Bidentate nitrogen-manganese complex and preparation method thereof, catalyst composition and application thereof

Abstract

The invention discloses a method for preparing a tetrahydroquinolinyl nitrogen-nitrogen bidentate manganese complex and its application in catalyzing the transfer oxidation of secondary alcohols to prepare ketones. The general formula of the di-tetrahydroquinolinyl nitrogen-nitrogen manganese complex is as shown in Formula I. The manganese compound of Formula I is used as a catalyst, which has high selectivity and high activity in the transfer oxidation reaction of secondary alcohols and has important applications in the preparation of ketone fine chemicals. The preparation method of the manganese complex in the invention is simple, has high yield and good stability. For the transfer oxidation reaction of secondary alcohols, the manganese-based catalytic system has high catalytic activity, small manganese loading, simple method, low environmental pollution and high yield.

Description

Technical Field

[0001] The invention relates to a manganese complex, in particular to a bidentate manganese complex and a preparation method thereof, as well as a catalyst composition using the complex as an active component and an application of the catalyst composition in catalyzing oxidation of secondary alcohols to ketones. Background Art

[0002] The oxidation of alcohols to carbonyl compounds is an important transformation process for the synthesis of ketone fine chemicals. Usually, a stoichiometric oxidant (MnO 2 , OsO 4 , high-valent iodine reagents, hypochlorites, peroxides, etc.) or some organic name reactions to complete this transformation. However, such strong oxidants are dangerous and harmful to the environment. The ketone products are obtained with the generation of a large amount of waste, which is inconsistent with the concept of green synthesis. In the past two decades, due to the need for process environmental compatibility and sustainable development, O 2 or H 2 O 2 As a green oxidant, the metal-catalyzed oxidation of alcohols to ketones is well known. However, from the perspective of production safety, the acceptor-free dehydrogenation (ADH) and transfer dehydrogenation (TDH) of alcohols to form carbonyl compounds (such as ketones or aldehydes) is a greener and more sustainable production route. Expensive and cheap metal (such as Pd, Ru, Ir, Os, Fe, Co, Mn) complex catalysts have been applied to this type of catalytic oxidation reaction and have effectively obtained aliphatic and aromatic alcohols. Compared with the harsh conditions of high temperature (>120℃) and excessive strong base (such as t-BuOK) required by the ADH catalytic system, the operating conditions of the TDH catalytic system are milder and the scope of application of substrates is wider.

[0003] In the context of "dual carbon", efficient utilization of biomass resources is the only way to solve the shortage of fossil resources and effectively obtain carbon resources. THD oxidation of bio-based alcohols provides a green and feasible synthetic route for the sustainable acquisition of aldehyde and ketone compounds. Acetone is a cheap, readily available, low-toxic organic solvent that can be regenerated by biomass conversion. In this field, a variety of precious metal catalysts have been reported to catalyze the transfer dehydrogenation oxidation of secondary alcohols. However, as mentioned above, efficient catalysts are mainly concentrated in precious metal Ru(II) and Ir(III) complex catalysts. Currently, only three non-precious metal catalysts have been reported to be suitable for TDH alcohol oxidation, and these catalysts require special ligands, which brings difficulties to industrial applications. Therefore, there is an urgent need to design new and inexpensive ligands and catalysts to solve the problems of low catalyst activity and high cost in the process of alcohol dehydrogenation oxidation to ketones. Summary of the invention

[0004] The object of the present invention is to provide a bidentate nitrogen-manganese complex, which exhibits excellent catalytic performance such as high catalyst activity, wide substrate application range, mild reaction conditions, etc. in the process of catalyzing the deoxidation and oxidation reaction of secondary alcohols to prepare ketone compounds.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The bidentate nitrogen-manganese complex has a structure as shown in Formula I:

[0007]

[0008] Wherein, R is a C1-C8 alkyl group or a C6-C10 aryl group.

[0009] Preferably, R is n-butyl, isobutyl, sec-butyl, n-propyl, isopropyl, ethyl, methyl, phenyl, tolyl, ethylphenyl, benzyl or phenethyl.

[0010] Another object of the present invention is to provide a method for preparing a bidentate nitrogen-manganese complex, wherein the compound represented by formula II and the compound represented by formula III are reacted to obtain a compound represented by formula I.

[0011]

[0012] Wherein, R is n-butyl, isobutyl, sec-butyl, n-propyl, isopropyl, ethyl, methyl, phenyl, benzyl or phenethyl.

[0013] The third object of the present invention is to provide a catalyst composition, comprising an active ingredient and an auxiliary agent, wherein the active ingredient is the bidentate nitrogen-manganese complex and the auxiliary agent is a base.

[0014] Preferably, the auxiliary agent is t-BuOK, t-BuONa, i-PrONa, EtONa, MeONa, KOH, NaOH, NaHBEt 3 KBH 4 , NaBH 4 One or more of the .

[0015] Preferably, the application is to catalyze the dehydrogenation and oxidation reaction of secondary alcohols to prepare ketone compounds.

[0016] Preferably, the aliphatic or aromatic secondary alcohol and the catalyst composition are added to acetone or butanone solvent, and reacted at 50-110° C. for 2-48 hours under an inert gas atmosphere to obtain the corresponding ketone.

[0017] Preferably, the catalyst composition is the bidentate nitrogen-manganese complex and KBH 4 A combination of the bidentate nitrogen-manganese complex and NaBH 4The combination of the bidentate nitrogen manganese complex and KBH 4 or NaBH 4 The molar ratio is 1:2-10.

[0018] In the above chemical formula, Me represents methyl and Et represents ethyl. i- Pr represents isopropyl, t- Bu represents tert-butyl.

[0019] The bidentate nitrogen-manganese complex provided by the present invention introduces a cyclohexyl ring into the ligand skeleton, and by regulating the ring tension and steric hindrance of the cycloalkyl ring, the reactivity and stability of the manganese metal center can be effectively adjusted, and the catalytic activity of the manganese metal system can be significantly improved. The catalyst composition with the manganese complex as the active ingredient has the advantages of high catalyst activity, wide substrate application range, mild reaction conditions, etc. in the process of catalyzing the deoxidation and oxidation reaction of secondary alcohols to prepare ketone compounds, showing the advantages of low cost and stable performance, simple operation, and high yield. In the process of deoxidation and oxidation of secondary alcohols to ketones, the bidentate nitrogen-manganese complex is used in combination with a base, and a suitable base has an activation effect on the catalyst. The activated catalyst obtains hydrogen from the secondary alcohol and transfers it to acetone or butanone as a solvent, and finally obtains the secondary alcohol oxidation product, i.e., the corresponding ketone. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the crystal structure of the Mn1 compound prepared in Example 7. DETAILED DESCRIPTION

[0021] The term "C1-C8 alkyl" refers to an alkyl group having 1 to 8 carbon atoms, including straight or branched chain alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, etc.

[0022] The term "C6-C10 aryl group" refers to a benzene-containing hydrocarbon group having 6 to 10 carbon atoms, such as a benzene-containing hydrocarbon group having 6, 7, 8, 9 or 10 carbon atoms, such as phenyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, xylyl, diethylphenyl, and the like.

[0023] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0024] The potassium hydroxide (KOH), sodium hydroxide (NaOH), lithium hydroxide (LiOH), sodium methoxide (MeONa), sodium ethoxide (EtONa), sodium isopropoxide (i-PrONa), sodium tert-butoxide (t-BuONa), and potassium tert-butoxide (t-BuOK) used were purchased from Beijing Inokai Technology Co., Ltd.

[0025] Example 1 Preparation of N-isopropyl-5,6,7,8-tetrahydroquinolin-8-amine (L1)

[0026]

[0027] Based on the support of similar synthesis steps (J.Org.Chem.1996,61,3849-3862; Catal.Sci.Technol.,2021,11,8026-8036; ACS Catal.2016,6,1247-1253): Under a nitrogen atmosphere, 1.47g (10mmol) 5,6,7-trihydroquinolin-8-one, 0.71g (12mmol, 1.2eq.) 2-propylamine, 0.6g (10mmol) acetic acid and 6.33g (30mmol, 3.0eq.) sodium triacetoxyborohydride were placed in a 250mL single-necked flask, and then 80mL 1,2-dichloroethane (DCE) was added. The mixture was stirred at 30°C for 12 hours. 100mL NaHCO was added. 3 The reaction was quenched with saturated aqueous solution and the pH was adjusted to 9. The target product was extracted with ethyl acetate (3×30 mL). The organic phases were combined and washed with Na 2 SO 4 After drying and desolvation, a yellow oil was obtained by column chromatography, namely L1 (1.72 g, yield 90%).

[0028] The structural confirmation data are as follows:

[0029] 1 H NMR (400 MHz, CDCl 3 )δ8.37(d,J=4.1Hz,1H),7.34(d,J=7.4Hz,1H),7.03(dd,J=7.5,4.7Hz,1H),3.88(d,J=6.3Hz,1H),3.71(s,1H),3.11–2.99(m ,1H),2.76(dd,J=13.3,5.2Hz,2H),2.12(t,J=11.5Hz,1H),2.04–1.93(m,1H),1.79–1.68(m,2H),1.16(dd,J=9.7,6.4Hz,6H); 13 C NMR (100 MHz, CDCl 3)δ157.95,146.82,136.86,132.37,121.70,55.12,46.00,29.26,28.86,24.64,22.07,19.65.

[0030] Example 2 Preparation of N-butyl-5,6,7,8-tetrahydroquinolin-8-amine (L2)

[0031]

[0032] Using similar procedures and molar ratios as L1, L2 (1.92 g, 94% yield) was obtained as a yellow oil.

[0033] The structural confirmation data are as follows:

[0034] 1 H NMR (400 MHz, CDCl 3 )δ8.35(d,J=4.4Hz,1H),7.32(d,J=7.6Hz,1H),7.01(dd,J=7.6,4.8Hz,1H),3.74(t,J=6.3Hz,1H),2.78–2.66(m,4H),2.17–2.05(m,1H), 1.96(dd,J=11.7,6.2Hz,1H),1.72(ddd,J=13.5,9.5,3.9Hz,2H),1.58–1.48(m,2H),1.37(dd,J=14.9,7.4Hz,2H),0.90(t,J=7.3Hz,3H); 13 C NMR (100 MHz, CDCl 3 )δ157.55,146.82,146.77,136.83,136.78,132.33,121.74,121.69,77.58,7 7.27,76.95,58.15,47.55,47.51,32.50,28.88,28.65,20.63,19.66,14.04.

[0035] Example 3 Preparation of N-benzyl-5,6,7,8-tetrahydroquinolin-8-amine (L3)

[0036]

[0037] Using similar procedures and molar ratios as L1, L3 (2.25 g, yield 93%) was obtained as a yellow oil.

[0038] The structural confirmation data are as follows:

[0039] 1 H NMR (400 MHz, CDCl3 )δ8.34(d,J=4.1Hz,1H),7.38(d,J=7.4Hz,2H),7.29(dd,J=14.3,7.1Hz,3H) ,7.22–7.16(m,1H),7.00(dd,J=7.6,4.8Hz,1H),3.94(s,1H),3.82(dd,J=7. 3,5.6Hz,1H),3.01(s,1H),2.85–2.74(m,1H),2.73–2.64(m,1H),2.15(dt,J =12.1,5.1Hz,1H),2.04–1.93(m,1H),1.83–1.74(m,1H),1.72–1.61(m,1H); 13 C NMR (100 MHz, CDCl 3 )δ157.40,146.86,140.57,140.54,136.90,132.50,128.46,128.38,127.13,126.93,121.90,57.60,51.84,28.90,28.62,19.77.

[0040] Example 4 Preparation of N-phenyl-5,6,7,8-tetrahydroquinolin-8-amine (L4)

[0041]

[0042] Using similar procedures and molar ratios as described for L1, a white solid L4 (1.32 g, yield 58%) was obtained. Mp: 105-106°C.

[0043] The structural confirmation data are as follows:

[0044] 1 H NMR (400 MHz, CDCl 3 )δ8.45(d,J=4.2Hz,1H),7.44(d,J=7.6Hz,1H),7.20(t,J=7.9Hz,2H),7.14(dd,J=7.6,4.7 Hz,1H),6.79–6.71(m,3H),4.51(t,J=5.5Hz,1H),2.85(q,J=6.6Hz,2H),2.01–1.82(m,4H); 13 C NMR (100 MHz, CDCl 3 )δ156.55,148.10,147.20,137.13,132.86,129.25,122.36,117.62,113.84,53.98,29.16,28.52,19.29.

[0045] Example 5 Preparation of 8-(2-phenylhydrazinylidene)-5,6,7,8-tetrahydroquinoline (L5)

[0046]

[0047] Under nitrogen atmosphere, 1.47 g (10 mmol) of 5,6,7-trihydroquinolin-8-one and 1.08 g (10 mmol) of freshly distilled phenylhydrazine were refluxed in 10 mL of ethanol for 6 h. The red solution was cooled to room temperature. The suspension was filtered under reduced pressure to collect the resulting orange-yellow crystals, which were washed with cold ethanol (5-10 mL) to obtain an orange-yellow solid L5 (1.2 g, yield 50%). Mp: 114-115 °C.

[0048] The structural confirmation data are as follows:

[0049] 1 H NMR (400 MHz, CDCl 3 )δ14.00(s,1H),8.51(d,J=4.7Hz,1H),7.54(d,J=7.6Hz,1H),7.31–7.26(m,2H),7.22(d,J=8.2Hz,2H),7.15(d d,J=7.6,4.9Hz,1H),6.83(dd,J=8.8,4.3Hz,1H),2.88(t,J=6.1Hz,2H),2.85–2.80(m,2H),2.05–1.95(m,2H); 13 C NMR (100 MHz, CDCl 3 )δ151.11,151.08,145.34,145.02,136.86,135.31,133.08,129.24,121.82,119.63,112.83,112.82,34.18,30.21,22.84.

[0050] Example 6 Preparation of N-(2-(1H-benzo[d]imidazole-2-)ethyl)-5,6,7,8-tetrahydroquinolin-8-amine (L6)

[0051]

[0052] Using similar procedures and molar ratios as described for L1, L6 was obtained as a yellow oil (1.65 g, 56% yield).

[0053] The structural confirmation data are as follows:

[0054] 1 H NMR (400 MHz, CDCl 3)δ8.55(d,J=4.3Hz,1H),7.60–7.50(m,2H),7.49–7.42(m,1H),7.21–7.11(m,3H),3.95(d,J=6.4Hz,1H),3.29–3.09 (m,4H),2.81(dd,J=12.2,5.8Hz,2H),2.17(dd,J=12.0,5.2Hz,1H),1.96(dd,J=12.1,6.5Hz,1H),1.89–1.76(m,2H); 13 C NMR (100 MHz, CDCl 3 )δ157.24,154.75,146.57,137.47,133.10,122.36,121.75,114.71,57.05,45.07,29.07,28.85,28.78,19.77.

[0055] Example 7 Bidentate nitrogen manganese complex (Ni-Pr-8-NHC 9 H 10 N)Mn(CO) 3 Preparation of Br(Mn1)

[0056]

[0057] Under nitrogen atmosphere, 190 mg (1 mmol) of L1 and 275 mg (1 mol) of Mn(CO) 5 Br and 10 mL of tetrahydrofuran were added to a 25 mL Schlenk bottle. The mixture was heated at 65 ° C for 24 hours. After the mixture was cooled to room temperature, the mixture was concentrated under reduced pressure. The solid residue was washed with n-hexane (10 mL) and then dried to obtain Mn1 (365 mg, yield 89%) as a yellow solid.

[0058] 1 H NMR (400 MHz, CDCl 3 )δ8.93(d,J=25.1Hz,1H),7.54(d,J=4.7Hz,1H),7.30(d,J=2.1Hz,1H),4.21(t,J=13.5Hz,1H),3.64(t,J=12.1Hz,1H),3.30 –3.16(m,1H),2.90–2.79(m,1H),2.68(d,J=6.0Hz,1H),2.18(d,J=5.5Hz,1H),1.85–1.74(m,1H),1.56(s,3H),1.45(s,3H); 13C NMR (100MHz, DMSO) δ222.98,222.85,222.18,158.38,152.18,139.37,135.19,125.10,63.02,48.46,27.69,27.60,23.24,20.84,19.11; IR (ATR, cm -1 ,KBr):1906(s,v CO ),1922(s,v CO ),2017(s,v CO ); Elemental analysis: [C 15 H 18 BnN 2 O 3 (Mw: 409.16)]: C, 44.03; H, 4.43; N, 6.85. Found: C, 44.11; H, 4.48; N, 6.84%.

[0059] The crystal structure diagram of Mn1 is shown in Figure 1 As shown. Figure 1 It can be seen that the central metal Mn of the complex Mn1 adopts a hexacoordination mode, and is coordinated with the two nitrogen atoms N1, N2 and three carbonyl carbons C13, C14, C15 and a bromine atom on the ligand 8-aminotetrahydroquinoline ring, presenting a distorted octahedral structure.

[0060] Example 8 Manganese complex (Nn-Bu-8-NHC 9 H 10 N)Mn(CO) 3 Preparation of Br(Mn2)

[0061]

[0062] Using similar procedures and molar ratios as described for Mn1, Mn2 (392 mg, 92% yield) was isolated as a yellow powder.

[0063] 1 H NMR(500MHz,DMSO-d)δ8.76(d,J=4.9Hz,1H),7.77(s,1H),7.51–7.43(m,1H),4.20–4.08(m,1H),3.58(d,J=10.7Hz,1H),3.32(s,1H),3.16(d, J=5.3Hz,2H),2.87–2.73(m,2H),2.05–1.93(m,2H),1.85–1.75(m,2H),1.65–1.58(m,1H),1.44(dd,J=14.4,7.2Hz,2H),0.98(t,J=7.2Hz,3H);13 C NMR(125MHz,DMSO-d)δ223.14,222.53,221.95,158.01,151.98,139.27(d,J=26.6Hz),135.1 3(d,J=23.9Hz),125.17,63.54,51.04,31.16,28.74,27.28,20.71,20.39,14.21; IR(ATR,cm -1 ,KBr):1916(s,v CO ),1938(s,v CO ),2017(s,v CO ); Elemental analysis: [C 16 H 20 BnN 2 O 3 (Mw: 423.19)]: C, 45.41; H, 4.76; N, 6.62. Found: C, 45.49; H, 4.78; N, 6.60%.

[0064] Example 9 Manganese complex (N-Bn-8-NHC 9 H 10 N)Mn(CO) 3 Preparation of Br(Mn3)

[0065]

[0066] Using similar procedures and molar ratios as described for Mn1, Mn3 (413 mg, 90% yield) was isolated as a yellow powder.

[0067] 1 H NMR(500MHz,DMSO-d)δ8.76(s,1H),7.75(s,1H),7.53(s,1H),7.41(d,J=29.7Hz,5H),4.63–4.47(m,1H),4.33( d,J=42.5Hz,2H),3.33(s,1H),2.77(d,J=14.7Hz,2H),2.62–2.55(m,1H),1.95(s,1H),1.67(d,J=99.8Hz,2H); 13 C NMR(125MHz,DMSO-d)δ222.44,220.76,219.95,160.06,150.59,139.13,135.30,129.37,128 .98,128.79,128.46,128.18,127.79,124.24,62.99,53.87,27.62,26.05,21.44;IR(ATR,cm-1 ,KBr):1904(s,v CO ),1936(s,v CO ),2019(s,v CO ); Elemental analysis: [C 19 H 18 BnN 2 O 3 (Mw: 457.21)]: C, 49.91; H, 3.97; N, 6.13. Found: C, 49.91; H, 4.02; N, 6.15%.

[0068] Example 10 Manganese complex (N-Ph-8-NHC 9 H 10 N)Mn(CO) 3 Preparation of Br(Mn4)

[0069]

[0070] Using similar procedures and molar ratios as described for Mn1, Mn4 was isolated as a yellow powder (365 mg, 82% yield).

[0071] 1 H NMR(500MHz,DMSO)δ8.86(d,J=74.1Hz,1H),7.83(d,J=3.2Hz,1H),7.60–7.37(m,4H),7.24–7.15(m,1H ),5.92–5.65(m,1H),5.15–4.92(m,1H),3.42–3.30(m,1H),2.81(d,J=48.3Hz,2H),1.97~1.79(m,2H); 13 C NMR (125MHz, DMSO) δ223.18, 222.60, 220.79, 158.65, 157.25, 152.24, 150.95, 147.43 (d, J = 18.3Hz) 139.44, 135.45 ( d,J=34.5Hz),129.93,125.45(d,J=18.7Hz),124.61,120.64,64.14,27.39(d,J=29.8Hz).,26.58,20.59; IR(ATR,cm -1 ,KBr):1907(s,v CO ),1949(s,v CO ),2023(s,v CO ); Elemental analysis: [C 18 H 16 BnN 2 O3 (Mw: 443.18)]: C, 48.78; H, 3.64; N, 6.32. Found: C, 48.81; H, 3.68; N, 6.31%.

[0072] Example 11 Manganese complex (N-Ph-8-NHC 9 H 10 N)Mn(CO) 3 Preparation of Br(Mn5)

[0073]

[0074] Using similar procedures and molar ratios as described for Mn1, Mn5 (408 mg, 89% yield) was isolated as a yellow powder.

[0075] 1 H NMR(500MHz,DMSO-d)δ9.71(br,1H),8.90(br,1H),7.88(br,1H),7.50–6.97(m,5H),2.89(br,2H),1.86(br,2H),0.93(br,2H); 13 C NMR(125MHz,DMSO-d)δ223.23,221.25,219.03,167.64,151.84,145.06,140. 28,138.79,129.00,126.50,122.22,118.12,28.67,27.66,21.17;IR(ATR,cm -1 ,KBr):1919(s,v CO ),1942(s,v CO ),2027(s,v CO ); Elemental analysis: [C 18 H 15 BnN 3 O 3 (Mw: 456.18)]: C, 47.39; H, 3.31; N, 9.21. Found: C, 47.40; H, 3.33; N, 9.28%.

[0076] Example 12 Preparation of manganese complex Mn6

[0077]

[0078] To a 25 mL Schlenk bottle maintained under nitrogen was added a solution of L6 (292 mg, 1 mmol) in toluene (5 mL), followed by the addition of Mn(CO) 5Br (275mg, 1mol) in toluene orange solution (10mL). The reaction mixture was then stirred and heated at 110 ° C for 24 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure. The solid residue was washed with n-hexane (10mL) and then dried to obtain Mn6 (426mg, yield 83%) as a green-yellow solid.

[0079] 1 H NMR(500MHz,DMSO-d)δ8.73(s,1H),8.28(d,J=8.0Hz,1H),7.76(d,J=7.6Hz,1H),7.44(d,J=7.5Hz,2H),7.36(d,J=6.3Hz,2H),6.8 6(br,1H),4.54(d,J=4.9Hz,1H),3.07(br,2H),2.80(br,2H),2.22(br,1H),2.07(dd,J=22.2,11.9Hz,2H),1.90(d,J=9.5Hz,2H); 13 C NMR(125MHz,DMSO-d)δ220.21,219.82,218.92,159.71,158.87,151.53,151.48,140.02,139.88,135.77,135.68,12 5.56,125.13,123.94,123.72,123.44,123.00,117.09,113.41,67.49,65.11,27.51,26.69,25.59,21.18; IR(ATR,cm -1 ,KBr):1912(s,v CO ),1930(s,v CO ),2027(s,v CO ); Elemental analysis: [C 21 H 20 BnN 4 O 3 (Mw: 511.26)]: C, 49.34; H, 3.94; N, 10.96. Found: C, 49.40; H, 3.98; N, 10.94%.

[0080] Example 11 Compound Mn1 catalyzes the dehydrogenation of 1-phenylethanol (a1) to produce acetophenone (b1) in the presence of different base additives

[0081] In N 2Under the atmosphere, 61 mg (0.5 mmol) of 1-phenylethanol, 4.0 mg (10 umol) of Mn1, and 10 umol of base promoter were placed in a 25 mL Schlenk bottle, and 2.0 mL of acetone was added. The reaction mixture was stirred at 60 ° C for 24 hours. After cooling to room temperature, the results of GC analysis (with dodecane as the internal standard) are shown in Table 1.

[0082] Table 1. Results of dehydrogenation reaction preparation under different promoters.

[0083]

[0084]

[0085] a Reaction conditions: 0.5mmol 1-phenylethanol, 10μmol (2mol%) Mn1, 50μmol base promoter, 2mL acetone, 60℃, 24h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0086] From Table 1, we can see that KHDMS (potassium bis(trimethylsilyl)amide), NaHDMS (sodium bis(trimethylsilyl)amide), LiHDMS (lithium bis(trimethylsilyl)amide, KBH 4 or NaBH 4 When used as a base promoter, Mn1 showed high catalytic activity. When sodium bis(trimethylsilyl)amide and potassium borohydride were used as base promoters, the system showed the highest catalytic activity after 24 hours of reaction, with a conversion rate of 100% and a product yield of 99%.

[0087] Example 12: Catalytic oxidation of 1-phenylethanol (a1) to acetophenone (b1) by changing the molar ratio of compound Mn1 to substrate in the presence of a preferred base auxiliary

[0088] In N 2 Under the atmosphere, 240 mg (2 mmol) 1-phenylethanol, 4.0 mg (10 umol) Mn1, and 0.05 mmol base auxiliary were placed in a 25 mL Schlenk bottle, and 2.0 mL acetone was added. The reaction mixture was stirred at 60 ° C for 24 hours. Cooled to room temperature, the results of GC analysis (with dodecane as the internal standard) are shown in Table 2.

[0089] Table 2 Results of preparing acetophenone by reducing the amount of catalyst with different bases as co-catalysts

[0090]

[0091]

[0092] a Reaction conditions: 2mmol 1-phenylethanol, 10μmol (0.5mol%) Mn1, 0.05mmol base promoter, 2mL acetone, 60℃, 24h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0093] Example 13 Screening of Catalyst Dosage

[0094] In N 2 Under atmosphere, (0.5–50 mmol) 1-phenylethanol, 4.0 mg (10 umol) Mn1, 50.0 umol KBH 4 Place in a 25 mL Schlenk bottle and add 2.0 mL acetone. Stir the reaction mixture at 60-90°C for 2-48 hours. Cool to room temperature and analyze by GC (with dodecane as internal standard). The results are shown in Table 3.

[0095] Table 3 Screening of catalyst dosage

[0096]

[0097]

[0098] a Reaction conditions: 0.5-50 mmol 1-phenylethanol, 10 μmol (2.0–0.02 mol%) Mn1, 0.05 mmol NaBH 4 , 2mL acetone, 60-90 o C; 2–48 h; b The conversion rate and yield were detected by GC with dodecane as the internal standard; S / C was the mole number of substrate / mole number of catalyst; and TON was the mole number of substrate converted per 1 mol of catalytic active center.

[0099] Example 14 Screening of Hydrogen Acceptors

[0100] In N 2 Under atmosphere, 2.40 g (20 mmol) 1-phenylethanol, 4.0 mg (10 umol, 0.50 mol%) Mn1, 50.0 umol KBH 4 Place in a 25 mL Schlenk bottle, add 2.0 mL hydrogen acceptor ketone (also used as solvent) and 2 mL toluene. Stir the reaction mixture at 90°C for 24-48 hours. Cool to room temperature, and analyze by GC (with dodecane as internal standard). The results are shown in Table 4.

[0101] Table 4. Selection of tetrahydrocannabinol acceptors

[0102]

[0103]

[0104]

[0105] a Reaction conditions: 20 mmol 1-phenylethanol, 10 μmol (2.0–0.02 mol%) Mn1, 0.05 mmol KBH 4 , 2mL acetone, 60℃, 24h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0106] Example 15 Screening of reaction temperature

[0107] In N 2 Under atmosphere, 2.40 g (20 mmol) 1-phenylethanol, 4.0 mg (10 umol, 0.05 mol%) Mn-1, 50.0 umol KBH 4 The mixture was placed in a 25 mL Schlenk bottle and 2.0 mL acetone was added. The reaction mixture was stirred at 60-120° C. for 24 hours. After cooling to room temperature, the mixture was analyzed by GC (with dodecane as internal standard). The results are shown in Table 5.

[0108] Table 5 Screening of reaction temperature

[0109]

[0110]

[0111] a Reaction conditions: 20 mmol 1-phenylethanol, 10 μmol (0.05 mol%) Mn1, 0.05 mmol KBH 4 ,2mL acetone,60-

[0112] 120℃, 24h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0113] Example 15 Screening of acetone dosage

[0114] In N 2 Under atmosphere, 6.0 g (50 mmol) 1-phenylethanol, 4.0 mg (10 umol, 0.02 mol%) Mn1, 50.0 umol KBH 4 Place in a 25 mL Schlenk bottle and add 2.0-10.0 mL acetone. Stir the reaction mixture at 90° C. for 24 hours. Cool to room temperature and analyze by GC (with dodecane as internal standard). The results are shown in Table 6.

[0115] Table 6 Screening of Acetone Dosage

[0116]

[0117]

[0118] a Reaction conditions: 50 mmol 1-phenylethanol, 10 μmol (0.02 mol%) Mn1, 0.05 mmol KBH 4 , 2-10mL acetone, 90℃, 36h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0119] Example 16 Catalyst Type Screening

[0120] In N 2 Under atmosphere, 1.20 g (10 mmol) 1-phenylethanol, 10 umol (0.1 mol%) catalyst, 50.0 umol KBH 4 The mixture was placed in a 25 mL Schlenk bottle and 2.0 mL acetone was added. The reaction mixture was stirred at 90° C. for 24 hours. The mixture was cooled to room temperature and analyzed by GC (with dodecane as internal standard). The results are shown in Table 7.

[0121] Table 7 Screening of the best catalyst

[0122]

[0123]

[0124] a Reaction conditions: 10 mmol 1-phenylethanol, 10 μmol (0.1 mol%) Mn1, 0.05 mmol KBH 4 , 2 mL acetone, 90 ° C, 36 h; b The conversion and yield were determined by GC with dodecane as the internal standard.

[0125] Example 17 Compound Mn1 of Formula 1 catalyzes the dehydrogenation of aromatic secondary alcohol (a) to aromatic ketone (b)

[0126] Under nitrogen, 4.0 mmol of aromatic secondary alcohol, 4.0 mg (10 umol, 0.25 mol%) of Mn1, 2.7 mg (50 umol) of KBH 4 Place in a 25 mL Schlenk bottle and add 2.0 mL acetone. Stir the reaction mixture at 90 °C for 24 hours and cool to room temperature. Take a small amount of the reaction solution and test the secondary alcohol conversion rate by GC. Add 5 mL saturated NH4 Cl aqueous solution, extracted with ethyl acetate (3×10 mL), the organic phases were combined and desolventized to obtain a crude oil. The crude product was purified by flash column chromatography using a gradient of petroleum ether and ethyl acetate (eluent system) (from pure petroleum ether to petroleum ether: ethyl acetate = 10:1) to obtain pure ketone products. The results of aromatic ketone products are shown in Table 8.

[0127] Table 8 Dehydrogenation of aromatic secondary alcohols (a) to aromatic ketones (b) catalyzed by Mn1

[0128]

[0129] a Reaction conditions: 4.0 mmol aromatic secondary alcohol, 4.0 mg (10 umol, 0.25 mol%) Mn1, 2.7 mg (50 umol) KBH 4 , 90°C, 2 mL acetone, 24 h; b The conversion rate and yield were detected by GC with dodecane as the internal standard, and the separation yield is in brackets.

[0130] Example 18 Compound Mn-1 of Formula 1 catalyzes the dehydrogenation of aliphatic secondary alcohol (a) to form aliphatic ketone (b)

[0131] Under nitrogen atmosphere, 4.0 mmol of aliphatic secondary alcohol, 4.0 mg (10 umol, 0.25 mol%) of Mn1, 2.7 mg (50 umol) of KBH 4 Place in a 25 mL Schlenk bottle and add 2.0 mL acetone. Stir the reaction mixture at 90 °C for 24 hours and cool to room temperature. Take a small amount of the reaction solution and test the secondary alcohol conversion rate by GC. Add 5 mL saturated NH 4 Cl aqueous solution, extracted with ethyl acetate (3×10 mL), the organic phases were combined and desolventized to obtain a crude oil. The crude product was purified by flash column chromatography using a gradient of petroleum ether and ethyl acetate (eluent system) (from pure petroleum ether to petroleum ether: ethyl acetate = 10:1) to obtain a pure aliphatic ketone product. The results of the aliphatic product are shown in Table 9.

[0132] Table 9 Dehydrogenation of aliphatic secondary alcohols (a) to aliphatic ketones (b) catalyzed by Mn1

[0133]

[0134]

[0135] This patent applies the conversion process of dehydrogenation and oxidation of secondary alcohols into ketones, including but not limited to the secondary alcohol substrates involved in the patent.

[0136] Acetophenone

[0137]

[0138] 1 H NMR(400MHz,DMSO-d 6 )δ7.92(dd,J=8.8,0.9Hz,2H),7.62–7.58(m,1H),7.52–7.46(m,2H),2.54(s,3H); 13 C NMR(100MHz,DMSO-d 6 )δ198.54,137.33,133.74,129.23,128.70,27.24.

[0139] 4'-methylacetophenone

[0140]

[0141] 1 H NMR(400MHz,DMSO-d 6 )δ7.81(d,J=8.2Hz,2H),7.28(d,J=8.4Hz,2H),2.50(s,3H),2.33(s,3H); 13 C NMR(100MHz,DMSO-d 6 )δ197.98,144.04,134.93,129.74,128.81,27.11,21.65.

[0142] 4'-methoxyacetophenone 2

[0143]

[0144] 1 H NMR(400MHz,DMSO-d 6 )δ7.89(d,J=9.0Hz,2H),6.99(d,J=8.9Hz,2H),3.79(s,3H),2.47(s,3H); 13 C NMR(100MHz,DMSO-d 6 )δ196.80,163.63,131.00,130.41,114.32,56.00,26.89.

[0145] 4'-fluoroacetophenone 2b,2c

[0146]

[0147] 1 H NMR(400MHz,DMSO-d 6 )δ8.02–7.95(m,2H),7.33–7.25(m,2H),2.53(s,3H); 13 CNMR(100MHz,DMSO-d 6 )δ197.03,166.82,164.31,134.12,134.09,131.72,131.62,116.26,116.04,27.19.

[0148] 4'-chloroacetophenone 2b,2c

[0149]

[0150] 1 H NMR(400MHz,DMSO-d 6 )δ7.92(d,J=8.6Hz,2H),7.54(d,J=8.6Hz,2H),2.54(s,3H); 13 CNMR(1000MHz,DMSO-d 6 )δ197.45,138.66,135.98,130.60,129.30,27.23.

[0151] 4'-bromoacetophenone

[0152]

[0153] 1 H NMR(400MHz,DMSO-d 6 )δ7.84(d,J=8.6Hz,2H),7.68(d,J=8.6Hz,2H),2.53(s,3H); 13 CNMR(100MHz,DMSO-d 6 )δ197.67,136.30,132.27,130.72,127.84,27.23.

[0154] 1-phenylbutan-1-one

[0155]

[0156] 1 H NMR(400MHz,DMSO-d6 )δ8.00–7.93(m,2H),7.62(td,J=7.2,6.7,3.6Hz,1H),7.52(t,J=7.6Hz,2H),2.98(t,J=7.1Hz,2H),1.64(h,J=7.4Hz,2H),0.93(t,J=7.4Hz,3H); 13 CNMR(100MHz,DMSO-d 6 )δ200.34,137.26,133.40,129.10,128.27,17.70,14.04.

[0157] 1'-acetonaphthone

[0158]

[0159] 1 H NMR(400MHz,DMSO-d 6 )δ8.63–8.57(m,1H),8.12–8.05(m,2H),7.98–7.92(m,1H),7.60–7.50(m,3H),2.68(s,3H); 13 CNMR(101MHz,DMSO-d 6 )δ202.24,135.40,134.05,133.35,129.96,129.78,129.04,128.40,126.89,126.06,125.35,30.55.

[0160] phenyl(p-tolyl)methanone

[0161]

[0162] 1 H NMR(400MHz,DMSO-d 6 )δ7.72–7.68(m,2H),7.67–7.61(m,3H),7.57–7.51(m,2H),7.35(d,J=0.9Hz,1H),7.34–7.32(m,1H),2.38(s,3H); 13 C NMR(100MHz,DMSO)δ195.87,143.57,137.83,134.76,132.85,130.30,129.91,129.57,129.54,128.93,21.64.

[0163] (4-chlorophenyl)(phenyl)methanone

[0164]

[0165] 1 H NMR(400MHz,DMSO-d 6 )δ7.74(td,J=6.5,1.9Hz,4H),7.70–7.66(m,1H),7.62(d,J=8.6Hz,2H),7.56(t,J=7.7Hz,2H); 13 CNMR(100MHz,DMSO-d 6 )δ195.13,138.10,137.14,136.13,133.31,131.93,130.04,129.16,129.08.

[0166] benzoylferrocene

[0167]

[0168] 1 H NMR(400MHz,DMSO-d 6 )δ7.89(d,J=7.6Hz,2H),7.58(dt,J=30.6,7.6Hz,3H),4.84(s,2H),4.69(s,2H),4.25(s,5H); 13 CNMR(100MHz,DMSO-d 6 )δ198.27,139.80,132.05,128.91,128.29,78.30,73.13,71.56,70.49.

[0169] 2-acetylfuran

[0170]

[0171] 1 H NMR(400MHz,DMSO-d 6 )δ7.93(dd,J=1.7,0.8Hz,1H),7.40(dd,J=3.6,0.8Hz,1H),6.66(dd,J=3.6,1.7Hz,1H),2.37(s,3H); 13 CNMR(101MHz,DMSO-d 6 )δ186.40,152.61,148.19,119.09,113.00,26.48.

[0172] 1-(thiophen-2-yl)ethan-1-one

[0173]

[0174] 1 H NMR(400MHz,DMSO-d 6 )δ7.95(dd,J=4.9,1.1Hz,1H),7.89(dd,J=3.8,1.1Hz,1H),7.20(dd,J=4.9,3.8Hz,1H),2.50(s,3H); 13 CNMR(101MHz,DMSO-d 6 )δ191.32,144.68,135.40,134.45,129.25,27.23.

[0175] Benzylacetone

[0176]

[0177] 1 H NMR(400MHz,DMSO-d 6 )δ7.25–7.20(m,2H),7.18–7.10(m,3H),2.73(s,4H),2.05(s,3H); 3 C NMR(100MHz,DMSO-d 6 )δ208.15,141.72,128.80,128.73,126.35,44.67,30.24,29.60。

Claims

1. A bidentate nitrogen-manganese complex, the structure of which is shown in Formula I: ， in, R is a C1-C8 alkyl group or a C6-C10 aryl group.

2. The bidentate nitrogen-manganese complex according to claim 1, characterized in that The R is n-butyl, isobutyl, sec-butyl, n-propyl, isopropyl, ethyl, methyl, phenyl, tolyl, or ethylphenyl.

3. The method for preparing the bidentate nitrogen-manganese complex according to claim 2, characterized in that The compound represented by formula II and the compound represented by formula III are reacted to obtain the compound represented by formula I. ， Among them, R is n-butyl, isobutyl, sec-butyl, n-propyl, isopropyl, ethyl, methyl, or phenyl.

4. A catalyst composition, characterized in that The invention comprises an active ingredient and an auxiliary agent, wherein the active ingredient is the bidentate nitrogen-manganese complex as claimed in claim 1 or 2, and the auxiliary agent is t -BuOK, t -BuONa, i -One or more of PrONa, EtONa, MeONa, KOH, NaOH, NaHBEt3, KBH4, NaBH4.

5. The use of the catalyst composition as claimed in claim 4, characterized in that The application is to catalyze the deoxidation and oxidation reaction of secondary alcohol to prepare ketone compounds, wherein the aliphatic or aromatic secondary alcohol and the catalyst composition are added to acetone or butanone solvent, and the reaction mixture is heated at 50 to 110°C under an inert gas atmosphere. o C for 2 to 48 h to obtain the corresponding ketone compound.

6. The use according to claim 5, characterized in that The catalyst composition is a combination of the bidentate nitrogen manganese complex and KBH4 or a combination of the bidentate nitrogen manganese complex and NaBH4, and the molar amount of the bidentate nitrogen manganese complex is 0.02-2% of the molar amount of the secondary alcohol, and the molar ratio of the bidentate nitrogen manganese complex to KBH4 or NaBH4 is 1:2-10.

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