparation method thereof clearer and easier to understand, please refer to the following actual operation process, but it is not intended to limit the structure of the diamine compound of the present invention and each step included in the preparation method thereof .

Example 1: Synthesis of dinitro compounds

The reaction mechanism is as follows:

First, 95.0 g of N-methyl-2-(4-nitrophenyl)ethanamine hydrochloride was charged into the reaction flask, and 665 ml of CH ₂ Cl ₂ was added, followed by stirring uniformly. Next, after adding 8.92 g of 4-dimethylaminopyridine (DMAP) to the aforementioned mixed solution, 88.66 g of triethylamine was slowly added dropwise, and this was the reaction solution A.

Put 9 grams of solid triphosgene into the isobaric titration funnel, add 115 ml of CH ₂ Cl ₂ and shake until it is completely dissolved, this is the reaction solution B.

The aforementioned reaction solution B was dropped into the reaction solution A within 1 hour, and was controlled to room temperature with an ice bath.

Repeated preparation of reaction solution B and dropwise addition of reaction solution A twice. When the last prepared reaction solution B was prepared, the amount of triphosgene was reduced to 8 g, and the amount of CH ₂ Cl ₂ was reduced to 95 ml. After the dropwise addition was completed, the reaction was maintained at room temperature for 1 hour.

After the excess CH ₂ Cl ₂ was removed by concentration under reduced pressure, 3 liters of n-Hexane was added to precipitate a pale orange powder. After filtration, 1 liter of water was added and stirred to remove triethylamine hydrochloride. After filtering again, the powder was taken out and dried in an oven to obtain 68.0 g of light orange powder as a dinitro compound with a yield of 80.3%.

¹ H-NMR (500MHz, DMSO-d6, δ ppm): 8.15 (m, 2H), 7.34 (d, 2H), 3.40 (t, 2H), 2.95 (t, 2H), 2.74 (s, 3H).

Example 2: Synthesis of Diamine Compounds

The reaction mechanism is as follows:

First, take 68.0 g of the above-mentioned dinitro compound, put it into a 1-liter reaction flask, and then add 150 ml of ethanol (EtOH) and stir evenly. Then add catalyst 6.8 g of Pd/C, heat to reflux, then slowly drop 88 g of 80% hydrazine (Hydrazine), and then reflux for 1 hour after dropping.

。 Filtration was performed to remove the palladium-carbon catalyst (Pd/C), and the filtrate was concentrated under reduced pressure to obtain 49.5 g of beige powder with a yield of 86.2%. It is determined by NMR that it is the target product diamine compound

.

¹ H-NMR (500MHz, CDCl3, δ ppm): 6.95 (d, 2H), 6.59 (d, 2H), 3.56 (s, 2H), 3.28 (m, 2H), 2.73 (s, 3H) , 2.70 ( m, 2H).

Comparative Example 1: Reaction of bis(4-nitrophenyl) carbonate with N-methyl-2-(4-nitrophenyl)ethanamine hydrochloride

Since in order to prepare diamine compounds with alkyl protection, the synthesis of intermediate dinitro compounds is quite important. According to the method adopted by Nissan Chemical Nakahara Shoichiro et al. in Patent Publication No. TW201030059A of the Republic of China, the designed reaction mechanism is as follows:

The experimental steps taken are as follows:

First, 3.0 g of N-methyl-2-(4-nitrophenyl)ethanamine hydrochloride and 2.0 g of bis(4-nitrophenyl) carbonate were charged into a bottle, and 25 ml of CH After ₂ Cl ₂ , stir well. This is reaction solution C. After adding 0.16 g of DMAP to the reaction solution C, 4.0 g of triethylamine was slowly added dropwise. After the dropwise addition was completed, the reaction was followed by TLC, and after no starting material was observed, water was added to separate out the product. After filtration, a pale orange powder was obtained. After identification, this product is an unknown mixture, not the intended target product (dinitro compound).

As can be seen from the results of Comparative Example 1, the dinitro compound having a methyl group could not be successfully synthesized by the above-mentioned reaction mechanism. That is to say, after the -NH ₂ hydrochloride of the reactant is replaced by a methyl group, the dinitro compound cannot be successfully synthesized.

Compared with the prior art, the diamine compound and its preparation method provided by the present invention use an alkyl group to protect the N-CO-N bond in the diamine compound to stabilize the overall structure. When used as an alignment reactant, N The -CO-N bond is not easily destroyed, so the generation of by-products can be reduced, the liquid crystal composition of the liquid crystal panel is relatively simple, and the quality of the panel is improved.

Although the present invention has been disclosed with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the appended patent application.

Claims (10)

A preparation method of a diamine compound, comprising steps: (1) mixing NR-2-(4-nitrophenyl)ethylamine hydrochloride and a solvent to form a reaction solution; (2) in the reaction solution adding a basic substance to make the reaction solution alkaline; (3) adding triphosgene to the reactant to form a dinitro compound; and (4) subjecting the dinitro compound to a reduction reaction to form a diamine compound, wherein the diamine compound has the structure shown in the following formula (I):

wherein R is methyl or ethyl. The method for preparing a diamine compound according to claim 1, wherein the solvent is dichloromethane, toluene, xylene, tetrahydrofuran or 1,4-dioxane. The method for producing a diamine compound according to claim 1, wherein R is a methyl group. The method for preparing a diamine compound according to claim 1, wherein the basic substance is sodium hydroxide, potassium carbonate, diisopropylethylamine, 4-dimethylaminopyridine, triethylamine or a mixture thereof. The preparation method of the diamine compound as claimed in claim 1, wherein the dinitro compound has the structure shown in the following formula (II):

wherein R is methyl or ethyl. The method for preparing a diamine compound according to claim 1, wherein the reduction reaction is to use a catalyst and a reducing agent to reduce the nitro group (-NO ₂ ) of the dinitro compound to an amine group (-NH ₂ ) . The method for preparing a diamine compound according to claim 6, wherein the catalyst is Pd/C, platinum oxide, iron powder or tin chloride. The method for preparing a diamine compound according to claim 6, wherein the reducing agent is hydrogen, hydrazine, hydrogen chloride or ammonium chloride. A kind of diamine compound, has the structure shown in following formula (I):

wherein R is methyl or ethyl. The diamine compound as claimed in claim 9, wherein R is a methyl group.