Preparation method of N '-Fmoc-L-lysine derivative medical intermediate

Abstract

The invention discloses a preparation method of an N '-Fmoc-L-lysine derivative medical intermediate, which comprises the following steps: complexing L-lysine serving as a raw material with anhydrous cupric sulfate, performing Fmoc protection, removing copper ions, dissociating, and performing alpha-NH2 protection reaction to prepare the target product N'-Fmoc-L-lysine derivative medical intermediate. The preparation method has the advantages of cheap and easily available raw materials, low cost, simple post-treatment and high purity. The method avoids the removal of N alpha site protecting groups during the hydrolysis of trifluoroacetyl in the prior art, greatly improves the yield, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical intermediate synthesis, and specifically relates to a method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative. Background Art

[0002] Type 2 diabetes mellitus (T2DM) is a chronic disease caused by insufficient or inefficient use of insulin, which is common in adults. The occurrence of this disease is the result of the combined effects of genetic and environmental factors, including unhealthy lifestyles, overnutrition, and lack of adequate physical activity.

[0003] Semaglutide is a new type of hypoglycemic drug and a glucagon-like peptide-1 (GLP-1) receptor agonist, mainly used to treat type II diabetes. It acts in the body through a series of mechanisms, including stimulating insulin secretion in a glucose concentration-dependent manner and simultaneously reducing insulin secretion, thereby effectively controlling blood sugar levels. In addition, semaglutide can also increase satiety by inhibiting gastrointestinal motility and delaying gastric emptying, thereby inhibiting appetite and reducing food intake, thereby achieving the purpose of weight loss. Therefore, this drug has also been widely welcomed in the field of weight loss. Its molecular formula is shown below:

[0004]

[0005] N'-Fmoc-L-lysine derivatives are important intermediates for the synthesis of semaglutide, and their structural formula is as follows:

[0006]

[0007] Lysine has two amino groups, both of which need to be protected. At present, the general synthetic route of the N'-Fmoc-L-lysine derivative pharmaceutical intermediate was proposed by Xu Jiaxi et al. in 2000 (Chemical Bulletin, 2000, 01, 26-29), which is as follows: first, lysine is complexed with copper salt and then Nε protected, then the copper ion is decoupled, and finally α-NH2 is protected using other protective reagents under ethanol reflux. This route has the disadvantages of long reaction time and low yield.

[0008] On this basis, in 2024, Changxing Yisheng Technology Co., Ltd. (CN 117776978A) reported the synthesis of the N'-Fmoc-L-lysine derivative pharmaceutical intermediate, and optimized its synthetic route: using Nε-trifluoroacetyl-L-lysine as the starting material, after Nα protection, removing the Nε-trifluoroacetyl protecting group, and finally protecting it with Nε-[(9H-fluorene-9-ylmethoxy)carbonyl] to obtain the target product N'-Fmoc-L-lysine derivative pharmaceutical intermediate. Although this synthetic route avoids the use of copper chelating agents and effectively avoids safety and environmental protection issues in the copper removal process, the Nα protecting group will also be removed when the trifluoroacetyl group is hydrolyzed with sodium hydroxide, and the impurities generated are not easy to remove, and the total yield is not high.

[0009]

[0010] Wherein R is any one of the protecting groups Dde, ivDde and alloc. Summary of the invention

[0011] In view of the above problems existing in the prior art, the present invention provides a method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative. The preparation method has cheap and readily available raw materials, low cost, simple post-processing, high product yield and purity, and is suitable for industrial production.

[0012] The specific technical solutions are as follows:

[0013] The synthetic preparation method of a lysine derivative pharmaceutical intermediate is to use L-lysine (II) as a starting material, complex with anhydrous copper sulfate, use Fmoc-Osu to protect ε-NH2, then remove the copper ion and dissociate to obtain N'-Fmoc-L-lysine (IV), and finally add the corresponding protecting group to obtain N'-Fmoc-L-lysine derivative (I). The synthetic route is as follows:

[0014]

[0015] Wherein R is any one of the protecting groups Dde, ivDde and alloc.

[0016] The specific operation process includes the following steps:

[0017] (1) Add the compound of formula (II) to solvent A, complex with anhydrous copper sulfate under the action of a base, then add Fmoc-Osu and stir to obtain a solid compound represented by (III);

[0018] (2) adding the compound represented by formula (III) to an EDTA solution or an 8-hydroxyquinoline solution to dissociate the copper ions in the copper complex, and then filtering to obtain the compound represented by formula (IV);

[0019] (3) The compound represented by formula (IV) is added to solvent B, and subjected to substitution reaction with a protecting agent under the action of a base. After the reaction is completed, the solvent is removed by concentration, and the compound represented by formula (I) is obtained by extraction, washing, and recrystallization.

[0020] Furthermore, the solvent A in step (1) is ethyl acetate, acetonitrile, tetrahydrofuran, acetone or dichloromethane, preferably tetrahydrofuran or acetone; the base is sodium carbonate, sodium bicarbonate, sodium hydroxide or potassium hydroxide; the temperature of the complex reaction is -10 to 90°C;

[0021] Furthermore, in step (1), the molar ratio of the compound represented by formula (II), anhydrous copper sulfate, alkali, and Fmoc-Osu is 1:0.2-1.5:1-2.5:1-2.

[0022] Furthermore, the temperature for dissociating copper ions in step (2) is 15 to 65°C.

[0023] Furthermore, in step (2), the molar ratio of the compound represented by formula (III) to EDTA is 1:1-4.

[0024] Furthermore, in step (2), the molar ratio of the compound represented by formula (III) to 8-hydroxyquinoline is 1:0.5-1.5.

[0025] Furthermore, the solvent B in step (3) is anhydrous methanol, anhydrous ethanol, isopropanol, n-butanol or ethylene glycol; the base is pyridine, 2,4-lutidine, 2,4,6-trimethylpyridine, triethylamine or N,N-diisopropylethylamine; and the substitution reaction temperature is 20 to 80°C.

[0026] Furthermore, in step (3), the molar ratio of the compound represented by (IV), the base and the protecting agent is 1:1 to 5:1 to 1.5.

[0027] Furthermore, the protecting agent is 2-(1-hydroxyethylidene)-5,5-dimethyl-1,3-cyclohexanedione, 2-(1-hydroxy-3-methylbutylidene)-5,5-dimethyl-1,3-cyclohexanedione or allyl chloroformate.

[0028] The meanings of the abbreviations or English full names used in the present invention are as follows:

[0029] Fmoc-Osu: fluorenylmethoxycarbonyl succinimide;

[0030] EDTA: ethylenediaminetetraacetic acid;

[0031] CuSO4: anhydrous copper sulfate;

[0032] Dde: 2-(1-ethyl)-5,5-dimethylcyclohexane-1,3-dione;

[0033] Dde-OH: 2-(1-hydroxyethylidene)-5,5-dimethyl-1,3-cyclohexanedione;

[0034] ivDde: 2-(3-methylbutyl)-5,5-dimethyl-1,3-cyclohexanedione;

[0035] ivDde-OH: 2-(1-hydroxy-3-methylbutylidene)-5,5-dimethyl-1,3-cyclohexanedione;

[0036] Alloc: allyl formyl;

[0037] Alloc-Cl: allyl chloroformate.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The process is simple, the operation is easy, and the reaction conditions are mild;

[0040] (2) The reaction time is shortened, which increases the reaction rate;

[0041] (3) Impurities are easy to remove, post-processing is simple, and the purity and yield are high. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described by the following specific embodiments, but the protection scope of the present invention is not limited thereto.

[0043] Step 1: Preparation of N6-[(9H-fluoren-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III)

[0044] Example 1

[0045] L-lysine (1.46 g, 10 mmol), sodium carbonate (2.12 g, 20 mmol) and 40 mL of water were added to a 250 mL three-necked flask with magnetic stirring and a thermometer, anhydrous copper sulfate (0.96 g, 6 mmol) was dissolved in 10 mL of water, slowly poured into the reaction bottle, stirred for 30 min, then Fmoc-Osu (3.71 g, 11 mmol) and ethyl acetate (60 mL) were added, kept at 30 ° C, and the reaction was monitored by TLC. After the reaction was completed, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III) was obtained by filtration without purification, with a yield of 76.4%.

[0046] Example 2

[0047] L-lysine (1.46 g, 10 mmol), sodium carbonate (2.12 g, 20 mmol) and 40 mL of water were added to a 250 mL three-necked flask with magnetic stirring and a thermometer, anhydrous copper sulfate (0.96 g, 6 mmol) was dissolved in 10 mL of water, slowly poured into the reaction bottle, stirred for 30 min, then Fmoc-Osu (3.71 g, 11 mmol) and acetonitrile (60 mL) were added, kept warm at 40°C, and the reaction was monitored by TLC. After the reaction was completed, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III) was obtained by filtration without purification, with a yield of 78.2%.

[0048] Example 3

[0049] L-lysine (1.46 g, 10 mmol), sodium carbonate (2.33 g, 22 mmol) and 40 mL of water were added to a 250 mL three-necked flask with magnetic stirring and a thermometer, anhydrous copper sulfate (0.96 g, 6 mmol) was dissolved in 10 mL of water, slowly poured into the reaction bottle, stirred for 30 min, then Fmoc-Osu (3.71 g, 11 mmol) and tetrahydrofuran (60 mL) were added, kept at 60° C., and the reaction was monitored by TLC. After the reaction was completed, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III) was obtained by filtration without purification, with a yield of 83.4%.

[0050] Example 4

[0051] L-lysine (1.46 g, 10 mmol), sodium carbonate (2.33 g, 22 mmol) and 40 mL of water were added to a 250 mL three-necked flask with magnetic stirring and a thermometer, anhydrous copper sulfate (0.96 g, 6 mmol) was dissolved in 10 mL of water, slowly poured into the reaction bottle, stirred for 30 min, then Fmoc-Osu (3.71 g, 11 mmol) and acetone (60 mL) were added, kept at 60° C., and the reaction was monitored by TLC. After the reaction was completed, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III) was obtained by filtration without purification, with a yield of 84.1%.

[0052] Example 5

[0053] L-lysine (1.46 g, 10 mmol), sodium carbonate (2.65 g, 25 mmol) and 40 mL of water were added to a 250 mL three-necked flask with magnetic stirring and a thermometer, anhydrous copper sulfate (1.28 g, 8 mmol) was dissolved in 10 mL of water, slowly poured into the reaction bottle, stirred for 30 min, then Fmoc-Osu (3.71 g, 11 mmol) and acetone (60 mL) were added, kept at 60° C., and the reaction was monitored by TLC. After the reaction was completed, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (III) was obtained by filtration without purification, with a yield of 83.2%.

[0054] Step 2: Preparation of N6-[(9H-fluoren-9-ylmethoxy)-carbonyl]-L-lysine (IV)

[0055] Example 6

[0056] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL) and EDTA (2.92 g, 10 mmol) were added and stirred at 36°C for 8 h to completely dissociate. A white solid was obtained by filtration and purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 72% and a purity of 99.1%.

[0057] 1 H NMR (400MHz, DMSO-d6) δ7.88(d,J=7.5Hz,2H),7.68(d,J=7.4Hz,2H),7.44-7.37(m,2H),7.33(dd,J=7.4,1.2Hz,2H),7.31-7.27(m,1H),4.28(d,J=6 .9Hz,2H),4.20(t,J=6.9Hz,1H),3.26(dd,J=6.9,5.2Hz,1H),2.96(q,J=6 .4Hz,2H),1.79-1.50(m,2H),1.43-1.27(m,4H; MS(ESI):m / z=369.5[M+H] + .

[0058] Example 7

[0059] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL) and EDTA (3.21 g, 11 mmol) were added and stirred at 45 ° C for 6 h to completely dissociate. The white solid was filtered and purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 78.1% and a purity of 99.3%.

[0060] Example 8

[0061] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, add N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL), and EDTA (5.84 g, 20 mmol) and stir at 45 ° C for 6 h to completely dissociate. Filter to obtain a white solid, which is purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 76.3% and a purity of 99.2%.

[0062] Example 9

[0063] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL), tetrahydrofuran (20 mL), and 8-hydroxyquinoline (1.31 g, 9 mmol) were added and stirred at 20°C for 2 h to completely dissociate. The solid was filtered out, and the tetrahydrofuran was spun off. The aqueous solution was adjusted to pH = 2 with 10% HCl aqueous solution, and a white solid precipitated. The white solid was filtered out and purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 76.2% and a purity of 99.5%.

[0064] Example 10

[0065] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL), tetrahydrofuran (20 mL), and 8-hydroxyquinoline (1.60 g, 11 mmol) were added and stirred at 40° C. for 1.5 h to completely dissociate. The solid was filtered out and the tetrahydrofuran was spun off. The aqueous solution was adjusted to pH=2 with 10% HCl aqueous solution, and a white solid precipitated. The white solid was filtered out and purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 73.8% and a purity of 99.4%.

[0066] Embodiment 11

[0067] In a 100 mL three-necked flask with a magnetic stirrer and a thermometer, N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine copper complex (7.98 g, 10 mmol), water (60 mL), tetrahydrofuran (20 mL), and 8-hydroxyquinoline (1.74 g, 12 mmol) were added and stirred at 40°C for 1.5 h to completely dissociate. The solid was filtered out and the tetrahydrofuran was spun off. The aqueous solution was adjusted to pH = 2 with 10% HCl aqueous solution. A white solid precipitated. The white solid was filtered out and purified by slurrying with n-heptane and petroleum ether to obtain N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (IV) with a yield of 72.1% and a purity of 99.1%.

[0068] Step 3: Preparation of N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysine (Ia)

[0069]

[0070] Example 12

[0071] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous methanol (40 mL), ivDde-OH (2.47 g, 11 mmol), and pyridine (3.16 g, 40 mmol) were added to a 100 mL three-necked flask with magnetic stirring and a thermometer, and heated under reflux and stirring at 60°C. The reaction was detected by TLC to be complete. After concentrating the reaction solution, dichloromethane was added, and the solution was washed with 10% hydrochloric acid solution and water in sequence, and then dried over anhydrous sodium sulfate (2 g). After filtration and concentration, the solution was recrystallized from ethyl acetate-n-hexane to obtain N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ia), with a yield of 81.6% and a purity of 99.6%.

[0072] 1H NMR (400MHz, DMSO-d6) δ7.89 (d, J=7.5Hz, 2H), 7.67 (d, J=7.4Hz, 2H), 7.41 (t, J= 7.4Hz,2H),7.32(t,J=7.4Hz,2H),7.28(d,J=5.7Hz,1H),4.57(q,J=7.1Hz,1H),4 .31-4.24(m,2H),4.19(t,J=6.8Hz,1H),2.97(d,J=6.3Hz,3H),2.26(s,4H),1.8 1-1.74(m,3H),1.46-1.23(m,4H),0.97-0.83(m,13H); MS(ESI):m / z=575.7[M+H] + .

[0073] Embodiment 13

[0074] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), ivDde-OH (2.47 g, 11 mmol), and pyridine (3.16 g, 40 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 60°C with stirring. The reaction was completed by TLC detection. After the reaction solution was concentrated, dichloromethane was added, washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ia) was obtained with a yield of 82.3% and a purity of 99.2%.

[0075] Embodiment 14

[0076] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), isopropanol (40 mL), ivDde-OH (2.47 g, 11 mmol), and pyridine (3.96 g, 50 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 60°C with stirring. The reaction was detected to be complete by TLC. After the reaction solution was concentrated, dichloromethane was added, and the mixture was washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ia) was obtained with a yield of 83.1% and a purity of 99.4%.

[0077] Step 3: Preparation of N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-N2-[(2-propylene-1-oxy)carbonyl]-L-lysine (Ib)

[0078]

[0079] Embodiment 15

[0080] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), Alloc-Cl (1.33 g, 11 mmol), and pyridine (3.16 g, 40 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 65° C., and the reaction was completed by TLC detection. The reaction solution was concentrated, and dichloromethane was added, and the mixture was washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-N2-[(2-propylene-1-oxy)carbonyl]-L-lysine (Ib) was obtained by recrystallization from ethyl acetate-n-hexane, with a yield of 77.8% and a purity of 98.6%.

[0081] 1 H NMR (400MHz, CDCl3) δ7.75(d,J=7.6Hz,2H),7.57(d,J=7.7Hz,2H),7.39(t,J=7.5Hz,2H),7.30(t,J= 7.5Hz,2H),5.89(dd,J=10.9,5.4Hz,1H),5.60(dd,J=18.3,7.2Hz,1H),5.29(dd,J=17.6,9.0Hz,1H), 5.19(t,J=11.4Hz,1H),4.55(d,J=6.4Hz,2H),4.45(d,J=6.8Hz,1H),4.38(t,J=5.5Hz,2H),4.21(q,J =7.1Hz,1H),3.12(d,J=51.6Hz,2H),1.98-1.66(m,2H),1.61-1.30(m,4H); MS(ESI):m / z=453.6[M+H] + .

[0082] Example 16

[0083] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous methanol (40 mL), Alloc-Cl (1.69 g, 14 mmol), and pyridine (3.16 g, 40 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 65° C., and the reaction was completed by TLC detection. After concentrating the reaction solution, dichloromethane was added, and the solution was washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentrating, N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-N2-[(2-propylene-1-oxy)carbonyl]-L-lysine (Ib) was obtained by recrystallization from ethyl acetate-n-hexane, with a yield of 76.3% and a purity of 98.4%.

[0084] Embodiment 17

[0085] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), Alloc-Cl (1.33 g, 11 mmol), and pyridine (3.96 g, 50 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 65° C., and the reaction was completed by TLC detection. After concentrating the reaction solution, dichloromethane was added, and the solution was washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentrating, N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-N2-[(2-propylene-1-oxy)carbonyl]-L-lysine (Ib) was obtained by recrystallization from ethyl acetate-n-hexane, with a yield of 79.1% and a purity of 98.6%.

[0086] Embodiment 18

[0087] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), Alloc-Cl (1.69 g, 14 mmol), and pyridine (3.96 g, 50 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and heated under reflux at 65° C., and the reaction was completed by TLC detection. After concentrating the reaction solution, dichloromethane was added, and the solution was washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentrating, N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-N2-[(2-propylene-1-oxy)carbonyl]-L-lysine (Ib) was obtained by recrystallization from ethyl acetate-n-hexane, with a yield of 79.8% and a purity of 98.9%.

[0088] Step 3 Preparation of N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl]-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysine (Ic)

[0089]

[0090] Embodiment 19

[0091] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), Dde-OH (2.00 g, 11 mmol), and triethylamine (2.02 g, 20 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and the mixture was heated under reflux at 75°C with stirring. The reaction was detected to be complete by TLC. The reaction solution was concentrated and then added with dichloromethane, washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, the mixture was recrystallized from ethyl acetate-n-hexane to obtain N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ic), with a yield of 82.1% and a purity of 98.6%.

[0092] 1 H NMR (400MHz, CDCl3) δ7.75(d,J=7.5Hz,2H),7.57(d,J=7.6Hz,2H),7.38(t,J=7.4Hz ,2H),7.29(t,J=7.7Hz,2H),5.15(s,1H),4.43(t,J=6.2Hz,2H),4.37(d,J=7.0Hz,1 H),4.20(q,J=9.0Hz,1H),3.28-3.04(m,2H),2.53(s,3H),2.41-2.36(m,4H),1.97( q,J=7.3Hz,2H),1.62-1.38(m,4H),1.02(d,J=5.3Hz,6H); MS(ESI):m / z=533.6[M+H] + .

[0093] Embodiment 20

[0094] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous methanol (40 mL), Dde-OH (2.55 g, 14 mmol), and triethylamine (2.02 g, 20 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and the mixture was heated to reflux at 60°C with stirring. The reaction was completed by TLC detection. The reaction solution was concentrated and then added with dichloromethane, washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, the mixture was recrystallized from ethyl acetate-n-hexane to obtain N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ic), with a yield of 81.3% and a purity of 98.2%.

[0095] Embodiment 21

[0096] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous methanol (40 mL), Dde-OH (2.00 g, 11 mmol), and triethylamine (2.02 g, 20 mmol) were added to a 100 mL three-necked flask with a magnetic stirrer and a thermometer, and the mixture was heated to reflux at 60°C with stirring. The reaction was completed by TLC detection. The reaction solution was concentrated and then added with dichloromethane, washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, the mixture was recrystallized from ethyl acetate-n-hexane to obtain N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ic), with a yield of 83.2% and a purity of 98.7%.

[0097] Embodiment 22

[0098] N6-[(9H-fluorene-9-ylmethoxy)-carbonyl]-L-lysine (3.68 g, 10 mmol), anhydrous ethanol (40 mL), Dde-OH (2.55 g, 14 mmol) and pyridine (3.16 g, 40 mmol) were added to a 100 mL three-necked flask with magnetic stirring and a thermometer, and the mixture was heated under reflux at 75°C with stirring. The reaction was detected to be complete by TLC. The reaction solution was concentrated and then added with dichloromethane, washed with 10% hydrochloric acid solution and water, and then dried over anhydrous sodium sulfate (2 g). After concentration, the mixture was recrystallized from ethyl acetate-n-hexane to obtain N2-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl]-N6-[(9H-fluorene-9-ylmethoxy)carbonyl]-L-lysine (Ic), with a yield of 83.9% and a purity of 98.4%.

[0099] Finally, it should be noted that the above implementation is only used to illustrate the technical solution of the present invention rather than to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should all be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative, characterized in that: L-lysine is used as the raw material, and then Fmoc protection is performed after anhydrous copper sulfate complexation, followed by copper ion dissociation, and then α-NH2 protection reaction to obtain the target product N'-Fmoc-L-lysine derivative intermediate. The synthetic route is as follows: Where R is a protective group 2-(1-ethyl)-5,5-dimethylcyclohexane-1,3-dione, 2-(3-methylbutyl Any one of a 5,5-dimethyl-1,3-cyclohexanedione group and a formyl allyl ester group.

2. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 1, characterized in that: The specific steps include: (1) adding the compound of formula (II) into solvent A, complexing with anhydrous copper sulfate under the action of a base, and then adding Fmoc-Osu and stirring to obtain a solid compound of formula (III); (2) adding the compound represented by formula (III) into an EDTA solution or an 8-hydroxyquinoline solution to dissociate the copper ions in the copper complex, and then filtering to obtain the compound represented by formula (IV); (3) The compound represented by formula (IV) is added to solvent B, and subjected to substitution reaction with a protecting agent under the action of a base. After the reaction is completed, the solvent is removed by concentration, and the compound represented by formula (I) is obtained by extraction, washing, and recrystallization.

3. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: The solvent A in step (1) is ethyl acetate, acetonitrile, tetrahydrofuran, acetone or dichloromethane, preferably tetrahydrofuran or acetone; the base is sodium carbonate, sodium bicarbonate, sodium hydroxide or potassium hydroxide; and the temperature of the complex reaction is -10 to 90°C.

4. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: In step (1), the molar ratio of the compound represented by formula (II), anhydrous copper sulfate, alkali, and Fmoc-Osu is 1:0.2-1.5:1-2.5:1-2.

5. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: The temperature for dissociating copper ions in step (2) is 15 to 65°C.

6. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: In step (2), the molar ratio of the compound represented by formula (III) to EDTA is 1:1-4.

7. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: In step (2), the molar ratio of the compound represented by formula (III) to 8-hydroxyquinoline is 1:0.5-1.

5.

8. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: The solvent B in step (3) is anhydrous methanol, anhydrous ethanol, isopropanol, n-butanol or ethylene glycol; the base is pyridine, 2,4-lutidine, 2,4,6-trimethylpyridine, triethylamine or N,N-diisopropylethylamine; and the substitution reaction temperature is 20 to 80°C.

9. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 2, characterized in that: In step (3), the molar ratio of the compound represented by formula (IV), the base and the protecting agent is 1:1 to 5:1 to 1.

5.

10. The method for preparing a pharmaceutical intermediate of an N'-Fmoc-L-lysine derivative according to claim 9, characterized in that: The protecting agent is 2-(1-hydroxyethylidene)-5,5-dimethyl-1,3-cyclohexanedione, 2-(1-hydroxy-3-methylbutylidene)-5,5-dimethyl-1,3-cyclohexanedione or allyl chloroformate.

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