Process for the preparation of a class of catechol derivatives and their use and administration

Abstract

This invention relates to the field of biomaterial synthesis technology, specifically disclosing a method for preparing a class of catechol derivatives and their applications, administration, and preparation apparatus. The methods include: preparing dopa or carbidopa derivatives using a sodium sulfite-boric acid-argon protective system in an organic-aqueous mixture; or using dopa as a raw material, performing a methyl esterification reaction with SOCl2 and anhydrous methanol, followed by an exchange reaction with methyl trifluoroacetate to achieve a one-pot synthesis of Tfa-DOPA-OMe; or preparing acetal-protected tanshinone derivatives based on dopa derivatives or tanshinone and its derivatives; or using acetal-protected tanshinone and its esters to prepare natural catechol compounds such as Shimobashiric acid C, and preparing non-natural catechol compounds through coupling reactions with organic acids, amino acids and their derivatives, oligopeptides and polypeptides, alcohols, or sugars. Highly selective deprotection conditions achieve the goal of completely and thoroughly removing the acetal protection of catechols without destroying the ester bonds within the molecular structure.

Description

Technical Field

[0001] This invention relates to the field of biomaterial synthesis technology, specifically to a method for preparing a class of catechol derivatives and their applications, administration, and preparation apparatus. Background Technology

[0002] Catechols are organic compounds that exist as functional groups (catechin groups) in natural products and their derivatives, such as caffeic acid, dopamine, levodopa (L-DOPA), tanshinone (DSS), rosmarinic acid (RMA), salvianolic acid (including but not limited to A to H, J to Y), shikonin, thalidomide, yunnaneic acids, shimobashiric acids (B, C), and globoidnan A. They often possess certain biological activities, and some have even become drugs or health supplements. For example, levodopa is the most effective and important drug for treating Parkinson's disease; tanshinone is used to treat chest tightness and angina pectoris in patients with coronary heart disease; salvianolic acid is used to treat acute myocardial infarction, cerebral thrombosis, and other conditions; and rosmarinic acid is used as an antioxidant and anti-ultraviolet additive.

[0003] Both levodopa and tanshinone are catechol derivatives and belong to the phenylpropionic acid class (C6+C3) of natural products. CarbiDOPA, also known as methyldopahydrazine, is a synthetic levodopa derivative and a dopa decarboxylase DDC inhibitor (DDCI). They are structurally very similar, differing only in the substituents at the α-C position.

[0004] The catechin groups in catechin derivatives are easily oxidized into quinones. Quinones can undergo irreversible cross-linking reactions with themselves or other reagents, and may even produce substances with toxic side effects. This seriously affects the purity and activity of catechin derivatives. Therefore, exploring suitable catechin protecting groups or protective measures is the key to successfully preparing natural products or derivatives containing catechins.

[0005] Moreover, as early as 1974, patents such as US 3803120 and US4035507 proposed using dopa-containing oligopeptides as anti-Parkinson's disease prodrugs, and pointed out that these oligopeptides have good water solubility; however, the synthesis method of dopa-containing oligopeptides is relatively complicated, requiring multiple steps of reaction, and there are problems such as the reaction process being too complicated and the cost being high.

[0006] Meanwhile, in terms of drug delivery, current research suggests various delivery methods including oral administration, gastrostomy administration via DuoDOPA enteric gel, subcutaneous injection, continuous intravenous administration, continuous administration via dental braces, continuous transdermal administration, and pulmonary administration. However, oral administration experiences a period of dissipation over time, and gastrointestinal dysfunction and food effects can affect the absorption of levodopa. Furthermore, gastrostomy administration of DuoDOPA enteric gel requires Parkinson's patients to undergo a gastrostomy—implanting a tube into the duodenum—for drug delivery, and the suspension formulation is prone to complications during prolonged storage. The drug has several drawbacks: it causes precipitation and aggregation of DOPA; byproducts include ammonia and hydrazine, leading to drug deterioration; it has a short shelf life, requires storage and transportation at -20℃, is cumbersome to use, and is expensive to treat; furthermore, gastrostomy tube administration is prone to tube dislocation, displacement, blockage, tube kinking, connector damage and accidental removal, and also increases the risk of stoma and other infections; subcutaneous injection results in smaller doses, and drug absorption is greatly affected by skin site and thickness, as well as individual and gender differences; continuous intravenous administration requires patients to actively adhere to subcutaneous injections. This leads to poor patient compliance and carries a risk of infection during injection. In continuous oral administration via braces, the levodopa / carbidopa combination is packaged in a cartridge on one side of the brace and absorbed through saliva absorption and swallowing. Patients using this method experience significantly lower fluctuations in blood drug concentration compared to intermittent oral administration. However, the braces are bulky, causing severe foreign body sensation in the mouth with prolonged use, significantly impacting daily life. Furthermore, the combination formulation lacks necessary flavoring agents, resulting in a bland taste and low patient compliance. Transdermal continuous administration, via a micropump, provides continuous 24-hour subcutaneous stable administration. Oral administration can provide stable and effective levodopa levels, with lower variability than standard oral levodopa. However, it is minimally invasive but still causes wounds, and it is mainly targeted at people with advanced Parkinson's disease, with a small applicable population. In pulmonary administration, levodopa, as an inhaled drug, does not rely on gastrointestinal absorption and is rapidly absorbed into the bloodstream through the lungs. It is administered using a passive breathing-driven drug delivery system. However, due to the many factors affecting the deposition rate of drug particles in the lungs, the reproducibility is relatively poor. In addition, this method of administration is prone to causing various adverse reactions such as sneezing, coughing, and shortness of breath.

[0007] Tanshinone derives into numerous natural products, such as salvianolic acid, through the formation of ester bonds with its α-hydroxyl groups. Tanshinone and its derivatives have wide applications in the pharmaceutical industry. The Pharmacopoeia of the People's Republic of China (2020 edition) records 179 prescriptions containing tanshinone; in 2022, the in-hospital sales of drugs containing tanshinone exceeded 7.34 billion yuan. Currently, in the artificial synthesis of tanshinone derivatives (such as salvianolic acid AD), the use of strong catechol protection measures (such as methyl ethers) requires stringent reaction conditions to achieve effective deprotection after constructing the carbon skeleton. This leads to the breakage of numerous ester bonds within the tanshinone derivative, resulting in low yields of the target product, numerous impurities, difficulties in separation and purification, and poor economic efficiency. Summary of the Invention

[0008] To address the aforementioned problems, this invention aims to provide a method and apparatus for preparing a class of catechol derivatives, as well as applications and application apparatus for these catechol derivatives.

[0009] The first objective of this invention is to provide a method for preparing a class of catechol derivatives, comprising: using sodium sulfite-inert gas protection, with or without the addition of boric acid to effectively prevent the oxidation of catechols; preparing levodopa or carbidopa derivatives in an aqueous phase or an aqueous-organic phase mixture; achieving a one-pot synthesis of Tfa-DOPA-OMe by adjusting the protection sequence of the amino and carboxyl groups of L-DOPA; preparing acetal-protected tanshinone derivatives based on levodopa derivatives, tanshinone or their derivatives; preparing natural catechol compounds using acetal-protected tanshinone and its esters; and preparing non-natural catechol compounds through coupling reactions with organic acids, amino acids and their derivatives, oligopeptides and polypeptides, alcohols or sugars.

[0010] A second object of the present invention is to provide applications of the above-mentioned class of catechol derivatives, including solid or liquid formulations containing dopa prepared based on the catechol derivatives.

[0011] The third objective of this invention is to provide an oral continuous or intermittent drug delivery device that can be used to administer the above-mentioned liquid formulations. The device pumps an appropriate amount of drug from the cup into the metering pool at regular intervals using a micro-peristaltic pump. This drug delivery device has extremely high compliance and excellent drug control effect. It can control the blood drug concentration to be neither too high nor too low within a certain period of time with small fluctuations. It is suitable for patients in the middle and late stages of Parkinson's disease, with a wide coverage and extremely high feasibility and practicality.

[0012] A fourth object of the present invention is to provide a preparation apparatus for acetal / ketal protection of catechol groups.

[0013] The first technical solution adopted in this invention is: a method for preparing a class of catechol derivatives, wherein the method for preparing a class of catechol derivatives includes ① the preparation of levodopa or carbidopa derivatives, ② one-pot synthesis of Tfa-DOPA-Ome, ③ the preparation of tanshinone derivatives protected by acetal condensate, and ④ the preparation of natural catechol compounds and non-natural catechol compounds.

[0014] ① Preparation of levodopa or carbidopa derivatives;

[0015] L-DOPA or carbidopa derivatives were prepared in high yield and high purity in an organic-aqueous mixture using a sodium sulfite-boric acid-argon gas protection system. Furthermore, for L-DOPA or carbidopa derivatives protected by acid-labile protecting groups, deprotection can be performed using hydrochloric acid or trifluoroacetic acid (TFA) to obtain dipeptides of L-DOPA or carbidopa. For L-DOPA or carbidopa derivatives protected by acid-stable protecting groups, an acetone cyclization reaction can be performed to protect the phenolic hydroxyl groups of catechols.

[0016] The preparation method of levodopa or carbidopa derivatives includes the following steps:

[0017] S1: Add the reducing agent, boric acid compound and mixed solvent to the reaction apparatus, and bubble with inert gas for 10-30 minutes to remove oxygen from the reaction apparatus;

[0018] S2: Add compound I and the base to the reaction apparatus (add compound I and the base as solid powder or prepare a solution of compound I and the base with a mixed solvent and add dropwise), stir and continue to pass inert gas for 10-30 minutes;

[0019] S3: Add reactant II in batches as a solid powder or dropwise into the reaction apparatus as a solution, stir and continue to pass inert gas for 3-24 hours, and after acidification, obtain compound III; the reaction formula is as follows:

[0020]

[0021] The molar ratio of compound I to reactant II is from 1:1.3 to 1:0.3, preferably 1:0.8.

[0022] Step S3 further includes: after the reaction is complete (i.e., after stirring and continuing to pass inert gas for 3-24 hours), washing multiple times with an organic solvent (e.g., ethyl acetate) at pH 6.5-11; then, extraction with an organic extractant (e.g., ethyl acetate) under relatively strong acid conditions at pH 1-5, and taking the organic phase; then washing the organic phase with acid, brine, and pure water respectively; then taking the organic layer, drying with anhydrous magnesium sulfate, filtering, and removing the solvent by rotary evaporation to obtain the crude product; and then recrystallizing to obtain high-purity compound III. The organic solvent and organic extractant include, but are not limited to, ethyl acetate (EA), tetrahydrofuran (THF), dichloromethane (DCM), toluene (TLN), petroleum ether (PE), n-hexane (HXN), methyl tert-butyl ether, etc.; preferably EA.

[0023] The mixed solvent includes, but is not limited to, combinations of two or more of the following: water, tetrahydrofuran (THF), acetone, dioxane (DIOX), and dimethylformamide (DMF), with a preference for a mixed solvent formed from THF and water. The reducing agent includes, but is not limited to, sodium thiosulfate, sodium sulfite, sodium metabisulfite, vitamin C, and isoascorbic acid, with a preference for sodium sulfite and sodium thiosulfate. Boric acid compounds include, but are not limited to, sodium borate, potassium borate, boric acid, and phenylboronic acid; sodium borate is preferred. If boric acid causes undesirable side reactions, it may be omitted, and a reducing agent may be used in combination with an inert gas, or only a reducing agent may be added. The inert gas includes, but is not limited to, argon (Ar) and nitrogen (N2), with Ar being preferred.

[0024] The base includes, but is not limited to, triethylamine (Et3N), sodium carbonate, sodium bicarbonate, potassium carbonate, sodium phosphate, sodium hydroxide, etc.; sodium carbonate is preferred. Compound I includes, but is not limited to, L-DOPA, methyldopa, carbidopa, dopamine, etc. In compound I, R1 includes, but is not limited to, substituents such as H, Me (methyl), COOH (carboxyl), CH2COOH, etc.; R2 includes, but is not limited to, substituents such as H, Me, Et, F, Cl, Br, OH, etc.; R3 includes, but is not limited to, substituents such as NH2, NHNH2, etc.

[0025] Reagent II (R4-X) is an acyl halide, acid anhydride, N-hydroxysuccinimide-type activated ester (-OSu), 1-hydroxybenzotriazole (HOBt)-type activated ester, pentafluorophenol-type activated ester (PFP), or other reactive compounds that can react with an amino group; wherein, R4 is an amino protecting group, an amino acid and its derivatives, or an organic acyl group; the amino protecting group includes, but is not limited to, fluorenemethoxycarbonyl (Fmoe-), benzyloxycarbonyl (Cbz-), tert-butoxycarbonyl (Boc-), phthaloyl (Phth-), etc., and the amino acid and its derivatives include, but are not limited to, Fm The amino acyl or oligopeptidyl group (i.e., N-modified amino protecting group) includes oc-AA (amino acid)-, Boc-AA-, Cbz-AA-, Phth-AA-, Boc-AA-AA-, etc. Organic acyl groups include, but are not limited to, acetyl, propionyl, butyryl, valeryl, fatty acyl (C6-C30), etc., or combinations of two or more of the above amino protecting groups, amino acids and their derivatives, organic acyl groups, or fatty acids, including but not limited to fatty acylamino acyl groups, such as dipeptidyl acyl, etc.; X is the activated form, including but not limited to acyl halides, acid anhydrides, activated esters, or other activated forms. As a partial example of R4-X, reactant II is fluorenemethyloxycarbonyl chloride (Fmoc-Cl), phthaloyl chloride, fluorenemethyloxycarbonyl succinimide (Fmoc-OSu), (Boc)20, Fmoc-AA-OSu, Fmoc-AA-OBt, Boc-AA-OSu, Boc-AA-PFP, Boc-AA-AA-OSu, C 11 H 23 CO-Asp(OtBu)-OSu, N-ethoxycarbonyl phthalimide (Phth-CE), OSu or OBt esters of hyaluronic acid, activated esters of carboxymethyl cellulose, etc.

[0026] Acidification is achieved by adding one or more of hydrochloric acid, citric acid, phosphoric acid, sulfuric acid, or trifluoroacetic acid.

[0027] R5 in compound III is a group formed by the condensation reaction of reactant II (R4-X) and R3. As an example of R1 / R2 / R3 / R4, compound III includes, but is not limited to, Fmoc-DOPA-OH, Cbz-DOPA-OH, Fmoc-Val-DOPA-OH, Boc-Met-DOPA-OH, Cbz-Aps(Bzl)-DOPA-OH, Boc-Ser(tBu)-DOPA-OH, C12H25CO-Asp(OtBu)-DOPA-OH, Fmoc-CarbiDOPA-OH, and Boc-Met-CarbiDOPA-OH.

[0028] This invention employs three measures to prevent the oxidative cross-linking of catechol groups under alkaline conditions: a. The reducing agent reacts with residual oxygen, thereby consuming dissolved oxygen and preventing the oxidation of catechol groups by oxygen; b. An inert gas is used to maintain the reaction system under anaerobic conditions; c. The catechol groups form oxidation-resistant complexes in situ with boric acid. Furthermore, this invention avoids the large-scale occurrence of Lossen rearrangement byproducts or oligopeptide byproducts by controlling the molar ratio of compound I to reactant II.

[0029] Meanwhile, this invention utilizes the fact that compound III dissolves in a mixed solvent as a salt under high pH conditions (6.5-11), facilitating the removal of low-polarity impurities using an organic extractant, and compound III is only slightly or not washed away at all. Adjusting the pH of the mixed solution to 1-5 allows compound III to exist as a neutral molecule, which is then extracted into the organic phase by the organic extractant, while unreacted compound I is protonated and does not enter the organic phase. Finally, the organic phase is washed sequentially with acid solution, salt water, and pure water to further remove highly polar impurities, thereby obtaining compound III (i.e., a catechol derivative) with very high purity. Recrystallization in a suitable solvent can further improve the purity of compound III, meeting pharmaceutical purity requirements.

[0030] Preferably, for levodopa or carbidopa derivatives protected by acid-labile protecting groups (e.g., Boc), deprotection can be performed using hydrochloric acid or TFA to obtain levodopa or carbidopa dipeptides. Specifically, when compound III is a Boc-modified catechol derivative (e.g., Boc-AA-DOPA-OH and Boc-AA-CarbiDOPA-OH), the Boc- in the catechol derivative is further converted to H- (i.e., the amino protecting group is removed, and the catechol derivative is deprotected to obtain an amino acid-modified catechol derivative). For example, Boc-AA-DOPA-OH and Boc-AA-CarbiDOPA-OH are converted to H-AA-DOPA-OH and H-AA-CarbiDOPA-OH.

[0031] Preferably, for levodopa or carbidopa derivatives protected by acid-stable protecting groups (e.g., Fmoc-, Phth-, 2-C1-Cbz-), a further acetal / ketal cyclization reaction can be performed to protect the phenolic hydroxyl groups of the catechols, forming useful reagents (e.g., Fmoc-DOPA(Acetonide)-OH, Phth-DOPA(Acetonide)-OH, 2-C1-Cbz-DOPA(Acetonide)-OH), i.e., further acetal / ketal protection of the catechol groups in the levodopa or carbidopa derivatives; alternatively, the levodopa or carbidopa derivatives can be deprotected (i.e., the amino protecting group is removed) to obtain amino acid-modified catechol derivatives / dipeptides; wherein, acetal / ketal protection of the catechol groups in the catechol derivatives includes the following steps:

[0032] S10: In a reaction apparatus (e.g., a three-necked flask), add a certain amount of compound IV (compound IV includes N-modified (e.g., N-Fmoc, N-Phth, N-Tfa, fatty acids, lipopeptides, etc.) catechol derivatives of compound III, but excludes Boc-modified catechol derivatives) and a cosolvent, and heat to form a solution.

[0033] S20: Add a certain amount of carrier to the reaction device and pass in an inert gas, heat to 70-120℃, reflux for about 20 minutes, and use the absorbent in the absorption device to absorb water and by-products.

[0034] S30: Add reactant V (the molar ratio of compound IV to reactant V is controlled between 1:1 and 1:10, preferably 1:2) and catalyst, and continue reflux for about 2-5 hours until most of compound IV is consumed; add a small amount of reactant V again (0.5-3 molar equivalents of reactant V, preferably 1 molar equivalent), distill off some volatile substances (about 20 minutes), and stop the reaction to obtain compound VI; the reaction formula is as follows:

[0035]

[0036] Step S30 further includes: after stopping the reaction, when the temperature drops to near room temperature, slowly add an appropriate amount of pyridine (2 equivalents) using a syringe, remove volatiles by rotary evaporation, extract the residue with EA, wash with 0.01N 0.5mol / L citric acid solution, and wash with pure water; take the organic phase, add magnesium sulfate to dry, filter, and rotary evaporate to dryness; recrystallize the obtained crude product in TLN / n-hexane (HXN) to obtain high-purity compound VI.

[0037] Wherein, compound IV includes, but is not limited to, compound III; R1 includes, but is not limited to, substituents such as Me, COOH, and CH2COOH; R2 includes, but is not limited to, substituents such as H, Me, Et, F, Cl, Br, and OH; R5 is a combination of amino or hydrazine groups and their corresponding protecting groups, including, but not limited to, -NHFmoc, -NHNHFmoc, -NHCbz, -NPhth, -NHTfa, -NTFa-NHTfa, C 15 H 31 CO-NH-, C 12 H 25 CO-NH-, C 12 H 25 CO-Val-NH-, Fmoc-Val-NH-, etc.

[0038] The co-solvent is a solvent with high solubility for compound IV, including but not limited to THF, acetone, methyl ethyl ketone, diethyl ether, etc., with acetone being preferred. The carrier is including but not limited to benzene, TLN, xylene, etc., with benzene being preferred; the carrier is used to remove water and byproducts from the reaction system by azeotropic distillation. The inert gas includes but is not limited to Ar, N2, with Ar being preferred.

[0039] The absorption device includes, but is not limited to, a Soxhlet extractor, a constant-pressure dropping funnel, and the improved constant-pressure dropping funnel disclosed in this invention. The absorbent includes, but is not limited to, calcium chloride, calcium oxide, magnesium sulfate, sodium sulfate, phosphorus pentoxide, molecular sieves, etc., with calcium chloride being preferred.

[0040] The catalyst is an acid, including but not limited to p-toluenesulfonic acid (TsOH), camphorsulfonic acid, trifluoromethanesulfonic acid, TFA, HCl, lactic acid, hydrogen ion exchange resin, etc.; the appropriate concentration and equivalent amount of catalyst are selected according to the different reactivity of catechol and the accompanying side reactions; preferably 2.5% equivalent of TsOH.

[0041] The reactant V includes, but is not limited to, aldehydes, ketones, and hemiacetals and hemiketals of aldehydes and ketones; aldehydes include, for example, formaldehyde, acetaldehyde, benzaldehyde, etc.; ketones include, for example, acetone, butanone, cyclopentanone, cyclohexanone, benzophenone, ethylene glycol; hemiacetals and hemiketals of aldehydes and ketones include, for example, 2,2-dimethoxypropane (DMP) and 2,2-dimethoxy-2-phenylacetophenone; preferably, DMP, cyclohexanone, and benzophenone.

[0042] In compound VI, R6 is a structure formed by reacting reactant V with a catechol group through acetal or ketal formation, including but not limited to formaldehyde, acetal, benzaldehyde, acetone, cyclopentanone, cyclohexanone, benzophenone, methoxymethylene (MOM), ethoxymethylene (EOM), etc., preferably acetone. Compound VI includes, but is not limited to, Fmoc-DOPA(Acetonide)-OH, Fmoc-DOPA(Cyclohexanonide)-OH, Fmoc-DOPA(benzophenone)-OH, Phth-DOPA(Acetonide)-OH, Cbz-DOPA(Acetonide)-OH, Tfa-DOPA(Acetonide)-OH, Fmoc-Val-DOPA(Acetonide)-OH, Fmoc-(2-Cl-Cbz)CarbiDOPA(Acetonide)-OH, C 12 H 25 CO-Val-DOPA(Acetonide)-OH, etc.

[0043] This invention employs a batch-addition method for reactant V, which avoids both the generation of excessive byproducts due to excess reactant V and the low conversion rate of compound IV due to insufficient reactant V. The first addition of reactant V involves controlling the molar ratio of compound IV to reactant V within the range of 1:1 to 1:10, preferably 1:2. The second addition of reactant V involves adding 0.5-3 molar equivalents of reactant V, preferably 1 molar equivalent, just before the reaction is nearing completion.

[0044] This invention employs a more efficient byproduct removal device (the absorption device of this invention), which improves conversion efficiency, increases product purity, and reduces the difficulty of product separation and purification. Furthermore, this invention successfully scales up the ketal reaction multiple times using absorption device A, enabling mass production. Moreover, this invention uses a TLN / HXN solvent system for recrystallization, which better separates the target product from its methyl ester, reduces impurity content, and improves the purity of target product VI.

[0045] Preferably, it further includes converting the dopamine methyl ester byproduct into the target carboxylic acid;

[0046] When protecting the catechol groups in catechol derivatives with acetals / ketones, dopa methyl ester-containing byproducts are generated. This invention provides a method for converting dopa methyl ester-containing byproducts into target carboxylic acids, and a method for preparing acetal / ketone-protected carboxylic acid substances for dopa analogs. This method can selectively decompose methyl ester compound VII and convert it into compound VIII (including but not limited to compound VI).

[0047] The conversion of dopamine methyl ester-containing byproducts into target carboxylic acids includes:

[0048] 1) In the reaction apparatus, a certain amount of methyl ester compound VII and organic solvent are added to obtain a solution of methyl ester compound VII;

[0049] 2) Dissolve a certain amount of lithium salt (LiX) in a small amount of water to obtain a lithium salt solution. Add the lithium salt solution to the above methyl ester compound VII solution. Adjust the pH of the reaction system to 7-8 with hydrochloric acid, then add a certain amount of alkali and stir for 3-24 hours.

[0050] 3) The organic phase was concentrated by rotary evaporation, water was added, and the pH was adjusted to 3-5 with HCl solution. Extraction was performed using EA, and the organic phase was washed with acidic water and pure water, respectively. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the volatiles were removed by rotary evaporation. Recrystallization in TLN / HXN yielded high-purity compound VIII. The reaction formula is as follows:

[0051]

[0052] The lithium salt includes, but is not limited to, lithium halides, lithium trifluoromethanesulfonate, lithium perchlorate, etc.; lithium bromide is preferred. The organic solvent includes, but is not limited to, THF, acetonitrile, acetone, etc.; acetonitrile is preferred. The base is a common organic base, including but not limited to, Et3N, diisopropylethylamine (DIEA), etc.; DIEA is preferred.

[0053] The definitions of R2, R5, and R6 shown in compounds VII and VIII are the same as those shown in compound VI; compound VII includes, but is not limited to, Fmoc-DOPA(Acetonide)-OMe, Phth-DOPA(Acetonide)-OMe, Cbz-DOPA(Acetonide)-OMe, Tfa-DOPA(Acetonide)-OMe, etc. Compound VIII includes, but is not limited to, Fmoc-DOPA(Acetonide)-OH, Phth-DOPA(Acetonide)-OH, Cbz-DOPA(Acetonide)-OH, Tfa-DOPA(Acetonide)-OH, etc.

[0054] ② One-pot synthesis of Tfa-DOPA-OMe;

[0055] A one-pot synthesis of Tfa-DOPA-OMe using levodopa as a starting material employs SOCl2 / MeOH methylation instead of the CH3I / KHCO3 / DMF esterification reaction of existing synthetic routes. Following this, an ester-amide exchange reaction with methyl trifluoroacetate is used to achieve a one-pot synthesis, which is simple and efficient in protecting the carboxyl and amino groups. Specific steps include:

[0056] L-DOPA and anhydrous methanol (MeOH) were added to the reaction apparatus, argon gas was introduced, and SOCl2 was slowly added dropwise under ice bath conditions. After removing the ice bath, stirring was continued overnight. The mixture was heated and stirred, argon gas was turned on for bubbling, the temperature was lowered, and triethylamine and methyl trifluoroacetate were slowly added and stirred until the reaction was complete. After rotary evaporation and concentration, the pH of the solution was adjusted to 3-4, and the solution was extracted. The obtained organic phase was washed with water, dried over anhydrous magnesium sulfate, rotary evaporated, and dried under vacuum to obtain Tfa-DOPA-OMe.

[0057] The reaction mechanism for the one-pot synthesis of Tfa-DOPA-OMe is as follows: First, levodopa is converted into methyl ester hydrochloride under the action of SOCl2 / MeOH. Although methanol is a poor solvent for levodopa, it is a good solvent for the intermediate methyl ester hydrochloride, thus promoting the completeness of this step. After methyl esterification, reflux heating in an oil bath with argon bubbling can remove excess SOCl2 from the reaction system. There are several schemes for the trifluoroacetylation of amino groups. The ester-amide exchange reaction is more effective than direct acylation with trifluoroacetic anhydride, as the former has milder reaction conditions and almost no racemization. In addition, since methyl trifluoroacetate (Tfa-OMe) is slightly more reactive than ethyl trifluoroacetate, it is more suitable. Among these, the amount of triethylamine is crucial. Too little will result in a slow reaction, while too much will lead to waste and decomposition of methyl ester. After screening, a molar ratio of triethylamine to L-DOPA of 4 is found to be optimal.

[0058] Furthermore, based on Tfa-DOPA-OMe, acetal-protected L-DOPA intermediates (Tfa-DOPA(Acetonide)-OMe) can be successfully prepared; and by completely removing the amino and carboxyl protection and then coupling with an N-protecting group or selectively removing only the methyl ester, other acetal-protected L-DOPA reagents can be obtained, such as Boc-DOPA(Acetonide)-OH, Fmoc-DOPA(Acetonide)-OH, Phth-DOPA(Acetonide)-OH, Tfa-DOPA(Acetonide)-OH, etc.

[0059] While this invention advocates the advantage of carrying out two-step reactions in one reactor, it also advocates that, with this improvement, the one-pot method be changed to carrying out the two-step reactions advocated by this invention in two containers.

[0060] ③ Preparation of acetone-protected tanshinone derivatives;

[0061] Tanshinone derivatives protected by DOPA derivatives are prepared, specifically including:

[0062] Acetal-protected L-DOPA derivatives were deaminated and then reacted with nitrous acid in water or a mixture of water and an organic solvent under acid catalysis. Following hydrolysis, acetal-protected L-tanshinone derivatives were generated. Correspondingly, acetal-protected D-tanshinone derivatives were prepared using dextro-DOPA derivatives.

[0063] The preparation of acetone-protected tanshinone derivatives based on tanshinone or its derivatives specifically includes:

[0064] First, the carboxyl group of tanshinone is protected into an ester or amide to improve its solubility in organic solvents, and the alcohol hydroxyl group of tanshinone is protected into an ester or ether, preferably an ester, to avoid the Oxa-Pictet-Spengler side reaction, thus obtaining a tanshinone intermediate; for example, methyl rosmarinic acid ester, in which the α-hydroxyl group of the tanshinone structure is protected into an ester by caffeic acid, and its carboxyl group is protected into a methyl ester; then, the tanshinone intermediate is reacted with an acetal cyclizing agent to achieve acetal protection of the catechol group of tanshinone; finally, through selective hydrolysis, alcoholysis or aminolysis, the acetal-protected tanshinone derivative is obtained.

[0065] ④ Preparation of natural and non-natural catechin compounds;

[0066] Using acetal-protected tanshinone and its esters as raw materials, natural catechins such as rosmarinic acid, lithospermic acid, salvianolic acid, salicylic acid, Yunnaeic acids, SBA-C, and globoidnanA are prepared through esterification (including esterification reactions involving Mitsunobu configuration inversion), amide formation, or etherification reactions. This process is also used to prepare non-natural catechins formed with organic acids, amino acids and their derivatives, oligopeptides and polypeptides, alcohols, and sugars.

[0067] In the reaction of tanshinone protected with acetal ether to form ester, amide, or ether bonds, if the reactant contains a catechol group, that catechol group should also be protected with acetal ether. If there is no catechol group but an isolated phenolic hydroxyl group is present, that phenolic hydroxyl group should be appropriately protected, preferably with protecting groups in acid-labile orthogonal systems, including but not limited to MOM, EOM, Boc, and tBu. This ensures that other protecting groups that need to be removed are also removed during the removal of acetal ether protection, reducing the difficulty of synthesis.

[0068] Finally, using moderate concentrations of TFA, HCl, HBr, or TsOH as catalysts, the acetal protection is removed under relatively mild conditions to obtain the target catechol compound. These deprotection conditions do not destroy the desired but unstable ester bonds, glycosidic bonds, amide bonds, hydrazide bonds, ether bonds, or disulfide bonds in the intermediate and target product structures. A 60% TFA and DCM mixture is preferred, with the addition of 10 equivalents of water and 10 equivalents of triisopropylsilane (TIS). The target product yield is close to 100%, and the ester bonds formed by the α-hydroxyl groups of the methyl ester and tanshinone are not destroyed. For example, this method can be used for the synthesis of the natural product SBA-C.

[0069] The second technical solution adopted in this invention is: the application of a class of catechol derivatives, including the preparation of solid and liquid formulations containing dopa oligopeptides based on the catechol derivatives.

[0070] (1) Solid formulation containing dopa oligopeptide (DOSF);

[0071] Solid dosage forms containing dopa oligopeptides include catechol derivatives API-1, which are L-DOPA derivatives. API-1 includes, but is not limited to, one or more of L-DOPA, dopa esters, fatty acyl dopa, L-DOPA-containing oligopeptides (preferably dipeptides or tripeptides), and L-DOPA-containing liposomes (preferably liposomes).

[0072] Solid dosage forms containing dopa oligopeptides also include other active ingredients and / or excipients (FE); other active ingredients include API-2 and / or API-3, wherein API-2 is classified as DDCI (dopa decarboxylase inhibitor), and API-2 includes one or more of the following: benserazide hydrochloride, CarbiDOPA, CarbiDOPA-containing oligopeptides (preferably dipeptides or tripeptides), and CarbiDOPA-containing ester oligopeptides (preferably lipodipeptides); API-3 is classified as other active pharmaceutical ingredients, and API-3 includes other anti-Parkinson's disease drugs, such as COMT inhibitors, MAO-B inhibitors, etc.

[0073] Excipients (FE) include ion modifiers (FE-1), pH adjusters (FE-2), thickeners / physical gelling agents (FE-3), antioxidants (FE-4), flavoring agents (FE-5), preservatives and antibiotics (FE-6), etc.; ion modifiers include, for example, NaCl; pH adjusters include, for example, citrate salt, phosphate salt, acetate salt, phthalate salt, etc.; thickeners / physical gelling agents include, for example, carboxymethyl cellulose salt, hyaluronic acid salt, polyacrylic acid salt, etc.; antioxidants include, for example, isoascorbic acid, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium thiosulfate, vitamin C, vitamin E, etc.; flavoring agents include, for example, aspartame, sucrose, steviol glycosides, agar, sodium bicarbonate, pineapple flavor, etc.; preservatives and antibiotics include, for example, benzoic acid, methyl / ethyl p-hydroxybenzoate, chlorhexidine acetate, etc.

[0074] Because the aforementioned dopa oligopeptide solid dosage forms do not contain water, the degradation rate, resulting in the production of ammonia and hydrazine, is very slow during production, packaging, transportation, and storage. The oxidation rate of the catechol groups is also very slow, thus meeting the requirements for a longer shelf life of the drug. When used by patients as a replacement for liquid dosage forms such as Duopa, Sirio, and ABBV-951, pre-prepared solvent (PPM) can be added, and the mixture can be shaken for 5-30 minutes to form a clear, homogeneous, and transparent liquid for use.

[0075] The solvent (PPM) is, for example, a pharmaceutical solvent or a pre-prepared solution; the pharmaceutical solvent (PPM-1) is, for example, water for injection, physiological saline for injection, or glucose solution for injection; the pre-prepared solution is, for example, PPM-2, PPM-3, or PPM-4. PPM-2 includes, for example, water, 0.1-10% (by weight) carboxymethyl cellulose salt, preservatives, and antibiotics, or includes water, 0.1-10% (by weight) carboxymethyl cellulose salt, alkali, preservatives, and antibiotics, or an aqueous solution of 0.1-10% (by weight) carboxymethyl cellulose salt; PPM-3 includes, for example, water, 0.1-10% (by weight) hyaluronic acid salt, alkali, preservatives, and antibiotics, or includes an aqueous solution of 0.1-10% hyaluronic acid salt; PPM-4 includes, for example, water, 0.1-10% (by weight) polyacrylate, alkali, preservatives, and antibiotics.

[0076] (2) Liquid formulations containing dopamine oligopeptides;

[0077] Liquid preparations containing dopa oligopeptides include dipeptides containing dopa and carbidopa dipeptides, as well as flavoring agents, thus forming oral liquid preparations with a pleasant taste (high patient compliance); the drug exists in solution form and is not easily deteriorated or ineffective in a short period of time.

[0078] Flavoring agents include sweeteners and / or flavorings.

[0079] Sweeteners are divided into two main categories: natural sweeteners and synthetic sweeteners. Natural sweeteners include sucrose, simple syrups, steviol glycosides, etc.; synthetic sweeteners include sodium saccharin, cyclamate, aspartame, etc. Other flavoring agents (also known as flavoring agents) that do not affect the efficacy of the medicine can also be added to formulate oral liquids with different special flavors, such as orange flavor, apple flavor, etc. Effervescent agents and gelling agents that interfere with taste can also be added.

[0080] The third technical solution adopted in this invention is: providing an oral continuous or intermittent drug delivery device, including a cup body and a cup lid, which are detachably connected; the cup body is a container for holding liquid preparations; the cup lid is provided with a switch button, a battery slot, a micro-peristaltic pump, a delivery tube, a metering chamber, and an output tube; the switch button is used to turn the micro-peristaltic pump on or off; the battery slot is used to install a battery to power the micro-peristaltic pump; the micro-peristaltic pump is used to pump the liquid medicine in the cup body into the metering chamber in a timely and measured manner through the delivery tube; the delivery tube is installed on the micro-peristaltic pump, with one end of the delivery tube located at the bottom of the cup body and the other end located at the bottom of the metering chamber; the output tube passes through the cup lid and extends into the metering chamber for the patient to obtain the liquid medicine.

[0081] The fourth technical solution adopted in this invention is: a preparation apparatus for acetal and ketone protection of catechol groups, comprising a reactor, a condenser, an absorption tower, a gas pipeline and a liquid pipeline; the reactor and the condenser are connected through the gas pipeline, the reactor and the absorption tower are connected through the liquid pipeline, the absorption tower and the condenser are connected through the liquid pipeline, and a valve is provided on the liquid pipeline.

[0082] The reactor includes, but is not limited to, flasks and reaction vessels; the gas pipeline includes, but is not limited to, glass tubes, plastic tubes, ceramic tubes, metal tubes, etc., preferably glass tubes with vacuum sleeves; the condensation equipment includes, but is not limited to, glass or metal condenser tubes, cold traps, etc., preferably glass condenser tubes; the absorption tower includes, but is not limited to, glass tubes, ceramic tubes, metal tubes, etc., preferably stainless steel tubes; the absorbent includes, but is not limited to, one or more of calcium chloride, molecular sieves, calcium oxide, caustic soda, magnesium sulfate, sodium sulfate, etc., in any combination of any two proportions, preferably calcium chloride; the liquid pipeline includes, but is not limited to, metal tubes, plastic tubes, rubber tubes, glass tubes, etc., preferably polytetrafluoroethylene plastic tubes.

[0083] Preferably, in industrial production equipment, the condensing equipment and the absorption tower are connected in a parallel manner, while in small-scale laboratory production equipment, the condensing equipment and the absorption tower are connected vertically from top to bottom.

[0084] Preferably, the present invention also discloses an improved constant-pressure dripping funnel, wherein the reactor is connected to the lower interface of the improved constant-pressure dripping funnel via a liquid pipeline, and the condensing device is vertically connected to the upper interface of the improved constant-pressure dripping funnel via a liquid pipeline.

[0085] The improved constant-pressure dropping funnel includes a dropping funnel body, a constant-pressure tube, a vacuum sleeve, and a condensing sleeve. A regulating valve is located in the middle of the dropping funnel body, dividing it into an upper and lower section. The constant-pressure tube connects the upper and lower sections of the dropping funnel. The upper section of the dropping funnel has an upper interface, and the lower section has a lower interface. A dropping nozzle is located within the lower interface and communicates with the upper section of the dropping funnel. A sand core plate is located at the lower end of the upper section of the dropping funnel body. The vacuum sleeve surrounds the constant-pressure tube, and the condensing sleeve is fitted over the upper section of the dropping funnel.

[0086] The improved Soxhlet extractor's intermediate tube includes the main body, a constant pressure tube (with or without a vacuum sleeve), a siphon tube, and a finger-shaped condenser inlet or an external condenser sleeve. The siphon tube replaces the regulating valve of the dropping funnel for ease of use.

[0087] The beneficial effects of the above technical solution are as follows:

[0088] (1) In the preparation method of a class of catechol derivatives disclosed in this invention, the preparation of levodopa or carbidopa derivatives utilizes a combination of inert gas / reducing agent / borate for protection, which effectively avoids the oxidation of catechol derivatives. This method is a two-step synthesis and has the advantages of simple operation, high product yield and purity.

[0089] (2) Compared with the existing technology (CN110294789A) which uses propionate protection, the synthesis scheme requires multiple steps, is too complicated and has high cost; the present invention optimizes the synthesis method of AA-L-DOPA type dipeptide, adopts inert gas / reducing agent / borate combined protection, and develops a two-step synthesis method that is simple, has high yield and high purity.

[0090] (3) This invention extends to the synthesis of other N-modified L-DOPA complexes (catechol derivatives), including various amino protecting groups such as N-Fmoc, N-Phth, N-Tfa, fatty acids, lipopeptides, etc.; it mainly solves the following problems: 1) It solves the problem of low product purity, and the need for high-purity products to be obtained by liquid chromatography, which requires the use of inert gas / reducing agent / borate combined protection; 2) It reduces the ratio of N-modified groups to L-DOPA, avoiding the Lossen rearrangement caused by -OSu activated esters and the generation of dipeptide / tripeptide impurities caused by acyl chlorides.

[0091] (4) In this invention, the DMP (reactant V)-TsOH (catalyst) system is used to protect the catechol groups with acetal condensation; at the same time, the reactant V is added in batches, which avoids the generation of more by-products when reactant V is in excess, and also avoids the problem of low conversion rate of compound IV when reactant V is insufficient. First addition of reactant V: the molar ratio of compound IV to reactant V is controlled between 1:1 and 1:10, preferably 1:2; Second addition of reactant V: 0.5-3 molar equivalents of reactant V are added before the reaction is almost over, preferably 1 molar equivalent.

[0092] (5) This invention provides a simpler and more efficient method for preparing dopa oligopeptides (catechol derivatives). The prepared L-DOPA derivatives have high purity and are suitable as prodrugs for formulation or scientific research. This invention provides a more efficient and economical preparation method for preparing dopa oligopeptide prodrugs, a synthetic method for preparing carbidopa oligopeptide prodrugs with good water solubility, and intermediates used in the preparation of dopa oligopeptides, especially acetone-protected intermediates.

[0093] (6) Compared with the prior art, the one-pot synthesis of Tfa-DOPA-OMe disclosed in this invention greatly simplifies the reaction process by adjusting the protection order of the amino and carboxyl groups of L-DOPA, performing carboxyl protection first and then amino protection. It avoids the use of high-boiling-point DMF as a solvent and does not use expensive and environmentally harmful iodomethane reagent. That is, this invention does not use non-volatile DMF and does not use expensive reagent CH3I, which is environmentally friendly. The two reaction steps are combined into a one-pot reaction, which has the advantages of being simple, efficient, saving reagents and low cost.

[0094] (7) This invention prepares a solid dosage form containing dopa oligopeptide based on catechol derivatives, which can be used as a replacement for liquid dosage forms such as Duopa, Sirio, and ABBV-951. When used as a substitute for Duopa, it mainly addresses the following issues: 1) Aqueous liquid suspensions are unstable and easily decompose to produce harmful components such as ammonia and hydrazine. Compared to Duopa, this invention prepares a solid dosage form, which is injected with water using a syringe or similar method to mix and form a solution, thus meeting the requirement for a longer shelf life. 2) The active ingredients of Duopa, L-DOPA and carbidopa, are... The solubility of levodopa in aqueous phase pH range (5.8-6.8) is low, at 5 g / L and 5 mg / L respectively. In this invention, levodopa is prepared into oligopeptides, dipeptides, or tripeptides, which improves the solubility (by about 10 times, which meets the requirements). Carbidopa is also converted into a prodrug, which further improves the solubility (also meeting the usage requirements). However, this invention still uses soluble benserazide hydrochloride as a substitute for carbidopa. 3) The synthesis method for preparing dipeptides or tripeptides of N-terminal levodopa has been optimized, which greatly reduces the synthesis cost of this type of prodrug, making the cost affordable for patients.

[0095] As an alternative to Sirio, Madopar, and Sinemet from Italian pharmaceutical company Cassie, levodopa has poor water solubility, leading to drug accumulation and purging of the levodopa powder contained in Madopar and Sinemet. Sirio, developed by Cassie, uses methyl dopa (a levodopa prodrug) instead of levodopa, avoiding the aforementioned problems. However, methyl dopa is an organic amine and does not have an isoelectric point, so it can only exist in the form of hydrochloride, which is highly hygroscopic and difficult to handle. Therefore, this invention synthesizes a dipeptide / tripeptide prodrug of levodopa, structurally similar to an amino acid, with an isoelectric point, thus forming a neutral internal salt and greatly reducing absorption.

[0096] As an alternative to ABBV-951 formulation, ABBV-951 uses FoslevoDopa and Foscarbidopa as prodrugs, which are complex to prepare and very expensive. Compared to ABBV-951 formulation, this invention uses dopa oligopeptide prodrugs and carbidopa dipeptide prodrugs as substitutes to reduce costs.

[0097] (8) The “milk tea cup” type drug delivery device of the present invention can pump an appropriate amount of medicine from the cup into the quantitative pool on time, so that the patient can drink it once every 5 to 10 minutes, so that the amount of medicine the patient drinks each time is adapted to the interval time; the medicine is convenient to drink, tastes good, is non-invasive and painless, and can basically stabilize the blood drug concentration of Parkinson's patients without surgery, braces, or skin perforation. Patient compliance is very high and a good therapeutic effect can be achieved.

[0098] (9) The high temperature of the reflux liquid in the inner cylinder of the Soxhlet extractor is not conducive to methanol absorption, and the small inner cylinder results in insufficient absorbent dosage, leading to large fluctuations in yield and difficulty in scaling up the reaction. To address the above technical problems, this invention designed experimental apparatus A, which is applied to mass production. Experimental apparatus A-1 (including its absorbent holding part A-1-1) was designed to ensure that the absorbent absorbs methanol in a low-temperature environment and introduces gradient absorption, which has a good effect, slightly increases the yield, and the yield is stable and highly reproducible. That is, when protecting the catechol group with acetal / ketal, this invention uses a more effective byproduct removal device (the absorption device of this invention), which improves the conversion efficiency, increases the product purity, and reduces the difficulty of product separation and purification. In addition, this invention successfully scaled up the ketal reaction many times using absorption device A, realizing mass production.

[0099] (10) In the prior art CN111153885A, Fmoc-DOPA(Acetonide)-OH and the impurity Fmoc-DOPA(Acetonide)-OMe are mixed together and difficult to remove completely. To address the above technical problem, this invention explores a better recrystallization method, using toluene and petroleum ether (n-hexane) for recrystallization, achieving a purity of over 98.5%. That is, this invention uses a TLN / HXN solvent system for recrystallization, which better separates the target product from its methyl ester, reduces the impurity content, and improves the purity of the target product VI. Moreover, the byproduct Fmoc-DOPA(Acetonide)-OMe in CN111153885A affects the yield, and discarding it is a serious waste. This invention discloses a highly efficient method for converting the byproduct Fmoc-DOPA(Acetonide)-OMe to Fmoc-DOPA(Acetonide)-OH, with excellent results; the total yield is over 90%. Attached Figure Description

[0100] Figure 1 This is a side view of an oral continuous or intermittent drug delivery device provided according to an embodiment of the present invention;

[0101] Figure 2 A top view of the cup lid in an oral continuous or intermittent drug delivery device according to an embodiment of the present invention;

[0102] Figure 3 This is a schematic diagram of the structure of the preparation apparatus A provided in one embodiment of the present invention;

[0103] Figure 4 This is a schematic diagram of the preparation apparatus A-1 provided in one embodiment of the present invention;

[0104] Figure 5 A schematic diagram of the structure of an improved constant-pressure dropping funnel A-1-1 provided in an embodiment of the present invention;

[0105] Figure 6 A schematic diagram of the structure of the improved Soxhlet extractor intermediate tube A-1-2 provided in one embodiment of the present invention;

[0106] Figure 7 A schematic diagram of the structure of the improved Soxhlet extractor intermediate tube A-1-3 provided in one embodiment of the present invention;

[0107] Among them, 100-cup lid, 101-switch button, 102-battery slot, 103-micro peristaltic pump, 104-transfer tube, 105-output tube, 106-speed control button, 107-flow rate display screen, 108-quantitative cell; 200-cup body, 201-cup body shell; 1-dropping funnel body, 11-regulating valve, 12-upper part of dropping funnel, 13-lower part of dropping funnel, 14-first upper interface, 15-first lower interface; 2-first constant pressure tube; 3-vacuum sleeve; 4-condensation sleeve, 41-coolant inlet connector, 42-coolant outlet connector; 5-sand core plate; 2.1- 2.2-Second constant pressure tube, 2.3-First glass tube sealed bottom, 2.4-First glass tube frosted bottom, 2.5-Soxhlet extractor body, 2.6-First siphon tube, 2.7-Side ground joint, 2.8-Second upper interface, 2.9-Vacuum sleeve of Soxhlet extractor intermediate tube; 301-Third upper interface, 302-Sealed cooling sleeve, 303-Coolant outlet, 304-Coolant inlet, 305-Second glass tube frosted bottom, 306-Second siphon tube, 307-Third lower interface, 308-Third constant pressure tube, 309-Second glass tube sealed bottom, 310-Tube body. Detailed Implementation

[0108] The present invention will be further illustrated below with specific embodiments. It should be noted that those skilled in the art can make several modifications and improvements without departing from the principle of the present invention, and these should also be considered to fall within the protection scope of the present invention.

[0109] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0110] Example 1: Preparation of L-DOPA or Carbidopa Derivatives

[0111] 1-1: Synthesis of Fmoc-DOPA-OH

[0112]

[0113] Method A: In a 500 mL three-necked flask, add 9.53 g (25 mmol) Na₂B₄O₇·10H₂O, 1.75 g Na₂S₂O₃, and 100 mL of water, stir and incubate for 30 min; add 9.86 g (50 mmol) L-DOPA, 3.98 g (37.5 mmol) sodium carbonate, 75 mL of water, and 75 mL of THF; add a total of 13.48 g (40 mmol, 0.8 eq) Fmoc-OSu in batches, stir overnight; then, concentrate the reaction solution by rotary evaporation, wash the residual liquid several times with EA, and retain the aqueous phase; adjust the pH of the aqueous phase to 2 with 2N hydrochloric acid, and extract three times with EA; combine the organic phases and wash several times successively with 0.1N hydrochloric acid, saturated sodium chloride, and water. Next, the organic phase was dried with MgSO4, filtered, and subjected to rotary evaporation to obtain a crude product. Finally, it was recrystallized in EA / HXN to obtain 16.3 g of white powder, Fmoc-DOPA-OH, with a purity >98% and a yield of 97% (based on Fmoc-OSu). The HPLC retention time (HPLC RT) was 14.7 min.

[0114] High-performance liquid chromatography (HPLC) analysis conditions: Waters e2695 HPLC instrument, detection wavelength 280 / 215nm, Symmetry C18 (4.6×250mm, 5μm) reversed-phase column; mobile phase A (89.8% water, 10% acetonitrile, 0.1% TFA) and B (89.9% acetonitrile, 10% water, 0.1% TFA), linear gradient elution from 100% A to 100% B for 20 min, followed by isocratic elution with 100% B for 20 min; flow rate 1 mL / min.

[0115] Method B uses Fmoc-Cl instead of Fmoc-OSu, with a purity >98% and a yield of approximately 75%.

[0116] Both methods produced Fmoc-DOPA-OH with high purity, and no Lossen rearrangement byproducts caused by Fmoc-OSu or dipeptide byproducts caused by Fmoc-Cl were detected. Neither method required liquid chromatography purification.

[0117] 1-2: Synthesis of Phth-DOPA-OH

[0118] In a reaction vessel, 71.5 g (187 mmol) of Na₂B₄O₇·10H₂O, 1500 mL of water, and 15 g of Na₂SO₃ were added, and the mixture was mechanically stirred for 30 min. Then, 73.9 g of L-DOPA (375 mmol), 30 g of Na₂CO₃, and 1500 mL of THF were added. A total of 73.5 g (335 mmol) of Phth-CE was added in batches; the reaction mixture was stirred at room temperature for approximately 3–16 h. The reaction solution was concentrated by rotary evaporation, the pH was adjusted to 1–2 with HCl, and the mixture was extracted multiple times with EA. The combined organic phases were washed successively with 1 mM hydrochloric acid, saturated brine, and water. After drying with MgSO₄, filtration, and rotary evaporation, a yellow crude product was obtained. Recrystallization from a DCM and PE mixture (5:1) yielded a white solid with a yield of 75% and a purity of 100% (HPLC RT 13.2 min).

[0119] 1-3: Synthesis of Boc-Met-DOPA-OH

[0120] In a 500 mL three-necked flask, 9.53 g (25 mmol) Na₂B₄O₇·10H₂O, 1.75 g Na₂S₂O₃, and 175 mL of water were added, and the mixture was stirred for 30 min. Then, 9.85 g (50 mmol) L-DOPA, 3.0 g (26.3 mmol) Na₂CO₃, and 75 mL THF were added. Next, a total of 13.85 g (40 mmol) Boc-Met-OSu was added in portions, and the mixture was stirred overnight. The reaction solution was concentrated by rotary evaporation, and the pH was adjusted to 7-8. The solution was washed multiple times with EA. The pH of the aqueous phase was adjusted to 3 with 1 M citric acid solution, and the solution was extracted three times with EA. The organic phase was washed successively with 1 mM HCl, saturated brine, and water. The organic phase was dried over MgSO₄, filtered, and evaporated to dryness. The resulting solid was recrystallized in EA / HXN to give 10.9 g of white powder, with a yield of 64% and an HPLC RT of 11.50 min.

[0121] 1-4: Synthesis of Boc-Met-CarbiDOPA-OH

[0122] The reaction conditions were similar to those in Examples 1-3, using 12.2 g (50 mmol) L-CarbiDOPA and 13.85 g (40 mmol) Boc-Met-OSu as reactants. The crude product was recrystallized in EA / HXN to give 16.4 g of white powder Boc-Met-CarbiDOPA-OH, yield 90%, with an HPLC RT of 11.6 min.

[0123] 1-5: Synthesis of Fmoc-NH-NH-CarbiDOPA-OH

[0124] In a 1000 mL three-necked flask, 19.06 g (50 mmol) of Na₂B₄O₇·10H₂O, 2.0 g of sodium sulfite, and 150 mL of water were added, and Ar was bubbled through for 30 min. Then, 21.32 g (100 mmol) of carbidopa, 7.96 g (75 mmol) of Na₂CO₃, 75 mL of water, and 150 mL of THF were added. A total of 26.96 g (80 mmol) of Fmoc-OSu was added in portions, and the mixture was stirred overnight. Using a similar process to steps 1-3, 32.27 g of a white solid powder was obtained, with a yield of 90% and an HPLC RT of 14.99 min. HRMS (ESI): C₂₅H₂₄N₂O₆Calcd. for [M+H] + 449.1707, found 449.1706.

[0125] 1-6: Synthesis of H-Met-DOPA-OH

[0126] In a 500 mL flask, add 10 g of Boc-Met-DOPA-OH, 250 mL of 2 M HCl / DIOX solution, and 25 mL of TIS. Stir magnetically for 4 h. Remove HCl and solvent by rotary evaporation, dissolve in a small amount of methanol, precipitate with cold PE, centrifuge, and dry under vacuum to obtain 9.3 g of white foamy solid.

[0127] 1-7: Synthesis of H-Met-CarbiDOPA-OH

[0128] Take 0.1 g of Boc-Met-CarbiDOPA-OH, add 20 mL of TFA / TIS / H2O / DCM (25:5:5:65) deprotection solution, and stir magnetically for 2-4 hours; evaporate to dryness by rotary evaporation, dissolve in a small amount of methanol, and precipitate with ice-cold diethyl ether; after vacuum drying, dissolve in 10 mL of water and freeze-dry; 0.066 g of white solid H-Met-CarbiDOPA-OH is obtained, with a yield of 64.0% and an HPLC RT of 12.1 min.

[0129] 1-8: Coupling reaction of hyaluronic acid and levodopa methyl ester

[0130] Dissolve 1.9 g of hyaluronic acid (1.5 MDa, 5 mmol structural units) in 200 mL of water. Add 0.96 g (5 mmol) of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) hydrochloride and HOSu (1.15 g, 10 mmol). Seal the solution with a rubber stopper and stir at room temperature for 24 h. Add 0.5 g (4 mmol) of Na₂SO₃ and 1.23 g (5 mmol) of H-DOPA-OMe hydrochloride. Adjust the pH to 6.8 with 1 M NaOH solution, seal the solution, and stir at room temperature for 24-48 h. Dialyze the solution using a semi-permeable membrane (molecular weight cutoff 2000 Da) for 2-3 days, then freeze-dry to obtain a white solid. The solution remains colorless throughout the reaction process due to the protective effect of the antioxidant Na₂SO₃.

[0131] 1-9: Coupling reaction of hyaluronic acid and carbidopa methyl ester

[0132] Using a method similar to Examples 1-8, carbidopa methyl ester hydrochloride was used instead of H-DOPA-OMe hydrochloride; due to the protective effect of the antioxidant Na2SO3, the solution was light yellow throughout the reaction process.

[0133] 1-10: Synthesis of other Boc-AA-DOPA-OH and Boc-AA-CarbiDOPA-OH

[0134] Using Boc-AA-OSu as reactants, Boc-AA-DOPA-OH and Boc-AA-CarbiDOPA-OH were prepared using methods similar to those in Examples 1-3 and 1-4. The corresponding characterization data are summarized below.

[0135] Boc-Met-DOPA-OH: Yield 64%, HRMS Calcd. for [MH] - 427.1544, found 427.1544. 11H NMR (400 MHz, MEOD) δ 6.66 (dd, J = 7.1, 4.9 Hz, 3H), 6.53 (dd, J = 8.0, 1.8 Hz, 1H), 4.59 (t, J = 6.3 Hz, 1H), 4.22 - 4.03 (m, 1H), 3.03 (dd, J = 13.9, 5.1 Hz, 1H), 2.90 (dd, J = 13.9, 7.5 Hz, 2H), 2.10 - 2.03 (m, 3H), 2.02 - 1.90 (m, 1H), 1.80 (td, J = 14.0, 8.4 Hz, 1H), 1.43 (s, 9H). 13C NMR (101 MHz, MEOD) δ 174.48, 174.31, 157.70, 146.11, 145.22, 129.29, 121.78, 117.36, 116.28, 80.81, 55.04, 54.97, 37.68, 32.85, 31.02, 28.67, 15.17.

[0136] Boc-Val-DOPA-OH: Yield 82%, HRMS calcd. for [M - H] - 395.1824, found 395.1825. 1 1H NMR (400 MHz, MEOD) δ 6.66 (d, J = 8.1 Hz, 2H), 6.54 (dd, J = 8.1, 1.8 Hz, 1H), 4.60 (dd, J = 7.7, 5.6 Hz, 1H), 3.86 (d, J = 6.8 Hz, 1H), 3.02 (dd, J = 13.9, 5.3 Hz, 1H), 2.86 (dd, J = 13.9, 8.0 Hz, 1H), 2.04 1.93 (m, 1H), 1.43 (s, 9H), 0.88 (dd, J = 9.2, 6.8 Hz, 6H). 13C NMR (101 MHz, MEOD) δ 174.63, 174.15, 157.89, 146.14, 145.20, 129.5, 121.74, 117.32, 116.27, 80.64, 61.51, 55.12, 37.95, 32.04, 28.70, 19.71, 18.40.

[0137] Boc-Ala-DOPA-OH: Yield 57%, HRMS Calcd for [M-H]-367.1511, found 367.1509. 1H NMR (400 MHz, MEOD) δ 6.71 - 6.50 (m, 3H), 4.62 - 4.50 (m, 1H), 4.14 - 3.93 (m, 1H), 3.02 (dd, J = 13.7, 5.0 Hz, 1H), 2.90 (dd, J = 13.7, 6.9 Hz, 1H), 1.56 - 1.09 (m, 12H). 13C NMR (101 MHz, MEOD) δ 175.45, 174.46, 157.55, 146.08, 145.21, 129.28, 121.82, 117.44, 116.26, 80.71, 54.94, 51.55, 37.73, 28.67, 18.30.

[0138] Boc-β-Ala-DOPA-OH: Yield 42%, HRMS Calcd for [M+H] + 369.1656, found 369.1657. 1 1H NMR (400 MHz, MEOD) δ 6.72 - 6.51 (m, 3H), 4.64 - 4.54 (m, 1H), 3.31 - 3.18 (m, 1H), 3.04 (dd, J = 14.0, 5.1 Hz, 1H), 2.81 (dd, J = 14.0, 8.8 Hz, 1H), 2.43 - 2.30 (m, 2H), 1.42 (s, 9H). 13C NMR (101 MHz, MEOD) δ 174.95, 173.70, 158.26, 146.15, 145.16, 129.75, 121.61, 117.22, 116.24, 80.19, 55.28, 37.81, 36.99, 28.71.

[0139] Boc-Phe-DOPA-OH: Yield 63%, HRMS Calcd. for [M-H] - 443.1824, found 443.1829. 1H NMR (400 MHz, MEOD) δ 7.41 - 7.03 (m, 5H), 6.68 (d, J = 8.1 Hz, 2H), 6.54 (d, J = 7.9 Hz, 1H), 4.60 (t, J = 6.3 Hz, 1H), 4.30 (dd, J = 9.6, 4.7 Hz, 1H), 3.13 - 2.97 (m, 2H), 2.89 (dd, J = 13.9, 7.4 Hz, 1H), 2.73 (dd, J = 13.8, 9.9 Hz, 1H), 1.58 - 1.02 (m, 9H). 13C NMR (101 MHz, MEOD) δ 174.40, 174.08, 157.54, 146.14, 145.26, 138.63, 130.29, 129.33, 127.59, 121.83, 117.43, 116.30, 80.71, 57.35, 55.07, 39.13, 37.81, 28.61.

[0140] Boc-Leu-DOPA-OH: Yield 78%, HRMS Calcd for [M+Na] + 433.1945, found 433.1942. 1 1H NMR (400 MHz, MEOD) δ 6.71 - 6.47 (m, 3H), 4.63 - 4.50 (m, 1H), 4.14 - 3.92 (m, 1H), 3.03 (dd, J = 13.9, 5.3 Hz, 1H), 2.89 (dd, J = 13.9, 7.4 Hz, 1H), 1.70 - 1.32 (m, 12H), 1.03 - 0.85 (m, 6H). 13C NMR (101 MHz, MEOD) δ 175.32, 174.43, 157.75, 146.07, 145.21, 129.27, 121.81, 117.44, 116.24, 80.67, 54.83, 54.57, 42.07, 37.76, 28.68, 25.84, 23.40, 21.84.

[0141] Boc-Ile-DOPA-OH: Yield 88%, HRMS Calcd for [M+Na] + 433.1945, found 433.1941. 11H NMR (400 MHz, MEOD) δ 6.69 - 6.52 (m, 3H), 4.71 - 4.51 (m, 1H), 3.90 (d, J = 7.2 Hz, 1H), 3.02 (dd, J = 13.9, 5.2 Hz, 1H), 2.86 (dd, J = 13.9, 8.1 Hz, 1H), 1.73 (d, J = 6.5 Hz, 1H), 1.43 (s, 10H), 1.19 - 1.00 (m, 1H), 0.97 - ...... 13C NMR (101 MHz, MEOD) δ 174.51, 174.23, 157.82, 146.13, 145.20, 129.46, 121.73, 117.29, 116.25, 80.64, 60.66, 54.98, 38.29, 37.92, 28.70, 25.63, 15.85, 11.45.

[0142] Boc - Gly - DOPA - OH: Yield 66%, HRMS Calcd for [M - H] - 353.1354, found 353.1354. 1 1H NMR (400 MHz, MEOD) δ 6.75 - 6.46 (m, 3H), 4.66 - 4.53 (m, 1H), 3.81 - 3.60 (m, 2H), 3.02 (dd, J = 13.9, 5.1 Hz, 1H), 2.89 (dd, J = 13.9, 7.3 Hz, 1H), 1.43 (s, 9H). 13C NMR (101 MHz, MEOD) δ 174.58, 172.11, 158.33, 146.18, 145.27, 129.29, 121.73, 117.35, 116.31, 80.81, 55.02, 44.44, 37.77, 28.66 (3C).

[0143] Boc - Glu(OtBu) - DOPA - OH: Yield 72%, HRMS Calcd for [M + Na] + 505.2160, found 505.2150. 1H NMMR (400 MHz, MEOD) δ 6.71 - 6.51 (m, 3H), 4.58 (t, J = 6.4 Hz, 1H), 4.13 - 3.91 (m, 1H), 3.03 (dd, J = 13.9, 5.1 Hz, 1H), 2.89 (dd, J = 13.8, 7.4 Hz, 1H), 2.28 (t, J = 7.4 Hz, 2H), 2.01 - 1.73 (m, 2H), 1.44 (s, 18H). 13C NMR (101 MHz, MEOD) δ 174.38, 174.16, 174.06, 157.66, 146.13, 145.25, 129.28, 121.78, 117.34, 116.29, 81.78, 80.78, 54.98, 37.72, 32.62, 28.67, 28.55, 28.33.

[0144] Boc-Asp(OtBu)-DOPA-OH: Yield 76% HRMS Calcd for [M+Na] + 491.2001, found 491.2000. 1H NMR (400 MHz, MEOD) δ 6.74 - 6.48 (m, 3H), 4.62 - 4.52 (m, 1H), 4.50 - 4.32 (m, 1H), 3.01 (dd, J = 13.9, 5.3 Hz, 1H), 2.90 (dd, J = 13.9, 6.9 Hz, 1H), 2.71 (dd, J = 16.0, 5.2 Hz, 1H), 2.48 (dd, J = 16.0, 8.7 Hz, 1H), 1.44 (s, 18H). 13 C NMR (101 MHz, MEOD) δ 174.22, 173.20, 171.43, 157.54, 146.16, 145.30, 129.10, 121.82, 117.39, 116.30, 82.38, 80.97, 55.04, 52.61, 38.71, 37.66, 28.66, 28.26.

[0145] Boc-Ala-CarbiDOPA-OH: Yield 52%, HRMS Calcd for [M-H] -396.1776, found 396.1778. 1H NMR (400 MHz, MEOD) δ 6.68 (dd, J = 9.1, 5.0 Hz, 2H), 6.55 (dd, J = 8.1, 2.0 Hz, 1H), 4.02 (q, J = 7.2 Hz, 1H), 2.87 (dd, J = 35.9, 13.6 Hz, 2H), 1.43 (s, 9H), 1.29 (t, J = 3.6 Hz, 6H). 13C NMR (101 MHz, MEOD) δ 177.81, 175.12, 157.51, 146.05, 145.45, 128.23, 122.61, 118.36, 116.18, 80.73, 66.66, 51.06, 44.11, 28.66, 21.27, 18.00.

[0146] Boc-Val-CarbiDOPA-OH: Yield 78%, HRMS Calcd for [M+H]+ 426.2235, found 426.2236. 1 1H NMR (400 MHz, MeOD) δ 6.72 - 6.52 (m, 3H), 3.83 (d, J = 6.7 Hz, 1H), 2.87 (d, J = 3.8 Hz, 2H), 2.10 - 2.00 (m, 1H), 1.43 (s, 9H), 1.28 (s, 3H), 1.03 - 0.83 (m, 6H). 13C NMR (101 MHz, MeOD) δ 177.61, 173.53, 157.95, 146.03, 145.44, 128.26, 122.68, 118.41, 116.16, 80.72, 66.69, 60.84, 44.00, 31.45, 28.68, 21.22, 19.74, 18.44.

[0147] Boc-Met-CarbiDOPA-OH: Yield 90%, HRMS Calcd for [M-H]-456.1810, found 456.1806. 1H NMR (400 MHz, MeOD) δ 6.71 - 6.51 (m, 3H), 4.19 - 4.11 (m, 1H), 3.04 - 2.74 (m, 2H), 2.61 - 2.47 (m, 2H), 2.07 (s, 3H), 2.04 - 1.97 (m, 1H), 1.91 - 1.79 (m, 1H), 1.43 (s, 9H), 1.28 (s, 3H). 13C NMR (101 MHz, MeOD) δ 177.83, 173.95, 157.71, 146.04, 145.44, 128.26, 122.64, 118.38, 116.18, 80.86, 66.56, 54.36, 32.35, 31.19, 28.66, 21.38, 15.17.

[0148] Boc-Leu-CarbiDOPA-OH: Yield 92%, HRMS Calcd for [M-H]-438.2246, found 438.2243. 1H NMR (400 MHz, MeOD) δ 6.72 - 6.49 (m, 3H), 4.03 (t, J = 7.6 Hz, 1H), 2.97 - 2.75 (m, 2H), 1.77 - 1.61 (m, 1H), 1.51 (t, J = 7.1 Hz, 2H), 1.43 (s, 9H), 1.28 (s, 3H), 0.97 - 0.88 (m, 6H). 13C NMR (101 MHz, MeOD) δ 177.91, 174.82, 157.70, 146.02, 145.42, 128.27, 122.62, 118.36, 116.17, 80.72, 66.57, 53.86, 44.09, 41.70, 28.67(3C), 25.89, 23.34, 21.75, 21.35.​​​​​​13C NMR (101 MHz, MeOD) δ 177.78, 173.50, 157.87, 145.98, 145.38, 128.31, 122.67, 118.39, 116.14, 80.69, 66.56, 59.86, 44.05, 37.76, 28.67, 25.82, 21.30, 16.01, 11.52.

[0150] Boc-Gly-CarbiDOPA-OH: Yield 67%, HRMS Calcd for [M-H] - 382.1620, found: 382.1619. 1 1H NMR (400 MHz, MeOD) δ 6.72 - 6.52 (m, 3H), 3.78 - 3.61 (m, 2H), 3.02 - 2.70 (m, 2H), 1.43 (s, 9H), 1.29 (s, 3H). 13C NMR (101 MHz, MeOD) δ 177.99, 171.68, 158.29, 146.01, 145.41, 128.34, 122.63, 118.37, 116.16, 80.86, 66.50, 44.08, 43.84, 28.64, 21.3 April 29, 2020 4

[0151] Boc-Phe-CarbiDOPA-OH: Yield 59%, HRMS Calcd. for [M + H] + 474.2235, found 474.2235. 1 1H NMR (400 MHz, MEOD) δ 7.28 - 7.18 (m, 5H), 6.69 - 6.63 (m, 2H), 6.53 (dd, J = 8.1, 2.0 Hz, 1H), 4.27 (dd, J = 9.1, 6.1 Hz, 1H), 3.07 (dd, J = 13.8, 6.1 Hz, 1H), 2.91 - 2.72 (m, 3H), 1.36 (s, 9H), 1.13 (s, 3H). 13 13C NMR (101 MHz, MEOD) δ 177.69, 173.42, 157.53, 146.01, 145.41, 138.45, 130.25, 129.49, 128.30, 127.79, 122.63, 118.38, 116.15, 80.78, 66.48, 56.68, 44.07, 38.80, 28.61, 21.15.

[0152] Boc-β-Ala-CarbiDOPA-OH: Yield 42%, HRMS Calcd. for [M + H]+ 398.1922, found 398.1923. 1H NMR (400 MHz, MEOD) δ 6.68 (dd, J = 10.5, 5.0 Hz, 2H), 6.55 (dd, J = 8.1, 2.1 Hz, 1H), 3.31 - 3.27 (m, 2H), 2.95 - 2.78 (m, 2H), 2.42 - 2.27 (m, 2H), 1.41 (s, 9H), 1.27 (s, 3H). 13C NMR (101 MHz, MEOD) δ 177.64, 172.87, 158.26, 145.96, 145.33, 128.48, 122.71, 118.44, 116.10, 80.20, 66.44, 44.04, 37.98, 35.39, 28.71, 20.97.

[0153] Boc-Glu(OtBu)-CarbiDOPA-OH: Yield 84%, HRMS Calcd for [N + Na]+ 534.2422, found 534.2421. 1H NMR (400 MHz, MeOD) δ 6.73 - 6.52 (m, 3H), 4.09 - 3.95 (m, 1H), 2.98 - 2.75 (m, 2H), 2.32 (t, J = 7.4 Hz, 2H), 2.07 - 1.94 (m, 1H), 1.87 - 1.73 (m, 1H), 1.45 (t, J = 8.7 Hz, 18H), 1.28 (s, 3H). 13C NMR (101 MHz, MeOD) δ 177.81, 173.86, 173.72, 157.64, 146.01, 145.41, 128.27, 122.64, 118.37, 116.17, 81.85, 80.82, 66.50, 54.62, 44.07, 32.69, 28.66, 28.32, 21.32.

[0154] Boc-Asp(OtBu)-CarbiDOPA-OH: Yield 79%, HRMS Calcd for [M + Na] +520.2266, found: 520.2266.1HNMR (400MHz, MeOD) δ6.73-6.51 (m, 3H), 4.45-4.33 (m, 1H), 2.91 (d, J =13.6Hz, 1H), 2.82 (d, J = 13.6Hz, 1H), 2.74 (dd, J = 16.3, 5.8Hz, 1H), 2.53 (dd, J = 16.2, 8.1Hz, 1H), 1 .43 (s, 18H), 1.28 (s, 3H).13CNMR (101MHz, MeOD) δ177.89, 172.74, 171.26, 157.49, 146.02, 145.41 , 128.25, 122.61, 118.35, 116.16, 82.41, 80.98, 66.50, 51.88, 44.00, 38.32, 28.65, 28.27, 21.38.

[0155] 1-11 Synthesis of other H-AA-DOPA-OH and H-AA-CarbiDOPA-OH

[0156] Other H-AA-DOPA-OH and H-AA-CarbiDOPA-OH dipeptides were prepared using a Boc deprotection method similar to that used in Examples 1-6 and 1-7. The corresponding characterization data are summarized below.

[0157] H-Met-DOPA-OH: Yield 93%, HRMS: m / z Calcd for C 14 H 20 N2O5S, 327.1020, found: 327.1017[MH] - . 1 H NMR (400MHz, MeOD) δ6.70 (m, 2H), 6.59 (m, 1H), 4.61 (m, 1H), 3.96 (m, 1H), 3.11 (dd, J=14.1, 4.7Hz, 1H), 2.86 (dd, J=14.1, 9.4Hz, 1H), 2.61 (m, 2H), 2.2 2-1.98 (m, 5H).13CNMR (101MHz, MeOD) δ174.24, 169.70, 146.21, 145.25, 1 29.58, 121.56, 117.19, 116.34, 55.68, 53.51, 37.33, 32.23, 29.44, 15.03.

[0158] H-Met-DOPA-OH: Yield 93%, HRMS Calculation for [MH] -327.1020, found 327.1017. 1 HNMR (400 MHz, MeOD) δ 6.70 (m, 2H), 6.59 (m, 1H), 4.61 (m, 1H), 3.96 (m, 1H), 3.11 (dd, J = 14.1, 4.7 Hz, 1H), 2.86 (dd, J = 14.1, 9.4 Hz, 1H), 2.61 (m, 2H), 2.22 - 1.98 (m, 5H). 13C NMR (101 MHz, MeOD) δ 174.24, 169.70, 146.21, 145.25, 129.58, 121.56, 117.19, 116.34, 55.68, 53.51, 37.33, 32.23, 29.44, 15.03.

[0159] H-Phe-DOPA-OH: Yield 87%, HRMS Calcd for [M + H] + 345.1145, found 345.1142. 1 HNMR (400 MHz, MeOD) δ 7.42 - 7.23 (m, 5H), 6.80 - 6.64 (m, 2H), 6.64 - 6.48 (m, 1H), 4.63 (m, 1H), 4.19 - 4.08 (m, 1H), 3.34 - 3.26 (m, 1H), 3.16 - 2.98 (m, 2H), 2.87 (m, 1H). 13 13C NMR (101 MHz, MeOD) δ 174.20, 169.61, 146.20, 145.27, 135.42, 130.61, 130.08, 129.57, 128.82, 121.63, 117.28, 116.33, 55.73, 55.44, 38.46, 37.69.

[0160] H-Ala-DOPA-OH: Yield 85%, HRMS Calcd for [M + H] + 269.1132, found 269.1131. 1HNMR(400MHz,MeOD)δ6.72-6.64(m,2H),6.57(dd,J8.1,2.0Hz,1H),4.56(dd,J9.1,4.8Hz,1H),3.90(q,J N7.0Hz,1H),3.10(dd,J)14.1,4.8Hz,1H),2.84(dd,J D14.1,9.2Hz,1H),1.48(d,J7.0Hz,3H).13CNMR(101 MHz,MeOD)δ175.15,170.90,146.15,145.16,129.93,121.64,117.28,116.29,56.16,50.09,37.69,17.58.

[0161] H-Val-DOPA-OH:Volume 98%,HRMS Calcd for[M+H] + 297.1445,found 1 HNMR(400MHz,MeOD)δ6.78-6.55(m,3H),4.68-4.57(m,1H),3.83 -3.73(m,1H),3.09(dd,J)14.1,5.0Hz,1H),2.87(dd,J14.1,9 Hz,1H),2.42-2.10(m,1H),1.12-0.99(m,6H).13CNMR(101MHz,MeOD)δ173.09,168.16,14 4.84,143.89,128.33,120.24,115.91,114.97,58.08,54.44,36.23,30.21,17.52,1

[0162] H-Leu-DOPA-OH:dispersion 82%,HRMS Calcd for[M+H] + 311.1601,found 311.1603. 1HNMR (400 MHz, MeOD) δ 6.74 - 6.54 (m, 3H), 4.64 - 4.54 (m, 1H), 3.93 - 3.82 (m, 1H), 3.10 (dd, J = 14.1, 5.0 Hz, 1H), 2.88 (dd, J = 14.1, 9.3 Hz, 1H), 1.78 - 1.61 (m, 3H), 1.01 - 0.95 (m, 6H). 13C NMR (101 MHz, MeOD) δ 174.38, 170.69, 146.20, 145.24, 129.73, 121.58, 117.26, 116.33, 55.77, 52.85, 41.68, 37.46, 25.19, 23.18, 21.98。

[0163] H-Ile-DOPA-OH: Yield 84%, HRMS Calcd for [M + H] + 311.1601, found 311.1600. 1 HNMR (400 MHz, MeOD) δ 6.81 - 6.35 (m, 3H), 4.70 - 4.50 (m, 1H), 3.79 - 3.71 (m, 1H), 3.09 (dd, J = 14.1, 5.0 Hz, 1H), 2.87 (dd, J = 14.1, 9.1 Hz, 1H), 2.02 - 1.92 (m, 1H), 1.63 - 1.50 (m, 1H), 1.22 - 1.15 (m, 1H), 1.09 - 故1(m, 6H). 1 C NMR (101 MHz, MeOD) δ 174.64, 169.47, 146.04, 145.09, 129.78, 121.67, 117.27, 116.32, 58.90, 55.81, 38.08, 37.52, 24.97, 15.10, 11.71。

[0164] H-Gly-DOPA-OH: Yield 86%, HRMS Calcd for [M - H] - 253.0830, found 253.0831. 1HNMR (400 MHz, D2O) δ 6.85 - 6.62 (m, 3H), 4.67 - 4.60 (m, 1H), 3.77 (s, 1H), 3.73 (s, 1H), 3.08 (dd, J = 14.1, 5.5 Hz, 1H), 2.87 (dd, J = 14.1, 8.7 Hz, 1H). 13C NMR (101 MHz, MeOD) δ 175.01, 167.15, 146.15, 145.20, 129.68, 121.68, 117.31, 116.32, 55.82, 41.40, 37.93。

[0165] H-Asp-DOPA-OH: Yield 72%, HRMs Calcd for [M+H] + 313.1030, found 313.1027. 1 HNMR(400MHz, MeOD) δ6.81 - 6.47(m, 3H), 4.61(dd, J = 9.3, 4.7Hz, 1H), 4.19(dd, J = 9.2, 3.9Hz, 1H), 3.77 - 3.65(m, 1H), 3.14 - 2.97(m, 2H), 2.86 - 2.79(m, 1H). 13C NMR(101MHz, MeOD) δ174.22, 172.87, 169.23, 146.20, 145.26, 129.53, 121.60, 117.20, 116.33, 55.74, 50.80, 37.44, 35.98。

[0166] H-Met-CarbiDOPA-OH: Yield 64%, HRMS Calcd for [M+H]+ 358.1431, found 358.1431. 1 H NMR(400MHz, MeOD) δ6.78 - 6.54(m, 6H), 4.48 - 4.40(m, 1H), 3.93(m, 1H), 2.97 - 2.88(m, 2H), 2.78 - 2.​​​​​​​​1H NMR (400 MHz, MeOD) δ 6.74 - 6.67 (m, 4H), 6.60 - 6.50 (m, 2H), 4.23 (q, J = 6.9 Hz, 1H), 3.97 (q, J = 6.9 Hz, 1H), 2.96 - 2.67 (m, 4H), 1.56 - 1.41 (m, 6H), 1.31 - 1.16 (m, 6H). 13C NMR (101 MHz, MeOD) δ 179.47, 178.47, 175.25, 170.76, 145.89, 145.82, 145.27, 128.56, 128.47, 123.06, 122.75, 118.78, 118.45, 116.18, 116.00, 66.87, 66.27, 64.25, 54.79, 44.40, 44.18, 21.05, 20.17, 17.93, 16.68.

[0168] H-Val-CarbiDOPA-OH: Yield 67%, HRMS Calcd for [M+H] + 326.1710, found 326.1708. <m:math xmlns:m="http: / / schemas.openxmlformats.org / officeDocument / 2006 / math" xmlns:o="urn:schemas-microsoft-com:office:office"><m:r><m:t>0000061< / m:t>< / m:r>< / m:math><m:math xmlns:m="http: / / schemas.openxmlformats.org / officeDocument / 2006 / math" xmlns:o="urn:schemas-microsoft-com:office:office"><m:r><m:t>< / m:t>< / m:r>< / m:math>1H NMR (400 MHz, MeOD) δ 6.75 - 6.65 (m, 4H), 6.60 - 6.55 (m, 2H), 4.17 (d, J = 4.5 Hz, 1H), 3.68 (d, J = 5.8 Hz, 2H), 2.89 (d, J = 13.3 Hz, 1H), 2.76 (d, J = 10.4 Hz, 1H), 2.46 - 2.28 (m, 1H), 2.25 - 2.05 (m, 2H), 1.26 (s, 6H), 1.13 - 0.9 (m, 12H). 13 13C NMR (101 MHz, MeOD) δ 180.99, 179.77, 173.81, 168.94, 145.90, 145.83, 145.22, 145.15, 129.05, 129.00, 123.05, 122.79, 118.84, 118.48, 116.13, 115.95, 67.03, 66.87, 58.76, 56.66, 44.53, 44.42, 31.44, 30.28, 21.93, 20.59, 19.46, 18.87, 18.12, 16.70.

[0169] H-Phe-CarbiDOPA-OH: Yield 71%, HRMS Calcd for [M+H] [[ID=~13]] + 374.1710, found 374.1712. 1H NMR (400MHz, MeOD) δ7.44-7.02(m, 10H), 6.79-6.48(m, 6H), 4.56-4.46(m, 1H), 4.07-3.96( m, 1H), 3.31-3.09 (m, 2H), 3.04-2.78 (m, 4H), 2.76-2.56 (m, 2H), 1.24 (s, 3H), 0.96 (s, 3H). 13 C NMR (101MHz, MeOD) δ181.69, 180.85, 173.60, 169.68, 145.94, 145.85, 145.16, 145.11, 136.32, 136.01, 130.59, 130.48, 130.08, 130.00, 129. 47, 129.42, 128.67, 128.56, 123.02, 122.80, 118.73, 118.47, 116.06, 67.39, 67.18, 55.07, 53.14, 44.85, 44.49, 38.93, 37.86, 22.01, 21.37.

[0170] 1-12: Testing the solubility of the synthesized L-DOPA dipeptide and CarbiDOPA dipeptide

[0171] (1) Plot the standard line between absorbance and concentration: Dissolve 50.2 mg L-DOPA in 50 mL of 11 mmol / L citrate-sodium citrate (pH 6.4) buffer solution. After multiple dilutions, measure the absorbance of the sample at 280 nm and plot the standard line between L-DOPA concentration and absorbance. The R value of the standard line is greater than 0.99.

[0172] (2) The effectiveness of the method was evaluated by measuring the solubility of L-DOPA: 100 mg of L-DOPA was added to 5 mL of 11 mmol / L citrate-sodium citrate buffer solution (pH 6.4), vortexed, allowed to stand, and the supernatant was taken. The solubility was measured to be between 2.4 and 2.6 mmol / 100 mL, which is close to the relevant literature values ​​(5 g / L or 2.5 mmol / 100 mL).

[0173] (3) Preparation of L-DOPA dipeptide or CarbiDOPA dipeptide sample: Weigh about 0.1 mmol of L-DOPA dipeptide or CarbiDOPA dipeptide (in HCl or TFA salt form) solid, add it to 200-1200 μL of 2M sodium citrate solution, vortex and centrifuge, take 100 μL of the supernatant, dilute with water to 3 mL, measure its pH and record it as the initial pH.

[0174] Prepare 100 μL of the supernatant again, dilute with 11 mmol / L citrate-sodium citrate buffer (pH 6.4) to an appropriate concentration, and calculate the solubility of the sample in the initial pH citrate-sodium citrate solution by measuring its absorbance; the actual solubility should be greater than the calculated value. The specific solubility of L-DOPA dipeptide or CarbiDOPA dipeptide at different pH values ​​is shown in Table 2, with the unit of solubility being mmol / 100 mL.

[0175] Table 1. Solubility of L-DOPA dipeptide or CarbiDOPA dipeptide at different pH values

[0176]

[0177] Table 1 shows that the solubility of L-DOPA dipeptide (H-AA-DOPA-OH) measured between pH 6.1 and 6.5 was greater than that of L-DOPA, indicating that all L-DOPA dipeptides exhibit good water solubility. H-Gly-DOPA-OH showed the best solubility, exceeding that of L-DOPA by more than 10 times at pH 6.3. This aligns with earlier findings in US3803120 and US4035507. At pH 6.1, all measured L-DOPA dipeptides provided a drug loading greater than 10 mmol / 100 mL of L-DOPA. At pH 6.3, L-DOPA modified with amino acids having smaller side chains and lower nonpolarity showed an advantage, also providing a drug loading of 10 mmol / 100 mL of L-DOPA.

[0178] The measured CarbiDOPA dipeptide exhibited better solubility than CarbiDOPA; under the measured pH conditions, the CarbiDOPA dipeptide provided a soluble drug loading of approximately 0.7 mmol / 100 mL. Therefore, solid powder formulations made from L-DOPA dipeptide and CarbiDOPA dipeptide can form a clear solution upon addition of water or an aqueous solution containing excipients.

[0179] Example 2

[0180] 2-1: One-pot synthesis of Tfa-DOPA-OMe

[0181] In a 500 mL two-necked flask, L-DOPA (19.7 g, 100 mmol) and 150 mL of anhydrous methanol were added. SOCl2 (14.5 mL, 200 mmol) was slowly added dropwise using a dropping funnel under ice bath conditions. The ice bath was removed, and stirring continued for 3 h. The dropping funnel was replaced with a condenser, and the reaction mixture was heated to reflux in an oil bath while bubbling was initiated for 1 h. Heating was stopped, and the mixture was cooled to room temperature. 30.2 mL (300 mmol) of methyl trifluoroacetate and 56.0 mL (400 mmol) of Et3N were slowly added, and stirring continued for 6–12 h. After rotary evaporation and concentration, 100 mL of saturated sodium chloride solution was added, and the pH was adjusted to 3 with 1 M HCl. Extraction was performed with EA. The resulting organic phase was washed with water, dried over MgSO4, rotary evaporated, and then dried under vacuum to obtain 28.8 g of a white solid, Tfa-DOPA-OMe, with a yield of 94%. Then, using the experimental method of US8227628, Tfa-DOPA-OMe was successfully converted into Tfa-DOPA(Acetonide)-OMe.

[0182] 2-2: Synthesis of Tfa-DOPA(Acetonide)-OH

[0183] Weigh 6.9 g (20 mmol) of Tfa-DOPA(Acetonide)-OMe, add 100 mL of acetonitrile, 2 mL of water, 17.4 g (200 mmol) of LiBr and 5.1 mL (30 mmol) of DIEA, and stir the reaction at room temperature for about 24 h. Add 20 mL of 1 M citric acid solution, remove acetonitrile by rotary evaporation, and then extract with 100 mL of EA. After washing with water, drying with MgSO4, filtering and rotary evaporation, and vacuum drying, a white solid was obtained. Recrystallization in DCM yielded 4.8 g of white needle-like crystals, with a yield of 73%. 1 13C NMR (101MHz, CDCl3) δ: 175.0, 157.0 (q, JC-F=38.0Hz), 148.0, 147.2, 127.1, 12 2.0, 118.5, 115.6 (q, JC-F=287.5Hz), 109.3, 108.6, 53.5, 36.8, 25.9 (2C).HRMS Calcd For[M+H] + 334.0897, found 334.0867.

[0184] 2-3: Synthesis of Fmoc-DOPA(Acetonide)-OH

[0185] In a 500 mL three-necked flask, add 8.4 g (20 mmol) of Fmoc-DOPA-OH, 45 mL of acetone, and 300 mL of benzene. Connect apparatus A-1-1 (containing calcium chloride) to the middle neck of the flask, and then connect a reflux condenser to it. Purge with argon gas and reflux for 20 min. Then add 5 mL (40.66 mmol) of DMP and 86 mg (0.5 mmol) of TsOH. React for 2-3 h, then add 2 mL (16.3 mmol) of DMP and continue the reaction for another 0.5 h. Cool to room temperature, add 1.7 mL (20.5 mmol) of pyridine, and rotary evaporate to dryness. Add 100 mL of EA to extract the product, wash successively with 0.5 M citric acid and water, dry with MgSO4, filter, and rotary evaporate to obtain the crude product.

[0186] HPLC analysis revealed that the crude product contained 93% Fmoc-DOPA(Acetonide)-OH and 7% Fmoc-DOPA(Acetonide)-OMe. Recrystallization in TLN / HXN yielded 7.2 g of white solid. The purity of Fmoc-DOPA(Acetonide)-OH in the product was >98%, and the yield was 78% (the recrystallization mother liquor was converted to yield 1.8 g of Fmoc-DOPA(Acetonide)-OH, with an overall yield >90%).

[0187] 2-4: Synthesis of Boc-DOPA(Acetonide)-OH.

[0188] Method A: 3.47 g (10 mmol) of Tfa-DOPA (Acetonide)-OMe was dissolved in 60 mL of THF, and 720 mg (30 mmol) of LiOH was dissolved in 20 mL of water. The mixture was stirred at room temperature for approximately 2.5 h. The pH was adjusted to 7-8 with 1 M HCl, and 2.12 g (20 mmol) of Na₂CO₃ and 2.62 g (12 mmol) of di-tert-butyl carbonate anhydride (Boc₂O) were added. The mixture was stirred at room temperature for 3 h. The pH was adjusted to 3-4 with 1 M HCl, and the mixture was extracted with EA. The organic phase was washed with 0.001 M hydrochloric acid and water, dried over MgSO₄, and rotary evaporated to obtain the crude product. Recrystallization in EA / HXN yielded 2.86 g of a white solid, with a yield of 85%.

[0189] Method B: 4.6 g (10 mmol) of Fmoc-DOPA(Acetonide)-OH was dissolved in 50 mL of THF, and 0.96 g (40 mmol) of LiOH was dissolved in 50 mL of water. These were then mixed with 50 mL of PE and stirred at room temperature for 3 h. The aqueous phase was separated using a separatory funnel, washed once each with EA and PE, and filtered to obtain a clear aqueous solution. Then, 4.37 g (20 mmol) of Boc₂O was dissolved in 50 mL of THF and added to the aforementioned clear aqueous solution. The mixture was stirred for 5 h. The pH was adjusted to 3-4 with 1 M citric acid solution, and the mixture was extracted three times with EA. The combined organic phases were washed with water, dried over MgSO₄, filtered, and rotary evaporated. The resulting solid was dried in a vacuum oven to obtain a white, foamy solid with a yield of approximately 81%.

[0190] 1 H NMR (400MHz, CDCl3) δ: 10.00 (br, 1H), 6.73-6.49 (m, 3H), 5.00 (d, J=8.0Hz, 1H), 4.63- 4.20 (m, 1H), 3.11-3.06 (m, 1H), 3.02-2.75 (m, 1H), 1.65 (s, 6H), (1.42, 1.31) (s, 9H). 13 C NMR (101MHz, CDCl3)δ: (176.6, 176.0) (1C), (156.6, 155.5) (1C), 147.7 (1C), 146.7 (1C), (129.6, 128.8) (1C), (122.3, 122.0) (1C) ), 118.0(1C), 109.6(1C), 108.3(1C), (81.5, 80.4)(1C), (56.3, 54.5)(1C), (39.2, 37.6)(1C), (28.4, 27.5)(3C), 26.0(2C).HRMS Calcdfor[MH] - 336.1453, Found 336.1450.

[0191] Examples 2-5: Synthesis of Phth-DOPA(Acetonide)-OH

[0192] Method A replaced Boc2O with N-ethoxycarbonyl phthalamide (CE-Phth) as the acylation reagent, yielding 2.78 g of white crystals Phth-DOPA(Acetonide)-OH, with a yield of 75%.

[0193] Method B, using CN111153885A, involves taking 75g (0.229mol) Phth-DOPA-OH, using 200mL acetone as a co-solvent, 1.97g TsOH as a catalyst, and reacting it with 42.3mL DMP via an acetone cyclization reaction to obtain 53g of solid, with a yield of 70%.

[0194] 1 H NMR (400MHz, CDCl3) δ: 7.79 (dd, J=5.5, 3.0Hz, 2H), 7.68 (dd, J=5.5, 3.0Hz, 2H), 6.5 7-6.49 (m, 3H), 5.16-5.11 (m, 1H), 3.48 (d, J=8.3Hz, 2H), 1.59 (s, 3H), 1.55 (s, 3H); 13 C NMR (101MHz, CDCl3) δ: 174.8, 167.6 (2C), 147.6 (2C), 146.4, 134.3 (2C), 131.7 ,129.5,123.7(2C),121.5,117.9,109.2,108.3,53.5,34.2,25.83,25.78.HRMS Calcd for[M+H] + 368.1129, found 368.1114.

[0195] 2-6: Synthesis of Phth-DOPA(Acetonide)-OtBu

[0196] In a 500 mL flask, Phth-DOPA(Acetonide)-OH (43 g, 0.117 mol), Boc₂O (51 g, 2 eq.), tBuOH (22.4 mL, 2 eq), 300 mL of dry DCM and DMAP (8.54 g, 0.6 eq) were added. The flask was sealed with an oil seal, and the mixture was stirred at room temperature for 5 h. The organic phase was washed with ammonium chloride solution and water, dried over MgSO₄, filtered, and rotary evaporated to give 25 g of a white solid, with a yield of 60%. 1 H NMR (400MHz, CDCl3) δ7.73 (ddd, J=43.1, 5.4, 3.1Hz, 4H), 6.53 (dd, J=16.1, 8.6Hz, 3H) , 4.98 (dd, J=9.9, 6.5Hz, 1H), 3.49-3.35 (m, 2H), 1.57 (d, J=14.9Hz, 6H), 1.44 (s, 9H). 13C NMR (101MHz, CDCl3) δ167.98, 167.82, 147.59, 146.25, 134.11, 131.88, 130.31, 123.49, 121.39, 117.77, 82.84, 54.57, 34.53, 28.03, 25.86.HRMS Calcd for[M+H] + 424.1755, found 424.1733.

[0197] 2-7: Synthesis of H-DOPA(Acetonide)-OtBu

[0198] In a 500 mL flask, Phth-DOPA(Acetonide)-OtBu (0.423 g, 1 mmol), 60 mL DCM, 60 mL methanol, and 2 mL hydrazine hydrate (5 mmol) were added. The flask was sealed with a rubber stopper and stirred at room temperature for 3 h. The volatile solvent was removed by rotary evaporation, and the mixture was extracted with 60 mL DCM and refrigerated. The white precipitate was removed by filtration, and after rotary evaporation, 0.24 g of a colorless oil was obtained, with a yield of 83%. 1 H NMR (400MHz, CDCl3) δ6.59 (m, 3H), 3.66 (s, 1H), 2.93 (dd, 1H), 2.84 (dd, 1H), 1.60 (s, 6H), 1.38 (s, 9H). 13 C NMR (101MHz, CDCl3) δ172.35, 147.63, 146.48, 129.31, 121.98, 117.88, 109.51, 108.11, 82.12, 55.76, 39.47, 27.94, 25.83.HRMS Calcd for [M+H] + 294.1700, found 294.1686.

[0199] 2-8: Synthesis of Boc-DOPA(Acetonide)-Asp-Phe-OMe

[0200] In a 250 mL flask, add Boc-DOPA(Acetonide)-OH (3.37 g, 10 mmol), HOSu (1.73 g, 15 mmol), 150 mL of dry DCM and DCC (2.26 g, 11 mmol), stir for 12 h, filter, and retain the filtrate. In another flask, add aspartame (2.94 g, 10 mmol), 50 mL of DMF, and 3.23 mL of DIEA (20 mmol), and slowly add the above filtrate, continuing the reaction for 12-16 h. Adjust the pH to 3 with 0.1 M citric acid solution, extract with EA; wash the organic phase with water, dry with MgSO4, filter and rotary evaporate to obtain the crude product; separate by silica gel column chromatography using EA / HXN (0.5% acetic acid) as the mobile phase, to obtain 3.1 g of white powder, yield 50%, HPLC RT 17.5 min.

[0201]

[0202] 1 H NMR (400MHz, CDCl3) δ7.44 (d, J=8.0Hz, 1H), 7.22-7.01 (m, 6H), 6.52 (d, J=7.0Hz, 1H), 4.87-4.54 (m, 2H ), 3.57 (s, 3H), 2.99 (m, 3H), 2.91-2.69 (m, 3H), 2.61 (dd, J=17.1, 6.4Hz, 1H), 1.55 (s, 6H), 1.28 (s, 9H). 13 C NMR (101 MHz, CDCl3)δ 13 C NMR (101MHz, CDCl3) δ175.67, 174.39, 172.15, 171.69, 170.26, 155.93, 147.72, 146.52, 135.94, 129.35, 128.68, 12 7.22, 121.88, 117.98, 109.45, 108.22, 80.63, 55.84, 54.03, 52.43, 49.32, 37.99, 37.78, 35.83, 28.30, 25.92.HRMS Calcd for[MH] - 612.2562, found 612.2563.

[0203] Synthesis of the 2-9 tripeptide H-DOPA-Asp-Phe-OMe

[0204] Take a 50 mL flask, add Boc-DOPA(Acetonide)-Asp-Phe-OMe (0.2 g), deprotection solution (10 mL 2M HCl DIOX solution, 0.25 mL TIS and 0.25 mL water), stir and react for 2 h; the mixture is rotary evaporated to obtain crude product, dissolved in 1 mL methanol, precipitated with ice-cold diethyl ether, centrifuged and dried to obtain white solid, yield 54%, HPLC RT 11.6 min.

[0205] Example 3: Preparation of Tanshinone-type Catechol Derivatives

[0206]

[0207] 3-1: Oxa-Pictet-Spengler reaction product of D-tanshinone methyl ester (3B-2)

[0208] Tanshinone B (content 60%) was hydrolyzed under high pressure to convert into tanshinone A and tanshinone; then reacted with SOCl2 / MeOH to generate a mixture of D-tanshinone methyl ester and tanshinone A methyl ester; this mixture underwent an acetone cyclization reaction in an acetone-benzene-TsOH-DMP system, and a colorless crystal was isolated, which was characterized as compound 3B-2.

[0209] 1 H NMR (400MHz, CDC13) δ6.45 (s, 1H), 6.43 (s 2H), 4.42 (dd, J=11.4, 3.2Hz, 1H), 3.79 (s, 3H), 2.94 (dd, J=15.6, 11.4Hz, 1H), 2.81 (dd, J=15.7, 3.2Hz, 1H), 1.64 (s, 6H), 1.55 (s, 3H), 1.49 (s, 3H). 13 C NMR (101MHz, CDC13) δ172.04, 146.47, 146.04, 134.71, 123.80, 117.93, 108.03, 105.10, 76.74, 68.84, 52.33, 32.34, 31.39, 28.43, 25.94.HRMSCalcd for[M+Na] + , 315.1203, found 315.1201.

[0210] 3-2: Synthesis of Methyl Rosmarinate (3B-3)

[0211] Method A: In a 500 mL flask, rosmarinic acid (5 g, 13.8 mmol) and 100 mL anhydrous methanol were added. The flask was cooled in an ice bath and magnetically stirred. SOCl2 (1.5 mL, 20.7 mmol) was slowly added dropwise. The ice bath was removed, and the mixture was allowed to warm. The reaction was monitored by HPLC, and the reaction was complete after 1–1.5 h. The solvent was removed by rotary evaporation, and the product was dried under vacuum to obtain crude methyl rosmarinic acid product 3B-3 with a purity of 95%.

[0212] Method B involves adding 5 g of rosmarinic acid (13.8 mmol), 25 mL of anhydrous methanol, 100 mL of DMP, and 17.25 mL of catalyst Me3SiCl to a 250 mL flask and stirring for 3 h. The solvent is removed by rotary evaporation, and the residue is dried in a vacuum drying phase with a purity of 95%.

[0213] HPLC RT 11.4min; HRMS Calcd for [M+Na] + 397.0894, found 397.0898.

[0214] 3-3: Synthesis of diacetone-protected methyl rosmarinic acid (3B-4)

[0215] In a 250 mL three-necked flask, methyl rosmarinate (1.46 g, 3.6 mmol) was dissolved in 10 mL of acetone, and 150 mL of benzene was added. Argon gas was introduced, an oil seal was established, and the mixture was magnetically stirred and heated to reflux for 10–30 min. DMP (3.5 mL, 8 eq.) and TsOH (0.12 g, 0.2 eq.) were added, and the reaction was moved to equilibrium using CaCl2 adsorbent. The mixture was refluxed for 2–5 h, and the reaction progress was monitored by TLC. After rotary evaporation and silica gel column chromatography, 1.37 g of a yellow oily substance was obtained, with a yield of 83% and an HPLC RT of 22.1 min. 1H NMR (400MHz, CDCl3) δ7.60 (d, J=15.9Hz, 1H), 7.00-6.93 (m, 2H), 6.71 (d, J=7.9Hz, 1H), 6.66-6.64 (m, 3H), 6.27 (d, J=15.9Hz, 1H), 5.27 (dd , J=7.7, 4.8Hz, 1H), 3.74 (s, 3H), 3.12 (dd, J=14.1, 4.8Hz, 1H), 3.07 (dd, J=14.1, 7.7Hz, 1H), 1.68 (s, 6H), 1.654 (s, 3H), 1.648 (s, 3H).13C NMR (101MHz, CDCl3) δ170.48, 166.60, 149.93, 148.28, 147.59, 146.57, 146.26, 129.04, 128.16, 124.54, 1 21.93, 119.09, 117.98, 114.39, 109.64, 108.49, 108.15, 106.54, 73.26, 52.43, 37.38, 26.00, 25.96.HRMS Calcd for[M+Na] + , 477.1520, found 477.1535.

[0216] 3-4: Synthesis of rosmarinic acid (3B-5) protected by diacetone

[0217] In a 50 mL single-necked flask, compound 3B-4 (0.26 g, 0.57 mmol), 12 mL THF, and 6 mL water were added. The flask was cooled in an ice bath, and LiOH (0.027 g, 1.14 mmol) solution was added dropwise. The reaction was stirred for 2 h, and the reaction progress was monitored by TLC (EA / PE / acetic acid = 1:2:0.01, R0). f =0.43). After adding saturated ammonium chloride solution, extracting with EA, washing the organic phase with water, drying with MgSO4, filtering and rotary evaporating, the crude product 3B-5 was obtained, which was then purified by liquid column chromatography (EA / PE) with a yield of 98% and an HPLC RT of 19.7 min. 1 H NMR (400MHz, CDCl3) δ7.61 (d, J=15.9Hz, 1H), 6.96 (d, J=8.7Hz, 2H), 6.67 (dt, J=16.7, 9.3Hz, 4H), 6. 25 (t, J=14.9Hz, 2H), 5.29 (d, J=4.2Hz, 1H), 3.14 (ddd, J=22.8, 14.4, 6.0Hz, 2H), 1.73-1.56 (m, 12H). 13C NMR (101MHz, CDCl3) δ174.54, 166.77, 149.95, 148.26, 147.57, 146.57, 146.52, 129.02, 128.14, 124.63, 122.01, 119.10, 118.00, 114.22, 109.69, 108.48, 108.20, 106.61, 77.16, 73.12, 37.15, 25.95.HRMSCalcd for [MH]-439.1398, found 439.1416.

[0218] 3-5: Synthesis of monoacetone-protected methyl rosmarinic acid (3B-6)

[0219] In a 250 mL three-necked flask, methyl rosmarinate (1.46 g, 3.6 mmol) was dissolved in 10 mL of acetone, and 150 mL of benzene was added. Argon gas was introduced, an oil seal was established, and the mixture was magnetically stirred and heated to reflux for 10–30 min. DMP (0.88 mL, 2 eq.) and TsOH (17 mg, 2.5%) were added, and a small amount of CaCl2 was used to move the reaction to equilibrium. The mixture was refluxed for 1–1.5 h, and HPLC was used to monitor the reaction progress, revealing a peak (RT 17.5 min) accounting for approximately 80%. 1 HNMR (400MHz, MEOD) δ7.56 (d, J=15.8Hz, 1H), 7.04 (d, J=2.1Hz, 1H), 6.94 (dd, J=8.1, 2.1Hz, 1H), 6.77 (d, J=8.1Hz, 1H), 6.70-6.63 (m, 3H), 6.25 ( d, J=15.8Hz, 1H), 5.21 (dd, J=7.6, 5.1Hz, 1H), 3.71 (s, 3H), 3.11 (dd, J=14.2, 5.1Hz, 1H), 3.06 (dd, J=14.2, 7.6Hz, 1H), 1.62 (s, 3H), 1.61 (s, 3H). 13 C NMR (101MHz, MEOD) δ171.98, 168.23, 149.87, 148.82, 148.01, 147.83, 146.80, 130.31, 127.46, 12 3.24, 123.00, 118.97, 116.50, 115.24, 114.01, 110.50, 108.89, 74.50, 52.71, 38.09, 25.88.HRMS Calcd for [MH]-413.1242, found 413.1257.

[0220] 3-6: Synthesis of D-tanshinone methyl ester (3B-7) protected by acetal condensate

[0221] In a 50 mL single-necked flask, compound 3B-4 (0.454 g, 1 mmol) was added, followed by 10 mL of anhydrous methanol. The mixture was then cooled in an ice bath. 10 mL of anhydrous methanol solution of sodium methoxide (0.054 g, 1 mmol) was added. The reaction was monitored by TLC, and the reaction was complete in approximately 1 hour. 30 mL of saturated ammonium chloride solution was added, and the mixture was extracted with EA. The organic phase was washed with water, dried over MgSO4, filtered, and rotary evaporated to obtain the crude product. This crude product was then purified by liquid chromatography (EA / PE elution = 1:5) to give 0.2 g of a yellow solid, with a yield of 80%. HPLC RT 14.7 min. 1 H NMR (400MHz, MEOD) δ6.63 (t, J=1.2Hz 1H), 6.61 (d, J=1.2Hz, 2H), 4.30 (dd, J=7.6, 4.9Hz, 1H), 3.69 (s, 3H), 2.95 (dd, J=13.9, 4.9Hz, 1H), 2.81 (dd, J=13.9, 7.6Hz, 1H), 1.61 (s, 6H); 13 C NMR (101MHz, MEOD) δ175.70, 148.68, 147.51, 131.48, 122.93, 118.71, 110.57, 108.73, 73.17, 52.34, 41.30, 25.91.HRMS Calcd for [MH] - , 251.0925, found 251.0938.

[0222] 3-7: Synthesis of L-tanshinone methyl ester (3B-8) protected by acetal condensate

[0223] In a 100 mL double-necked flask, add H-DOPA (Acetonide)-OMe (1.12 g, 4.4 mmol) and 5 mL THF. After cooling with a saline-ice bath (-5 °C), add acetic acid solution (36%, 3.5 mL); then add 10 mL of sodium nitrite solution (0.455 g, 6.6 mmol). After removing the ice bath and warming to room temperature, stirring was continued for 1 hour. Extraction was performed using EA. The organic phase was washed with water and dried with anhydrous MgSO4. The HPLC peak (RT 14.7 min) accounted for approximately 35%. Semi-preparative HPLC separation was used, and structural characterization confirmed that the peak corresponded to 3B-8. 1H NMR (400 MHz, MEOD) δ 6.63 (s, 1H), 6.61 (s, 2H), 4.30 (m, 1H), 3.69 (s, 3H), 2.95 (m, 1H), 2.81 (m, 1H), 1.61 (s, 6H). 13C NMR (101MHz, MEOD) δ175.70, 148.73, 147.57, 131.52, 122.94, 118.72, 110.58, 108.73, 73.21, 52.31, 41.34, 25.90.HRMS Calcd for [M+H] + , 253.1071, found 253.1075.

[0224] 3-8: Synthesis of Boc-DSS-(Acetonide)-OMe (3B-9)

[0225] In a 10 mL flask, add 3B-7 (0.10 g, 0.4 mmol), DCC (0.13 g, 0.6 mmol), and 10 mL of dry DCM. After stirring to dissolve, add 4-dimethylaminopyridine (DMAP) (10 mg, 0.2 eq.) and react at room temperature for 30 min. Add 10 mL of 0.1 M lemon solution, extract three times with EA, wash the organic phase with water, dry to MgSO4, filter, and rotary evaporate to obtain the crude product. Then purify by liquid chromatography (EA / PE = 1:5) to obtain a yellow oily substance with a yield of 98% (HPLC RT 20.4 min). 1 H NMR (400MHz, CDCl3) δ6.66-6.58 (m, 3H), 5.02 (dd, J=8.2, 4.7Hz, 1H), 3.76-3.69 (m, 3H), 3.02 (qd, J=14.4, 6.5Hz, 2H), 1.64 (s, 6H), 1.44 (s, 9H). 13 C NMR (101MHz, CDCl3) 6170.28, 152.87, 147.56, 146.56, 128.78, 121.96, 117.90 ,109.64,108.14,83.11,77.16,77.16,75.51,52.36,37.34,27.74,25.92.HRMS Calcd for[M+Na] + 375.1414, found 375.1421.

[0226] 3-9: Synthesis of Boc-DSS-(Acetonide)-OH (3B-10)

[0227] In a 10 mL flask, add 3B-9 (0.18 g, 0.5 mmol), 10 mL THF, and 5 mL water; slowly add 12 mL LiOH (0.027 g, 1.14 mmol) solution dropwise, and stir the reaction at room temperature for 2 h. Quench with saturated ammonium chloride solution, extract with EA, wash the organic phase with water, dry with MgSO4, filter, and rotary evaporate to obtain the crude product, which is then purified by liquid chromatography (EA / PE) to obtain a yellow solid with a yield of 98% (HPLC RT 17.6 min). 1 H NMR (400MHz, CDCl3) δ6.68-6.63 (m, 3H), 5.07 (dd, J=8.6, 4.2Hz, 1H), 3.15-2.99 (m, 2H), 1.65 (s, 6H), 1.44 (d, J=10.0Hz, 9H). 13 C NMR (101MHZ, CDCl3) δ175.65, 152.87, 147.59, 146.63, 128.61, 122.05, 117.98, 109.69, 108.22, 83.43, 77.16, 76.84, 37.14, 27.75, 25.95.HRMS Calcd for[MH] - 337.1293, found 337.1273.

[0228] 3-10: Synthesis of Fmoc-Val-D-DSS(Acetonide)-OMe (3B-11)

[0229] In a 50 mL flask, 3B-7 (0.1 g, 0.4 mmol), Fmoc-Val-OH (0.136 g, 0.4 mmol), 10 mL LDCM, DCC (0.1 g, 0.48 mmol), and DMAP (10 mg, 0.2 eq.) were added; the mixture was stirred at room temperature for 3 h. The precipitate was removed by filtration, and the organic phase was washed with water, dried over MgSO4, filtered, and rotary evaporated to obtain the crude product. This crude product was then purified by high-performance liquid chromatography (EA / PE) to give a white solid in 89% yield (HPLC RT 23.35 min). 1HNMR (400MHz, CDCl3) δ7.77 (d, J=7.5Hz, 2H), 7.61 (d, J=7.1Hz, 2H), 7.36 (dt, J= 34.6, 7.4Hz, 4H), 6.62 (d, J=8.3Hz, 3H), 5.26 (d, J=7.8Hz, 1H), 4.57-4.27 (m, 3H ), 4.24 (t, J=7.0Hz, 1H), 3.75 (s, 3H), 3.07 (ddd, J=23.8, 14.2, 6.5Hz, 2H), 2.11 (dt, J=34.9, 17.4Hz, 1H), 1.63 (s, 6H), 0.99-0.82 (m, 3H), 0.72 (d, J=6.8Hz, 3H). 13 C NMR (101MHz, CDCl3) δ171.48, 169.59, 156.23, 147.68, 146.64, 144.04, 143.90, 141.41, 128.65, 127.81, 127.17, 125.22, 125.19, 121.83, 120.08, 118.03, 109.39, 108.20, 77.16, 73.93, 67.18, 58.94, 52.93, 47.29, 37.06, 31.33, 26.10, 18.91, 16.88.HRMSCalcd for[M+Na] + , 337.1293, found 337.1273.

[0230] 3-11: Synthesis of acetone-protected caffeic acid dimer (3B-12)

[0231] In a 10 mL flask, add 3B-1 (0.11 g, 0.5 mmol), 1 mL of ethanol and 4 mL of water to form a suspension. Place the suspension in front of a black light lamp at 300 nm-400 nm and stir overnight at room temperature. Filter to obtain the crude product. Recrystallize in methanol to obtain white crystals with a purity ≥99% and a yield of 94%. HPLC RT 15.4 min. 1H NMR (400MHz, DMSO-d6) δ6.83 (s, 2H), 6.79-6.66 (m, 4H), 4.15 (dd, J=10.3, 7.4Hz, 2H), 3.67 (dd, J=10.3, 7.3Hz, 2H), 1.62 (s, 12H).13C NMR (101MHz, DMSO-d6) δ173.08, 146.77, 145.66, 132.77, 120.43, 117.78, 107.98, 107.71 ,46.69,40.81,40.15,39.94,39.73,39.52,39.52,39.31,39.10,38.89,25.62.HRMSCalcd for[MH] - 439.1398, found 439.1394.

[0232] 3-12: Synthesis of tert-butyl rosmarinic acid protected by diacetone (3B-13)

[0233] In a 50 mL flask, 3B-5 (0.09 g, 0.2 mmol), tert-butanol (0.86 mL), and 9 mL of dry DCM were added and stirred until well mixed. Then, DCC (0.05 g, 0.24 mmol) and DMAP (0.122 g, 0.5 mmol) were added, and the mixture was stirred for 3–4 h. Extraction was performed using EA. The organic phase was washed with water, dried over MgSO4, filtered, and rotary evaporated to obtain a crude product. This crude product was then separated by semi-preparative HPLC and freeze-dried to obtain a yellow oily substance with a yield of 60%. HPLC RT was 24.1 min. 1 H NMR (400MHz, CDCl3) δ7.75-7.69 (m, 1H), 7.09-7.05 (m, 2H), 6.84-6.75 (m, 4H), 6.42-6.36 (m, 1H), 5.25 (dd, J =7.1, 5.8Hz, 1H), 3.22-3.16 (m, 2H), 1.80-1.75 (m, 12H), 1.54 (s, 9H).13CNMR (101MHz, CDCl3) δ168.97, 166.6 0, 149.81, 148.25, 147.48, 146.43, 145.85, 129.30, 128.18, 124.38, 122.02, 119.02, 118.00, 114.74, 109.80 , 108.53, 107.93, 106.56, 82.32, 77.16, 73.65, 37.34, 28.12, 25.55.HRMSCalcd.for[M+Na]+519.1989, found 519.1983.

[0234] 3-13: Synthesis of a diacetone-protected rosmarinic acid-isoborneol complex (3B-14)

[0235] In a 50 mL single-necked flask, 3B-5 (0.88 g, 0.2 mmol), isoborneol (62 mg, 0.4 mmol), and 8 mL of LDCM were added and stirred until homogeneous. Then, DCC (50 mg, 0.4 mmol) and DMAP (48.8 mg, 0.4 mmol) were added, and the mixture was stirred for 3–6 h. Extraction was performed using EA, and the organic phase was dried over water and MgSO4, filtered, and rotary evaporated. Separation by semi-preparative HPLC yielded a white solid powder with a yield of 70% and an HPLC RT of 30.3 min. 1 H NMR (400MHz, MeOD) δ8.27-5.68 (m, 6H), 4.88 (s, 10H), 4.60 (s, 1H), 3.06 (dd, J=15.8, 10.1Hz, 2H), 1.56 (dd, J=69.8, 64.3Hz, 12H), 1.19 (ddd, J=81.4, 32.5, 25.5Hz, 3H), 0.98-0.57 (m, 6H). 13 C NMR (101MHz, MeOD) δ171.16, 168.07, 151.36, 149.69, 148.90, 147.98, 147.45, 130.10, 129.46, 125.78, 123.22, 120.26, 119.01, 115. 27, 110.66, 109.38, 108.94, 107.38, 83.52, 74.97, 49.00, 47.84, 46.37, 39.40, 38.23, 34.69, 27.85, 26.00, 25.95, 20.45, 11.71.HRMS Calcd for[M+Na]+ 599.2615, found 599.2626.

[0236] 3-14: Synthesis of a diacetone-protected rosmarinic acid-phenylalanine complex (3B-15)

[0237] In a 10 mL three-necked flask, Ar was bubbled through for 10 min. Then, 3B-5 (0.88 mg, 0.2 mmol), DCC (50 mg, 0.24 mmol), HOSu (46 mg, 0.4 mmol), and 10 mL of dry DCM were added and stirred until dissolved. Next, H-Phe-OtBu hydrochloride (51.5 mg, 0.2 mmol) and DIEA (0.1 mL, 0.2 mmol) were added, and the reaction was stirred for 4 h. The yield was 98% (HPLC), with HPLC RT 23.9 min. 1H NMR (400MHz, Methanol-d4) δ7.57 (d, J=15.8Hz, 1H), 7.25-7.10 (m, 6H), 7.08 -6.99 (m, 2H), 6.75 (d, J=8.0Hz, 1H), 6.63 (s, 1H), 6.59 (s, 2H), 6.31 (d, J=15. 8Hz, 1H), 5.22(dd,J=7.4, 5.5Hz, 1H), 4.53(dd,J=8.2, 6.0Hz, 1H), 3.07(dd,J =13.8, 6.0Hz, 1H), 2.99-2.84(m, 3H), 1.66(s, 6H), 1.58(s, 6H), 1.41(s, 9H). 13 C NMR (101MHz, MEOD) δ171.97, 171.57, 167.51, 151.34, 149.67, 148.83, 147.80, 147.43, 137.97, 130.45, 130.42, 129.51, 129.47, 127.87, 125.80,123.10,120.23,118.89,115.29,110.63,109.35,108.87,107.41,83.16,75.65,55.45,38.83,38.35,28.21,25.94,25.92.HRMS Calcd for[M+H] + 644.2854, found 644.2851.

[0238] 3-15: Coupling of acetone-protected methyl rosmarinic acid 3B-4

[0239] In a 50 mL flask, caffeic acid protected with acetal (0.044 g, 0.2 mmol), D-tanshinone methyl ester protected with acetal (0.05 g, 0.2 mmol), 10 mL of dry dichloromethane, dicyclohexylcarbodiimide (0.045 g, 0.22 mmol), and DMAP (0.016 g, 0.1 mmol) were added, and the mixture was reacted under magnetic stirring for 12 h. The reaction progress was monitored by HPLC, and the peak (RT 22.1 min) accounted for approximately 98% of the total; its retention time was consistent with that of the 3B-4 mixture.

[0240] 3-16: Synthesis of acetal-protected shimobashiric acid C-methyl ester (3B-16)

[0241] In a 50 mL flask, 3B-7 (0.75 g, 3 mmol), 3B-11 (0.66 g, 1.5 mmol), and 100 mL of dry DCM, DMAP (0.75 g, 4.6 mmol), and DCC (0.75 g, 3.6 mmol) were added. The reaction was monitored by HPLC and ended in approximately 4 hours. The precipitate was removed by filtration. The organic phase was washed with water, dried, filtered, and rotary evaporated to obtain the crude product. This crude product was then purified by liquid column chromatography (DCM) to give 1.27 g of a white solid, with a yield of 85%. HPLC RT 25.1 min. 1 H NMR (400MHz, CDCl3) δ6.64-6.41 (m, 12H), 4.91 (dd, J=7.8, 5.3Hz, 1H), 4.76 (t, J=6.1Hz, 1H), 4.31-4.22 (m, 2H), 3.90 -3.83 (m, 2H), 3.59 (d, J=14.4Hz, 6H), 2.88 (ddd, J=22.0, 14.1, 6.6Hz, 2H), 2.76-2.61 (m, 2H), 1.63 (t, J=8.4Hz, 24H). 13 C NMR (101MHz, CDCl3) δ171.52, 170.83, 169.86, 169.60, 147.69, 147.64, 147.62, 147.50, 146.6 6, 146.59, 146.57, 146.56, 131.60, 131.48, 128.67, 128.61, 128.38, 128.33, 121.96, 121.92, 1 20.23, 119.96, 118.11, 117.99, 117.96, 109.65, 109.54, 108.25, 108.20, 108.10, 107.99, 107 .74, 77.16, 73.48, 73.44, 52.23, 47.07, 46.98, 41.77, 41.37, 37.43, 37.06, 25.97, 25.93.HRMS Calcd for[M+Na] + 931.3148, found 931.319.

[0242] 3-17: Synthesis of acetal-protected Shimobashiric acid C (3B-17)

[0243] In a 100 mL flask, compound 3B-16 (0.054 g, 0.58 mmol), 24 mL THF, and 12 mL water were added. After cooling in an ice bath, 12 mL of LiOH (0.086 g, 3.6 mmol) solution was slowly added dropwise, and the reaction was stirred for 4 h. The pH was adjusted to 4 with 0.5 M citric acid solution, and the mixture was extracted with EA. The organic phase was washed with water, dried, filtered, and rotary evaporated to obtain the crude product. The crude product was then purified by high-performance liquid chromatography (EA / PE) to give 0.05 g of a white solid, with a yield of 95% (HPLC RT 21.3 min). 1 H NMR (400MHz, CDCl3) δ6.62-6.45(m, 12H), 4.96-4.72(m, 2H), 4.33-4.18(m, 2H), 3.85(d d, J=17.1, 9.9Hz, 2H), 2.82 (dddd, J=41.4, 34.8, 14.3, 4.7Hz, 4H), 1.70-1.54 (m, 24H). 13 C NMR (101MHz, CDCl3) δ174.34, 173.91, 171.53, 170.81, 147.68, 147.63, 147.49, 146.65, 146.64, 146.60, 131.49, 131.20, 128.50, 128.27, 122.03, 120.19, 119. 96, 118.16, 118.06, 118.02, 109.73, 109.58, 108.29, 108.18, 107.66, 73.08, 73 .02, 47.02, 46.91, 41.72, 41.44, 37.21, 36.83, 26.01, 25.94, 25.86.HRMSCalcd for[MH] - , 879.2870, found 879.2872.

[0244] 3-18: Synthesis of Shimobashiric acid C-methyl ester (3B-18)

[0245] In a 10 mL flask, compound 3B-16 (0.06 g) and 6 mL of deprotection solution (TFA / DCM / H2O / Tis = 55:44:0.5:0.5) were added. The mixture was stirred in an ice bath for 2 h, concentrated by rotary evaporation, and then water was added and lyophilized to give 0.049 g of white solid, with a yield of nearly 100%. HPLC RT was performed for 11.4 min. 1H NMR (400MHz, MEOD) δ6.77-6.37 (m, 12H), 4.93 (s, 8H), 4.77 (d, J=6.2Hz, 1H), 4.56 (t, J=6.2Hz, 1H), 4.25-4.15 (m, 2H), 3.88 (dd, J =10.6, 7.2Hz, 1H), 3.77 (dd, J=10.5, 7.0Hz, 1H), 3.57 (t, J=14.4Hz, 6H), 2.86-2.75 (m, 2H), 2.62 (ddd, J=38.7, 14.0, 6.2Hz, 2H). 13 C NMR (101MHz, MEOD) δ173.21, 172.62, 171.95, 171.47, 146.18, 146.16, 146.03, 1 45.99, 145.50, 145.35, 145.29, 145.28, 131.47, 131.37, 128.34, 128.08, 122.01 ,120.37,119.66,117.54,117.40,116.40,116.36,116.31,116.27,115.96,115 .54, 74.94, 52.65, 52.56, 49.00, 48.32, 48.00, 42.66, 42.08, 37.88, 37.58.HRMS Calcd for[MH] - , 747.1931, found 747.1937.

[0246] 3-19: Synthesis of Shimobashiric acid C (3B-19)

[0247] In a 10 mL flask, 6 mL of deprotection solution (TFA / DCM / H2O / Tis = 55:44:0.5:0.5) was added. After cooling in an ice bath, 60 mg of 3B-17 was added, and the mixture was stirred in an ice bath for 4 h. The mixture was concentrated by rotary evaporation, water was added, and the solution was lyophilized to give 49 mg of a white solid. The yield was nearly 100%, the purity was 99%, and the reaction was performed by HPLC RT for 10.6 min. 1 H NMR (400MHz, MEOD) δ6.82-6.25 (m, 12H), 4.98 (s, 10H), 4.72 (dd, J=7.3, 5.2Hz, 1H), 4.57 (t, J=5.9Hz, 1H), 4.25-4. 14 (m, 2H), 3.91 (dd, J=10.5, 7.5Hz, 1H), 3.75 (dd, J=10.2, 6.8Hz, 1H), 2.75 (dddd, J=51.3, 45.1, 14.1, 5.4Hz, 4H). 13C NMR (101MHz, MEOD) δ173.37, 173.29, 172.83, 172.70, 146.15, 146.09, 145.93, 1 45.87, 145.40, 145.26, 145.16, 145.11, 131.62, 131.50, 128.83, 128.53, 122.18 , 122.15, 120.51, 119.34, 117.77, 117.49, 116.46, 116.39, 116.39, 116.24, 115. 98, 115.49, 74.91, 74.81, 49.00, 48.57, 47.88, 42.74, 41.99, 37.80, 37.48.HRMS Calcd for[MH] - , 719.1618.found 719.1618.

[0248] 3-20: Screening of reaction conditions for highly selective acetone decondensation

[0249] To explore highly selective deprotection conditions that can rapidly and completely remove acetal protection without disrupting unstable intramolecular ester bonds, this invention used 3B-4 and 3B-16 as substrates, TFA, HCl, and acetic acid as catalysts, and DCM, THF, DIOX, and H2O as solvents. The effects of various deprotection conditions were monitored using HPLC. Approximately 20 mg of 3B-4 was deprotected in 2 ml of a mixed solution (TFA / DCM / H2O / TIS, 50 / 40 / 5 / 5) at room temperature: after 30 min, 3B-4 was undetectable, and the product 3B-3 accounted for approximately 90%; after 1 h, 3B-3 accounted for approximately 87%. Deprotection was also performed in 2 ml of a mixed solution (TFA / DCM / H2O / TIS, 25 / 65 / 5 / 5) at room temperature; after 30 min, 3B-4 was undetectable, and 3B-3 accounted for 93%; after 1 h, 3B-3 accounted for 91%. Deprotection was performed using a 2 ml mixture (TFA / DCM / H2O / TIS, 50 / 40 / 5 / 5) under ice bath conditions; after 30 min of reaction, 3B-4 was undetectable, and 3B-3 accounted for 94%. Ultimately, it was found that using a 50-70% TFADCM solution in the presence of trace amounts of water resulted in the best selective deprotection effect against acetone. For example, the deprotection methods used in Examples 3-19 and 3-18.

[0250] Example 4: Preparation of Dopamine Oligopeptide Solid Formulation (DOSF) Based on Catechol Derivatives

[0251] 4-1: DOSF-1 freeze-dried powder;

[0252] Weigh 9.3g of H-Met-DOPA-OH hydrochloride and dissolve it in 30mL of water. Under Ar protection, add about 220mL of 0.1M NaOH solution (Ar to remove oxygen) dropwise to adjust the pH to 5.6. Freeze-dry to obtain a fluffy white solid, which is DOSF-1 lyophilized powder.

[0253] 4-2: DOSF-2 freeze-dried powder;

[0254] Weigh 8.4g of H-Val-DOPA-OH hydrochloride and dissolve it in 30mL of water. Under Ar protection, add about 220mL of 0.1M NaOH solution (Ar to remove oxygen) dropwise to adjust the pH to 5.6. Freeze-dry to obtain a fluffy white solid, which is DOSF-2 lyophilized powder.

[0255] 4-3: DOSF-3 powder;

[0256] Weigh out 0.84g of DOSF-1 lyophilized powder, 0.148g of benzylhydrazine hydrochloride, 40mg of sodium sulfite, 24mg of L-DOPA, 0.2g of sodium carboxymethyl cellulose, and 0.1g of sodium citrate, mix them thoroughly, and grind them evenly to form a solid powder formulation, namely DOSF-3 powder.

[0257] When using, take a vial containing DOSF-3 powder, add 20 mL of solvent PPM-2 (1% sodium carboxymethyl cellulose aqueous solution), shake for 5-30 minutes to obtain a clear and homogeneous solution.

[0258] 4-4: DOSF-4 powder;

[0259] Weigh out 0.84g of DOSF-2 lyophilized powder, 0.148g of benzylhydrazine hydrochloride, 40mg of sodium sulfite, 24mg of L-DOPA, 0.2g of sodium carboxymethyl cellulose, and 0.1g of sodium citrate, mix them thoroughly, and grind them evenly to form a solid powder formulation, namely DOSF-4 powder.

[0260] DOSF-4 powder can be used as an alternative to Duopa. 30 minutes before use, take a vial containing DOSF-4 powder, add 20 mL of solvent PPM-2 (1% sodium carboxymethyl cellulose aqueous solution), shake for 5-30 minutes to obtain a clear and homogeneous solution. This solution does not contain any insoluble matter, has a certain viscosity, and exhibits thixotropy: it forms a gel when standing, and forms a sol when pressure is applied. The sol can be passed through a syringe.

[0261] 4-5: DOSF-5 granules;

[0262] Weigh 0.84g of DOSF-1 lyophilized powder, 0.148g of benzylhydrazine hydrochloride, 40mg of sodium sulfite, 24mg of L-DOPA, and 0.1g of sodium citrate and mix them well. Add 3g of sucrose, grind and mix evenly, add a small amount of water to make a soft material, pass the soft material through a 10-mesh nylon sieve to obtain wetted granules, place the wetted granules in a vacuum drying oven to dry them to obtain dry granules, pass the dry granules through a 10-mesh sieve, then through a No. 5 sieve to remove fine powder, and then package them to obtain DOSF-5 granules.

[0263] 4-6: DOSF-6 tablets;

[0264] Weigh 0.84g of DOSF-1 lyophilized powder, 0.148g of benzylhydrazine hydrochloride, 40mg of sodium sulfite, 24mg of L-DOPA, and 0.1g of sodium citrate and mix them well. Then add 3g of sucrose and 25mg of magnesium stearate, grind and mix evenly to form granules. Compress the granules into tablets using a tableting machine to obtain DOSF-6 tablets.

[0265] 4-7: Oral liquid;

[0266] The above-mentioned dopa-containing dipeptide and carbidopa dipeptide powder, granules or tablets are added to a 0.01 g / mL sucrose aqueous solution (or a 0.0001 g / mL aspartame aqueous solution) to prepare an oral solution. The dopa dipeptide in the oral solution has good water solubility, is relatively stable, does not precipitate, and has no particulate matter. At the same time, it has a good taste, which greatly improves patients' medication compliance, thereby better controlling the symptoms, stabilizing blood drug concentration, and improving patients' quality of life.

[0267] Example 5: Oral continuous or intermittent drug delivery device

[0268] like Figure 1 As shown, the oral continuous or intermittent drug delivery device is designed as a "milk tea cup", including a cup lid 100 and a cup body 200; the cup body and cup lid are made of plastic or metal materials or a combination of both, making the cup lightweight and portable, not easily broken, relatively stable, easy to change the color and shape of the cup body, and easy to adapt to the storage and use of drugs.

[0269] The outer shell 201 of the cup is made of plastic cloth and metal. The space enclosed by the outer shell is called the cup body 200. The cup body 200 contains all the medicine liquid to be used within a certain period of time. By controlling the amount of medicine liquid, it is ensured that the patient finishes taking it within the corresponding time and that the medicine does not deteriorate or settle.

[0270] like Figure 2As shown, the cup lid 100 is equipped with a switch button 101, a battery compartment 102, a micro peristaltic pump 103, a delivery tube 104 (i.e., an oral liquid delivery tube), and an output tube 105 (i.e., an oral liquid output tube); a metering pool 108 is provided at the lower end of the cup lid. The metering pool 108 is small, with a volume of about 25ml. When the cup lid and the cup body are connected, the metering pool 108 is located inside the cup body.

[0271] The switch button 101 is used to turn the miniature peristaltic pump on or off; the battery slot 102 is used to install a battery, such as a 1.5V-3V battery, to power the miniature peristaltic pump; the delivery tube 104 is installed on the miniature peristaltic pump, with one end of the delivery tube 104 located at the bottom of the cup body and the other end located at the bottom of the metering pool; the miniature peristaltic pump 103 is used to pump the liquid medicine in the cup body 200 into the metering pool 108 at the right time and in the right amount through the delivery tube, controlling the amount of medicine taken by the patient each time to be appropriate, and the cutoff threshold can be adjusted. If the patient has not drunk for more than 10 minutes, the miniature peristaltic pump will no longer pump the liquid medicine into the metering pool, which ensures that the amount of liquid medicine is not too large when the patient takes it next time, which may cause motor complications (dyskinesia), etc.; the output tube 105 passes through the upper part of the cup lid and extends into the metering pool 108, which is used by the patient to draw the liquid medicine from the metering pool. That is, the output tube inserted into the metering pool can be used as a straw for the patient to drink directly, or it can be connected to other auxiliary drinking tubes.

[0272] Furthermore, in one embodiment, the cup lid 100 is also provided with a speed adjustment button 106 and a flow rate display screen 107. The speed adjustment button 106 is used to adjust the current flow rate of the medicine being pumped from the cup into the metering pool, that is, the speed adjustment button 106 is used to adjust the amount of medicine delivered per minute according to the patient's needs; the flow rate display screen 107 displays the current flow rate of the medicine being pumped from the cup into the metering pool.

[0273] like Figure 1 The cup body and lid shown are detachably connected. For example, the cup body and lid can be tightly connected by threads, or they can be connected by snap fasteners, magnetic attraction, or other suitable methods; rubber rings or silicone rings can be used or not to help with sealing.

[0274] The oral continuous or intermittent drug delivery device disclosed in this invention is similar to a water cup, which can pump an appropriate amount of medication from the cup into a storage metering pool at regular intervals. Patients only need to take the oral tablets of Parkinson's disease in the morning or at noon, 2 hours later, when the blood drug concentration is about to drop, to start using the oral liquid in Example 12 of this invention. The oral liquid is administered through the oral continuous or intermittent drug delivery device of this invention. Patients drink the oral liquid every 5-10 minutes, which can stabilize the blood drug concentration at 2-5 micrograms / ml until the next dose of tablet medication is taken. The oral liquid in Example 12 and the drug delivery method disclosed in this invention can greatly reduce the pain of taking medication while stabilizing the blood drug concentration. The appropriate sweetness ratio can enhance the patient's pleasure in taking medication. The drug delivery device is lightweight, convenient, and easy to carry. It can also be made into a cup shape such as a water bag, which can be well integrated into normal life, reduce the stigma of Parkinson's disease patients, and provide patients with a more comfortable and dignified life and treatment.

[0275] Example 6: Apparatus for the preparation of acetal / ketal protection of catechol groups

[0276] 6-1: Preparation Apparatus A

[0277] An apparatus A for preparing dopa oligopeptide intermediates, such as... Figure 3 As shown, it includes a reactor, a condensation device, an absorption tower, a gas pipeline, and a liquid pipeline; the reactor is connected to the condensation device via the gas pipeline, the reactor is connected to the absorption tower via the liquid pipeline, and the absorption tower is connected to the condensation device via the liquid pipeline, with valves installed on the liquid pipeline.

[0278] Through azeotropic distillation, volatile byproducts in the reactor are carried by a carrier through a gas pipeline to a condenser. After effective condensation in the condenser, condensate is formed. The condensate then enters an absorption tower (one or more) containing an absorbent through a liquid pipeline. The gradient absorption in the absorption tower completely removes the byproducts from the condensate. Finally, the condensate after the byproducts are removed returns to the reactor through a liquid pipeline, maximizing the shift of the reaction equilibrium to the forward direction.

[0279] Furthermore, in one embodiment, the preparation apparatus also includes a bubbler connected to a condenser; an inert gas pipeline is provided on the reactor.

[0280] The reactor includes, but is not limited to, flasks and reaction vessels; the gas pipeline includes, but is not limited to, glass tubes, plastic tubes, ceramic tubes, metal tubes, etc., preferably glass tubes with vacuum sleeves; the condensation equipment includes, but is not limited to, glass or metal condenser tubes, cold traps, etc., preferably glass condenser tubes; the absorption tower includes, but is not limited to, glass tubes, ceramic tubes, metal tubes, etc., preferably stainless steel tubes; the absorbent includes, but is not limited to, one or more of calcium chloride, molecular sieves, calcium oxide, caustic soda, magnesium sulfate, sodium sulfate, etc., in any combination of any two proportions, preferably calcium chloride; the liquid pipeline includes, but is not limited to, metal tubes, plastic tubes, rubber tubes, glass tubes, etc., preferably polytetrafluoroethylene plastic tubes.

[0281] Furthermore, in one embodiment, such as Figure 4 As shown, the condensation equipment and the absorption tower are vertically connected to form the preparation device A-1.

[0282] 6-2: Improved Constant Pressure Dropping Funnel A-1-1

[0283] The present invention also discloses a preparation apparatus for preparing dopa oligopeptide intermediates, including a reactor, a condensation device, a liquid pipeline, and an improved constant pressure dropping funnel (i.e., a device A-1-1 connecting the absorption tower and the gas pipeline); the reactor is connected to the lower end of the improved constant pressure dropping funnel through the liquid pipeline, and the condensation device is vertically connected to the upper end of the improved constant pressure dropping funnel through the liquid pipeline.

[0284] like Figure 5 As shown, the improved constant-pressure dropping funnel A-1-1 includes a dropping funnel body 1, a first constant-pressure tube 2, a vacuum sleeve 3, and a condensing sleeve 4. A regulating valve 11 is installed in the middle of the dropping funnel body 1, dividing it into an upper dropping funnel 12 and a lower dropping funnel 13. The first constant-pressure tube 2 connects the upper dropping funnel 12 and the lower dropping funnel 13. The upper dropping funnel 12 has a first upper interface 14 (i.e., an internal ground joint 40 / 38), and the lower dropping funnel has a first lower interface 15 (i.e., an external ground joint 24 / 29). A dropping nozzle is installed in the lower interface and communicates with the upper dropping funnel. A sand core plate 5 is installed at the lower end of the upper dropping funnel 12 body; the sand core plate is, for example, a sand core plate G3. The sand core plate provides support for the solid absorbent added to the improved constant-pressure dropping funnel, while ensuring that only condensed liquid flows into the reactor, without any solid absorbent.

[0285] The vacuum sleeve 3 is wrapped around the outside of the first constant pressure tube 2, ensuring the smooth passage of high-temperature distilled gas; and the inner diameter of the constant pressure tube (i.e., gas pipeline) is larger than that of a conventional constant pressure dripping funnel, for example, 12 mm; the outer diameter of the vacuum sleeve is for example, 20 mm.

[0286] The condenser sleeve 4 is fitted onto the upper part of the dropping funnel body 1. The height of the condenser sleeve is preferably half the height of the upper part of the dropping funnel body. The condenser sleeve 4 ensures that the absorbent works at a lower temperature, thus improving absorption efficiency and capacity. The coolant inlet connector 41 and outlet connector 42 of the condenser sleeve are both 8mm pagoda connectors. Moreover, the height of the condensate remaining on the sand core plate 5 can be selected by controlling the regulating valve 11, thus adjusting the contact time between the condensate and the absorbent. In the device A-1-1 of the present invention, the upper interface is wide, facilitating the removal and placement of the absorbent. The upper interface is connected to a condensation device (such as a glass condenser tube). The lower interface matches the reactor interface, serving as the outlet for distilled gas and the inlet for the condensate to return to the reactor. The improved constant pressure dropping funnel A-1-1 is mainly made of glass, with only the regulating valve using a polytetrafluoroethylene stopcock. Its volume is, for example, 250ml. The improved constant pressure dropping funnel A-1-1 disclosed in this invention combines the advantages of a constant pressure dropping funnel, a Soxhlet extractor, and a condenser tube.

[0287] Through azeotropic distillation, volatile byproducts in the reactor are carried by a carrier through a liquid pipeline to an improved constant-pressure dropping funnel A-1-1. The volatile byproduct gas enters the lower part of the dropping funnel, then passes through a constant-pressure tube into the upper part of the dropping funnel, then through the upper interface of the upper part of the dropping funnel, and enters the condenser through the liquid pipeline. After effective condensation in the condenser, condensate is formed. The condensate then enters the upper part of the dropping funnel through the upper interface through the liquid pipeline. The condensate passes through the sand core plate at the top of the dropping funnel, completely removing the byproducts from the condensate. Finally, the condensate after removing the byproducts flows into the lower part of the dropping funnel, and enters the liquid pipeline back into the reactor through the lower interface.

[0288] 6-3: Improved Soxhlet extractor intermediate tube A-1-2

[0289] The present invention also discloses a preparation apparatus for preparing dopa oligopeptide intermediates, including a reactor, a condenser, a liquid pipeline, and an improved Soxhlet extractor intermediate tube A-1-2; the reactor is connected to the lower end of the improved Soxhlet extractor intermediate tube through the liquid pipeline, and the condenser is vertically connected to the upper end of the improved Soxhlet extractor intermediate tube through the liquid pipeline.

[0290] like Figure 6As shown, the improved Soxhlet extractor intermediate tube includes a second lower interface 2.1 (i.e., the lower ground joint of the Soxhlet extractor, generally an external ground joint connected to the reaction flask), a second constant pressure tube 2.2 (i.e., the gas flow tube), a first glass tube sealed bottom 2.3, a first glass tube frosted bottom 2.4, a Soxhlet extractor body 2.5, a first siphon tube 2.6, a side ground joint 2.7 (generally an internal ground joint, connected to a finger-shaped condenser tube), and a second upper interface 2.8 (i.e., the upper ground joint, which is generally an internal ground joint, connected to the condenser tube); the first glass tube sealed bottom 2.3 divides the Soxhlet extractor body 2.5 into an upper part and a lower part, and the upper part of the Soxhlet extractor body is provided with a second upper interface 2.8 at the upper end, and the second upper interface 2.8 connects to the first glass tube. A side ground joint 2.7 is provided between the sealed bottom of the tube 2.3; the second constant pressure tube 2.2 connects the upper part and the lower part of the Soxhlet extractor body, the upper end of the second constant pressure tube 2.2 is located on the opposite side between the side ground joint 2.7 and the second upper interface 2.8, and the lower end is located between the sealed bottom of the first glass tube 2.3 and the second lower interface 2.1; the lower end of the upper part of the Soxhlet extractor body is provided with a first glass tube frosted bottom 2.4; the first siphon tube 2.6 connects the upper part and the lower part of the Soxhlet extractor body, the upper end of the first siphon tube 2.6 is located between the sealed bottom of the first glass tube 2.3 and the first glass tube frosted bottom 2.4, and the lower end is located between the sealed bottom of the first glass tube 2.3 and the lower end of the second constant pressure tube 2.2.

[0291] Furthermore, in one embodiment, the improved Soxhlet extractor intermediate tube further includes a vacuum sleeve 2.9, which is wrapped around the second constant pressure tube 2.2.

[0292] Soxhlet extractors are well-suited for extracting natural products by reusing refluxed solvent. They can also be used to remove volatile byproducts generated during the reaction if an absorbent (such as CaCl2) is placed in the sample cartridge. However, they have four drawbacks: the sample cartridge is relatively small, limiting the amount of absorbent that can be held; the refluxed solvent temperature is high, reducing the absorbent's adsorption capacity; the siphon tube is relatively tall, requiring a large volume of liquid; and the absorption is entirely immersion-based, failing to create an absorption gradient.

[0293] This invention modifies the intermediate tube of the Soxhlet extractor, avoiding the aforementioned drawbacks. First, instead of using a sample cylinder, a frosted plate is added to the bottom of the intermediate tube, allowing the entire intermediate tube to hold the absorbent, thus increasing its volume. Second, a ground glass inlet is added to the side of the intermediate tube for inserting a finger-shaped condenser, effectively reducing instability in the absorption area and ensuring the absorption efficiency and capacity of the absorbent. Third, the height of the siphon tube is appropriately lowered, reducing the volume of solvent retained in the intermediate tube and maintaining an appropriate amount of reaction liquid in the reaction flask. Fourth, by appropriately lowering the height of the siphon tube, the absorbent in the intermediate tube absorbs the byproducts to be removed in a gradient manner. The absorbent above the siphon tube height absorbs the reflux liquid containing high concentrations of byproducts by rinsing, while the absorbent below the siphon tube height absorbs the reflux liquid containing lower concentrations of byproducts by soaking.

[0294] 6-4: Improved Soxhlet extractor intermediate tube A-1-3

[0295] The present invention also discloses a preparation apparatus for acetal / ketal protection of catechol groups, namely, an apparatus for preparing dopa oligopeptide intermediates, comprising a reactor, a condenser, a liquid pipeline, and an improved Soxhlet extractor intermediate tube A-1-3; the reactor is connected to the lower end of the improved Soxhlet extractor intermediate tube A-1-3 via a liquid pipeline, and the condenser is vertically connected to the upper end of the improved Soxhlet extractor intermediate tube A-1-3 via a liquid pipeline.

[0296] like Figure 7As shown, the improved Soxhlet extractor intermediate tube A-1-3 includes: tube body 310, third lower interface 307 (i.e., the lower interface of the Soxhlet extractor, generally with an external ground joint, such as 24 / 29, connected to the reaction flask), third constant pressure tube 308 (i.e., the gas flow tube), second glass tube sealed bottom 309, second glass tube frosted bottom 305, second siphon tube 306, third upper interface 301 (i.e., the upper interface, generally with an internal ground joint, such as 40 / 38, connected to the condenser tube), and sealed cooling jacket 302; the second glass tube sealed bottom 309 divides the tube body 310 of the Soxhlet extractor intermediate tube into The upper and lower parts of the tube body 310 are provided with a third upper interface 301 at the upper end of the upper part; the third constant pressure tube 308 connects the upper and lower parts of the tube body 310; a second glass tube frosted bottom 305 is provided at the lower end of the upper part of the tube body 310; the second siphon tube 306 connects the upper and lower parts of the tube body 310, the upper end of the second siphon tube 306 is located between the second glass tube closed bottom 309 and the second glass tube frosted bottom 305, and the lower end of the second siphon tube 306 extends out of the third lower interface 307 of the tube body 310, the third lower interface 307 is located at the lower end of the lower part of the tube body 310. The upper and lower parts of the tube body 310 are connected by a third constant pressure tube 308 for gas flow. Steam from the lower part of the middle tube of the Soxhlet extractor is introduced to the upper part, and the gas is converted into liquid by the condenser connected to the upper part of the Soxhlet extractor. The upper and lower parts are connected by a second siphon tube 306 for liquid flow. The upper part of the second glass tube frosted bottom 305 (e.g., a sand core plate) above the sealed bottom 309 is filled with an adsorbent (e.g., calcium chloride). Water and methanol in the condensate are selectively absorbed by the adsorbent here. Then the condensate is filtered through the second glass tube frosted bottom 305 and returned to the reactor connected to the third lower interface 307 of the tube body 310 through the second siphon tube 306.

[0297] A glass-enclosed cooling jacket 302 is provided on the outer side of the lower end of the upper part of the tube body 310, and its height accounts for 40-100% of the upper part of the tube body 310. The coolant inlet 304 below the cooling jacket 302 is connected to the outlet of the circulating cooling pump, and the coolant outlet 303 above the cooling jacket is connected to the inlet of the circulating cooling pump. The enclosed cooling jacket 302 ensures that the absorbent in the intermediate tube body 310 of the Soxhlet extractor operates at a lower temperature, thereby improving the absorption efficiency and absorption capacity of water and methanol.

[0298] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments; the above descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention; the scope of protection of the present invention is determined by the appended claims.

Claims

1. A method for preparing a class of catechol derivatives, characterized in that, The preparation method includes the following steps: S1: Add the reducing agent, boric acid compound and mixed solvent to the reaction apparatus, and use inert gas bubbling to remove oxygen from the reaction apparatus; S2: Add compound I and the base to the reaction apparatus, stir and continue to pass inert gas; S3: Add reactant II to the reaction apparatus, stir, and continue to pass inert gas. After acidification, compound III is obtained; the reaction formula is as follows: Wherein, R1 includes one of H, Me, COOH, and CH2COOH; R2 includes one of H, Me, Et, F, Cl, Br, and OH; and R3 includes one of NH2 and NHNH2. The reactant II includes one of acyl halide, acid anhydride, N-hydroxysuccinimide type activated ester and pentafluorophenol type activated ester; reactant II is R4-X, where X is an active group and R4 is an inactive group; R5 is the fragment formed after R3 reacts with R4-X. Among them, acetal / ketal protection is performed on compound IV, which is protected by an acid-stable protecting group in compound III, including: S10: In the reaction apparatus, a certain amount of compound IV and a co-solvent are added and heated to form a solution; S20: Add a certain amount of carrier to the reaction device and pass in an inert gas, heat to 70-120℃, reflux for about 20 minutes, and use the absorbent in the absorption device to absorb water and by-products. S30: Add reactant V and catalyst, maintaining the molar ratio of compound IV to reactant V between 1:1 and 1:10; continue reflux for approximately 2-5 hours; add another 0.5-3 molar equivalents of reactant V, distill off volatile substances, and stop the reaction to obtain compound VI; after stopping the reaction, wait for the temperature to drop to room temperature, slowly add 2 equivalents of pyridine, remove volatiles by rotary evaporation, extract the residue with EA, wash with 0.5 mol / L citric acid solution, and wash with pure water; take the organic phase, add magnesium sulfate, dry, filter, and rotary evaporate to dryness; recrystallize the obtained crude product in toluene and n-hexane to obtain compound VI; wherein, reactant V includes aldehydes, ketones, hemiacetals and hemiketals of aldehydes and ketones; the reaction formula is as follows: Among them, R5 includes -NHFmoc, -NHNHFmoc, -NHCbz, -NPhth, -NHTfa, -NTFa-NHTfa, C 15 H 31 CO-NH-, C 12 H 25 CO-NH-, C 12 H 25 One of CO-Val-NH- and Fmoc-Val-NH-.

2. The method for preparing the catechol derivative according to claim 1, characterized in that, This also includes the conversion of dopa-containing methyl esters generated during acetal / ketal protection of catechol groups into the target carboxylic acid, including: 1) In the reaction apparatus, methyl ester compound VII and an organic solvent are added to obtain a solution of methyl ester compound VII; 2) Dissolve a certain amount of lithium salt in water to obtain a lithium salt solution, add the lithium salt solution to the above methyl ester compound VII solution; adjust the pH of the reaction system to 7-8 with hydrochloric acid, then add a certain amount of alkali and stir for 3-24 hours; 3) The organic phase was concentrated by rotary evaporation, water was added, and the pH was adjusted to 3-5 with HCl solution. Extraction was performed using EA, and the organic phase was washed with acidic water and pure water, respectively. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the volatiles were removed by rotary evaporation. Recrystallization in TLN / HXN yielded compound VIII. The reaction formula is as follows: R6 includes formaldehyde, acetal, benzaldehyde, acetone, cyclopentanone, cyclohexanone, benzophenone, and methoxymethylene.

3. The method for preparing the catechol derivative according to claim 1, characterized in that, This also includes the generation of acetal-protected L-tanshinone derivatives from acetal-protected levodopa derivatives: The acetal-protected L-DOPA derivative was deaminated and reacted with nitrous acid in water or a mixture of water and organic solvent under acid catalysis. After hydrolysis, an acetal-protected L-tanshinone derivative was generated.

4. A catechol derivative prepared by the method according to any one of claims 1-3.

5. The use of a catechol derivative prepared by the preparation method according to any one of claims 1-3 in the preparation of solid and liquid formulations containing dopa oligopeptides.

6. The application of the catechol derivative according to claim 5 in the preparation of solid and liquid formulations containing dopa oligopeptides, characterized in that, The oral continuous or intermittent administration device for the liquid formulation includes a cup body (200) and a cup cap (100), wherein the cup body (200) and the cup cap (100) are detachably connected. The cup body (200) is a container for oral liquid; The cup lid (100) is equipped with a switch button (101), a battery slot (102), a micro peristaltic pump (103), a delivery tube (104), an output tube (105), and a metering cell (108). The switch button (101) is used to turn the micro peristaltic pump on or off. The battery slot (102) is used to install a battery to power the micro peristaltic pump (103). The delivery tube (104) is mounted on the micro peristaltic pump, with one end located at the bottom of the cup body (200). The other end is located at the bottom of the metering pool (108); the micro peristaltic pump (103) is used to pump the liquid medicine in the cup body (200) into the metering pool (108) through the transfer pipe (104); the metering pool (108) is located at the lower end of the cup lid (100), and when the cup lid and the cup body are connected, the metering pool (108) is located inside the cup body (200); the output pipe (105) passes through the cup lid (100) and extends into the metering pool (108).

7. The application of the catechol derivative according to claim 6 in the preparation of solid and liquid formulations containing dopa oligopeptides, characterized in that, The cup lid is also equipped with a speed adjustment button and a flow rate display screen.

8. The method for preparing the catechol derivative according to claim 1, characterized in that, The reaction apparatus for acetal / ketal protection includes a reactor, condensation equipment, absorption tower, gas pipelines, and liquid pipelines; The reactor is connected to the condensing equipment via a gas pipeline, the reactor is connected to the absorption tower via a liquid pipeline, and the absorption tower is connected to the condensing equipment via a liquid pipeline. The reactor includes one of a flask and a reaction vessel; the gas pipeline includes one of a glass tube, a plastic tube, a ceramic tube, and a metal tube; the condensation equipment includes one of a glass or metal condenser tube and a cold trap; the absorption tower includes one of a glass tube, a ceramic tube, and a metal tube; and the liquid pipeline includes one of a metal tube, a plastic tube, a rubber tube, and a glass tube.

9. The method for preparing the catechol derivative according to claim 1, characterized in that, The acetal / ketone protected reaction apparatus includes a reactor, condensation equipment, an improved constant-pressure dropping funnel, and liquid piping. The reactor is connected to the lower interface of the improved constant pressure dropping funnel via a liquid pipeline, and the condensation device is vertically connected to the upper interface of the improved constant pressure dropping funnel via a liquid pipeline. The improved constant-pressure dropping funnel includes a dropping funnel body (1), a first constant-pressure tube (2), a vacuum sleeve (3), and a condensing sleeve (4). A regulating valve (11) is installed in the middle of the dropping funnel body (1), dividing the dropping funnel body (1) into an upper part (12) and a lower part (13). The first constant-pressure tube (2) connects the upper part (12) and the lower part (13). The upper part (12) is provided with a first upper interface (14), the lower part (13) of the dripping funnel is provided with a first lower interface (15), the first lower interface (15) is provided with a dripping nozzle, and the dripping nozzle is connected to the upper part of the dripping funnel; a sand core plate (5) is provided at the lower end of the upper part (12) of the dripping funnel; the vacuum sleeve (3) is wrapped around the outside of the first constant pressure tube (2), and the condensation sleeve (4) is fitted on the upper part (12) of the dripping funnel.

10. The method for preparing the catechol derivative according to claim 1, characterized in that, The acetal / ketone protected reaction apparatus includes a reactor, a condenser, an improved Soxhlet extractor intermediate tube, and a liquid pipeline; the reactor is connected to the lower interface of the improved Soxhlet extractor intermediate tube via the liquid pipeline, and the condenser is vertically connected to the upper interface of the improved Soxhlet extractor intermediate tube via the liquid pipeline. The improved Soxhlet extractor intermediate tube includes a second lower interface (2.1), a second constant pressure tube (2.2), a first glass tube sealed bottom (2.3), a first glass tube frosted bottom (2.4), a Soxhlet extractor body (2.5), a first siphon tube (2.6), a side ground joint (2.7), and a second upper interface (2.8); the first glass tube sealed bottom (2.3) divides the Soxhlet extractor body (2.5) into an upper part and a lower part, and the upper end of the upper part of the Soxhlet extractor body is provided with a second upper interface (2.8), and a side ground joint (2.7) is provided between the second upper interface (2.8) and the first glass tube sealed bottom (2.3); the second constant pressure tube (2.2) The upper part of the Soxhlet extractor body and the lower part of the Soxhlet extractor body are connected. The upper end of the second constant pressure tube (2.2) is located on the opposite side between the side ground port (2.7) and the second upper interface (2.8), and the lower end is located between the first glass tube closed bottom (2.3) and the second lower interface (2.1). The lower end of the upper part of the Soxhlet extractor body is provided with a first glass tube frosted bottom (2.4). The first siphon tube (2.6) connects the upper part of the Soxhlet extractor body and the lower part of the Soxhlet extractor body. The upper end of the first siphon tube (2.6) is located between the first glass tube closed bottom (2.3) and the first glass tube frosted bottom (2.4), and the lower end is located between the first glass tube closed bottom (2.3) and the lower end of the second constant pressure tube (2.2).

11. The method for preparing the catechol derivative according to claim 1, characterized in that, The acetal / ketone protected reaction apparatus includes a reactor, a condenser, an improved Soxhlet extractor intermediate tube, and a liquid pipeline; the reactor is connected to the lower interface of the improved Soxhlet extractor intermediate tube via the liquid pipeline, and the condenser is vertically connected to the upper interface of the improved Soxhlet extractor intermediate tube via the liquid pipeline. The improved Soxhlet extractor intermediate tube includes a tube body (310), a third lower interface (307), a third constant pressure tube (308), a second glass tube sealed bottom (309), a second glass tube frosted bottom (305), a second siphon tube (306), a third upper interface (301), and a sealed cooling jacket (302); the second glass tube sealed bottom (309) divides the tube body (310) into an upper part and a lower part; the upper end of the upper part of the tube body (310) is provided with the third upper interface (301); the third constant pressure tube (308) connects the upper part and the lower part of the tube body (310). The lower end of the upper part of the tube body (310) is provided with a second glass tube frosted bottom (305); the second siphon tube (306) connects the upper and lower parts of the tube body (310), the upper end of the second siphon tube (306) is located between the second glass tube closed bottom (309) and the second glass tube frosted bottom (305), the lower end of the second siphon tube (306) extends out of the third lower interface (307) of the tube body (310), and the third lower interface (307) is located at the lower end of the lower part of the tube body (310); the closed cooling sleeve (302) is provided at the lower end of the upper outer side of the tube body (310).

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