Method for industrially producing Fmoc-Tyr (tBu)-OH at low cost

Abstract

The invention discloses a low-cost industrial production method of Fmoc-Tyr (tBu)-OH, and belongs to the technical field of preparation of medical intermediates, and the method comprises the following steps: A, dissolving H-Tyr-OMe. HCl in a solvent system formed by mixing tert-butyl acetate and halogenated hydrocarbon, reacting with isobutene in the presence of an acid catalyst, and treating to obtain H-Tyr (tBu)-OMe; b, hydrolyzing the H-Tyr (tBu)-OMe in an alkali metal hydroxide aqueous solution to obtain H-Tyr (tBu)-OH; and C, the H-Tyr (tBu)-OH reacts with Fmoc-OSu, and Fmoc-Tyr (tBu)-OH is obtained after treatment is carried out on the H-Tyr (tBu)-OH and the Fmoc-OSu. The production method has fewer procedures, the total yield of the product is not lower than 70%, the purity of the product is not lower than 99.5% after HPLC detection, and the product quality and the production efficiency are superior to those of an existing method.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical intermediate preparation, and in particular to a method for industrially producing Fmoc-Tyr(tBu)-OH at low cost. Background Art

[0002] Fmoc-Tyr(tBu)-OH, systematic nomenclature: (S)-2-{[(9H-fluoren-9-yl)methoxy]carbonyl}-3-(4-tert-butoxyphenyl)propionic acid, is a protected amino acid, an organic synthesis intermediate and a pharmaceutical intermediate. It can be used in biochemical research, organic synthesis and pharmaceutical research and development. Its structural formula is shown below:

[0003] Because the alcoholic hydroxyl and carboxyl groups in the L-Tyr (tyrosine) molecular structure have similar chemical properties, to prevent side reactions and consider the solubility of the material, the amino and carboxyl groups are usually pre-protected first, the alcoholic hydroxyl group is tert-butylated, and then the pre-protection is removed. Finally, the required protecting group is introduced on the amino group. Patent CN103833593A reports a preparation method, which is also the mainstream method for industrial production. The process steps are roughly as follows: A. Using L-tyrosine (L-Tyr) as the starting material, it reacts with methanol to obtain H-Tyr-OMe·HCl (carboxyl group pre-protected); B. H-Tyr-OMe·HCl reacts with benzyl chloroformate to obtain Z-Tyr-OMe (amino group pre-protected); C. Z-Tyr-OMe reacts with isobutylene to obtain Z-Tyr(tBu)-OMe; D. Z-Tyr(tBu)-OMe is hydrolyzed to give Z-Tyr(tBu)-OH; E. Z-Tyr(tBu)-OH is hydrogenolyzed under the catalysis of palladium on carbon (Pd / C) to give H-Tyr(tBu)-OH; F, H-Tyr(tBu)-OH reacts with 9-fluorenylmethyl-N-succinimidyl carbonate (Fmoc-OSu) to obtain Fmoc-Tyr(tBu)-OH.

[0004] This method has long process steps, low yield, long working hours, and requires the use of expensive heavy metal catalysts, resulting in high production costs and is not suitable for industrial production.

[0005] Based on this, patent CN109111377A reports a preparation method that does not use heavy metal reagents. The process steps are roughly as follows: A. L-tyrosine (L-Tyr) is used as the starting material and reacts with methanol to obtain H-Tyr-OMe·HCl; B. H-Tyr-OMe·HCl reacts with Fmoc-OSu to obtain Fmoc-Tyr-OMe; C. Fmoc-Tyr-OMe reacts with tert-butyl alcohol to obtain Fmoc-Tyr(tBu)-OMe; D. Fmoc-Tyr(tBu)-OMe is hydrolyzed under alkaline conditions to obtain the target product Fmoc-Tyr(tBu)-OH.

[0006] This method reduces the number of steps from six to four and eliminates the use of heavy metal reagents. However, the conversion rate of intermediate 2 Fmoc-Tyr-OMe is low due to the significant steric hindrance of tert-butyl alcohol during the preparation of intermediate 3 Fmoc-Tyr(tBu)-OMe. Furthermore, the condensing agent N,N'-dicyclohexylcarbodiimide (DCC) converts to DCU (1,3-dicyclohexylurea) after the reaction, a genotoxic impurity that is difficult to remove. Furthermore, the preparation of Fmoc-Tyr(tBu)-OH from intermediate 3 Fmoc-Tyr(tBu)-OMe requires a strongly alkaline aqueous sodium hydroxide solution. However, the Fmoc protecting group is unstable under alkaline conditions and is easily removed. Therefore, this step requires the addition of Fmoc-OSu, which cannot be quantitatively determined. This makes the process unstable and unsuitable for industrial production.

[0007] To address the above issues, patent CN112094204A reports a preparation method, the process steps are as follows: A. L-tyrosine (L-Tyr) is used as the starting material and reacts with methanol to obtain H-Tyr-OMe·HCl; B. H-Tyr-OMe·HCl reacts with Fmoc-OSu to obtain Fmoc-Tyr-OMe; C. Fmoc-Tyr-OMe reacts with tert-butyl acetate / tert-butyl alcohol under the catalysis of perchloric acid to obtain Fmoc-Tyr(tBu)-OMe; D. Fmoc-Tyr(tBu)-OMe is hydrolyzed with a Lewis acid such as aluminum trichloride to obtain the target product Fmoc-Tyr(tBu)-OH.

[0008] Compared to patent CN109111377A, the first two steps are consistent, and the preparation of intermediate 3H-Tyr(tBu)-OMe no longer uses DCC. The catalyst used in the final hydrolysis step is a Lewis acid, which does not affect the Fmoc protecting group. However, due to the steric hindrance of tert-butyl alcohol itself, the conversion rate of intermediate 2Fmoc-Tyr-OMe is still low. The catalyst used in the final hydrolysis step to obtain the target product is a Lewis acid, which easily absorbs moisture from the air to produce acid mist. It requires anhydrous operation during use, which easily leaves metal ions in the target product, making it unsuitable for industrial production. Summary of the Invention

[0009] The object of the present invention is to provide a simple, efficient and environmentally friendly method for industrial production of Fmoc-Tyr(tBu)-OH in order to overcome the shortcomings of existing industrial production.

[0010] The technical solution adopted by the present invention is as follows: a method for industrially producing Fmoc-Tyr(tBu)-OH at low cost, comprising the following steps: A. Dissolving H-Tyr-OMe·HCl in a mixed solvent system of tert-butyl acetate and halogenated hydrocarbon, reacting with isobutylene in the presence of an acidic catalyst, and obtaining H-Tyr(tBu)-OMe after treatment; B. H-Tyr(tBu)-OMe is hydrolyzed in an aqueous solution of an alkali metal hydroxide to give H-Tyr(tBu)-OH; C. H-Tyr(tBu)-OH reacts with Fmoc-OSu and is treated to obtain Fmoc-Tyr(tBu)-OH.

[0011] The production method of the present invention, its synthetic route is as follows:

[0012] Furthermore, the mass ratio of H-Tyr-OMe·HCl to tert-butyl acetate is 1:2-5, for example, 1:2, 1:3, 1:3.5, 1:4, 1:5, etc.

[0013] Furthermore, the halogenated hydrocarbon is selected from one or more of dichloromethane, chloroform, and dichloroethane, and the mass ratio of the solvent system of H-Tyr-OMe·HCl, tert-butyl acetate, and the halogenated hydrocarbon is 1:5-10, for example, 1:5, 1:6, 1:7, 1:8, 1:10, etc.

[0014] Furthermore, the molar ratio of H-Tyr-OMe·HCl to isobutylene is 1:3-6, for example, 1:3, 1:4, 1:4.5, 1:5, 1:6, etc.

[0015] Furthermore, the acidic catalyst is perchloric acid, and the molar ratio of H-Tyr-OMe·HCl to perchloric acid is 1:1.1-1.5, for example, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0016] Furthermore, in step A, the reaction temperature is controlled at 0-10°C, for example, 0°C, 2°C, 5°C, 7°C, 10°C, etc.

[0017] Further, in step A, after the reaction is completed, the organic phase is obtained by washing and separation, and the organic phase is treated with Fe-containing 3+ After washing with aqueous solution and drying, H-Tyr(tBu)-OMe was obtained.

[0018] Furthermore, in step B, H-Tyr(tBu)-OMe is first dissolved in an organic solvent, and then an alkali metal hydroxide aqueous solution is added, and the temperature is controlled at 10-15°C (for example, 10°C, 12°C, 13°C, 15°C, etc.). After the reaction is complete, the pH value is adjusted to 5-6, and the mixture is centrifuged and dried to obtain H-Tyr(tBu)-OH.

[0019] Furthermore, in step C, H-Tyr(tBu)-OH is added to a mixture of water and an organic solvent to dissolve, potassium carbonate and / or potassium carbonate is added and stirred, and then Fmoc-OSu is added while controlling the temperature at 15-25°C (for example, 15°C, 17°C, 20°C, 22°C, 25°C, etc.) to react and obtain Fmoc-Tyr(tBu)-OH.

[0020] Further, in step C, after the reaction of H-Tyr(tBu)-OH and Fmoc-OSu is complete, the pH of the reaction system is adjusted to 2-3, the organic phase is taken, the organic phase is washed, and then concentrated under reduced pressure, slurried, centrifuged, and dried to obtain Fmoc-Tyr(tBu)-OH.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. Unlike current mainstream production processes and preparation methods reported in patent literature, the present invention does not require pre-protection of the amino group in the H-Tyr-OMe·HCl structure or tert-butylation after protection. The present invention has concluded through experimental research that, using a mixture of tert-butyl acetate and a halogenated hydrocarbon as a solvent, H-Tyr-OMe·HCl can be directly reacted with isobutylene to form a tert-butylated product H-Tyr(tBu)-OMe, which is then obtained through hydrolysis and substitution reactions. There is no need to pre-protect the amino group, and there is no subsequent deprotection step. This reduces two steps in the overall process and greatly shortens the reaction time. 2. Unlike the methods reported in patent literature, the present invention introduces the Fmoc protecting group in the final step. Therefore, there is no need to consider the stability of the Fmoc protecting group in the previous steps. Thus, while ensuring low-cost and efficient preparation of the target product, heavy metal catalysts and water-unstable Lewis acids are not used. In addition, the process significantly reduces working hours, and the product quality is stable, making it very suitable for industrial-scale production. 3. The total yield of Fmoc-Tyr(tBu)-OH prepared by the method of the present invention is not less than 70%, and the purity of the product after HPLC (high performance liquid chromatography) detection is not less than 99.5%. The product quality is better than the mainstream method (the mainstream method mentioned in the background technology), and due to the reduction of steps, the production efficiency is higher than the mainstream method. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] Example 1 A low-cost industrial production method for Fmoc-Tyr(tBu)-OH comprises the following steps: (1) Preparation of H-Tyr-OMe·HCl: S1. Add 800 kg of methanol and 200 kg of L-Tyr to a 3000 L glass-lined reactor, start stirring at 50 Hz, control the temperature at 15 ° C, and add 180 kg of thionyl chloride dropwise; After the addition, the temperature was raised to 40°C for reaction. The reaction of L-Tyr was monitored by TLC (thin layer chromatography). The mixture was concentrated under reduced pressure until no liquid was distilled out. 400 kg of ethyl acetate was added, and stirring was started at 50 Hz for 2 h. The mixture was centrifuged and dried to obtain 246 kg of an off-white solid (H-Tyr-OMe·HCl, molecular weight 231.68), with a yield of 96.2%. (2) Preparation of H-Tyr(tBu)-OMe: S1. Add 984 kg of tert-butyl acetate and 984 kg of dichloromethane to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 248 kg of H-Tyr-OMe·HCl, and add 183 kg of perchloric acid dropwise at a temperature of 2°C; S2, after the addition, 297 kg of isobutylene was added with the temperature controlled at 2°C; after the addition, the temperature was controlled at 6°C for the reaction, and the reaction endpoint was monitored by TLC; S3. After the reaction is completed, the pH value is adjusted to 5.8 with a 20w% sodium carbonate aqueous solution, the aqueous phase is discarded, and the organic phase is washed with a 20w% sodium chloride aqueous solution, each time using 400 kg. TLC monitors the organic phase for the absence of H-Tyr-OMe·HCl. S4, the organic phase was washed 3 times with a 5w% ferric chloride aqueous solution, each time using 50kg. After washing, the organic phase was washed with a 20w% sodium chloride aqueous solution until the pH value was about 6. The organic phase was dried over 25kg of anhydrous sodium sulfate and concentrated under reduced pressure until no liquid was distilled to give a brown oil. The yield was 100%, i.e. 306kg; (3) Preparation of H-Tyr(tBu)-OH: S1. Add 50 kg of acetone to the above 3000 L glass-lined reactor and stir at 50 Hz until the material is dissolved. Add 204 kg of water to another 3000 L glass-lined reactor and stir at 50 Hz. Add 51 kg of sodium hydroxide. After dissolution, cool to below 10° C. and control the temperature at 6° C. Transfer the acetone solution of H-Tyr(tBu)-OMe to the above aqueous sodium hydroxide solution, control the temperature at 12° C. and stir for 3 h. Monitor the reaction of H-Tyr(tBu)-OMe by TLC. S2. Adjust the pH to about 5 with 20w% citric acid aqueous solution, centrifuge, and dry to obtain 205 kg of off-white solid (H-Tyr(tBu)-OH, molecular weight 237.29); (4) Preparation of Fmoc-Tyr(tBu)-OH: S1. Add 1640 kg of water and 615 kg of acetone to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 169 kg of potassium carbonate, control the temperature at 20°C, and add 306 kg of Fmoc-OSu in batches. Monitor by TLC until the reaction of H-Tyr(tBu)-OH is complete. S2, after the reaction is completed, 1025kg of ethyl acetate is added, and the pH value is adjusted to about 2 with a 20w% citric acid aqueous solution, the liquid is allowed to stand, the aqueous phase is discarded, and the organic phase is washed with a 20w% sodium chloride aqueous solution to a pH value of about 6, each time using 200kg; S3. The organic phase was concentrated to dryness under reduced pressure, and 820 kg of n-hexane was added and slurried for 2 h. The mixture was centrifuged and dried to obtain 365 kg of a white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53). The total yield was 72.0%, and the purity determined by HPLC (liquid chromatography) was 99.7%.

[0024] Example 2 A low-cost industrial production method for Fmoc-Tyr(tBu)-OH comprises the following steps: (1) Preparation of H-Tyr-OMe·HCl: S1. Add 800 kg of methanol and 200 kg of L-Tyr to a 3000 L glass-lined reactor, start stirring at 50 Hz, control the temperature at 15 ° C, and add 180 kg of thionyl chloride dropwise; After the addition, the temperature was raised to 40°C for reaction. The reaction of L-Tyr was monitored by TLC. The mixture was concentrated under reduced pressure until no liquid was distilled out. 400 kg of ethyl acetate was added and stirred at 50 Hz for 2 h. The mixture was centrifuged and dried to obtain 248 kg of off-white solid (H-Tyr-OMe·HCl, molecular weight 231.68), with a yield of 97.0%; (2) Preparation of H-Tyr(tBu)-OMe: S1. Add 992 kg of tert-butyl acetate and 992 kg of dichloromethane to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 248 kg of H-Tyr-OMe·HCl, and add 182 kg of perchloric acid dropwise at a temperature of 2°C; S2, after the addition, add 270kg of isobutylene at 2°C; after the addition, control the temperature at 5-8°C to react, and monitor the reaction endpoint by TLC; S3. After the reaction is completed, the pH value is adjusted to 5.9 with a 20w% sodium carbonate aqueous solution, the aqueous phase is discarded, and the organic phase is washed with a 20w% sodium chloride aqueous solution, each time using 400 kg. TLC monitors the organic phase for the absence of H-Tyr-OMe·HCl. S4, the organic phase was washed three times with a 5w% aqueous solution of ferric sulfate, each time using 50kg; after washing, the organic phase was washed with a 20w% aqueous solution of sodium chloride until the pH value was about 6; the organic phase was dried over 25kg of anhydrous sodium sulfate and concentrated under reduced pressure until no liquid was distilled to give a brown oil, the yield of which was 100%, i.e. 308kg; (3) Preparation of H-Tyr(tBu)-OH: S1. Add 50 kg of acetone to the above 3000 L glass-lined reactor and stir at 50 Hz until the material is dissolved. Add 312 kg of water to another 3000 L glass-lined reactor and stir at 50 Hz. Add 78 kg of potassium hydroxide (molar ratio 1.3). After dissolution, cool to below 10°C and transfer the H-Tyr(tBu)-OMe acetone solution to the above sodium hydroxide aqueous solution at a controlled temperature of 5°C. Stir at a controlled temperature of 15°C for 3 h. Monitor the H-Tyr(tBu)-OMe reaction completion by TLC. S2. Adjust the pH to about 5 with 20w% citric acid aqueous solution, centrifuge, and dry to obtain 207kg of off-white solid (H-Tyr(tBu)-OH, molecular weight 237.29); (4) Preparation of Fmoc-Tyr(tBu)-OH: S1. Add 1656 kg of water and 621 kg of acetone to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 170 kg of potassium carbonate, control the temperature at 20°C, and add 309 kg of Fmoc-OSu in batches. Monitor by TLC until the reaction of H-Tyr(tBu)-OH is complete. S2, after the reaction is completed, 1035kg of ethyl acetate is added, and the pH value is adjusted to about 2 with a 20w% aqueous solution of citric acid, the liquid is allowed to stand, the aqueous phase is discarded, and the organic phase is washed with a 20w% aqueous solution of sodium chloride to a pH value of about 6, each time using 200kg; S3. The organic phase was concentrated to dryness under reduced pressure, and 828 kg of n-hexane was added and slurried for 2 h. The mixture was centrifuged and dried to obtain 362 kg of a white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53). The total yield was 71.4%, and the purity determined by HPLC was 99.6%.

[0025] Example 3 A low-cost industrial production method for Fmoc-Tyr(tBu)-OH comprises the following steps: (1) Preparation of H-Tyr-OMe·HCl: S1. Add 800 kg of methanol and 200 kg of L-Tyr to a 3000 L glass-lined reactor, turn on the stirring at 50 Hz, control the temperature at 17 ° C, and add 180 kg of thionyl chloride dropwise; After the addition, the temperature was raised to 45°C for reaction. The reaction of L-Tyr was monitored by TLC. The mixture was concentrated under reduced pressure until no liquid was distilled out. 400 kg of ethyl acetate was added and stirred at 50 Hz for 2 h. The mixture was centrifuged and dried to obtain 243 kg of an off-white solid (H-Tyr-OMe·HCl, molecular weight 231.68). The yield was 95.0%. (2) Preparation of H-Tyr(tBu)-OMe: S1. Add 1094 kg of tert-butyl acetate and 1094 kg of dichloromethane to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 243 kg of H-Tyr-OMe·HCl, and add 178 kg of perchloric acid dropwise at a temperature of 2°C; S2, after addition, add 282kg of isobutylene at 2°C, and after addition, control the temperature at 5°C to react, and monitor the reaction endpoint by TLC; S3. After the reaction is completed, the pH value is adjusted to 6.0 with a 20w% sodium carbonate aqueous solution, the aqueous phase is discarded, and the organic phase is washed with a 20w% sodium chloride aqueous solution, each time using 400 kg. TLC monitors the organic phase for the absence of H-Tyr-OMe·HCl. S4. The organic phase was washed three times with a 5w% aqueous solution of ferric chloride, using 50 kg each time. After washing, the organic phase was washed with a 20w% aqueous solution of sodium chloride until the pH value was about 6; the organic phase was dried over 25 kg of anhydrous sodium sulfate and concentrated under reduced pressure until no liquid was distilled out, obtaining a brown-yellow oil. The yield was 100%, i.e., 302 kg. (3) Preparation of H-Tyr(tBu)-OH: S1. Add 50 kg of acetone to the above 3000 L glass-lined reactor and stir at 50 Hz until the material is dissolved. Add 312 kg of water to another 3000 L glass-lined reactor and stir at 50 Hz. Add 58 kg of sodium hydroxide. After dissolution, cool to below 10° C. and control the temperature at 5° C. Transfer the acetone solution of H-Tyr(tBu)-OMe to the above aqueous sodium hydroxide solution, control the temperature at 16° C. and stir for 3 h. Monitor the reaction of H-Tyr(tBu)-OMe by TLC. S2. Adjust the pH to about 5 with 20w% citric acid aqueous solution, centrifuge, and dry to obtain 202 kg of off-white solid (H-Tyr(tBu)-OH, molecular weight 237.29); (4) Preparation of Fmoc-Tyr(tBu)-OH: S1. Add 1616 kg of water and 606 kg of acetone to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 165 g of potassium carbonate, control the temperature at 20°C, add 301 kg of Fmoc-OSu in batches, and monitor by TLC until the reaction of H-Tyr(tBu)-OH is complete; S2, after the reaction is completed, 1010kg of ethyl acetate is added, and the pH value is adjusted to about 2 with a 20w% citric acid aqueous solution, the liquid is allowed to stand, the aqueous phase is discarded, and the organic phase is washed with a 20w% sodium chloride aqueous solution to a pH value of about 6, with a dosage of 200kg each time; S3. The organic phase was concentrated to dryness under reduced pressure, and 808 kg of n-hexane was added and slurried for 2 h. The mixture was centrifuged and dried to obtain 358 kg of a white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53). The total yield was 70.6%, and the purity determined by HPLC was 99.8%.

[0026] Comparative Example 1 This comparative example was prepared according to the mainstream method of industrial production: (1) Preparation of H-Tyr-OMe·HCl: S1. Add 1020 kg of methanol to a 5000 L glass-lined reactor, start stirring at 50 Hz, add 200 kg of L-Tyr, control the temperature at 15 ° C, and add 320 kg of thionyl chloride dropwise; S2. After the addition is complete, the temperature is raised to 40°C for reaction. The reaction of L-Tyr is monitored by TLC to obtain a methanol solution of H-Tyr-OMe·HCl, which is directly used for the next reaction; (2) Preparation of Z-Tyr-OMe S1. Cool the mixture to below 10°C, start stirring at 50 Hz, and slowly add 600 kg of sodium carbonate to the methanol solution of H-Tyr-OMe·HCl. The temperature during the addition of sodium carbonate should be controlled at <20°C. S2, after the addition is complete, add 200kg of water and 1080kg of ethyl acetate, control the temperature to <20°C, and add 320kg of benzyl chloroformate dropwise; S3. After the addition is complete, monitor the reaction of H-Tyr-OMe·HCl by TLC. Adjust the pH to about 5 with hydrochloric acid. Discard the aqueous phase, collect the organic phase, dry it over 50 kg of anhydrous sodium sulfate for 1 h, and concentrate under reduced pressure until a large amount of solid precipitates. S4. Cool to 20°C, add 810 kg of petroleum ether, stir for crystallization, centrifuge, and dry to obtain 400 kg of white solid (Z-Tyr-OMe, molecular weight 267.28); (3) Preparation of Z-Tyr(tBu)-OMe S1. Add 3000 kg of dichloromethane to a 5000 L glass-lined reactor, start stirring at 50 Hz, and add 400 kg of Z-Tyr-OMe and 20 kg of sulfuric acid; S2, after the addition, control the temperature to <10 ° C, introduce 600 kg of isobutylene, keep the temperature <10 ° C and react for 48 hours to obtain a dichloromethane solution of Z-Tyr(tBu)-OMe, which is directly used for the next reaction; (4) Preparation of Z-Tyr(tBu)-OH S1. Add 720 kg of water and 144 kg of sodium hydroxide to a 5000 L glass-lined reactor, start stirring at 50 Hz, and cool to below 5°C after complete dissolution; S2. Transfer the dichloromethane solution of H-Tyr(tBu)-OMe from the previous step to a reactor, control the temperature at 10°C and stir for 3 h, separate the liquids, concentrate the organic phase under reduced pressure until no liquid is distilled out, combine it with the aqueous phase, control the temperature at 10°C and react, and monitor the completion of the H-Tyr(tBu)-OMe reaction by TLC; S3, adjust the pH to about 5 with hydrochloric acid, add 1200kg of ethyl acetate, let stand and separate, discard the aqueous layer, and obtain an ethyl acetate solution of H-Tyr(tBu)-OH, which is directly put into the next reaction; (5) Preparation of H-Tyr(tBu)-OH S1. Transfer the ethyl acetate solution of Z-Tyr(tBu)-OH from the previous step into a nitrogen-substituted hydrogenolysis kettle, add 5 kg of 5w% palladium on carbon, and seal the kettle lid; after nitrogen substitution, introduce hydrogen and control the pressure at 0.15 MPa for hydrogenolysis. Monitor the reaction of Z-Tyr(tBu)-OH by TLC. S2, add 800kg of water, filter out the insoluble palladium carbon, discard the organic layer after static stratification, transfer the aqueous layer to a 5000L glass-lined reactor to obtain an aqueous solution of H-Tyr(tBu)-OH, which is directly put into the next step of reaction; (6) Preparation of Fmoc-Tyr(tBu)-OH: S1. Add 600 kg of acetone and 200 kg of sodium carbonate to the above reactor, start stirring at 50 Hz, control the temperature at 20°C, and add Fmoc-OSu in batches; S2. TLC monitoring was performed until the reaction of H-Tyr(tBu)-OH was complete. After post-treatment, 215 kg of white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53) was obtained. The total yield was 42.4% and the purity determined by HPLC was 99.5%.

[0027] Comparative Example 2 This comparative example was prepared according to the method in the patent literature (CN109111377A): (1) Preparation of H-Tyr-OMe·HCl: S1. Add 800 kg of methanol to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 200 kg of L-Tyr, and add 320 kg of thionyl chloride dropwise at a temperature of 15°C; S2. After the addition is complete, the temperature is raised to 40°C for reaction. The reaction of L-Tyr is monitored by TLC. The solution is concentrated under reduced pressure to about 1 / 5 of the original volume and directly used in the next step. (2) Preparation of Fmoc-Tyr-OMe: S1. Add 1200 kg of 20 w% sodium carbonate aqueous solution to the above reactor, start stirring at 50 Hz, control the temperature at 12 ° C, and add 346 kg of Fmoc-OSu in batches; After the addition, the reaction was continued at 12°C and the reaction endpoint was monitored by TLC. After the reaction was completed, the pH value was adjusted to about 2 with 5N hydrochloric acid, and the mixture was centrifuged and dried to obtain 405 kg of a white solid (Fmoc-Tyr-OMe, molecular weight 417.45). (3) Preparation of Fmoc-Tyr(tBu)-OMe: S1, 575 kg of tert-butyl alcohol was added to a 3000 L glass-lined reaction kettle, stirring was started at 50 Hz, 405 kg of Fmoc-Tyr-OMe, 400 kg of N, N'-dicyclohexyl carbodiimide (DCC) were added; S2, after addition, control the temperature at 5 ℃ to react, monitor the reaction end point by TLC; after the reaction is completed, filter out the insoluble matter, and the obtained solution is directly put into the next step reaction; (4) Preparation of Fmoc-Tyr(tBu)-OH: S1, 220 kg of 30 w% sodium hydroxide aqueous solution was added to the above reaction kettle, stirring was started at 50 Hz, the temperature was controlled at 5 ℃ to react, and TLC monitoring was performed until Fmoc-Tyr(tBu)-OMe reaction was completed; S2, 2N hydrochloric acid was added to adjust the pH value to about 2, centrifugation and drying obtained 145 kg of white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53), total yield: 28.6%, HPLC detection purity: 99.2%.

[0028] Comparative Example 3 This comparative example was prepared according to the method of patent document (CN112094204A): (1) Preparation of H-Tyr-OMe·HCl: S1, 400 kg of methanol was added to a 1000 L glass-lined reaction kettle, stirring was started at 50 Hz, 100 kg of L-Tyr was added, and 160 kg of thionyl chloride was added dropwise while controlling the temperature at 15 ℃; S2, after dropwise addition, the temperature was raised to 40 ℃ to react, TLC monitoring was performed until L-Tyr reaction was completed, and the solution was concentrated under reduced pressure to about 1 / 5 of the original volume, 360 kg of petroleum ether was added and stirred for 2 h, centrifugation and drying obtained 122 kg of white solid (H-Tyr-OMe·HCl, molecular weight 231.68), yield: 95.4%; (2) Preparation of Fmoc-Tyr-OMe: S1, 800 kg of acetone and 250 kg of water were added to a 2000 L glass-lined reaction kettle, stirring was started at 50 Hz, 122 kg of H-Tyr-OMe·HCl was added, the pH value was adjusted to about 8 by sodium carbonate, and 428 kg of Fmoc-OSu was added in batches; S2, after addition, control the temperature at 20 ℃ to react, monitor the reaction end point by TLC; after the reaction is completed, adjust the pH value to about 2 by 1N hydrochloric acid, centrifugation and drying obtained 204 kg of white solid (Fmoc-Tyr-OMe, molecular weight 417.45), yield 92.8%; (3) Preparation of Fmoc-Tyr(tBu)-OMe: S1. Add 2250 kg of tert-butyl acetate and 450 kg of tert-butyl alcohol to a 5000 L glass-lined reactor, turn on the stirring to 50 Hz, control the temperature at 5 ° C, and add 700 kg of perchloric acid dropwise; After the addition, the reaction was continued at 5°C and the reaction endpoint was monitored by TLC. After the reaction was completed, the pH value was adjusted to about 5 with a 10% by weight aqueous sodium bicarbonate solution. The mixture was centrifuged and dried to obtain 134 kg of a white solid with a yield of 58.0% (Fmoc-Tyr(tBu)-OMe, molecular weight 473.56). (4) Preparation of Fmoc-Tyr(tBu)-OH: S1. Add 1340 kg of ethyl acetate to a 3000 L glass-lined reactor, start stirring at 50 Hz, add 134 kg of Fmoc-Tyr(tBu)-OMe, raise the temperature to 70°C, and add 91 kg of anhydrous aluminum chloride; S2. After the addition, the temperature was controlled at 70°C for reaction. The reaction was monitored by TLC until the reaction of Fmoc-Tyr(tBu)-OMe was complete. The temperature was then lowered to below 30°C. The impurities were washed with 10% hydrochloric acid. The endpoint was monitored by TLC. S3. The organic phase was dried over anhydrous sodium sulfate, and the insoluble matter was filtered out. The product was concentrated to dryness under reduced pressure. 670 kg of petroleum ether was added, stirred and crystallized for 2 h. The product was centrifuged and dried to obtain 98 kg of a white solid (Fmoc-Tyr(tBu)-OH, molecular weight 459.53). The yield was 75.4%, the total yield was 34.6%, and the purity determined by HPLC was 99.6%.

[0029] It can be seen that the process route of the present invention not only saves working hours but also improves the yield compared with the current mainstream method of Fmoc-Tyr(tBu)-OH; at the same time, although the method in the literature has a shorter working time, the yield is lower and is not suitable for industrial production.

[0030] Comparative Example 4 Comparative Example 4 is the same as Example 1, except that all tert-butyl acetate is replaced by dichloromethane.

[0031] Test results: Without changing other process parameters, after repeated experiments, the total yield was significantly lower than that in Example 1, only 25-35%, and the yield was greatly reduced.

[0032] Comparative Example 5 Comparative Example 5 is the same as Example 1, except that tert-butyl acetate is replaced by tert-butyl acetoacetate, ethyl acetate and propyl propionate having similar structures, respectively.

[0033] Test results: Without changing other process parameters, tert-butyl acetate was replaced by solvents with similar chemical structures such as tert-butyl acetoacetate, ethyl acetate, and propyl propionate. TLC monitoring showed that more by-product impurities were generated. At the same time, there were impurity types with a small polarity difference from the target product, which required multiple purifications to remove. It can be seen that the total yield will be significantly lower than that of Example 1.

[0034] Comparative Example 6 Comparative Example 6 is the same as Example 1, except that all dichloromethane is replaced by tert-butyl acetate.

[0035] Test results: Without changing other process parameters, after repeated experiments, the total yield was significantly lower than that of Example 1, only 30-40%.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for industrial production of Fmoc-Tyr(tBu)-OH at low cost, characterized in that: The steps include: A. Dissolving H-Tyr-OMe·HCl in a mixed solvent system of tert-butyl acetate and halogenated hydrocarbon, reacting with isobutylene in the presence of an acidic catalyst, and obtaining H-Tyr(tBu)-OMe after treatment; B. H-Tyr(tBu)-OMe is hydrolyzed in an aqueous solution of an alkali metal hydroxide to give H-Tyr(tBu)-OH; C. H-Tyr(tBu)-OH reacts with Fmoc-OSu and is treated to obtain Fmoc-Tyr(tBu)-OH.

2. The method according to claim 1, wherein The mass ratio of H-Tyr-OMe·HCl to tert-butyl acetate is 1:2-5.

3. The method according to claim 2, wherein The halogenated hydrocarbon is selected from one or more of dichloromethane, chloroform and dichloroethane, and the mass ratio of the solvent system of H-Tyr-OMe·HCl, tert-butyl acetate and halogenated hydrocarbon is 1:5-10.

4. The method according to claim 3, wherein The molar ratio of H-Tyr-OMe·HCl to isobutylene is 1:3-6.

5. The method according to claim 4, wherein The acidic catalyst is perchloric acid, and the molar ratio of H-Tyr-OMe·HCl to perchloric acid is 1:1.1-1.

5.

6. The method according to claim 1, wherein In step A, the reaction temperature is controlled at 0-10°C.

7. The method according to claim 1, wherein In step A, after the reaction is completed, the organic phase is obtained by washing and separation, and the organic phase is treated with Fe 3+ After washing with aqueous solution and drying, H-Tyr(tBu)-OMe was obtained.

8. The method according to any one of claims 1 to 7, wherein: In step B, H-Tyr(tBu)-OMe is first dissolved in an organic solvent, and then an alkali metal hydroxide aqueous solution is added. The temperature is controlled at 10-15° C. After the reaction is complete, the pH value is adjusted to 5-6, and the mixture is centrifuged and dried to obtain H-Tyr(tBu)-OH.

9. The method according to claim 8, wherein In step C, H-Tyr(tBu)-OH is added to a mixture of water and an organic solvent to dissolve, potassium carbonate and / or potassium carbonate are added and stirred, and then Fmoc-OSu is added at a temperature of 15-25° C. to react and obtain Fmoc-Tyr(tBu)-OH.

10. The method according to claim 9, wherein In step C, after the reaction of H-Tyr(tBu)-OH and Fmoc-OSu is complete, the pH of the reaction system is adjusted to 2-3, the organic phase is taken, washed, and then concentrated under reduced pressure, slurried, centrifuged, and dried to obtain Fmoc-Tyr(tBu)-OH.

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