Synthesis method of ester group substituted o-carborane derivative

Abstract

The invention provides a synthetic method of an o-carborane compound. The synthetic method is suitable for preparing an ester group substituted o-carborane derivative. The synthesis method comprises the following synthesis steps: by taking 1-carboxyl-2-(substituent)-o-carborane and a hypervalent iodine reagent as raw materials, carrying out hydration and substitution reaction in a solvent at the reaction temperature of 50-120 DEG C for 2-36 hours to generate the 1-ester-2-(substituent)-o-carborane compound. The reactants involved in the invention have good universality, and the functional groups of the substrate have good compatibility; the synthesis method provided by the invention is relatively high in selectivity and yield, single in reaction system composition, simple in post-treatment and easy to implement.

Description

Technical Field

[0001] The invention relates to a method for synthesizing carborane, in particular to a method for synthesizing an ester-substituted o-carborane derivative. Background Art

[0002] Carborane is a polyhedral closed cage structure with the characteristics of high calorific value, high boron content, good thermal stability and chemical stability. It is a type of high burning rate catalyst with excellent performance. In addition, carborane is used as metal ligand and neutron absorption material in the field of coordination chemistry and medicine. This type of compound is liquid at room temperature. In addition to its main role in regulating the burning rate in solid propellants, it also has the function of a plasticizer.

[0003] At present, the synthesis of carbon-substituted carborane requires metal lithium salt as a reaction reagent. The method includes three steps. The first step is the reaction of 1,2-carborane and n-butyl lithium to generate a carborane lithium salt intermediate; the second step is the reaction of carborane lithium salt and chemically equivalent cuprous chloride to obtain a carborane copper salt intermediate; the third step is the reaction of carborane copper salt and bromide to synthesize substituted carborane. However, this method requires the use of chemically equivalent cuprous chloride, has many reaction steps, low yield (only 43%), and high cost. In addition, when carborane containing carboxyl is used as a reaction raw material in literature reports, the carboxyl group is usually used as a positioning group to activate the BH bond on B (4,5) to achieve functionalization on the boron cage, and cannot be used as an intermediate for further reactions on the carbon position. Summary of the invention

[0004] In order to solve the deficiencies and defects of the prior art, the present invention provides a method for synthesizing an ester-substituted o-carborane derivative, which has the effects of high yield and good universality of reactants.

[0005] The scheme of the present invention comprises:

[0006] A method for synthesizing an ester-substituted o-carborane derivative, wherein the synthesis method uses 1-carboxyl-2-(substituted)-o-carborane and a high-valent iodine reagent as raw materials, and the reaction equation is as follows:

[0007]

[0008] Where R 1 is a linear alkyl group, a branched alkyl group, an aryl group, a benzyl group, a substituted aryl group or H;

[0009] R 2 It is a straight-chain alkyl group, a branched-chain alkyl group, an aryl group or a substituted aryl group.

[0010] Optionally, the molar ratio of 1-carboxyl-2-(substituted)-o-carborane to the high-valent iodine reagent is 1:(1-5), the reaction temperature is 50-120° C., and the reaction time is 2-36 h.

[0011] Optionally, the reaction temperature is 50-120° C., and the reaction time is 2-36 hours.

[0012] Optionally, the solvent is selected from one of toluene, xylene, mesitylene and dichloromethane;

[0013] The amount of the solvent added is: 1 ml of solvent for every 0.1 mmol of 1-carboxyl-2-(substituted)-o-carborane.

[0014] Optionally, the 1-carboxy-2-(substituted) o-carborane is selected from one of 1-carboxy-1,2-o-carborane, 1-carboxy-2-methyl-o-carborane, 1-carboxy-2-n-butyl-o-carborane, 1-carboxy-2-n-hexyl-o-carborane and 1-carboxy-2-substituted phenyl-o-carborane.

[0015] Optionally, R in the hypervalent iodine reagent 2 It is selected from methyl, ethyl, n-butyl, n-hexyl, cyclohexyl, aryl and substituted aryl, wherein the aryl contains one or more substituents on the benzene ring, and the substituents on the benzene ring are methyl, methoxy, halogen or trifluoromethyl.

[0016] Optionally, an additive is added, and the additive is acetic acid.

[0017] Optionally, the molar ratio of the additive to 1-carboxyl-2-(substituted)-o-carborane is 1:1.

[0018] Optional, 1-carboxy-2-n-hexyl-o-carborane, hypervalent iodine reagent, R 2 The molar ratio of phenyl, 1-carboxyl-2-(substituted)-o-carborane and high-valent iodine reagent is 1:1.2, toluene and acetic acid are added, and the reaction is stirred at 80°C for 5 hours. After the reaction is completed, the solvent is evaporated and purified by column chromatography to obtain 1-formyloxyacetophenone-2-n-hexyl-o-carborane;

[0019] Optionally, the amount of toluene added is: 1 ml of toluene for every 0.1 mmol of 1-carboxy-2-(substituted)-o-carborane; and the molar ratio of acetic acid to 1-carboxy-2-(substituted)-o-carborane is 1:1.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The reaction time of the present invention is short, and it is convenient and concise.

[0022] 2. The reactants involved in the method of the present invention have good universality.

[0023] 3. The yield of the reaction involved in the method of the present invention is high, the reaction system has a single composition, and the post-processing is relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0025] Figure 1 The NMR of 1-formyloxyacetophenone-2-n-hexyl-o-carborane obtained in Example 1 is 1 H NMR spectrum (500MHz, CDCl3);

[0026] Figure 2 The NMR of 1-formyloxyacetophenone-2-n-hexyl-o-carborane obtained in Example 1 is 13 C{ 1 H}NMR spectrum (126MHz, CDCl3);

[0027] Figure 3 The NMR of 1-formyloxyacetophenone-2-n-hexyl-o-carborane obtained in Example 1 is 11 B NMR spectrum (160MHz, CDCl3);

[0028] Figure 4 The NMR of 1-formyloxyacetophenone-2-n-hexyl-o-carborane obtained in Example 1 is 11 B{ 1 H}NMR spectrum (160MHz, CDCl3); DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] The present invention provides a method for synthesizing an ester-substituted o-carborane derivative, using 1-carboxyl-2-(substituted)-o-carborane and a high-valent iodine reagent as raw materials, and the reaction equation is as follows:

[0031]

[0032] Where R 1 is a straight-chain alkyl group, a branched-chain alkyl group, an aryl group, a benzyl group or a substituted aryl group;

[0033] R 2 It is a straight-chain alkyl group, a branched-chain alkyl group, an aryl group, or a substituted aryl group.

[0034] The method uses 1-carboxyl-2-(substituted group)-o-carborane and a high-valent iodine reagent as raw materials, and comprises the following steps: using 1-carboxyl-2-(substituted group)-o-carborane and a high-valent iodine reagent as raw materials, performing hydration and substitution reactions in a solvent to generate a 1-ester group-2-(substituted group)-o-carborane compound;

[0035] The solvent is toluene, xylene, mesitylene or dichloromethane; the amount of solvent added is: 1 ml of solvent for every 0.1 mmol of 1-carboxyl-2-(substituted)-o-carborane;

[0036] An additive is also added, and the additive is acetic acid; the molar ratio of the additive to 1-carboxyl-2-(substituted)-o-carborane is 1:1.

[0037] The molar ratio of 1-carboxyl-2-(substituted)-o-carborane to the high-valent iodine reagent is 1:(1-5), the reaction temperature is 50-120° C., and the reaction time is 2-36 hours.

[0038] The 1-carboxyl-2-(substituted)-o-carborane of the present invention is preferably 1-carboxyl-1,2-o-carborane, 1-carboxyl-2-methyl-o-carborane, 1-carboxyl-2-n-butyl-o-carborane, 1-carboxyl-2-n-hexyl-o-carborane, 1-carboxyl-2-substituted phenyl-o-carborane; the high-valent iodine reagent R 2 Preferred are methyl, ethyl, n-butyl, n-hexyl, cyclohexyl, aryl, and substituted aryl. The benzene ring contains one or more substituents, and the substituents on the benzene ring are preferably methyl, methoxy, halogen, and trifluoromethyl.

[0039] Example 1: Synthesis of 1-formyloxyacetophenone-2-n-hexyl-o-carborane

[0040] Take a 5 mL reaction bottle and put it into a magnetic bar. Then add 27 mg (0.1 mmol) of 1-carboxy-2-n-hexyl-o-carborane, a high-valent iodine reagent (R 2 To the mixture was added 44 mg (0.12 mmol) of phenyl) and 1 mL of toluene and 6 mg (0.1 mmol) of acetic acid. The mixture was stirred at 80°C for 5 hours. After the reaction, the solvent was evaporated and the mixture was purified by 200-300 mesh silica gel column chromatography (eluent: n-hexane and ethyl acetate, volume ratio: n-hexane: ethyl acetate = 5:1) to obtain 33 mg of 1-formyloxyacetophenone-2-n-hexyl-o-carborane with a yield of 85%.

[0041] Structure identification:

[0042] 1H NMR (500 MHz, deuterated chloroform, δ / ppm) δ7.88 (dd, J=8.3, 1.2 Hz, 1H), 7.65 (t, J=7.5 Hz, 1H), 7.51 (t, J=7.8 Hz, 1H), 5.47 (s, 1H), 2.56-2.34 (m, 2H), 1.59 (dt, J=10.4, 8.0 Hz, 1H), 1.40-1.21 (m, 3H), 0.88 (dd, J=9.2, 4.5 Hz, 2H). 13 C NMR (26 MHz, deuterated chloroform, δ / ppm) δ 189.53, 159.32, 134.38, 133.50, 129.07, 127.72, 82.03, 74.09, 68.80, 36.07, 31.25, 29.63, 28.72, 22.45, 13.96. 11 B NMR (160MHz, deuterated chloroform, δ / ppm) δ-1.49 (1B), -4.89 (1B), -9.68 (2B), -10.66 (6B). FTIR (KBr, cm -1 ):ν3500,3393,3065,2956,2931,2858,2583,1965,1758,1706,1599,1584,1451,1428,1367,1281,1227,1141,960,836,750,687.

[0043] The above structural characterization data confirmed that the obtained compound was 1-formyloxyacetophenone-2-n-hexyl-o-carborane.

[0044] Embodiments 2 to 19

[0045] Examples 2 to 19: 1-formyloxyacetophenone-2-n-hexyl-o-carborane was synthesized by the same method as in Example 1. 1 and R 2 The experimental results are shown in the following table:

[0046]

[0047]

[0048] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims

1. A method for synthesizing an ester-substituted o-carborane derivative, characterized in that: The synthesis method uses 1-carboxyl-2-(substituted)-o-carborane and a high-valent iodine reagent as raw materials, and the reaction equation is as follows: Where R 1 is a linear alkyl group, a branched alkyl group, an aryl group, a benzyl group, a substituted aryl group or H; R 2 It is a straight-chain alkyl group, a branched-chain alkyl group, an aryl group or a substituted aryl group.

2. The method for synthesizing an ester-substituted o-carborane derivative according to claim 1, characterized in that: The molar ratio of 1-carboxyl-2-(substituted)-o-carborane to the high-valent iodine reagent is 1:(1-5), the reaction temperature is 50-120° C., and the reaction time is 2-36 hours.

3. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: The reaction temperature is 50-120°C, and the reaction time is 2-36h.

4. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: The solvent is selected from one of toluene, xylene, mesitylene and dichloromethane; The amount of the solvent added is: 1 ml of solvent for every 0.1 mmol of 1-carboxyl-2-(substituted)-o-carborane.

5. The method for synthesizing the 1-ester-substituted-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: The 1-carboxyl-2-(substituted) o-carborane is selected from one of 1-carboxyl-1,2-o-carborane, 1-carboxyl-2-methyl-o-carborane, 1-carboxyl-2-n-butyl-o-carborane, 1-carboxyl-2-n-hexyl-o-carborane and 1-carboxyl-2-substituted phenyl-o-carborane.

6. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: R in the hypervalent iodine reagent 2 It is selected from methyl, ethyl, n-butyl, n-hexyl, cyclohexyl, aryl and substituted aryl, wherein the aryl contains one or more substituents on the benzene ring, and the substituents on the benzene ring are methyl, methoxy, halogen or trifluoromethyl.

7. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: An additive is also added, and the additive is acetic acid.

8. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 7, characterized in that: The molar ratio of the additive to 1-carboxyl-2-(substituted group)-o-carborane is 1:

1.

9. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 1 or 2, characterized in that: 1-Carboxy-2-n-hexyl-o-carborane, hypervalent iodine reagent, R 2 The molar ratio of phenyl, 1-carboxyl-2-(substituted)-o-carborane and high-valent iodine reagent is 1:1.2, toluene and acetic acid are added, and the reaction is stirred at 80°C for 5 hours. After the reaction is completed, the solvent is evaporated and purified by column chromatography to obtain 1-formyloxyacetophenone-2-n-hexyl-o-carborane.

10. The method for synthesizing a 1-ester-2-(substituted)-o-carborane derivative according to claim 9, characterized in that: The amount of toluene added is: 1 ml of toluene for every 0.1 mmol of 1-carboxy-2-(substituted)-o-carborane; The molar ratio of acetic acid to 1-carboxy-2-(substituted)-o-carborane is 1:1.

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