Bicyclo [2.2. 1] heptanone derivative as well as synthesis method and application thereof

Abstract

The invention discloses a bicyclo [2.2. 1] heptanone derivative as well as a synthesis method and application thereof. The invention relates to a bicyclo [2.2. 1] heptanone derivative, which has a structure shown as a formula IV, and in the formula IV, R1 is aryl or heteroaryl; r2 can be alkyl, ester group, CN or amide; and R3 is methyl, OTBS or phenyl. The invention provides a novel method for preparing the electroluminescent material monomer I. The preparation method of the electroluminescent material monomer I provided by the invention only needs four steps. Compared with the prior art, the method provided by the invention has the advantages of short route, simple and easily available raw materials, easy reaction control, avoiding of the use of a noble metal catalyst, reduction of the reaction cost, and high economic value. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the field of organic chemistry, and in particular to a bicyclo[2.2.1]heptanone derivative and a synthesis method and application thereof. Background Art

[0002] Electroluminescence is a physical phenomenon in which an electric field is generated by applying a voltage to two electrodes, and the electrons excited by the electric field hit the luminescent center, causing the electrons to transition, change, and recombine between energy levels, resulting in luminescence. Electroluminescent materials use this property to convert electrical energy into light energy under the action of an external electric field. Therefore, these materials can be patterned into active light-emitting layers in electroluminescent devices, such as organic light-emitting diodes (OLEDs) and organic diode lasers.

[0003] The Chinese patent with publication number CN102695774A (published on September 26, 2012) discloses a class of electroluminescent materials containing fluorene derivatives. Among these materials, an important synthesis of a bicyclo[2.2.1]heptane skeleton monomer is included, and the structure is shown in Formula I:

[0004]

[0005] The synthesis method of the monomer in the above patent:

[0006] In the first step, acetone dicarboxylate of structural formula A reacts with 1,2-dibromoethane under the action of a strong base to obtain a 2,5-substituted cyclopentanone compound B; in the second step, compound B continues to react with 1,2-dibromoethane under the action of a strong base to obtain a bicyclo[2.2.1]heptane derivative of structural formula C; in the third step, compound C is reduced to an alcohol by NaBH4; in the fourth step, compound D undergoes a bromination reaction under the action of PPh3PBr2 to obtain compound E; in the fifth step, compound E undergoes a coupling reaction with B2Pin2 under the catalysis of PdCl2(dppf) Compound F is obtained; in the sixth step, compound F and 2-phenyl trifluoromethanesulfonate are coupled under the catalysis of Pd(PPh3)4 to obtain compound G; in the seventh step, compound G undergoes benzylic carbon-hydrogen bond bromination reaction under the conditions of Br and benzoyl peroxide to obtain compound H; in the eighth step, compound H undergoes cyclization under the initiation of boron trifluoroamine ester ether to obtain compound J; in the ninth step, compound J is further reduced to obtain compound K; in the tenth step, compound K undergoes bromination reaction to obtain compound L; in the eleventh step, compound L is further reduced to debrominate atoms to obtain the final product I. The specific reaction route is as follows:

[0007]

[0008] 1.a. Lithium diisopropylamide, THF; b. 1,2-dibromoethane, c. NaH, THF; 2.a. Lithium diisopropylamide, THF; b. 1,2-dibromoethane, c. NaH, THF; 3. NaBH4, CH3OH; 4. Ph3PBr2, CH3CN; 5. Bis(pinacol)diboron, PdCl2(dppf), KOAc, dioxane; 6. 2-phenyl trifluoromethanesulfonate, Pd(PPh3)4, toluene, Na2CO3; 7. Br2, CCl4, dibenzoyl peroxide, UV light; 8. Boron trifluoroamine etherate, THF; 9. LiEt3BH, THF; 10. Ph3PBr2, CH3CN; 11. LiEt3BH, THF.

[0009] The problems with the above preparation method are:

[0010] First, the route to prepare the monomer requires 11 steps, which is cumbersome; second, the precious metal species palladium used in the fifth and sixth steps is expensive, which increases costs; third, the conditions of the multi-step reactions are relatively harsh, for example, strong bases are used in the first and second steps; fourth, the atom economy is low, and all functional groups in the initial raw material A need to be removed in this route.

[0011] Therefore, it is necessary to develop a preparation method with short steps, mild conditions, simple operation and high atom economy for the synthesis of this monomer. Summary of the invention

[0012] In order to overcome the shortcomings of the prior art, the present invention provides a bicyclo[2.2.1]heptanone derivative and a synthesis method and application thereof. The present invention provides a new method for preparing an electroluminescent material monomer I. Compared with the 11 steps disclosed in the prior art CN102695774A, the preparation method of the electroluminescent material monomer I provided by the present invention only requires 4 steps. In addition, the starting raw materials of the preparation method of the present invention are simple and easy to obtain, and the total yield is high.

[0013] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0014] A compound of formula IV,

[0015]

[0016] Among them, R 1 is aryl or heteroaryl; R 2 It can be alkyl, ester, CN, amide; R 3 It is methyl, OTBS, and phenyl.

[0017] As a preferred embodiment, R 1 is 2-phenylene, R 2is methyl, R 3 is a methyl group, and the compound is a compound of formula IV-1,

[0018]

[0019] The present invention provides a method for preparing a compound of structural formula IV: under a nitrogen atmosphere, a non-terminal alkyne and a 5-bromopentanal compound are added to a solution containing a photocatalyst and a base to form a reaction system. The system is reacted under irradiation of a 385-395 nm lamp (most preferably, under irradiation of a 40 W 390 nm lamp), and after the reaction is completed, a bicyclo[2.2.1]heptanone derivative IV is obtained.

[0020]

[0021] Where R 1 , R 2 and R 3 The definition of is as described above.

[0022] As a preferred embodiment, the present invention provides a method for preparing a compound of structural formula IV-1: under a nitrogen atmosphere, an alkyne compound and 5-bromo-3-methylpentanal are added to a solution containing a photocatalyst and a base, and the reaction is carried out under irradiation with a 385-395nm lamp (most preferably, the reaction is carried out under irradiation with a 40W 390nm lamp). After the reaction, the bicyclo[2.2.1]heptanone derivative IV-1 is obtained by treatment.

[0023]

[0024] In some embodiments, the molar ratio of the non-terminal alkyne to the 5-bromopentanal compound is 1:1 to 1:5; more preferably 1:2 to 1:3;

[0025] In some embodiments, the photocatalyst used is one of tetrabutylammonium decatungstate (TBADT) and sodium decatungstate (NaDT); more preferably tetrabutylammonium decatungstate (TBADT);

[0026] In some embodiments, the base used is one of K2CO3, Cs2CO3, K3PO4; more preferably K2CO3;

[0027] In some embodiments, the solvent used is one or more of MeCN, acetone, DMSO, and H2O; more preferably MeCN;

[0028] In some embodiments, the molar ratio of alkyne to base is 1:1 to 1:5; more preferably 1:2 to 1:3;

[0029] In some embodiments, the molar ratio of alkyne to photocatalyst is 200:1 to 10:1; more preferably 100:1 to 25:1;

[0030] In some embodiments, the reaction temperature is 30°C to 100°C, and the reaction time is about 20 hours, preferably 16 to 24 hours.

[0031] In some embodiments, after the reaction is completed, water is added to the reaction system to quench the reaction, the reaction is extracted three times with ethyl acetate, the organic phases are combined, washed with saturated sodium chloride solution and dried with anhydrous sodium sulfate, the solvent is spin-dried, and the target product is obtained by column chromatography.

[0032] The present invention also provides the use of the compound of the above structural formula IV-I in the preparation of the electroluminescent material monomer I.

[0033] Therefore, the present invention provides a method for preparing an electroluminescent material monomer I, using a compound of structural formula IV-1 as a starting material, and performing the following steps:

[0034]

[0035] Step 1, the compound of structural formula IV-1 undergoes Wolff-Kishner-Huang Minglong reduction reaction to obtain a compound of structural formula III;

[0036] Step 2, the compound of structural formula III reacts with a bromination reagent under the initiation of AIBN to obtain a compound of structural formula II;

[0037] Step 3: The compound of formula II undergoes an intramolecular Friedel-Crafts alkylation reaction to obtain a final compound of formula I.

[0038] Preferably, in step 1, the base used is sodium hydroxide;

[0039] Preferably, in the step 1, the solvents used are diethylene glycol (DEG) and ethylene glycol (EG), and the volume ratio of diethylene glycol to ethylene glycol in the solution is 4:1;

[0040] Preferably, in the step 1, the temperature of the Wolff-Kishner-Huang Minglong reduction reaction is 180-200° C., and the reaction time is 3-5 hours. The most preferred temperature of the reaction is 190° C., and the most preferred reaction time is 4 hours.

[0041] Preferably, in the step 2, the brominated substance used is bromosuccinimide (NBS);

[0042] Preferably, in step 2, the initiator used is azobisisobutyronitrile (AIBN);

[0043] Preferably, in step 2, the solvent used is CCl4;

[0044] Preferably, in the step 2, the reaction temperature is 70°C to 90°C, and the most preferred temperature for the reaction is 80°C;

[0045] Preferably, in step 3, the Lewis acid used is AlCl3;

[0046] Preferably, in step 3, the solvent used is toluene;

[0047] Preferably, in the step three, the reaction temperature is 100-120°C, most preferably 110°C.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] In summary, the present invention provides a simple method for preparing electroluminescent material monomers. Compared with the existing technology, the method of the present invention has a short route, simple and easy-to-obtain raw materials, easy reaction control, avoids the use of precious metal catalysts, reduces reaction costs, and has high economic value. DETAILED DESCRIPTION

[0050] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0051] Example 1 Preparation of compound of formula IV-1

[0052]

[0053] Under nitrogen atmosphere, 5-bromo-3-methylpentanal (71.2 mg, 0.4 mmol) and ethyl 2-phenylpropiolate (50 mg, 0.2 mmol) were added to 2 mL acetonitrile solution containing tetrabutylammonium decatungstate TBADT (10.6 mg, 0.04 mmol) and K2CO3 (55.2 mg, 0.4 mmol) to form a reaction system. After the system was reacted at 50°C for 20 hours under the irradiation of a photocatalytic lamp (Kessil PR160, 40 W, 390 nm), water was added to the reaction system to quench the reaction, and the reaction was extracted with ethyl acetate three times, the organic phases were combined, washed with a saturated sodium chloride solution and dried over anhydrous sodium sulfate, the solvent was spin-dried, and 42 mg of a colorless oily liquid product IV-1 was separated by column chromatography (PE: EA = 10: 1, silica gel column chromatography separation) with a yield of 72%.

[0054] Product IV-1 data characterization: 1H NMR(600MHz,Chloroform-d)δ7.71-7.63(m,2H),7.62-7.57(m,1H),7.53-7.47(m,2H),7.46-7.37(m,3H),7.36-7.29(m,1H),2.84(d,J=2.6 Hz,1H),2.10(dd,J=18.0,3.0Hz,1H),1.97-1.91(m,1H),1.91-1.86(m,1H),1.85-1.79(m,1H),1.65-1.61(m,2H),1.21(s,3H),1.04(s,3H); 13 C NMR(151MHz,Chloroform-d)δ217.0,143.6,140.8,133.2,129.5,129.3,127.9,127.8 ,127.3,127.0,122.3,62.2,58.5,53.7,46.1,34.1,31.1,18.7,12.5.; HRMS(ESI)m / z calcd for C 23 H 24 O3+Na + :371.1618[M+Na] + ; found 371.1621.

[0055] Example 2 Preparation of Compound of Formula III

[0056]

[0057] Under nitrogen atmosphere, the bicyclo[2.2.1]heptanone derivative IV-1 (69.6 mg, 0.2 mmol) was added to a mixed solution of diethylene glycol (DEG) and ethylene glycol (EG) (volume ratio 4:1) containing 10 mL of hydrazine, and reacted at 190°C for 2 hours. Then, the mixture was cooled to 80°C, sodium hydroxide (8 mg, 0.2 mmol) was added, and then the temperature was raised to 190°C for 4 hours. Water was added to the reaction system to quench the reaction, and the reaction was extracted with ethyl acetate three times. The organic phases were combined, washed with a saturated sodium chloride solution, and dried with anhydrous sodium sulfate. The solvent was dried by spin drying, and 36 mg of colorless oily liquid product III was separated by column chromatography (PE:EA=100:1, silica gel column chromatography separation) with a yield of 72%.

[0058] Product III data characterization: 1H NMR(600MHz,Chloroform-d)δ7.71-7.63(m,2H),7.62-7.57(m,1H),7.53-7.47(m,2H),7.46-7.37(m,3H),7.36-7.29(m,1H),2.94(s,1H),2 .54-2.45(m,1H),2.25-2.16(m,1H),1.83-1.70(m,3H),1.67-1.62(m ,1H),1.60-1.55(m,1H),1.46-1.41(m,1H),1.21(s,3H),1.03(s,3H).

[0059] Example 3 Preparation of Compound of Formula II

[0060]

[0061] Under nitrogen atmosphere, bicyclo[2.2.1]heptane derivative III (55.2 mg, 0.2 mmol) was added to 2 mL of carbon tetrachloride solution containing NBS (39.16 mg, 0.22 mmol) and AIBN (3 mg, 0.02 mmol). After the reaction system was reacted at 80 ° C for 4 hours, water was added to the reaction system to quench the reaction, and the reaction was extracted three times with ethyl acetate. The organic phases were combined, washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate, the solvent was dried by spin drying, and 64 mg of yellow oily liquid product II was separated by column chromatography (PE:EA=100:1, silica gel column chromatography separation) with a yield of 90%.

[0062] Product II data characterization: 1 H NMR(600MHz,Chloroform-d)δ7.81-7.73(m,2H),7.69-7.64(m,1H),7.56-7.50(m,2H),7.47-7.38(m,3H),7.34-7.27(m,1H),2.64-2 .55(m,1H),2.30-2.21(m,1H),1.90-1.77(m,2H),1.74-1.65(m,2H),1.63-1.57(m,1H),1.51-1.46(m,1H),1.29(s,3H),1.07(s,3H).

[0063] Example 4 Preparation of Compounds of Formula I

[0064]

[0065] Under nitrogen atmosphere, bicyclo[2.2.1]heptane derivative II (0.2 mmol) was added to 2 mL toluene solution containing aluminum chloride (58.5 mg, 0.44 mmol), and the reaction system was reacted at 110°C for 4 hours. After the reaction, water was added to the reaction system to quench the reaction, and the reaction was extracted with ethyl acetate three times. The organic phases were combined, washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate, the solvent was dried, and 48 mg of colorless oily liquid product I was separated by column chromatography (PE:EA=100:1, silica gel column chromatography separation) with a yield of 88%.

[0066] Product I data characterization: 1 H NMR(600MHz,Chloroform-d)δ7.64-7.61(m,2H),7.55(d,J=8.2Hz,2H),7.45(t,J=7.6Hz,2H),7.30-7.27(m,2H),2.59(m,2H ),2.33-2.26(m,2H),1.91-1.79(m,1H),1.77-1.71(m,1H),1.69-1.65(m,1H),1.56-1.50(m,1H),1.15(s,3H),1.08(s,3H); 13 C NMR (151MHz, Chloroform-d) δ138.6,138.2,129.0,128.0,127.9,126.9,62.2,56.3,48.1,37.6,36.4,34.9,31.3,19.2,14.1.

[0067] In summary, the present invention provides a simple method for preparing electroluminescent material monomers. Compared with the existing technology, the method of the present invention has a short route, simple and easy-to-obtain raw materials, easy reaction control, avoids the use of precious metal catalysts, reduces reaction costs, and has high economic value.

[0068] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A bicyclo[2.2.1]heptanone derivative, characterized in that The structure of formula IV is: Among them, R 1 is aryl or heteroaryl; R 2 is an alkyl group, an ester group, CN or an amide; R 3 is methyl, OTBS or phenyl.

2. The bicyclo[2.2.1]heptanone derivative according to claim 1, characterized in that It is a structure of formula IV-1, that is, R 1 is 2-phenylene, R 2 and R 3 For methyl:

3. The method for synthesizing the bicyclo[2.2.1]heptanone derivative according to claim 1, characterized in that: The following steps are involved: In a nitrogen atmosphere, a non-terminal alkyne of formula V and a 5-bromopentanal compound of formula VI are added to a solution containing a photocatalyst and a base, and reacted under irradiation with a 385-395 nm lamp, and after the reaction, a bicyclo[2.2.1]heptanone derivative of formula IV is obtained; Among them, R in Formula V, Formula VI, and Formula IV 1 , R 2 , R 3 Have the same meaning.

4. The method for synthesizing a bicyclo[2.2.1]heptanone derivative according to claim 2, characterized in that: The following steps are involved: Under a nitrogen atmosphere, a compound of formula V-1 and 5-bromo-3-methylpentanal are added to a solution containing a photocatalyst and a base, and reacted under irradiation with a 385-395 nm lamp. After the reaction, the compound is treated to obtain a bicyclo[2.2.1]heptanone derivative VI-1 of formula IV-1; 5. The method for synthesizing a bicyclo[2.2.1]heptanone derivative according to claim 4, characterized in that: The molar ratio of the compound of formula V-1 to 5-bromo-3-methylpentanal is 1:1 to 1:5; The photocatalyst is one of tetrabutylammonium decatungstate and sodium decatungstate; The base is one of K2CO3, Cs2CO3 and K3PO4.

6. The method for synthesizing a bicyclo[2.2.1]heptanone derivative according to claim 4, characterized in that: The reaction temperature is 30°C to 100°C, and the reaction time is 16 to 24 hours.

7. Use of the bicyclo[2.2.1]heptanone derivative as claimed in claim 1 in the preparation of electroluminescent material monomers.

8. Use of the bicyclo[2.2.1]heptanone derivative as claimed in claim 2 in the preparation of electroluminescent material monomers.

9. The use according to claim 8, characterized in that Specifically include: Step 1, the compound of structural formula VI-1 undergoes Wolff-Kishner-Huang Minglong reduction reaction to obtain a compound of structural formula III; Step 2, the compound of structural formula III reacts with a bromination reagent under the initiation of an initiator to obtain a compound of structural formula II; Step 3, the compound of structural formula II undergoes an intramolecular Friedel-Crafts alkylation reaction to obtain a compound of structural formula I, which is an electroluminescent material monomer; 10. The use according to claim 9, characterized in that In step 1, the base used in the Wolff-Kishner-Huang Minglong reduction reaction is sodium hydroxide; the solvent used in the Wolff-Kishner-Huang Minglong reduction reaction is diethylene glycol and ethylene glycol; the temperature of the Wolff-Kishner-Huang Minglong reduction reaction is 180-200° C., and the reaction time is 3-5 hours; In step 2, the initiator is azobisisobutyronitrile; the bromination reagent is bromosuccinimide; the reaction solvent is CCl4; the reaction temperature is 70°C to 90°C; In step 3, the Lewis acid used in the intramolecular Friedel-Crafts alkylation reaction is AlCl3; the solvent used in the intramolecular Friedel-Crafts alkylation reaction is toluene; and the temperature of the intramolecular Friedel-Crafts alkylation reaction is 100-120°C.

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