Rare earth metal amine compound and its preparation method and application

Abstract

To meet the requirements for use as a catalyst in the hydroboration of isocyanates, the present invention provides a rare earth metal amine compound, its preparation method, and application. The rare earth metal amine compound contains an indole-functionalized pyridine and has the structural formula shown in Formula A, wherein RE is a rare earth metal. When used in the hydroboration of isocyanates, this rare earth metal amine compound offers the advantages of low dosage, low cost, environmental friendliness, high catalytic efficiency, high reaction activity, and broad substrate compatibility. Furthermore, the preparation method of this rare earth metal amine compound offers the advantages of simple operation, low equipment requirements, and high yield, thus showing great potential for commercial application. #imgabs0#

Description

Technical Field

[0001] The present invention relates to the technical field of hydroboration of isocyanates, and in particular to a rare earth metal amine compound, a preparation method and application thereof. Background Art

[0002] In recent years, the hydroboration of unsaturated organic substrates has received extensive attention and research, however, reports on the hydroboration of isocyanates are extremely rare. Isocyanates are readily available and inexpensive raw materials and are important components of various organic transformations, such as precursors for the synthesis of urea, which is used in the synthesis of polyurethane polymers, as well as in the synthesis of pharmaceuticals, pesticides, and amides. The hydroboration of isocyanates can form three possible products: (a) N-boron carboxamide compounds; (b) methyleneamine boron compounds; and (c) N-methylamine boron compounds, making the selective reduction of isocyanates challenging. In 2016, Okuda's group used magnesium metal compound [Mg(THF)6][HBPh3]2 as catalyst to react tert-butyl isocyanate with pinacol borane (HBpin) in a 1:2 molar ratio to obtain diboronated methyleneamine boronate (Mukherjee, D.; Shirase, S.; Spaniol, TP; Mashima, K.; Okuda, J. Chem. Commun. 2016, 52, 13155). In 2017, Fang and Hill et al. used magnesium butylate [( DippNacnac)MgnBu] was used as a catalyst in the hydroboration reaction of isocyanates and pinacol borane. When the molar ratio of the isocyanate substrate to HBpin was 1:3, a fully hydroborated N-methylamine boronate was obtained (Yang, Y.; Anker, MD; Fang, J.; Mahon, MF; Maron, L.; Weetman, C.; Hill, M. S. Chem. Sci. 2017, 8, 3529). In 2021, Nembenna reported that divalent zinc hydride containing a biguanidine ligand can control the reduction of isocyanates to N-boron carboxamide compounds (Sahoo, RK, Sarkar, N. and Nembenna, S. Angew. Chem., Int. Ed., 2021, 60, 11991–12000). In 2023, Eisen reported that uranium amino complexes could selectively reduce isocyanate hydroboration reactions by controlling the feed ratio of the reaction substrates to obtain N-boron carboxamides and N-methylamine boron compounds, respectively. In the same year, Liptrot and Sen reported that carbene ligand-containing copper alkoxides and bisphosphine-containing carbazole methyl magnesium complexes could catalyze isocyanate hydroboration reactions, selectively obtaining N-boron carboxamide products (English, LE; Horsley Downie, TM; Lyall, CL; Mahon, MF; McMullin, CL; Neale, SE; Saunders, CM and Liptrot, DJ Chem. Commun., 2023, 59, 1074–1077; Kumar, R.; Sharma, V.; Banerjee, S.; Vanka, K. and Sen, SS Chem. Commun., 2023, 59, 2255–2258). Currently, there are no reports on the hydroboration of isocyanates catalyzed by rare earth metal compounds.

[0003] Therefore, the development of new, efficient, and highly selective rare earth metal compounds to catalyze the hydroboration reaction of isocyanates has important theoretical significance and practical application value. Summary of the Invention

[0004] The purpose of the present invention is to meet the requirements for use as a catalyst in a borohydration method for isocyanates, thereby providing a rare earth metal amine compound and its preparation method and application. When used in the borohydration reaction of isocyanates, the rare earth metal amine compound has the advantages of small dosage, low cost, no pollution to the environment, high reaction catalytic efficiency, high reaction activity and wide substrate universality. At the same time, the preparation method of the rare earth metal amine compound has the advantages of simple operation, low equipment requirements and high yield, and has high commercial application prospects.

[0005] In order to achieve the above object, the first aspect of the present invention provides a rare earth metal amine compound, which contains indole-functionalized pyridine. The structural formula of the rare earth metal amine compound is shown in Formula A:

[0006]

[0007] Among them, RE is a rare earth metal.

[0008] A second aspect of the present invention provides a method for preparing a rare earth metal amine compound, the method comprising: mixing an indole-functionalized pyridine proligand represented by formula B with a rare earth metal amine compound represented by formula C in a protective gas atmosphere in the presence of a solvent, subjecting the mixture to a thermal reaction, and removing the solvent;

[0009]

[0010] Wherein, RE in formula C is a rare earth metal.

[0011] The third aspect of the present invention provides a rare earth metal amine compound prepared by the above preparation method, wherein the rare earth metal amine compound contains indole-functionalized pyridine.

[0012] A fourth aspect of the present invention provides a use of the above-mentioned rare earth metal amine compound in the hydroboration of isocyanate.

[0013] A fifth aspect of the present invention provides a method for the hydroboration of isocyanate, comprising: mixing a boron reagent with an isocyanate in a protective gas atmosphere in the presence of a catalyst to carry out a hydroboration reaction; wherein:

[0014] The catalyst is the above-mentioned rare earth metal amine compound.

[0015] In the above technical scheme, the present invention first uses an indole-functionalized pyridine compound with a structure shown in Formula B as a ligand to carry out a coordination reaction with a precursor shown in Formula C to obtain a rare earth metal amine compound containing indole-functionalized pyridine with a structure shown in Formula A. The preparation method has a simple process, simple operation, mild conditions, high yield and easy separation, can be mass-produced, and is suitable for commercial production.

[0016] At the same time, the rare earth metal amine compound can be used as a hydroboration catalyst in the absence of solvent, with pinacol borane as the hydrogen source, and can efficiently catalyze the hydroboration reaction of isocyanate under relatively mild conditions, with the advantages of small dosage, low cost, and environmental friendliness.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 is the single crystal diffraction pattern of the product A1 of Example 1;

[0020] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the product A1 of Example 1,

[0021] Figure 3 This is the carbon NMR spectrum of the product A1 of Example 1. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0023] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0024] The first aspect of the present invention provides a rare earth metal amine compound, which contains indole-functionalized pyridine. The structural formula of the rare earth metal amine compound is shown in Formula A:

[0025]

[0026] Among them, RE is a rare earth metal.

[0027] The rare earth metal amine compound of the present invention has the advantages of small dosage, low cost, no pollution to the environment, high reaction catalytic efficiency, high reaction activity and wide substrate universality when used in the hydroboration reaction of isocyanate.

[0028] In a preferred embodiment of the present invention, the rare earth metal is selected from one or more of lanthanum, neodymium, samarium, dysprosium, erbium, ytterbium and yttrium.

[0029] A second aspect of the present invention provides a method for preparing a rare earth metal amine compound, the method comprising: mixing an indole-functionalized pyridine proligand represented by formula B with a rare earth metal amine compound represented by formula C in a protective gas atmosphere in the presence of a solvent, and subjecting the mixture to a thermal reaction;

[0030]

[0031] Wherein, RE in formula C is a rare earth metal.

[0032] The present invention first uses an indole-functionalized pyridine compound with a structure shown in formula B as a ligand to carry out a coordination reaction with a precursor shown in formula C to prepare a rare earth metal amine compound containing indole-functionalized pyridine with a structure shown in formula A. The preparation method has a simple process, simple operation, mild conditions, high yield and easy separation, can be produced in batches, and is suitable for commercial production.

[0033] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the rare earth metal is selected from one or more of lanthanum, neodymium, samarium, dysprosium, erbium, ytterbium and yttrium.

[0034] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the protective gas is selected from one or more of argon, nitrogen and helium.

[0035] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the solvent is selected from one or more of toluene, xylene, benzene and chlorobenzene.

[0036] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the conditions of the thermal reaction include: temperature 80-100° C., time 8-12 h.

[0037] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the preparation method further comprises: removing the solvent and / or purifying.

[0038] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the solvent is removed by vacuum extraction and / or reduced pressure distillation.

[0039] In a preferred embodiment of the present invention, in order to improve the catalytic performance of the rare earth metal amine compound of the present invention, the purification method is one or more of washing, recrystallization and sublimation.

[0040] In a preferred embodiment of the present invention, the recrystallization conditions include: the solvent is selected from one or more of toluene, n-hexane and tetrahydrofuran; the temperature is -4-25°C; and the mass ratio of the rare earth metal amine compound to the solvent is 1:3-15.

[0041] The third aspect of the present invention provides a rare earth metal amine compound prepared by the above preparation method, wherein the rare earth metal amine compound contains indole-functionalized pyridine.

[0042] A fourth aspect of the present invention provides a use of the above-mentioned rare earth metal amine compound in the hydroboration of isocyanate.

[0043] A fifth aspect of the present invention provides a method for the hydroboration of isocyanate, comprising: mixing a boron reagent with an isocyanate in a protective gas atmosphere in the presence of a catalyst to carry out a hydroboration reaction; wherein:

[0044] The catalyst is the above-mentioned rare earth metal amine compound.

[0045] The rare earth metal amine compound of the present invention can be used as a hydroboration catalyst in the absence of solvent, with pinacol borane as a hydrogen source, and can efficiently catalyze the hydroboration reaction of isocyanate under relatively mild conditions, with the advantages of small dosage, low cost, and environmental friendliness.

[0046] In a preferred embodiment of the present invention, the protective gas is selected from one or more of argon, nitrogen and helium.

[0047] In a preferred embodiment of the present invention, the molar ratio of the catalyst, the boron reagent and the isocyanate is 1:80-120:80-120.

[0048] In a preferred embodiment of the present invention, the boron reagent is pinacol borane

[0049] In a preferred embodiment of the present invention, the isocyanate is one or more of benzyl isocyanate, cyclohexyl isocyanate, cyclopentyl isocyanate, isopropyl isocyanate, tert-butyl isocyanate, allyl isocyanate, octadecyl isocyanate, 3-chloropropyl isocyanate, 2-methylphenyl isocyanate, 2,6-dimethylphenyl isocyanate, phenyl isocyanate and 3-methylphenyl isocyanate.

[0050] In a preferred embodiment of the present invention, the conditions of the hydroboration reaction include: temperature 25-80° C., and time 5-600 min.

[0051] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. In the following examples, the drugs and pharmaceuticals are all conventional commercial products.

[0052] Preparation Example 1

[0053]

[0054] At room temperature (20-30°C, 25°C here), indole 2-carboxaldehyde (10.0 mmol, 1.45 g) and 2-(2-aminoethyl)pyridine (10.0 mmol, 1.22 g) were mixed in a reaction flask and stirred for 30 minutes. The mixture was recrystallized using ethyl acetate and petroleum ether to obtain the indole-functionalized pyridine proligand (2.11 g, 85% yield) shown in Formula B.

[0055] Characterization data: 1 H NMR (500MHz, CDCl3): δ9.22(s,1H),8.55(d,J=4.5Hz,1H),8.18(s,1H),7.62(d,J=8.0Hz,1H),7.57(m,1H),7.35(d,J=8.0Hz, 1H),7.24(d,8.5Hz,1H),7.16(d,J=8.0Hz,1H),7.10-7.08(m,2H),6.71(s,1H),4.03(t,J=7.0Hz,2H),3.18(t,J=7.0Hz,2H).

[0056] 13 C NMR (125MHz, CDCl3): δ160.0,153.4,149.8,137.4,136.7,135.5,128.5,124.8,124.1, 122.1,121.8,120.5,111.8,108.1,77.7,77.5,77.2,61.0,40.1.HRMS(ESI)m / z:calcd for C 16 H 16 N3(M+H + )250.1339; Found:250.1343..

[0057] Example 1

[0058]

[0059] Under the protection of argon, a toluene solution of the indole-functionalized pyridine proligand (0.5 mmol) obtained in Preparation Example 1 as shown in Formula B was added to a toluene solution of [(Me3Si)2N]3La(μ-Cl)Li(THF)3 (0.5 mmol), and the reaction was carried out at 90°C for 10 hours. After the reaction, the solvent was removed under reduced pressure, and the product was washed with n-hexane and recrystallized from toluene and n-hexane to obtain a rare earth metal lanthanum amine compound as light yellow crystals, which was recorded as A1 (0.30 g, yield 85%).

[0060] The test results of the obtained rare earth metal lanthanum compound A1 are shown in Figure 1-3 ,in, Figure 1 is the single crystal diffraction pattern of the product, Figure 2 is the H NMR spectrum of the product, Figure 3 is the carbon NMR spectrum of the product, and the specific characterization result data are:

[0061] 1 H NMR (500MHz, C6D6): δ9.07(d,J=5.5Hz,1H),8.09(d,J=8.0Hz,1H),7.86(d,J=8.0Hz,1H),7.69(t,J=1.5Hz,1H),7.47-7.44(m,1H),7.16(t, J=5.0Hz,2H),7.02(s,1H),6.84-6.81(m,1H),6.51-6.48(m,1H),6.39(d,J=8.0Hz,1H),3.01-3.00(m,2H),2.84-2.82(m,2H),0.26(s,36H). 13 C NMR (126MHz, C6D6): δ165.4,150.5,128.3,128.1,127.9,125.0,124.8,122.4,119.6,113.1,54.0,4.8.Anal.Calcd for C 28 H 50 N5Si4La:C,47.50;H,7.12;N,9.89.Found:C,47.10;H,6.81;N,9.67.

[0062] Example 2

[0063]

[0064] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with the rare earth metal neodymium, to prepare a rare earth metal neodymium amide compound, which was designated as A2 (0.32 g, yield 89%).

[0065] The characterization results of A2 are as follows: IR (KBr pellets, cm -1 ):ν2944(w),1642(s),1613(s),1428(s),1335(m),1294(m),1253(s),1183(m),1121(m), 1046(m),1005(m),933(s),842(m),756(s),675(m),610(w),453(w),419(w).Anal.Calcd for C 28 H 50N5Si4Nd:C,47.15;H,7.07;N,9.82.Found:C,46.92;H,6.88;N,9.75.

[0066] Example 3

[0067]

[0068] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal samarium, to prepare a rare earth metal samarium amide compound, designated as A3 (0.30 g, yield 84%).

[0069] The characterization result data of A3 is: 1 H NMR (500MHz, C6D6): δ7.99(d,J=8.5Hz,1H),7.48(t,J=7.0Hz,1H),7.41(d,J=8.5Hz,1H),7.31(t,J=7.5Hz,1H),7.08(s,1H),6.66(s,2 H), 6.52 (d, J = 4.0Hz, 1H), 5.84 (t, J = 7.5Hz, 1H), 5.37 (d, J = 7.5Hz, 1H), 5.28 (t, J = 6.0Hz, 1H), 5.20 (s, 1H), 0.58 (s, 2H), 0.02 (s, 36H). 13 C NMR (125MHz, C6D6): δ165.9,157.7,151.1,150.0,147.2,139.0,130.0,125 .3,122.5,121.7,120.1,119.8,119.6,111.6,49.9,38.1,5.1,2.7.IR(KBr pellets,cm -1 ):ν2950(w),1637(s),1615(s),1431(s),1336(m),1295(m),1252(s),1183(m),1122(m), 1047(m),1008(m),933(s),842(m),753(s),676(m),612(w),452(w),422(w).Anal.Calcd for C 28 H 50 N5Si4Sm:C,46.75;H,7.01;N,9.73.Found:C,46.67;H,7.16;N,9.40.

[0070] Example 4

[0071]

[0072] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal gadolinium, to prepare a rare earth metal gadolinium amide compound, designated as A4 (0.31 g, yield 86%).

[0073] The characterization results of A4 are as follows: IR (KBr pellets, cm -1 ):ν3051(m),2950(w),1637(s),1615(s),1432(s),1337(m),1295(m),1251(s),1183(m),1122 (m),1047(m),1009(m),933(s),842(m),753(s),676(m),612(w),452(w),423(w).Anal.Calcd for C 28 H 50 N5Si4Gd:C,46.30;H,6.94;N,9.64.Found:C,46.18;H,6.55;N,9.42.

[0074] Example 5

[0075]

[0076] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal dysprosium, to prepare a rare earth metal dysprosium amide compound, which was designated as A5 (0.31 g, yield 85%).

[0077] The characterization results of A5 are as follows: IR (KBr pellets, cm -1 ):ν3049(m),2952(w),1637(s),1615(s),1433(s),1341(m),1294(m),1250(s),1182(m),1122 (m),1047(m),1009(m),933(s),843(m),753(s),676(m),613(w),452(w),423(w).Anal.Calcd for C 28 H 50 N5Si4Dy:C,45.97;H,6.89;N,9.57.Found:C,46.08;H,7.07;N,9.27.

[0078] Example 6

[0079]

[0080] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal erbium, to prepare a rare earth metal erbium amide compound, designated as A6 (0.32 g, yield 88%).

[0081] The characterization results of A6 are as follows: IR (KBr pellets, cm -1 ):ν2950(w),1636(s),1614(s),1432(s),1341(m),1294(m),1251(s),1183(m),1122(m), 1048(m),1009(m),933(s),843(m),753(s),675(m),614(w),452(w),423(w).Anal.Calcd for C 28 H 50 N5Si4Er:C,45.67;H,6.84;N,9.51.Found:C,45.57;H,6.75;N,9.22.

[0082] Example 7

[0083]

[0084] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal ytterbium, to prepare a rare earth metal ytterbium amide compound, which was designated as A7 (0.30 g, yield 82%).

[0085] The characterization data of A7 are as follows: IR (KBr pellets, cm-1): ν 2949 (w), 1636 (s), 1614 (s), 1432 (s), 1341 (m), 1295 (m), 1251 (s), 1183 (m), 1123 (m), 1048 (m), 1010 (m), 933 (s), 843 (m), 753 (s), 675 (m), 615 (w), 452 (w), 422 (w). Anal. Calcd for C28H50N5Si4Yb: C, 45.32; H, 6.79; N, 9.44. Found: C, 45.68; H, 7.12; N, 9.07.

[0086] Example 8

[0087]

[0088] The method of Example 1 was followed, except that the rare earth metal lanthanum was replaced with rare earth metal yttrium, to prepare a rare earth metal yttrium amide compound, which was designated as A8 (0.29 g, yield 88%).

[0089] The characterization results of A8 are as follows: 1 H NMR (500MHz, C6D6): δ9.41 (d, J=5.5Hz, 1H, py-H), 8.15 (d, J=8.0Hz, 1H, Ph-H), 7.81 (d, J=8.0Hz ,1H,Ph-H),7.55(s,1H,-CH=N-),7.46(t,J=7.0Hz,1H,Ph-H),7.13(t,J=7.5Hz,1H,Ph-H),7.00( s,1H,3-indole-H),6.83(t,J=7.8Hz,1H,py-H),6.51(t,J=6.5Hz,1H,py-H),6.38(d,J=8.0Hz,1 H,py-H),3.02-2.93(m,2H,-CH=N-CH2-),2.93-2.74(m,2H,-CH2-py),0.24(s,36H,-N(CH3)2-).

[0090] 13 C NMR (125MHz, C6D6): δ165.9,161.0,153.0,149.8,142.3,140.4,131.2,125.2,124.8,122.5,122.4,119.9,119.0,113.5,52.9,37.1,5.8,2.7.

[0091] IR(KBr pellets,cm -1 ):ν2952(w),1637(s),1615(s),1433(s),1341(s),1295(s),1250(s),1183(m),1122(m), 1048(m),1010(m),933(s),843(m),753(s),676(m),614(m),452(w),422(w).Anal.Calcd for C 28 H 50 N5Si4Y:C,51.11;H,7.66;N,10.64.Found:C,51.40;H,7.37;N,10.62.

[0092] Application Example 1

[0093] In an argon glove box, a polytetrafluoroethylene magnet was placed in a 25 mL single-necked reaction flask. 0.005 mmol of the rare earth metal lanthanum amine compound A1 prepared in Example 1 was weighed and placed therein. 0.5 mmol of pinacol borane was added, followed by 0.5 mmol of benzyl isocyanate. The reaction was carried out at 25°C for 5 min without solvent.

[0094] The conversion rate of benzyl isocyanate to hydroboration was determined to be 99% by H NMR spectroscopy.

[0095] Application Example 2

[0096] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of cyclohexyl isocyanate to carry out the reaction.

[0097] The conversion rate of hydroboration of cyclohexyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0098] Application Example 3

[0099] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of cyclopentyl isocyanate to carry out the reaction.

[0100] The conversion rate of cyclopentyl isocyanate by hydroboration was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0101] Application Example 4

[0102] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equimolar amount of isopropyl isocyanate to carry out the reaction.

[0103] The conversion rate of hydroboration of isopropyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0104] Application Example 5

[0105] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of tert-butyl isocyanate to carry out the reaction.

[0106] The conversion rate of tert-butyl isocyanate by hydroboration was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0107] Application Example 6

[0108] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equimolar amount of allyl isocyanate to carry out the reaction.

[0109] The conversion rate of the hydroboration of allyl isocyanate was determined to be 99% by H NMR spectroscopy.

[0110] Application Example 7

[0111] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of octadecyl isocyanate to carry out the reaction.

[0112] The conversion rate of hydroboration of octadecyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0113] Application Example 8

[0114] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of chloropropyl isocyanate to carry out the reaction.

[0115] The conversion rate of hydroboration of chloropropyl isocyanate was determined to be 99% by H NMR spectroscopy.

[0116] Application Example 9

[0117] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of 2-methylphenyl isocyanate to carry out the reaction.

[0118] The conversion rate of 2-methylphenylisocyanate by hydroboration was determined to be 99% by H NMR spectroscopy.

[0119] Application Example 10

[0120] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of 2,6-dimethylphenyl isocyanate to carry out the reaction.

[0121] The conversion rate of 2,6-dimethylphenylisocyanate to hydroboration was 99% as determined by H NMR spectroscopy.

[0122] Application Example 11

[0123] The reaction was carried out according to the method of Application Example 1, except that the amount of pinacol borane was replaced from 0.5 mmol to 1.525 mmol, the reaction temperature was replaced from 25° C. to 60° C., and the reaction time was replaced from 5 min to 3 h.

[0124] The conversion rate of benzyl isocyanate to hydroboration was determined to be 99% by H NMR spectroscopy.

[0125] Application Example 12

[0126] The method of Application Example 11 was followed, except that benzyl isocyanate was replaced with an equal molar amount of cyclohexyl isocyanate to carry out the reaction.

[0127] The conversion rate of hydroboration of cyclohexyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0128] Application Example 13

[0129] The reaction was carried out according to the method of Application Example 11, except that benzyl isocyanate was replaced by an equal molar amount of cyclopentyl isocyanate, the reaction temperature was changed from 60° C. to 80° C., and the reaction time was changed from 3 h to 10 h.

[0130] The conversion rate of cyclopentyl isocyanate by hydroboration was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0131] Application Example 14

[0132] The method of Application Example 11 was followed, except that benzyl isocyanate was replaced with an equimolar amount of isopropyl isocyanate to carry out the reaction.

[0133] The conversion rate of hydroboration of isopropyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0134] Application Example 15

[0135] The method of Application Example 11 was followed, except that benzyl isocyanate was replaced with an equal molar amount of tert-butyl isocyanate, and the reaction time was changed from 3 h to 10 h.

[0136] The conversion rate of tert-butyl isocyanate by hydroboration was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0137] Application Example 16

[0138] The method of Application Example 11 was followed, except that benzyl isocyanate was replaced with an equimolar amount of allyl isocyanate to carry out the reaction.

[0139] The conversion rate of the hydroboration of allyl isocyanate was determined to be 99% by H NMR spectroscopy.

[0140] Application Example 17

[0141] The reaction was carried out according to the method of Application Example 11, except that benzyl isocyanate was replaced by an equal molar amount of octadecyl isocyanate, the reaction temperature was changed from 60° C. to 80° C., and the reaction time was changed from 3 h to 5 h.

[0142] The conversion rate of hydroboration of octadecyl isocyanate was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0143] Application Example 18

[0144] The method of Application Example 11 was followed, except that benzyl isocyanate was replaced with an equal molar amount of chloropropyl isocyanate, and the reaction time was changed from 3 h to 5 h.

[0145] The conversion rate of hydroboration of chloropropyl isocyanate was determined to be 99% by H NMR spectroscopy.

[0146] Application Example 19

[0147] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced by an equal molar amount of phenyl isocyanate, and the reaction time was changed from 3 h to 5 h.

[0148] The conversion rate of phenyl isocyanate to hydroboration was determined to be 99% by H NMR spectroscopy.

[0149] Application Example 20

[0150] The method of Application Example 1 was followed, except that benzyl isocyanate was replaced with an equal molar amount of 3-methylphenyl isocyanate, and the reaction time was changed from 3 h to 5 h.

[0151] The conversion rate of 3-methylphenylisocyanate by hydroboration was determined to be 99% by hydrogen nuclear magnetic resonance spectroscopy.

[0152] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0153] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0154] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A rare earth metal amine compound, characterized in that: The rare earth metal amine compound contains indole-functionalized pyridine, and the structural formula of the rare earth metal amine compound is shown in Formula A: ； Among them, RE is rare earth metal; The rare earth metal is selected from one or more of lanthanum, neodymium, samarium, dysprosium, erbium, ytterbium and yttrium.

2. A method for preparing a rare earth metal amine compound, characterized in that: The preparation method comprises: mixing an indole functionalized pyridine proligand represented by formula B and a rare earth metal amine compound represented by formula C in a protective gas atmosphere in the presence of a solvent, and subjecting them to a thermal reaction; ， ； Wherein, RE in formula C is a rare earth metal; The rare earth metal is selected from one or more of lanthanum, neodymium, samarium, dysprosium, erbium, ytterbium and yttrium.

3. The preparation method according to claim 2, characterized in that The protective gas is selected from one or more of argon, nitrogen and helium; The solvent is selected from one or more of toluene, xylene, benzene and chlorobenzene; The conditions of the thermal reaction include: temperature 80-100° C., time 8-12 h.

4. The preparation method according to claim 2 or 3, characterized in that The preparation method further comprises: removing the solvent and / or purifying; The method of removing the solvent is vacuum extraction and / or reduced pressure distillation; The purification method is one or more of washing, recrystallization and sublimation; The recrystallization conditions include: the solvent is selected from one or more of toluene, n-hexane and tetrahydrofuran; the temperature is -4-25° C.; and the mass ratio of the rare earth metal amine compound to the solvent is 1:3-15.

5. A rare earth metal amine compound prepared according to the preparation method according to any one of claims 2 to 4, characterized in that: The rare earth metal amine compound contains indole-functionalized pyridine.

6. Use of the rare earth metal amine compound according to claim 1 or 5 in the hydroboration of isocyanate.

7. A method for the hydroboration of isocyanates, characterized in that: The method comprises: mixing a boron reagent and an isocyanate in a protective gas atmosphere and in the presence of a catalyst to carry out a hydroboration reaction; wherein, The catalyst is the rare earth metal amine compound according to claim 1 or 5.

8. The method according to claim 7, characterized in that The protective gas is selected from one or more of argon, nitrogen and helium; The molar ratio of the catalyst, the boron reagent and the isocyanate is 1:80-120:80-120; The boron reagent is pinacol borane; The isocyanate is selected from one or more of benzyl isocyanate, cyclohexyl isocyanate, cyclopentyl isocyanate, isopropyl isocyanate, tert-butyl isocyanate, allyl isocyanate, octadecyl isocyanate, 3-chloropropyl isocyanate, 2-methylphenyl isocyanate, 2,6-dimethylphenyl isocyanate, phenyl isocyanate and 3-methylphenyl isocyanate; The conditions of the hydroboration reaction include: temperature of 25-80° C. and time of 5-600 min.

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