A 7-aminodiphenylbenzofuran compound and preparation method thereof

Abstract

The invention provides a 7-aminodiphenylbenzofuran compound and a preparation method thereof. The present invention, under low temperature conditions, reacts diphenylbenzofuran, n-butyl lithium and triisopropyl borate to obtain an intermediate diphenylbenzofuran boronic acid compound, and then prepares the 7-aminodiphenylbenzofuran compound through 2,4-dinitrophenylhydroxylamine and potassium carbonate. The present invention has controllable impurities, convenient purification, and avoids the use of precious metal catalysts, and is controlled in cost. The present invention adopts diphenylbenzofuran boronic acid, 2,4-dinitrophenylhydroxylamine and potassium carbonate to react to obtain the target product of a high-purity 7-aminodiphenylbenzofuran compound. The preparation method of the present invention is simple to operate, and raw materials are easily available, and the product purity is high, the yield is high, and it is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of organic photoelectric technology, and in particular to a 7-aminodiphenylbenzofuran compound and a preparation method thereof. Background Art

[0002] Diphenylbenzofuran compounds are organic optoelectronic materials, among which amine-substituted diphenylbenzofuran compounds are organic functional intermediates for OLEDs. 7-Amino-substituted diphenylbenzofuran compounds, molecular formula C 20 H 15 NO, molecular weight: 285.12, structural formula is as follows:

[0003]

[0004] In the current prior art, there are almost no reports on the preparation of 7-aminodiphenylbenzofuran compounds. Since diphenylbenzofuran has many sites and the same group is introduced at different sites, the photoelectric properties and chemical properties of the material are quite different. Therefore, the positioning effect of the amino functional group is an indispensable effect in OLED organic functional intermediates. The activation effect of the amino functional group on the ortho and para sites accelerates the introduction of halogen atoms (Br -1 , Cl -1 , I -1 )’s reaction rate, ultimately achieving the purpose of introducing other groups at the ortho / para positions of the amino functional group, thereby improving the photoelectric and chemical properties of the compound.

[0005] Therefore, the development of 7-aminodiphenylbenzofuran compounds is particularly important. Summary of the invention

[0006] The invention provides a 7-aminodiphenylbenzofuran compound and a preparation method thereof, the purpose of which is to solve the above-mentioned problems existing in the background technology.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a 7-aminodiphenylbenzofuran compound and a preparation method thereof. The present invention adopts diphenylbenzofuran, n-butyl lithium and triisopropyl borate to react at low temperature to obtain an intermediate: a diphenylbenzofuran boronic acid compound, and then prepares an amino-substituted diphenylbenzofuran compound through 2,4-dinitrophenylhydroxylamine and potassium carbonate. The impurities of the present invention are controllable and the purification is convenient, avoiding the use of precious metal catalysts, and the cost is controlled. The present invention adopts 2,4-dinitrophenylhydroxylamine and potassium carbonate to react to obtain a target product of a high-purity 7-aminodiphenylbenzofuran compound.

[0008] The present invention provides a method for preparing a 7-aminodiphenylbenzofuran compound, comprising the following steps:

[0009] S1. Take diphenylbenzofuran and add tetrahydrofuran THF, cool down, add n-butyl lithium dropwise, heat to react, cool down again, add triisopropyl borate, heat to react, add hydrochloric acid to react, stir to crystallize, filter with suction to obtain an intermediate, diphenylbenzofuran boronic acid;

[0010] S2. Take the diphenylbenzofuran boronic acid, add potassium carbonate and toluene, stir, dropwise add a toluene solution of 2,4-dinitrophenylhydroxylamine, heat to react, extract, and concentrate to obtain a 7-aminodiphenylbenzofuran compound.

[0011] Preferably, the molar ratio of diphenylbenzofuran, n-butyl lithium, triisopropyl borate and hydrochloric acid is 1:(1.0-2.5):(2-3):(3-5).

[0012] Preferably, the molar ratio of diphenylbenzofuran, n-butyl lithium, triisopropyl borate and hydrochloric acid is 1:1.5:2.5:5.

[0013] Preferably, the usage amount of the 2,4-dinitrophenylhydroxylamine is 1.0 to 1.2 of the molar amount of the diphenylbenzofuran boronic acid compound, and the usage amount of the potassium carbonate is 1.0 to 3.0 of the molar amount of the diphenylbenzofuran boronic acid compound.

[0014] Preferably, the first heating condition in step S1 is: reacting at a temperature of 0 to 40° C. for 1 to 3 hours.

[0015] Preferably, the second heating condition in step S1 is: reacting at a temperature of 0 to 40° C. for 1 to 2 hours.

[0016] Preferably, the hydrochloric acid is added in step S1 for a reaction at a temperature of 20 to 30° C. for 1 to 5 hours.

[0017] Preferably, the heating reaction in step S2 is: reacting at a temperature of 70 to 130° C. for 2 to 8 hours.

[0018] Preferably, the heating reaction in step S2 is: reacting at a temperature of 80 to 110° C. for 2 to 6 hours.

[0019] Based on a general concept of the invention, the present invention also provides a 7-aminodiphenylbenzofuran compound obtained by the above-mentioned preparation method, the purity of which reaches 98.5%.

[0020] The synthetic route is as follows:

[0021]

[0022] The beneficial effects of the present invention are as follows:

[0023] 1) The present invention uses diphenylbenzofuran, n-butyl lithium and triisopropyl borate to react at low temperature, impurities are controllable, purification is convenient, and the use of precious metal catalysts is avoided, so the cost is controlled. The target product of 7-aminodiphenylbenzofuran compound with high purity can be obtained by using 2,4-dinitrophenylhydroxylamine and potassium carbonate for preparation.

[0024] 2) The first step of the present invention uses only lithium reagent at low temperature, accurately locates the 7-position of diphenylbenzofuran, and does not require the combined action of other organic bases and lithium reagents, thereby simplifying the reaction. After the lithium reagent is added dropwise, the reaction is kept at 25°C for 1 hour, which greatly improves the yield of the first step reaction compared to keeping at -80°C for 1 hour, and is also easier to purify.

[0025] 3) 2,4-dinitrophenylhydroxylamine is easy to deteriorate under high temperature and alkaline conditions, which ultimately makes the overall reaction yield low. The second step of the present invention adopts the method of dripping 2,4-dinitrophenylhydroxylamine toluene solution into the reaction system, which can greatly improve the utilization rate of 2,4-dinitrophenylhydroxylamine and ultimately improve the yield of the entire reaction.

[0026] 4) The synthesis method of the present invention is simple to operate, the raw materials used are easily available, the product has high purity and high yield, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The 7-aminodiphenylbenzofuran compound prepared in Example 1 of the present invention 1 H NMR spectra;

[0029] Figure 2 It is the mass spectrum of the 7-aminodiphenylbenzofuran compound prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0031] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0033] In view of the existing problems, the present invention provides a 7-aminodiphenylbenzofuran compound and a preparation method thereof.

[0034] Example 1

[0035] Step 1: Add 33 g of diphenylbenzofuran to a reaction flask, replace nitrogen, add 200 mL of ultra-dry THF, cool to -80 ° C, drop 114 mL of 1.6 M n-butyl lithium, keep warm at 25 ° C for 1 hour, add 70 mL of triisopropyl borate, heat to 25 ° C for 2 hours. Add 50 mL of 12 M hydrochloric acid and react for 1 hour, then stir and crystallize. Filter to obtain 35 g of white solid, diphenylbenzofuran boronic acid. Yield 91.3%.

[0036] Step 2: 35 g of diphenylbenzofuran boronic acid, 23 g of potassium carbonate and 200 mL of toluene were added to the reaction bottle, replaced with nitrogen three times, heated to 100°C, and then 30 mL of 4M toluene solution of 2,4-dinitrophenylhydroxylamine was dripped into the reaction bottle, reacted for 5 h, separated, concentrated and slurried with ethanol to obtain 28 g of solid. The yield was 88%. The hydrogen spectrum and mass spectrum are shown in Figures 1-2 , 1 H NMR (400MHz, DMSO-d6) δ7.71–7.62(m,2H),7.55–7.35(m,8H),6.97(t,J=7.7Hz,1H),6.62(t,J=7.8Hz,2H),5.47(s,2H).

[0037] Example 2

[0038] Step 1: Add 33 g of diphenylbenzofuran to a reaction flask, replace nitrogen, add 200 mL of ultra-dry THF, cool to -80 ° C, drop 114 mL of 1.6 M n-butyl lithium, keep warm at 25 ° C for 1 hour, add 42 mL of triisopropyl borate, heat to 25 ° C for 2 hours. Add 50 mL of 12 M hydrochloric acid and react for 1 hour, then stir and crystallize. Filter to obtain 30 g of white solid, diphenylbenzofuran boronic acid. Yield 78%.

[0039] Step 2: 28 g of diphenylbenzofuran boronic acid, 24.6 g of potassium carbonate and 200 mL of toluene were added to the reaction bottle, replaced with nitrogen three times, heated to 100°C, and then 24.5 mL of 4M toluene solution of 2,4-dinitrophenylhydroxylamine was dripped into the reaction bottle, reacted for 5 h, separated, concentrated and slurried with ethanol to obtain 19 g of solid. Yield 74.7%.

[0040] Example 3

[0041] Step 1: Add 33 g of diphenylbenzofuran to a reaction flask, replace nitrogen, add 200 mL of ultra-dry THF, cool to -80 ° C, drop 76 mL of 1.6 M n-butyl lithium, keep warm at 25 ° C for 1 hour, add 70 mL of triisopropyl borate, heat to 25 ° C for 2 hours. Add 50 mL of 12 M hydrochloric acid and react for 1 hour, then stir and crystallize. Filter to obtain 28 g of white solid, diphenylbenzofuran boronic acid. Yield 73%.

[0042] Step 2: 28 g of diphenylbenzofuran boronic acid, 12 g of potassium carbonate and 200 mL of toluene were added to the reaction bottle, replaced with nitrogen three times, heated to 100°C, and then 24 mL of 4M toluene solution of 2,4-dinitrophenylhydroxylamine was dripped into the reaction bottle, reacted for 5 h, separated, concentrated and slurried with ethanol to obtain 17 g of solid. The yield was 67%.

[0043] Comparative Example

[0044] Step 1: Add 33 g of diphenylbenzofuran to a reaction flask, replace nitrogen, add 200 mL of ultra-dry THF, cool to -80 ° C, drop 114 mL of 1.6 M n-butyl lithium, keep at -80 ° C for 1 hour, add 70 mL of triisopropyl borate, heat to 25 ° C for 2 hours. Add 50 mL of 12 M hydrochloric acid and react for 1 hour, then stir and crystallize. Filter to obtain 4 g of white solid, diphenylbenzofuran boronic acid. Yield 10.5%.

[0045] Step 2: 35 g of diphenylbenzofuran boronic acid, 23 g of potassium carbonate, 23.9 g of 2,4-dinitrophenylhydroxylamine and 230 mL of toluene were added to a reaction bottle, replaced with nitrogen three times, heated to 100°C, reacted for 5 h, separated, concentrated, and purified by column to obtain 14 g of solid. Yield: 44%.

[0046] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a 7-aminodiphenylbenzofuran compound, characterized in that: The steps include: S1. Take diphenylbenzofuran and add tetrahydrofuran THF, cool down, add n-butyl lithium dropwise, heat to react, cool down again, add triisopropyl borate, heat to react, add hydrochloric acid to react, stir to crystallize, filter with suction to obtain an intermediate, diphenylbenzofuran boronic acid; S2. Add potassium carbonate and toluene to the diphenylbenzofuran boronic acid, stir, dropwise add a toluene solution of 2,4-dinitrophenylhydroxylamine, heat to react, extract, and concentrate to obtain a 7-aminodiphenylbenzofuran compound; The molar ratio of the diphenylbenzofuran, n-butyl lithium, triisopropyl borate and hydrochloric acid is 1:(1.0-2.5):(2-3):(3-5); the amount of the 2,4-dinitrophenylhydroxylamine used is 1.0-1.2 of the molar amount of the diphenylbenzofuran boronic acid compound, and the amount of potassium carbonate used is 1.0-3.0 of the molar amount of the diphenylbenzofuran boronic acid compound; In step S1, the first heating condition is: reacting at a temperature of 0 to 40°C for 1 to 3 hours, the second heating condition is: reacting at a temperature of 0 to 40°C for 1 to 2 hours, and the hydrochloric acid addition reaction is: reacting at a temperature of 20 to 30°C for 1 to 5 hours; The heating reaction in step S2 is: reacting at a temperature of 70 to 130° C. for 2 to 8 hours.

2. The method for preparing a 7-aminodiphenylbenzofuran compound according to claim 1, wherein: The molar ratio of the diphenylbenzofuran, n-butyl lithium, triisopropyl borate and hydrochloric acid is 1:1.5:2.5:

5.

3. A method for preparing a 7-aminodiphenylbenzofuran compound according to claim 1, characterized in that: The heating reaction in step S2 is: reacting at a temperature of 80 to 110° C. for 2 to 6 hours.

4. The method for preparing a 7-aminodiphenylbenzofuran compound according to claim 1, wherein: The purity of the 7-aminodiphenylbenzofuran compound reaches 98.5%.

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