The invention relates to Fmoc-L-4apos and a preparation method thereof. Synthesis method of-tetrahydropyranyl glycine

Abstract

The invention relates to a synthesis method of Fmoc-L-4 '-tetrahydropyranyl glycine, which comprises the following steps of: synthesizing Fmoc-L-4'-tetrahydropyranyl glycine; the technical problem that the compound is easy to produce in large scale is mainly solved. The synthesis method comprises the following synthesis steps: reacting 4-iodotetrahydropyran and potassium tert-butoxide with ethyl diphenylmethylene glycinate in DMF (Dimethyl Formamide) to generate a compound 1, wherein the product does not need to be purified; the compound 1 is heated in 6M hydrochloric acid to generate a compound 2, and the product does not need to be purified; reacting the compound 2 with acetyl chloride in water and tetrahydrofuran to generate a compound 3, and pulping and purifying the product; hydrolyzing the compound 3 in a sodium hydroxide aqueous solution by using acetylase to obtain a compound 4, wherein the product does not need to be purified; and reacting the compound 4 and sodium bicarbonate with FmocOsu in water and tetrahydrofuran, and pulping the obtained crude petroleum ether / ethyl acetate (4 / 1) to obtain the target product.

Description

Technical Field

[0001] The present invention relates to the field of non-natural amino acid synthesis, and in particular to a method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine (CAS: 368866-31-3). Background Art

[0002] In order to further improve the effectiveness and activity of peptides, reduce proteolysis, and improve bioavailability, non-natural amino acids are widely introduced into the synthesis of various peptides. Fmoc-L-4'-tetrahydropyranylglycine is the raw material for the synthesis of the dodecapeptide UBC12, which plays an important role in the study of protein turnover in cells ( J. Med. Chem. 2018, 61, 5, 1934–1950). The current literature reported route for this compound is: Kalein reported that tetrahydropyran-4-carboxylic acid was used as the raw material and the target product was obtained through 7 steps of reaction (US2016 / 319312). However, this method requires the use of Grignard reagents, and the two enzymes used in the key step of introducing chiral amines are very expensive, which is not suitable for large-scale production. Summary of the invention

[0003] The purpose of the present invention is to provide a method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine, mainly to solve the technical problem of making this compound suitable for large-scale production.

[0004] The technical scheme of the present invention is as follows: A method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine comprises the following steps: (1) 4-iodotetrahydropyran and potassium tert-butoxide react with dibenzylideneglycine ethyl ester in DMF to generate compound 1. The product does not need to be purified. (2) Compound 1 is heated in hydrochloric acid to generate compound 2, and the product does not need to be purified; (3) Compound 2 reacts with acetyl chloride in water and tetrahydrofuran to generate compound 3, and the product is slurried and purified; (4) Compound 3 is hydrolyzed with acetylase in a sodium hydroxide aqueous solution to obtain compound 4, and the product does not need to be purified; (5) Compound 4 and sodium bicarbonate are reacted with FmocOsu in water and tetrahydrofuran, and the resulting crude product is slurried with petroleum ether / ethyl acetate to obtain the target product.

[0005] The reaction scheme of the present invention is as follows:

[0006] In the above reaction, the reaction temperature in step 1 is 20°C-40°C, preferably 25°C, and the reaction time is 4-12 hours, preferably 10 hours. The reaction temperature in step 2 is 60°C-120°C, preferably 100°C, and the reaction time is 2-8 hours, preferably 4 hours. The reaction temperature in step 3 is 0°C-30°C, preferably 15°C, and the reaction time is 2-8 hours, preferably 4 hours.

[0007] The beneficial effects of the present invention are as follows: providing a method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine, which has 5 steps in total, uses cheap reagents, is simple to purify, has mild reaction conditions, is suitable for scaled-up production, and has high market application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is the liquid chromatogram of the product of the present invention.

[0009] Figure 2 It is the chiral liquid chromatogram of the product of the present invention.

[0010] Figure 3 The mass spectrum of the product of the present invention is shown in FIG.

[0011] Figure 4 The NMR spectrum of the product of the present invention. DETAILED DESCRIPTION

[0012] Example 1: Fmoc-L-4'-tetrahydropyranylglycine.

[0013] Step 1: Add dibenzylidene glycine ethyl ester (200 g, 0.75 mol) to DMF (2 L), cool to 5-10 ° C in an ice-water bath, add potassium tert-butoxide (125.7 g, 1.12 mol) and 4-iodotetrahydropyran (190.8 g, 0.9 mol). After the addition, the reaction solution was stirred at 25 ° C for 10 hours. The reaction solution was poured into a saturated aqueous ammonium chloride solution (6 L) and extracted twice with ethyl acetate (2 L). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness under reduced pressure. The obtained crude compound 1 was used directly in the next step. MS (ESI) M / Z: 352.1 [M+H] + .

[0014] Step 2: The crude compound 1 (0.75 mol) from the previous step was added to 6M hydrochloric acid (1.5 L), heated to 100°C, and stirred for 4 hours. The reaction solution was cooled to room temperature, and dichloromethane (2 L) was added and stirred, and the liquid was separated. The pH value of the aqueous phase was adjusted to 8-8.5 with sodium hydroxide, and the aqueous solution of the obtained compound 2 was directly used in the next step. MS (ESI) M / Z: 160.1 [M+H] + .

[0015] Step 3: Add tetrahydrofuran (1.5 L) to the aqueous solution of compound 2 (0.75 mol) in the previous step, and cool to 0°C in an ice-water bath. Add acetyl chloride (70.6 g, 0.9 mol) dropwise to the reaction solution, and keep the pH value at 8-8.5 with 1N sodium hydroxide aqueous solution. After the addition, stir the reaction solution at 15°C for 4 hours. The reaction solution is acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 L*2). The organic phase is washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness under reduced pressure. The crude product is slurried with petroleum ether / ethyl acetate (volume ratio 2 / 1, 500 mL), filtered, and dried to obtain compound 3 (96.6 g, three-step yield: 64%). MS (ESI) M / Z: 202.05[M+H] + .

[0016] Step 4: Compound 3 (96.6 g, 0.48 mol) was added to 1N sodium hydroxide aqueous solution (500 mL), stirred to dissolve, and then adjusted to pH 8 with 2M hydrochloric acid. The reaction solution was heated to 38°C, and acetylase (15 g) was added thereto. After the addition was complete, the reaction solution was stirred at this temperature overnight. The reaction solution was acidified with concentrated hydrochloric acid and extracted with ethyl acetate (1 L*2). The aqueous phase was adjusted to a neutral pH with sodium hydroxide aqueous solution, and the obtained aqueous solution of compound 4 was directly used in the next step. MS (ESI) M / Z: 160.03 [M+H] + .

[0017] Step 5: To the aqueous solution of compound 4 (0.24 mol) in the previous step, sodium bicarbonate (60.5 g, 0.72 mol) and tetrahydrofuran (600 mL) were added, cooled to 5-10°C in an ice-water bath, and then FmocOsu (67.5 g, 0.2 mol) was added. After the addition, the reaction solution was stirred at room temperature overnight. The reaction solution was acidified with concentrated hydrochloric acid and extracted with ethyl acetate (1 L*2). The organic phases were combined, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness under reduced pressure. The obtained crude product was slurried with petroleum ether / ethyl acetate (volume ratio 3 / 1, 400 mL), filtered, and dried to obtain the target product (65 g, two-step yield: 71%). MS (ESI) M / Z: 382.2 [M+H] + The liquid chromatogram of the product is shown in Figure 1 The chiral liquid chromatogram of the product is shown in Figure 2 The mass spectrum of the product is shown in Figure 3 The NMR spectrum of the product is shown in Figure 4 .

[0018] In Example 2, the reaction temperature of step 1 is 20° C. and the reaction time is 12 hours; the reaction temperature of step 2 is 60° C. and the reaction time is 8 hours; the reaction temperature of step 3 is 0° C. and the reaction time is 8 hours. The rest is the same as in Example 1.

[0019] In Example 3, the reaction temperature of step 1 is 40° C. and the reaction time is 4 hours; the reaction temperature of step 2 is 120° C. and the reaction time is 2 hours; the reaction temperature of step 3 is 30° C. and the reaction time is 2 hours. The rest is the same as in Example 1.

Claims

1. A method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine, characterized in that: The following steps are involved: (1) 4-iodotetrahydropyran and potassium tert-butoxide react with dibenzylideneglycine ethyl ester in DMF to generate compound 1. The product does not need to be purified. (2) Compound 1 is heated in hydrochloric acid to generate compound 2, and the product does not need to be purified; (3) Compound 2 reacts with acetyl chloride in water and tetrahydrofuran to generate compound 3, and the product is slurried and purified; (4) Compound 3 is hydrolyzed with acetylase in a sodium hydroxide aqueous solution to obtain compound 4, and the product does not need to be purified; (5) Compound 4 and sodium bicarbonate react with FmocOsu in water and tetrahydrofuran, and the resulting crude product is slurried with petroleum ether / ethyl acetate to obtain the target product; The synthesis route is as follows: 。 2. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 1, characterized in that: The reaction temperature in step 1 is 20°C-40°C, and the reaction time is 4-12 hours.

3. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 2, characterized in that: The reaction temperature is 25° C. and the reaction time is 10 hours.

4. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 1, characterized in that: The reaction temperature in step 2 is 60°C-120°C, and the reaction time is 2-8 hours.

5. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 4, characterized in that: The reaction temperature is 100° C. and the reaction time is 4 hours.

6. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 1, characterized in that: The reaction temperature in step 3 is 0°C-30°C, and the reaction time is 2-8 hours.

7. The method for synthesizing Fmoc-L-4'-tetrahydropyranylglycine according to claim 6, characterized in that: The reaction temperature is 15° C. and the reaction time is 4 hours.

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