Preparation of alpha-hydroxyamide by reduction of alpha-ketoamide with sulfonyl hydrazide

Abstract

The invention relates to a method for preparing alpha-hydroxyamide by reducing alpha-ketoamide through sulfonyl hydrazide. The method comprises the following steps: in the presence of alkali and aryl sulfonyl hydrazide, reacting alpha-ketoamide in an organic solvent at 80-100 DEG C for 3-5 hours, and selectively reducing keto carbonyl in the alpha-ketoamide to obtain alpha-hydroxyamide. The preparation method disclosed by the invention is efficient, novel, simple and convenient to operate, cheap and easily available in raw materials and high in yield, and the obtained alpha-hydroxyamide intermediate is expected to be widely applied to the fields of medicine and chemical industry.

Description

[0001] Technical field: The present invention relates to a method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide, belonging to the technical field of organic synthesis. Background Art

[0002] α-Hydroxyamides are an important class of compounds. Many drugs and bioactive molecules contain α-hydroxyamide structural fragments, such as nuclear retinal acid receptor γ (RAR-γ) agonist BMS-961, γ-secretase inhibitor LY411575, antibiotic cefmandol, anti-cell proliferation agents and anti-tuberculosis drug molecules (Klaholz, BP, et al. PNAS, 2000, 97, 6322; Wong, GT, et al. J. Biol. Chem., 2004, 279, 12876; Wasserman HH, et al. Tetrahedron Lett., 1999, 40, 6163-6166; Vainionpaa S., et al. Arch. Orthop. Trauma. Surg., 1988, 107, 228-230; Que YA, et al. The J. Infect. Dis., 1998, 177, 146-154). In addition, α-hydroxyamide compounds are also important ligands and organic synthesis intermediates, and are often used in metal-catalyzed organic synthesis reactions and the preparation of pharmacologically active molecules. Based on the important role of α-hydroxyamides in the field of medicinal chemistry, the synthesis of this type of compound has attracted much attention.

[0003] In recent years, the synthesis of α-hydroxyamides has made great progress. The most direct and atom-economical method is to prepare α-hydroxyamides by selective hydrogenation reduction of the corresponding α-ketoamide substrates. At present, the methods for reducing the carbonyl group of α-ketoamide ketone mainly include the following four methods: (1) reduction with hydrogen or hydrosilane under transition metal catalysis (CN107417562A; CN108546238A; Mamillapalli NC, et al. Adv. Synth. Catal., 2015, 357, 3273-3283; Mamillapalli NC, et al. Chem. Commun., 2014, 50, 7881-7884); (2) reduction with hydrosilane in the presence of base (Kumar G., et al. Eur. J. Org. Chem., 2017, 4883-4890; Muthukumar A., ​​et al. Adv. Synth. Catal., 2016, 358, 643-652; Mamillapalli NC, et al. RSC Adv., 2014, 4, 61077-61085); (3) Reduced with sodium borohydride under the catalysis of nanocatalyst (Mishra A.A., et al. Asian J. Org. Chem., 2018, 7, 922-931); (4) Reduced with sodium formaldehyde sulfoxylate in the presence of alkali (Golla, S., et al. J. Org. Chem., 2022, 87, 9915–9925). However, the above four methods each have their disadvantages. Method (1) uses expensive transition metals and requires the additional introduction of ligands; method (2) uses inorganic bases (tetrabutylammonium fluoride, potassium phosphate, cesium carbonate) that are harmful to the environment and cannot be recycled, and hydrosilane is relatively expensive; method (3) uses cerium dioxide nanospheres that require special preparation as a catalyst; method (4) requires the use of a mixture of dimethyl sulfoxide and water in a certain proportion as a solvent, which is not conducive to the recycling of the solvent.

[0004] In summary, the current method of preparing α-hydroxyamide by direct reduction still has shortcomings, and it is still very meaningful to develop a new reduction method that is simple, efficient, environmentally friendly, safe, and suitable for industrial production. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide an efficient synthesis method for selectively reducing the carbonyl group of α-ketoamide with readily available raw materials, simple operation, low cost and no need to introduce catalysts or other additives.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide is characterized in that the α-ketoamide is reacted in an organic solvent at 80-100° C. for 3-5 hours in the presence of a base and an arylsulfonylhydrazide to selectively reduce the keto carbonyl therein to obtain the α-hydroxyamide, wherein the synthetic reaction formula of the target compound is:

[0008]

[0009] The α-ketoamide has the following structural formula:

[0010]

[0011] in:

[0012] R 1 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl;

[0013] The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl;

[0014] The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

[0015] R 2 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl;

[0016] The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl;

[0017] The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

[0018] R 3 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl;

[0019] The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl;

[0020] The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

[0021] Preferably, the arylsulfonyl hydrazide is benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, 2,4,6-trimethylbenzenesulfonyl hydrazide and 2,4,6-triethylbenzenesulfonyl hydrazide.

[0022] Preferably, the base is triethylamine, diisopropylethylamine, pyridine, potassium carbonate, sodium carbonate, sodium hydroxide or sodium bicarbonate.

[0023] Preferably, the organic solvent is dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, ethanol, isopropanol, tetrahydrofuran or dioxane.

[0024] Preferably, the mass ratio of the organic solvent to the α-ketoamide is 3 to 8:1.

[0025] Preferably, the molar ratio of the ketoamide to the arylsulfonylhydrazide is 1:1-3.

[0026] Preferably, the molar ratio of the ketoamide to the base is 1:0.1-3.

[0027] Preferably, the reaction temperature is 80-100°C.

[0028] Preferably, the reaction time is 3-5 hours. DETAILED DESCRIPTION

[0029] The present invention is further described by the following examples, but the following examples should not be construed as limiting the scope of protection of the present invention. Without departing from the technical scope of the present invention, any non-essential improvements and changes to the present invention should be included in the technical scope of the present invention.

[0030] Example 1

[0031] α-Ketoamide (1.00 g, 4.18 mmol), p-toluenesulfonyl hydrazide (1.17 g, 6.27 mmol) and sodium bicarbonate (0.18 g, 2.09 mmol) represented by formula (1a) were dissolved in 5.0 mL of dimethyl sulfoxide, and the resulting mixture was reacted at 80°C for 5 hours. Dimethyl sulfoxide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.97 g of white solid fine product 2a with a yield of 97%.

[0032]

[0033] Characterization data of compound 2a:

[0034]

[0035] White solid; 1HNMR (400MHz, CDCl3): δ8.02 (s, 1H), 7.53-7.45 (m, 2H), 7.43-7.33 (m, 5H), 7.11 (d, J = 8.1Hz, 2H), 5.18 (s, 1H), 2.30 (s, 3H).

[0036] Example 2

[0037] α-Ketoamide (1.00 g, 3.92 mmol) of formula (1b), benzenesulfonyl hydrazide (0.67 g, 3.92 mmol) and sodium hydroxide (0.02 g, 0.40 mmol) were dissolved in 3.5 mL of dimethyl sulfoxide, and the resulting mixture was reacted at 85°C for 4.5 hours. Dimethyl sulfoxide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.42 g of white solid fine product 2b with a yield of 42%.

[0038]

[0039] Characterization data of compound 2b:

[0040]

[0041] White solid; 1 HNMR (400MHz, CDCl3): δ8.03(s,1H),7.51-7.43(m,2H),7.43-7.35(m,5H),6.87-6.81(m,2H),5.15(s,1H),3.78(s,3H).

[0042] Example 3

[0043] α-Ketoamide (1.00 g, 3.86 mmol) of formula (1c), 2,4,6-trimethylbenzenesulfonylhydrazide (1.65 g, 7.72 mmol) and sodium carbonate (0.41 g, 3.86 mmol) were dissolved in 3.0 mL of dimethyl sulfoxide, and the resulting mixture was reacted at 90°C for 4 hours. Dimethyl sulfoxide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.91 g of white solid fine product 2c, with a yield of 90.0%.

[0044]

[0045] Characterization data of compound 2c:

[0046]

[0047] White solid; 1 H NMR (400MHz, DMSO-d6): δ10.10(s,1H),7.75(d,J=8.8Hz,2H),7.51(d,J=7.3Hz,2H),7.40-7.23(m,5H),6.49(d,J=4.5Hz,1H),5.10(d,J=4.5Hz,1H).

[0048] Example 4

[0049] α-Ketoamide (1.00 g, 4.11 mmol) of formula (1d), 2,4,6-triethylbenzenesulfonylhydrazide (3.16 g, 12.33 mmol) and potassium carbonate (0.85 g, 6.16 mmol) were dissolved in 6.0 mL of dimethyl sulfoxide, and the resulting mixture was reacted at 95°C for 3.5 hours. Dimethyl sulfoxide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.93 g of white solid fine product 2d with a yield of 93%.

[0050]

[0051] Characterization data of compound 2d:

[0052]

[0053] White solid; 1 H NMR (400MHz, DMSO-d6) δ10.02 (s, 1H), 7.77-7.69 (m, 2H), 7.51 (dd, J = 7.0, 1.6Hz, 2H), 7.39-7. 33(m,2H),7.31-7.27(m,1H),7.17-7.08(m,2H),6.46(d,J=4.6Hz,1H),5.09(d,J=4.6Hz,1H).

[0054] Example 5

[0055] α-Ketoamide (1.00 g, 3.64 mmol) represented by formula (1e), p-toluenesulfonyl hydrazide (1.35 g, 7.28 mmol) and pyridine (0.56 g, 7.28 mmol) were dissolved in 6.5 mL of N, N-dimethylformamide, and the resulting mixture was reacted at 100°C for 3 hours. N, N-dimethylformamide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.79 g of white solid fine product 2e with a yield of 79%.

[0056]

[0057] Characterization data of compound 2e:

[0058]

[0059] White solid; 1 H NMR (400MHz, DMSO-d6) δ10.07(s,1H),7.97-7.91(m,1H),7.89-7.84(m,1H),7.78(d,J=8.2Hz,1H),7.65-7.57 (m,3H),7.56-7.46(m,3H),7.43-7.36(m,2H),7.36-7.30(m,1H),6.57(d,J=4.8Hz,1H),5.27(d,J=4.8Hz,1H).

[0060] Example 6

[0061] The α-ketoamide (1.00 g, 3.72 mmol) of formula (1f), p-toluenesulfonyl hydrazide (1.38 g, 7.44 mmol) and diisopropylethylamine (1.44 g, 11.16 mmol) were dissolved in 7.0 mL of N,N-dimethylacetamide, and the resulting mixture was reacted at 80°C for 5 hours. N,N-dimethylacetamide was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.91 g of a white solid fine product 2f with a yield of 91%.

[0062]

[0063] Characterization data of compound 2f:

[0064]

[0065] White solid; 1 H NMR (400MHz, CDCl3): δ8.00 (s, 1H), 7.46-7.33 (m, 4H), 7.11 (d, J = 8.1Hz, 2 H),6.96-6.86(m,2H),5.12(s,1H),3.81(s,3H),3.39(s,1H),2.31(s,3H).

[0066] Example 7

[0067] α-Ketoamide (1.00 g, 4.08 mmol) shown in formula (1g), p-toluenesulfonyl hydrazide (1.52 g, 8.16 mmol) and triethylamine (0.82 g, 8.16 mmol) were dissolved in 7.5 mL of ethanol, and the resulting mixture was reacted at 80°C for 5 hours. The ethanol was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 2 g 0.76 g of a white solid fine product with a yield of 75%.

[0068]

[0069] Characterization data of compound 2g:

[0070]

[0071] White solid; 1 H NMR (400MHz, CDCl3): δ0.92 (t, J = 7.2Hz, 3H), 1.52-1.66 (m, 2H), 2.62-2.73 (m, 2H), 3.7 8(d,J=1.2Hz,1H), 4.87(d,J=1.2Hz,1H), 7.17(d,J=8.4Hz,2H), 7.50(d,J=8.4Hz,2H).

[0072] Example 8

[0073] α-Ketoamide (1.00 g, 3.15 mmol) of formula (1h), p-toluenesulfonyl hydrazide (1.17 g, 6.30 mmol) and sodium bicarbonate (0.53 g, 6.3 mmol) were dissolved in 8 mL of isopropanol, and the resulting mixture was reacted at 80°C for 5 hours. Isopropanol was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was evaporated under reduced pressure to obtain a white solid crude product. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.91 g of a white solid fine product 2h with a yield of 90%.

[0074]

[0075] Characterization data of compound 2h:

[0076]

[0077] White solid; 1 HNMR (400MHz, DMSO-d6): δ9.85 (s, 1H), 7.61-7.51 (m, 4H), 7.46 (d, J = 8.4Hz, 2H), 7.08(d,J=8.1Hz,2H),6.51(d,J=4.8Hz,1H),5.08(d,J=4.8Hz,1H),2.23(s,3H).

[0078] Example 9

[0079] α-Ketoamide (1.00 g, 3.15 mmol) represented by formula (1i), p-toluenesulfonyl hydrazide (1.17 g, 6.30 mmol) and sodium bicarbonate (0.53 g, 6.30 mmol) were dissolved in 5 mL of tetrahydrofuran, and the resulting mixture was reacted at 80°C for 5 hours. Tetrahydrofuran was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.69 g of white solid fine product 2i, with a yield of 68%.

[0080]

[0081] Characterization data of compound 2i:

[0082]

[0083] White solid; 1H NMR (400 MHz, CDCl3): δ8.07 (s, 1H), 7.60 (dd, J = 8.1, 1.2 Hz, 1H), 7.49 (dd, J = 7.7, 1.7 Hz, 1H), 7.43-7.31 (m, 3H), 7.21 (td, J = 7.7, 1.7 Hz, 1H), 7.12 (d, J = 8.1 Hz, 2H), 5.62 (d, J = 4.1 Hz, 1H), 4.09 (d, J = 4.5 Hz, 1H), 2.31 (s, 3H). Example 10

[0084] α-Ketoamide (1.00 g, 3.66 mmol) represented by formula (1j), p-toluenesulfonyl hydrazide (1.36 g, 7.32 mmol) and sodium bicarbonate (0.31 g, 3.66 mmol) were dissolved in 5 mL of dioxane, and the resulting mixture was reacted at 80°C for 5 hours. The dioxane was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:3) to obtain 0.65 g of white solid fine product 2j, with a yield of 64%.

[0085]

[0086] Characterization data of compound 2j:

[0087]

[0088] White solid; 1 H NMR(400MHz,DMSO-d6)δ9.85(s,1H),7.61-7.49(m,4H),7.46-7.38(m,2H),7. 09(d,J=8.1Hz,2H), 6.51(d,J=4.8Hz,1H), 5.10(d,J=4.8Hz,1H), 2.24(s,3H).

[0089] Embodiment 11

[0090] α-Ketoamide (1.00 g, 4.15 mmol) represented by formula (1k), p-toluenesulfonyl hydrazide (1.54 g, 8.30 mmol) and sodium bicarbonate (0.70 g, 8.30 mmol) were dissolved in 5 mL of dioxane, and the resulting mixture was reacted at 80°C for 5 hours. The dioxane was evaporated under reduced pressure, and then 10 mL of water was added, and the mixture was transferred to a separatory funnel, extracted with dichloromethane (10 mL×2), and the organic phases were combined. It was separated and purified by column chromatography with ethyl acetate / petroleum ether (volume ratio 1:5) to obtain 0.65 g of white solid fine product 2k, with a yield of 64%.

[0091]

[0092] Characterization data of compound 2k:

[0093]

[0094] White solid; 1 H NMR (400MHz, CDCl3): δ7.33-7.21(m,3H),7.16(dt,J=14.4,7.0Hz,3H),6.85-6.76(m,4H),5.01(d,J=6.5Hz,1H),4.52(d,J=6.9Hz,1H),3.30(s,3H).

Claims

1. A method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide, characterized in that: α-Ketoamide is reacted in an organic solvent at 80-100°C for 3-5 hours in the presence of a base and arylsulfonylhydrazide to obtain α-hydroxyamide, wherein the synthetic reaction formula of the target compound is:

2. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazine according to claim 1, characterized in that: α-Ketoamide has the following structural formula: in: R 1 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl; The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl; The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

3. The method for preparing α-hydroxyamide by reducing α-ketoamide according to claim 1, characterized in that: α-Ketoamide has the following structural formula: in: R 2 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl; The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl; The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

4. The method for preparing α-hydroxyamide by reducing α-ketoamide according to claim 1, characterized in that: α-Ketoamide has the following structural formula: in: R 3 is hydrogen, C1-10 alkyl, C3-8 cycloalkyl, aryl or C3-12 substituted aryl; The aryl group is phenyl, naphthyl, thienyl, furyl, pyrrolyl, indolyl, imidazolyl, thiazolyl, pyridyl or oxazolyl; The C3-12 substituted aryl group is a C1-6 alkyl substituted aryl group, a C3-8 cycloalkyl substituted aryl group, a C1-6 alkoxy substituted aryl group, a C2-6 alkenyl substituted aryl group, a C2-6 alkynyl substituted aryl group, a C2-6 alkenyloxy substituted aryl group, a C2-6 alkynyloxy substituted aryl group, a C1-6 alkylthiol substituted aryl group, a C2-6 alkenylthiol substituted aryl group, a C2-6 alkynylthiol substituted aryl group, a C1-6 Alkylamino, C1-6 alkanoylamino, C1-6 alkanesulfonylamino, C1-6 alkylcarbonyl-substituted aryl, C1-6 alkoxycarbonyl-substituted aryl, benzyloxycarbonyl, C2-6 alkenylcarbonyl-substituted aryl, C2-6 alkynylcarbonyl-substituted aryl, halogenated aryl, ester-substituted aryl, hydroxy-substituted aryl, cyano-substituted aryl, nitro-substituted aryl, amino-substituted aryl, trifluoromethyl-substituted aryl or trichloromethyl-substituted aryl.

5. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The aryl sulfonyl hydrazide is benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, 2,4,6-trimethylbenzenesulfonyl hydrazide and 2,4,6-triethylbenzenesulfonyl hydrazide.

6. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The base is triethylamine, diisopropylethylamine, pyridine, potassium carbonate, sodium carbonate, sodium hydroxide or sodium bicarbonate.

7. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The organic solvent is dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, ethanol, isopropanol, tetrahydrofuran or dioxane.

8. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The mass ratio of the organic solvent to the α-ketoamide is 3 to 8:

1.

9. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The molar ratio of the ketoamide to the arylsulfonylhydrazide is 1:1-3.

10. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The molar ratio of the ketoamide to the base is 1:0.1-3.

11. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The reaction temperature is 80-100°C.

12. The method for preparing α-hydroxyamide by reducing α-ketoamide with sulfonylhydrazide according to claim 1, characterized in that: The reaction time is 3-5 hours.

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