Preparation method of Eucalactam B

Abstract

This invention provides a method for preparing Eucalactam B, comprising the following steps: reacting compound 9 with compound 11 in a multi-step reaction to generate compound 7; reacting compound 7 with compound 8 in an olefin metathesis reaction to generate compound 4; and subjecting compound 4 to a macrocyclic endamidation reaction to obtain product 1, which is Eucalactam B. This synthetic method demonstrates high efficiency and selectivity in the construction of complex molecular structures, particularly in the stereoselective control of multi-step reactions, the high efficiency of the metathesis reaction, and the successful implementation of the macrocyclic reaction. By precisely controlling the reaction conditions, compound 4 was successfully cyclized to form the macrocyclic structure Eucalactam B, determining the absolute configuration of product 1. The extremely high purity of compound 4 effectively improved the yield of the synthesized product 1.

Description

Technical Field

[0001] The invention belongs to the field of synthetic chemistry, and in particular relates to a preparation method of Eucalactam B. Background Art

[0002] Eucalactam B is a macrocyclic ester peptide compound isolated by Gao's research group in 2020 from the culture extract of the endophyte Diaporthe eucalyptorum KY-9 of Melia azedarach1. Its structure is a 21-membered macrocyclic ester peptide with 8 chiral centers, composed of 3 natural amino acids (2 glycines and 1 threonine) and an unsaturated fatty hydroxy acid unit. Gao et al. performed a variety of two-dimensional nuclear magnetic resonance spectroscopy characterizations (HSQC, HMBC, 1H-1H COSY, HMQC-COSY, NOESY) on the natural sample of Eucalactam B, and then inferred the syn relative configuration of a pair of 1,3-dihydroxyl groups on the polyketone unit in the structure of Eucalactam B through chemical semi-synthesis (Gao YQ, Du ST, Xiao J, et al. Isolation and characterization of antifungalmetabolites from the Melia azedarach-associated fungus Diaporthe eucalyptorum[J]. Journal of agricultural and food chemistry, 2020, 68(8): 2418-2425.). For the threonine unit in the structure of Eucalactam B, Gao et al. identified the amino acid as L-threonine using the Marfey method.

[0003] In summary, the absolute configurations of other chiral centers in the polyketide unit of Eucalactam B were not initially determined, and the yield of Eucalactam B prepared by bacterial culture was low. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a preparation method of Eucalactam B, aiming to solve the problem that the configuration of Eucalactam B is not determined and the synthesis yield is low.

[0005] To solve the above technical problems, the present invention is achieved in this way. The present invention proposes a preparation method of Eucalactam B, comprising the steps of:

[0006] S1, subjecting compound 9 and compound 11 to a multi-step reaction to generate compound 7;

[0007] S2, the compound 7 and the compound 8 undergo olefin metathesis reaction to generate compound 4;

[0008] S3, subjecting the compound 4 to a macrocyclic lactamization reaction to obtain a product 1, wherein the product 1 is Eucalactam B;

[0009] Wherein, the structural formula of the above compound is as follows:

[0010] , , , , , .

[0011] In some embodiments of the present invention, step S3 includes:

[0012] S3.1, dissolving the compound 4 and placing it in an inert atmosphere, adding compound 5, dicyclohexylcarbodiimide and 4-dimethylaminopyridine to react to obtain compound 17;

[0013] S3.2, converting the compound 17 into compound 18 by reacting with compound 6, and introducing a protecting group;

[0014] S3.3, removing the protecting group of the compound 18 in a weak acid environment, and then adding HATU catalyst to carry out macrolactamization reaction to obtain the product 1;

[0015] Wherein, the structural formula of the above compound is as follows:

[0016] , , ,

[0017] , .

[0018] In some embodiments of the present invention, step S3.2 includes:

[0019] 2,2,2-trichloroethoxycarbonyl-L-threonine was dissolved and placed in an inert atmosphere, HATU, HOAt and DIPEA were first added, and then glycine hydrochloride was added to react to obtain compound 15;

[0020] The compound 15 is dissolved in a weak acid solution, lithium hydroxide is added to react, the solution after the reaction is acidified to pH=3, and extraction, drying and evaporation are performed in sequence to obtain the compound 6;

[0021] The compound 17 is dissolved and then an organic basic compound is added. After the reaction is completed, a solution of the compound 6 and HOAt are added, and then HATU is added for reaction. The compound 18 is obtained by washing, extraction, drying and evaporation.

[0022] Wherein, the structural formula of the above compound is as follows:

[0023] .

[0024] In some embodiments of the present invention, step S3.3 includes:

[0025] The compound 18 is dissolved in a weak acid environment, activated zinc powder is added, and then filtered, washed, extracted, and dried in sequence to obtain a crude product;

[0026] The crude product is dissolved in an anhydrous organic solvent, HOAT and DIPEA are first added in an inert atmosphere, and then HATU is added, followed by extraction, drying and evaporation to obtain compound 19;

[0027] The compound 19 is dissolved in a weak acid environment, and TBAF is added dropwise in an inert atmosphere, and after the conversion is completed, the compound 1 is obtained;

[0028] Wherein, the structural formula of the above compound is as follows:

[0029] .

[0030] In some embodiments of the present invention, the step of preparing the crude product comprises:

[0031] The zinc powder is activated in an acidic solvent and then dried;

[0032] Adding activated zinc powder to the acidic solution of compound 18, stirring vigorously, and then filtering and washing;

[0033] The filtrate is subjected to preliminary extraction, and the obtained aqueous phase is adjusted to a neutral solution;

[0034] The neutral aqueous phase is subjected to deep extraction again, and the organic phases obtained by the preliminary extraction and the deep extraction are mixed, dried and evaporated to obtain the crude product.

[0035] In some embodiments of the present invention, step S1 comprises:

[0036] S1.1, converting compound 2 into compound 9 through a multi-step reaction, and oxidizing compound 9;

[0037] S1.2, the oxidized compound 9 undergoes an aldol condensation reaction with the compound 11 to generate a compound 12;

[0038] S1.3, converting the compound 12 into a compound 14, and then subjecting the compound 14 to an esterification reaction to obtain the compound 7;

[0039] Wherein, the structural formula of the above compound is as follows:

[0040] , , .

[0041] In some embodiments of the present invention, step S1.1 comprises:

[0042] placing the compound 2 in an alkaline environment, adding tert-butyloxycarbonyl anhydride to react, and introducing a tert-butyloxycarbonyl group into the compound 2;

[0043] adding lithium aluminum hydride to carry out a reduction reaction to reduce the carboxyl group on the compound 2 to an alcohol group;

[0044] Pyridine chlorochromate is added to carry out oxidation reaction to oxidize the alcohol group into aldehyde group;

[0045] Methylenetriphenylphosphine is added in a weak acid environment to react, an allyl group is introduced into the compound 2, and the aldehyde group is oxidized to an allyl alcohol;

[0046] Add tert-butyldimethylsilyl chloride and imidazole to introduce tert-butyldimethylsilyl to protect allyl alcohol;

[0047] Trifluoroacetic acid is added to remove the tert-butyloxycarbonyl group, and then an oxidant is added to oxidize the alcohol group at the end of the allyl group to an aldehyde, thereby obtaining the compound 9.

[0048] In some embodiments of the present invention, step S1.3 includes:

[0049] The compound 12 is dissolved and placed in an inert atmosphere, and 2,6-lutidine is first added, and then tri-tert-butylsilyl trifluoromethanesulfonate is added to obtain compound 13;

[0050] The compound 13 is dissolved and placed in an inert atmosphere, sodium borohydride is first added to heat the reaction, and then anhydrous potassium carbonate is added to reduce the temperature to obtain a pre-product;

[0051] dissolving the pre-product in a weak acid buffer, adding sodium periodate to react, and extracting to obtain an aldehyde product;

[0052] The aldehyde product is dissolved and placed in an inert atmosphere, and sodium dihydrogen phosphate, 2-methyl-2-butene and sodium chlorite are added to react. After the reaction is completed, the compound 14 is obtained by extraction, drying and evaporation.

[0053] The compound 14 is dissolved and placed in an inert atmosphere, and 2,2,2-trichloroethanol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine are added to react, and after the reaction is completed, the compound 7 is obtained by washing, extracting, drying and evaporating in sequence;

[0054] Wherein, the structural formula of the above compound is as follows:

[0055] .

[0056] In some embodiments of the present invention, step S3 includes:

[0057] Adding DMP to the solution of compound 4 to react, followed by washing, extraction, drying and evaporation to obtain an aldehyde intermediate;

[0058] The compound 20 is dissolved and placed in an inert atmosphere, EDC and NHS are added for activation, and then mixed with the aldehyde intermediate to perform an esterification reaction to form an ester bond intermediate;

[0059] The ester bond intermediate is dissolved and a reducing agent is added, and the mixture is stirred for reaction, and then washed, extracted, dried, and evaporated in sequence to obtain an amide intermediate;

[0060] The amide intermediate is dissolved and a base catalyst is added, and the mixture is stirred for reaction, and then washed, extracted, dried, and evaporated to obtain compound 19;

[0061] The compound 19 is dissolved in a weak acid environment, and trifluoroacetic acid is added dropwise in an inert atmosphere, and after the conversion is completed, the compound 1 is obtained;

[0062] Wherein, the structural formula of the above compound is as follows:

[0063]

[0064] Compared with the prior art, the preparation method of Eucalactam B in the present invention has the following beneficial effects:

[0065] Compound 9 has olefin and alcohol functional groups, and the hydroxyl groups are protected by tert-butyldimethylsilyl (TBS), and compound 11 has ester and ketone groups. The starting material was successfully converted into the target intermediate 7 through multiple reaction steps. The generated compound 7 has two TBS-protected hydroxyl groups and a longer carbon chain connected by a trichloroethyl ester bond, laying the foundation for the subsequent construction of complex molecules.

[0066] The olefin group in compound 7 undergoes a metathesis reaction with the olefin group in compound 8 to form a new carbon-carbon double bond, generating compound 4. This reaction successfully achieves the expansion of the carbon skeleton through olefin metathesis to generate compound 4 with a more complex structure, while maintaining high regio- and stereo-selectivity. Due to the high efficiency of the metathesis reaction, compound 4 can be obtained with a high yield and purity, reducing the interference of impurities in subsequent reaction steps. By precisely controlling the reaction conditions, compound 4 successfully cyclized to form the macrocyclic structure Eucalactam B, and the absolute configuration of product 1 was determined. The extremely pure compound 4 effectively increased the yield of the synthesized product 1. This method provides a reliable path for the synthesis of similar complex organic molecules and has broad application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a schematic flow diagram of a method for preparing Eucalactam B in one embodiment of the present invention. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0069] Please refer to Figure 1 The present invention provides a method for preparing Eucalactam B, comprising the steps of:

[0070] S1, subjecting compound 9 and compound 11 to a multi-step reaction to generate compound 7;

[0071] S2, compound 7 and compound 8 undergo olefin metathesis reaction to generate compound 4;

[0072] S3. Compound 4 is subjected to macrolactamization reaction to obtain product 1, where product 1 is Eucalactam B.

[0073] Compound 9 has olefin and alcohol functional groups, and the hydroxyl groups are protected by tert-butyldimethylsilyl (TBS), and compound 11 has ester and ketone groups. The starting material was successfully converted into the target intermediate 7 through multiple reaction steps. The generated compound 7 has two TBS-protected hydroxyl groups and a longer carbon chain connected by a trichloroethyl ester bond, laying the foundation for the subsequent construction of complex molecules.

[0074] The olefin group in compound 7 undergoes a metathesis reaction with the olefin group in compound 8 to form a new carbon-carbon double bond to generate compound 4. This reaction successfully achieves the expansion of the carbon skeleton through olefin metathesis to generate compound 4 with a more complex structure while maintaining high regio- and stereo-selectivity. Due to the high efficiency of the metathesis reaction, compound 4 can be obtained with high yield and purity, reducing the interference of impurities in subsequent reaction steps. By precisely controlling the reaction conditions, compound 4 successfully cyclized to form the macrocyclic structure Eucalactam B, a process that is critical for generating molecules with specific biological activity or other unique properties.

[0075] This synthetic method demonstrates high efficiency and selectivity in the construction of complex molecular structures, especially stereoselective control in multi-step reactions, high efficiency in metathesis reactions, and successful implementation of macrocyclization reactions. This method provides a reliable path for the synthesis of similar complex organic molecules and has broad application potential.

[0076] In one embodiment, the retrosynthetic analysis of Eucalactam B is as follows:

[0077]

[0078] The present invention is designed to construct the macrocyclic ring system in product 1 through a macrocyclic lactamization reaction, wherein compound 4 provides a carboxyl portion and compound 6 provides an amino portion, both of which participate in the formation of an amide bond, resulting in the closure of the macrocyclic structure. Compound 4 as a polyketone skeleton can be constructed from fragments 7 and 8 through an olefin metathesis reaction. Fragment 8 is a known compound, and fragment 7 can be obtained from a known compound 9 through an aldol condensation reaction.

[0079] The specific synthetic route of product 1 is as follows:

[0080] (1) Synthesis of compound 7:

[0081] S1.1. Compound 2 is converted into compound 9 through a multi-step reaction, and compound 9 is oxidized. The specific steps include: placing compound 2 in an alkaline environment, adding tert-butyloxycarbonyl anhydride for reaction, introducing tert-butyloxycarbonyl group (BOC protecting group) into compound 2, the BOC protecting group is used to protect hydroxyl or amino groups to avoid their unnecessary reactions in subsequent reactions, the alkaline environment is conducive to deprotonation, promotes the reaction of tert-butyloxycarbonyl anhydride and compound 2, and successfully introduces tert-butyloxycarbonyl group.

[0082] Lithium aluminum hydride is added for reduction reaction to reduce the carboxyl group on compound 2 to an alcohol group. Lithium aluminum hydride is a strong reducing agent that reduces carboxylic acid to an alcohol group by providing hydrogen ions. Pyridine chlorochromate is added for oxidation reaction to oxidize the alcohol group to an aldehyde group. Pyridine chlorochromate is a mild oxidizing agent and is often used to oxidize primary alcohols to aldehyde groups without further oxidation to carboxylic acids.

[0083] Methylene triphenylphosphine was added to react in a weak acid environment to introduce an allyl group to compound 2, and the aldehyde group was oxidized to allyl alcohol. Tert-butyl dimethyl silyl chloride and imidazole were added to introduce tert-butyl dimethyl silyl to protect allyl alcohol. Tert-butyl dimethyl silyl chloride was used to protect the alcohol group to avoid unnecessary reactions in subsequent reactions. Imidazole was used as a base to promote the reaction between chlorosilane and alcohol group. Trifluoroacetic acid was added to remove the tert-butyloxycarbonyl group, and then an oxidant was added to oxidize the alcohol group at the end of the allyl group to an aldehyde to obtain compound 9. Trifluoroacetic acid is an acidic reagent that can effectively remove the BOC protecting group and expose the previously protected group.

[0084] S1.2. The oxidized compound 9 undergoes an aldol condensation reaction with compound 11 to generate compound 12.

[0085] The reaction produced a single isomer, indicating that the reaction has high stereoselectivity. This is particularly important for the preparation of chiral molecules, because only specific isomers have the desired biological activity, and the reaction produces few byproducts, thereby maximizing the yield of the target product. The use of the TBS protecting group successfully prevented the alcohol group at the end of the allyl group from participating in side reactions during the reaction, thereby maintaining the integrity of the molecule and providing the possibility for subsequent chemical modification.

[0086] S1.3, converting compound 12 into compound 14, and then subjecting the compound 7 to esterification reaction.

[0087] The specific steps include: dissolving compound 12 and placing it in an inert atmosphere, first adding 2,6-lutidine, and then adding tri-tert-butylsilyl trifluoromethanesulfonate to obtain compound 13, 2,6-lutidine is used as a base to neutralize the by-product acid in the reaction, thereby improving the reaction efficiency, and tri-tert-butylsilyl trifluoromethanesulfonate is used to protect the alcohol group to form tri-tert-butylsilyl (TBS) ether, which further protects the hydroxyl group from participating in subsequent chemical reactions.

[0088] After compound 13 is dissolved, it is placed in an inert atmosphere, sodium borohydride is first added for heating reaction, and then the temperature is lowered and anhydrous potassium carbonate is added to obtain a pre-product. Sodium borohydride is used as a reducing agent to reduce the carbonyl group to an alcohol group. Under heating conditions, the reaction is more rapid and complete. Anhydrous potassium carbonate is used to neutralize the acidic by-products produced in the reaction to ensure that the generated alcohol group will not be further protonated and affect subsequent reactions.

[0089] The pre-product is dissolved in a weak acid buffer, sodium periodate is added for reaction, and the aldehyde product is extracted. Sodium periodate is used as a strong oxidant to oxidize the vicinal diol to crack it into aldehyde or ketone. The weak acid buffer maintains the pH value of the reaction environment, which is conducive to the effective oxidation of sodium periodate.

[0090] The aldehyde product is dissolved and placed in an inert atmosphere, and sodium dihydrogen phosphate, 2-methyl-2-butene and sodium chlorite are added to react. After the reaction is completed, compound 14 is obtained after extraction, drying and evaporation. Sodium dihydrogen phosphate is used as a buffer to maintain the pH value of the reaction. 2-methyl-2-butene participates in the allylation reaction as a reaction regulating reagent. Sodium chlorite is used for further oxidation of the aldehyde group to oxidize the aldehyde into carboxylic acid or other oxidation products.

[0091] Compound 14 was dissolved and placed in an inert atmosphere, and 2,2,2-trichloroethanol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 4-dimethylaminopyridine (DMAP) were added to react. After the reaction was completed, compound 7 was obtained after washing, extraction, drying and evaporation. 2,2,2-trichloroethanol was used as a reagent for esterification or condensation reaction to form a new ester bond. EDC was used as a condensation reagent to promote the reaction of carboxylic acid with alcohol or amine to form an ester or amide bond. DMAP was used as a catalyst to accelerate the esterification or amidation reaction.

[0092]

[0093] (2) Synthesis of compound 4:

[0094] Compound 7 and compound 8 undergo olefin metathesis to generate compound 4. Olefin metathesis is a metal-catalyzed reaction that forms new carbon-carbon double bonds by exchanging olefin fragments. This reaction is carried out under the action of ruthenium-based catalysts (such as Grubbs II catalyst) and can effectively connect two different olefin fragments.

[0095]

[0096] (3) Synthesis of product 1:

[0097] In one embodiment, the specific synthesis steps of product 1 include:

[0098] S3.1. Dissolve compound 4 and place in an inert atmosphere, add compound 5, dicyclohexylcarbodiimide and 4-dimethylaminopyridine to react to obtain compound 17.

[0099] The TBS protecting group in compound 4 effectively protects other hydroxyl groups in the molecule, ensuring that only the target hydroxyl group reacts with compound 5 during the reaction. This selective protection avoids unnecessary side reactions and improves the selectivity and yield of the target product. By using DCC (N,N'-dicyclohexylcarbodiimide) and DMAP, the hydroxyl group in compound 4 successfully forms an ester bond with the carboxyl group in compound 5. This step is a key chemical connection step and provides an important intermediate for subsequent synthesis. The Fmoc protecting group in compound 5 protects the amino group in glycine to avoid its unwanted reaction with the functional group in compound 4. This ensures high selectivity of the synthesis and provides flexibility for subsequent reactions, as the Fmoc group can be removed at the appropriate time to expose the amino group for further chemical modification. The reaction is carried out in an inert atmosphere to prevent moisture and oxygen in the air from interfering with the reaction process, which is especially important when using sensitive reagents such as DCC. Such controlled reaction conditions ensure the high efficiency of the reaction and the purity of the product.

[0100] S3.2, converting compound 17 into compound 18 by reaction with compound 6, and introducing a protecting group. The steps include:

[0101] After 2,2,2-trichloroethoxycarbonyl-L-threonine was dissolved and placed in an inert atmosphere, HATU (O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate), HOAt (1-hydroxy-7-azabenzotriazole) and DIPEA (N,N-diisopropylethylamine) were first added, and then glycine hydrochloride was added to react to obtain compound 15. HATU and HOAt were used as condensation reagents to effectively combine the amino group of glycine with the carboxyl group of L-threonine to form an amide bond in compound 15. DIPEA was used as a base to help neutralize the by-products in the reaction, thereby improving the reaction efficiency and yield. The introduction of the trichloroethyl ester protecting group ensures that the terminal carboxyl group is not activated in subsequent reactions, so that it can be selectively removed or participate in the reaction in the subsequent steps of the synthesis.

[0102] Compound 15 was dissolved in a weak acid solution, lithium hydroxide was added for reaction, the solution after the reaction was acidified to pH=3, and then extracted, dried and evaporated in sequence to obtain compound 6. Compound 15 was hydrolyzed with lithium hydroxide, and its ester group was successfully hydrolyzed into a free carboxyl group (generating compound 6), and the carboxylic acid was ensured to exist in a free state by acidification to pH=3, which was convenient for extraction and purification. The Troc protecting group protected the amino group in compound 6, preventing it from reacting with other functional groups during the reaction. This selective protection strategy is particularly important for multi-step synthesis.

[0103] After compound 17 is dissolved, an organic alkaline compound is added. After the reaction is completed, a solution of compound 6 and HOAt are added, and then HATU is added for reaction. Compound 18 is obtained by washing, extraction, drying, and evaporation. First, the Fmoc protecting group in compound 17 is removed by an organic base (such as piperidine) to expose the amino group, which undergoes an amidation reaction with the carboxyl group in compound 6. Under the catalysis of HATU / HOAt, a new amide bond is efficiently formed to generate compound 18. During the reaction, TBS protects the hydroxyl group in compound 18, while Troc protects the amino group. These protecting groups ensure that specific functional groups can be treated in a targeted manner in subsequent reactions. Through a reasonable protecting group strategy and efficient amidation conditions, the complex compound 18 was successfully synthesized, which provides a variety of possibilities for further chemical modification.

[0104] S3.3. Compound 18 is first deprotected in a weak acid environment, and then HATU catalyst is added to carry out macrolactamization reaction to obtain product 1.

[0105] The specific steps include:

[0106] The zinc powder is activated in an acidic solvent and dried. The activated zinc powder is added to the acidic solution of compound 18, and the mixture is filtered and washed after vigorous stirring. The filtrate is subjected to preliminary extraction, and the obtained aqueous phase is adjusted to a neutral solution. The neutral aqueous phase is deeply extracted again. The organic phases obtained from the preliminary extraction and the deep extraction are mixed, and the crude product is obtained after drying and evaporation.

[0107] Activated zinc powder is usually used for reduction reactions, especially in acidic media, where it can effectively reduce certain functional groups, such as nitrogen protecting groups, halides or unsaturated bonds. The aqueous phase after the initial extraction is adjusted to neutrality, and further extraction can effectively separate the target product and impurities. The crude product obtained after mixing, drying and evaporating the organic phase is the basis for further reactions. Through preliminary and deep extraction, the target compound can be extracted more thoroughly, the residual polar impurities can be reduced, and the purity of subsequent reactions can be improved.

[0108] The crude product is dissolved in an anhydrous organic solvent, and HOAT and DIPEA are first added in an inert atmosphere, followed by HATU, followed by extraction, drying, and evaporation to obtain compound 19. This step continues to utilize the strong condensation ability of HATU and HOAt, combined with the alkalinity regulation of DIPEA, to further promote the formation of amide bonds or the removal of protective groups. The purpose of this step is to introduce new connections into the molecule and ultimately form compound 19. The use of an anhydrous organic solvent and an inert atmosphere can avoid the interference of moisture and oxygen on the reaction, ensure the efficient progress of the reaction, and obtain high-purity compound 19.

[0109] Compound 19 was dissolved in a weak acid environment, and TBAF was added dropwise in an inert atmosphere. After the conversion was completed, compound 1 was obtained. TBAF is used to remove silicon-based protecting groups. In this step, TBAF was used to remove the TBS protecting group from compound 19, exposing the hydroxyl group to form compound 1. The weak acid environment can help regulate the activity of TBAF, while the inert atmosphere avoids the influence of moisture or oxygen in the air on sensitive intermediates or products, ensuring the efficient deprotection reaction. Compound 1 was produced with high purity through precise control of reaction conditions and deprotection group operation.

[0110]

[0111] In another embodiment, the specific synthesis steps of product 1 include:

[0112] DMP (Dess-Martin periodinane) was added to the solution of compound 4, and the product was washed, extracted, dried and evaporated to obtain an aldehyde intermediate. DMP is a highly selective oxidant that can gently and effectively oxidize alcohol groups to aldehyde groups without affecting other sensitive functional groups. This step laid the foundation for the subsequent esterification reaction while retaining the integrity of other functional groups in the molecule.

[0113] After compound 20 is dissolved, it is placed in an inert atmosphere, EDC and NHS (N-hydroxysuccinimide) are added for activation, and then mixed with the aldehyde intermediate to undergo an esterification reaction to form an ester bond intermediate; EDC is used to activate the carboxyl group in compound 20, while NHS forms an activated NHS ester, making it easier for the carboxyl group to react with the aldehyde group or hydroxyl group in the aldehyde intermediate to form a stable ester bond. Through the activation of EDC / NHS, the carboxyl group of compound 20 can effectively combine with the aldehyde intermediate to form a new ester bond. This process is highly selective and avoids the formation of by-products, thereby ensuring the purity and yield of the target ester bond intermediate.

[0114] The ester bond intermediate is dissolved and a reducing agent is added, and the reaction is stirred, and then washed, extracted, dried, and evaporated to obtain an amide intermediate. The reducing agent can be sodium cyanoborohydride, which is used to reduce the ester bond to the corresponding alcohol or amine, realize the reduction conversion of the ester bond, and form a new amide bond intermediate. The amide bond has a high stability and provides a more reactive structure for subsequent reactions.

[0115] The amide intermediate is dissolved and a base catalyst is added, and the reaction is stirred. After washing, extraction, drying and evaporation, compound 19 is obtained. The base catalyst can be potassium carbonate, which is used to promote the intramolecular cyclization reaction to form the complex structure of compound 19. The base-catalyzed reaction can regulate the pH and reaction environment so that the target functional group can preferentially participate in the reaction. The base catalyst plays a key role in removing the protecting group or inducing the cyclization reaction, ensuring the efficient synthesis of the target product. This step is one of the key steps in the synthesis of compound 19.

[0116] Compound 19 was dissolved in a weak acid environment, and trifluoroacetic acid (TFA) was added dropwise in an inert atmosphere. After the conversion was completed, compound 1 was obtained. TFA was used to remove the acid-sensitive protecting group (TBS group). The use of TFA ensured the complete removal of the protecting group without affecting other functional groups, and finally generated high-purity compound 1. This deprotection step is crucial to achieve the functionalization of the target molecule.

[0117]

[0118] The present invention has been tested for many times, and some test results are now cited as references to further describe the invention in detail, and the following is a detailed description in conjunction with specific embodiments.

[0119] Embodiment 1:

[0120]

[0121] To a solution of compound 9 (1.16 g, 4.74 mmol, 1.0 eq.) in anhydrous DCM, NaHCO3 (1.6 g, 18.96 mmol, 4.0 eq) was added under argon protection at 0°C, followed by Dess-Martin oxidant (4.02 g, 9.48 mmol, 2.0 eq.). After stirring at room temperature for 3 h, the mixture was filtered through celite, the solvent was dried by spin drying, and the crude product was separated by silica gel column chromatography (2% EtOAc / hexanes) to obtain 1.126 g of the corresponding aldehyde.

[0122] Compound 11 (638 mg, 3.1 mmol, 0.67 eq.) was dissolved in 50 ml of anhydrous ether. Cy2BCl (4.64 ml, 1 M in diethyl ether, 1.0 eq.) was slowly added dropwise at -78 °C under argon protection, followed by dimethylethylamine (408 mg, 5.58 mmol, 1.2 eq.). After stirring for 5 minutes, the temperature was raised to 0 °C and stirred for 1 h. After cooling to -78 °C, the aldehyde obtained in the previous step was dissolved in ether and slowly added dropwise to the system, and stirred at -20 °C overnight. After the reaction was completed, 5 mL of methanol and 5 mL of pH 7.0 phosphate buffer were added to the system. After 5 min, 10 mL of 30% hydrogen peroxide was added and stirred at room temperature for 30 minutes. The obtained system was diluted with water and methyl tert-butyl ether and extracted. The organic phase was separated and dried over anhydrous sodium sulfate. The crude product was obtained after filtration and vacuum rotary evaporation. The crude product was separated by column chromatography (2% ~ 5% EtOAc / hexanes) to give compound 12 (1.490 g, 87%).

[0123] R f = 0.35 (10% EtOAc / hexanes), PMA stain. = +6.2 (c 1, CHCl3);HRMS(ESI, m / z) for C 25 H 40 O5SiNa + [M + Na] + : Calcd. 471.2538; Found 471.2537.IR(KBr)ν max 3520, 2953, 2926, 2856, 1708, 1699, 1641, 1602, 1454, 1257, 1114, 1070,1001, 908, 839, 773, 711, 509cm −1 . 1 H NMR(400 MHz, CDCl3)δ 8.13 – 8.02 (m, 2H),7.58 (t, J = 7.4 Hz, 1H), 7.45 (t, J = 7.9 Hz, 2H), 5.79 (ddt, J = 16.8, 10.0, 6.6Hz, 1H), 5.43 (q, J = 7.0 Hz, 1H), 5.22 – 4.75 (m, 2H), 3.97 (dd, J= 7.5, 5.3Hz, 1H), 3.91 (t, J = 8.6 Hz, 1H), 3.31 (brs, 1H), 2.91 (p, J = 7.0 Hz, 1H), 2.08(q, J = 8.1 Hz, 2H), 1.71 (ddd, J = 14.2, 5.3, 1.9 Hz, 1H), 1.56 (d, J = 7.0 Hz,3H), 1.22 (d, J = 7.1 Hz, 3H), 0.87 (s, 9H), 0.08 (s, 3H), 0.07 (s, 3H). 13 C NMR(101 MHz, CDCl3) δ 211.2, 166.0, 138.5, 133.5, 129.9, 129.6, 128.6, 114.8,75.0, 72.3, 72.1, 48.5, 40.1, 36.8, 29.1, 26.0, 18.1, 15.9, 13.6, -4.0, -4.5.

[0124] Embodiment 2:

[0125]

[0126] Compound 12 (1.490 g, 3.32 mmol) was dissolved in 30 mL of anhydrous DCM, and 2,6-lutidine (8.30 mmol, 2.5 eq.) was added under argon protection at 0°C, followed by TBSOTf (3.99 mmol, 1.2 eq.). After reacting at room temperature for 3 h, water was added to the reaction to quench the reaction, and the reaction was diluted with DCM. After separation, the organic phase was washed with copper sulfate solution and saturated brine, and dried over anhydrous sodium sulfate. The crude product was filtered and evaporated under reduced pressure, and compound 13 (1.832 g, 98%) was obtained by column chromatography (2% ~ 3% EtOAc / hexanes).

[0127] R f = 0.6 (5% EtOAc / hexanes), PMA stain. = +0.6 (c 1, CHCl3);HRMS(ESI, m / z) for C 31 H 54 O5Si2Na + [M + Na] +: Calcd. 585.3402; Found 585.3402.IR(KBr)ν max 3074, 2954, 2929, 2856, 1720, 1463, 1259, 1112, 1070, 837, 775, 771cm −1 . 1 HNMR(400 MHz, CDCl3) δ 8.07 (dt, J = 8.5, 1.4 Hz, 2H), 7.63 – 7.53 (m, 1H), 7.45(td, J = 7.6, 1.5 Hz, 2H), 5.89 – 5.74 (m, 1H), 5.42 (qd, J = 6.9, 1.4 Hz, 1H),5.06 – 4.89 (m, 2H), 4.11 – 4.02 (m, 1H), 3.92 (p, J = 6.0 Hz, 1H), 3.15 – 3.04(m, 1H), 2.20 – 1.99 (m, 2H), 1.72 (dt, J = 13.3, 6.3 Hz, 1H), 1.66 – 1.55 (m,1H), 1.52 (dd, J = 6.9, 1.4 Hz, 3H), 1.39 – 1.22 (m, 1H), 1.19 (dd, J = 7.1, 1.3Hz, 3H), 0.87 (dd, J = 9.9, 1.3 Hz, 18H), 0.06 (d, J = 1.3 Hz, 3H), 0.04 (d, J =1.3 Hz, 3H), 0.01 (d, J = 1.4 Hz, 3H), -0.04 (d, J = 1.3 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 209.0, 165.9, 139.1, 133.5, 130.0, 129.7, 128.6, 114.4, 74.7, 70.1, 68.6, 48.7, 40.6, 36.5, 29.2, 26.1, 26.0, 18.2, 18.1, 16.0, 12.2, -4.0, -4.2,-4.4, -4.5.

[0128] Embodiment 3:

[0129]

[0130] Compound 13 (1.615 g, 2.87 mmol) was dissolved in 30 mL of anhydrous ethanol, and sodium borohydride (5.74 mmol, 2 eq.) was added at 0°C under argon protection. The system was heated to room temperature and reacted for 30 minutes. It was then cooled to 0°C, and anhydrous potassium carbonate (1.59 g, 4 eq.) was added thereto, and the reaction was allowed to proceed overnight at room temperature. After the reaction was completed, the system was quenched with pH 7.0 phosphate buffer and quenched with water and methyl tert-butyl ether. After separation, the organic phase was washed with saturated ammonium chloride solution and saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure to obtain a crude product.

[0131] Dissolve the crude product from the previous step in 30 mL THF and 5 mL pH 7.0 phosphate buffer and cool to 0°C. Add 2.27 g sodium periodate to the system and react at room temperature for 3 h. Dilute the system with water and ethyl acetate and extract with ethyl acetate. Wash the organic phase with saturated brine and dry it over anhydrous sodium sulfate. Remove the solvent by rotary evaporation to obtain the crude product aldehyde.

[0132] The crude product from the previous step was dissolved in 30 mL of tert-butanol and 15 mL of water. Sodium dihydrogen phosphate (4.4 g), 2-methyl-2-butene (7.5 g) and sodium chlorite (4.0 g, 80%) were added under argon protection at 0°C and reacted at room temperature for 1 h. The reaction was quenched with ammonium chloride solution and extracted with ethyl acetate three times. The organic phase was dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure and purified by column chromatography (1% ~ 10% EtOAc / hexanes) to obtain compound 14 (940 mg, three-step yield 76%).

[0133] R f = 0.65 (20% EtOAc / hexanes w / 1‰ HCOOH), PMA stain. = -0.4 (c 1,CHCl3); HRMS(ESI, m / z) for C 22 H 44 O4Si2 - [M - H] - : Calcd. 429.2862; Found 429.2861. IR(KBr) ν max 2956, 2929, 2859, 1712, 1641, 1471, 1257, 1095, 835, 773, 667 cm −1 . 1 H NMR(400 MHz, CDCl3) δ 5.78 (ddt, J = 16.9, 10.2, 6.6 Hz, 1H), 5.17 – 4.86 (m, 2H), 4.02 (ddd, J = 8.1, 5.3, 3.0 Hz, 1H), 3.78 (dq, J = 8.1, 5.2 Hz, 1H), 2.71 (qd, J = 7.2, 3.0 Hz, 1H), 2.19 – 1.97 (m, 2H), 1.73 (ddd, J = 13.7, 8.3, 5.3 Hz, 1H), 1.67 – 1.60 (m, 1H), 1.60 – 1.49 (m, 2H), 1.24 (d, J = 7.2 Hz, 4H), 0.90 (d, J = 12.7 Hz, 18H), 0.12 (d, J = 6.6 Hz, 6H), 0.04 (d, J = 8.3 Hz, 6H). 13 C NMR(101 MHz, CDCl3) δ 177.1, 138.5, 114.9, 71.7, 68.7, 44.1, 42.0, 36.8, 29.0, 26.0, 25.9, 18.1, 18.0, 14.1, -4.0, -4.2, -4.4, -4.7.

[0134] Example 4:

[0135]

[0136] Under argon protection, 2,2,2-trichloroethanol (TceOH) (670 mg, 2 eq.), EDCI (640 mg, 1.5 eq.), DMAP (130 mg, 0.5 eq.) were added to a solution of compound 14 (940 mg, 2.18 mmol) in anhydrous DCM in sequence and stirred overnight. The reaction solution was diluted with ethyl acetate and washed with saturated ammonium chloride solution, saturated sodium bicarbonate solution and saturated saline solution, extracted with ethyl acetate, and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure and purified by column chromatography (1% ~ 2% EtOAc / hexanes) to obtain compound 7 (980 mg, 80%).

[0137] Rf= 0.6 (2% EtOAc / hexanes), PMA stain. = -8 (c 1, CHCl3)HRMS(ESI,m / z) for C 24 H 47 Cl3O4Si2Na + [M + Na] + : Calcd. 583.1971; Found 583.1975.IR(KBr) ν max 2954, 2927, 2856, 1755, 1641, 1463, 1382, 1257, 1097, 1051, 835, 773, 721,663, 572cm −1 . 1 H NMR (400 MHz, CDCl3) δ 5.81 (ddt, J = 16.9, 10.2, 6.6 Hz, 1H), 5.05 – 4.90 (m, 2H), 4.77 – 4.66 (m, 2H), 4.09 (dt, J = 7.4, 4.7 Hz, 1H), 3.87(qd, J = 6.4, 4.5 Hz, 1H), 2.85 (qd, J = 7.0, 4.1 Hz, 1H), 2.24 – 1.94 (m, 1H), 1.72 (ddd, J = 13.5, 7.5, 5.9 Hz, 1H), 1.64 – 1.58 (m, 1H), 1.45 (ddt, J = 13.6,10.5, 6.0 Hz, 1H), 1.21 (d, J= 7.1 Hz, 3H), 0.89 (d, J = 1.8 Hz, 18H), 0.06 (dd, J = 4.6, 2.7 Hz, 12H). 13 C NMR(101 MHz, CDCl3) δ 172.4, 139.0, 114.5, 95.1,74.1, 70.9, 68.9, 45.2, 41.0, 36.5, 29.4, 26.0, 26.0, 25.9, 18.2, 18.1, 11.6,-4.1, -4.2, -4.2, -4.6.

[0138] Embodiment 5:

[0139]

[0140] Grubbs II catalyst (28 mg, 0.1 eq.) was added to a solution of compound 7 (184 mg, 0.33 mmol) and 8 (142 mg, 3.0 eq.) in 1,2-dichloroethane (previously degassed with an argon stream), and the mixture was heated in an oil bath at 50°C for 24 h. After the reaction was completed, the solvent was removed by rotary evaporation under reduced pressure, and the crude product was purified by column chromatography (1% ~ 2% EtOAc / hexanes) to give compound 4 (131 mg, 59%).

[0141] Rf= 0.3 (3.3% EtOAc / hexanes), PMA stain. = -4 (c = 1, CHCl3)HRMS(ESI, m / z) for C 31 H 61 Cl3O5Si2Na + [M + Na] + : Calcd. 697.3016; Found 697.3020.IR(KBr) ν max 3581, 2956, 2929, 2887, 2856, 1755, 1728, 1652, 1555, 1471, 1377, 1257, 1097, 1062, 835, 773, 721, 663, 572cm −1 . 1 H NMR(400 MHz, CDCl3) δ 5.53(dt, J = 15.3, 6.6 Hz, 1H), 5.31 (dd, J= 15.3, 8.7 Hz, 1H), 4.78 – 4.65 (m, 2H),4.08 (dt, J = 7.6, 4.6 Hz, 1H), 3.85 (td, J = 6.2, 6.2 Hz, 1H), 3.17 (dd, J = 8.0,3.2 Hz, 1H), 2.84 (qd, J = 7.0, 4.1 Hz, 1H), 2.22 (p, J = 7.3 Hz, 1H), 2.17 –1.97 (m, 3H), 1.71 (dt, J = 13.5, 6.7 Hz, 1H), 1.66 – 1.38 (m, 4H), 1.31 (tdd, J = 15.3, 9.6, 5.4 Hz, 1H), 1.21 (d, J = 7.0 Hz, 3H), 0.95 (d, J = 6.7 Hz, 3H),0.92 (d, J = 7.6 Hz, 3H), 0.90 – 0.84 (m, 21H), 0.06 (dd, J = 5.7, 3.2 Hz, 12H). 13 C NMR(101 MHz, CDCl3) δ 172.4, 133.0, 132.8, 95.1, 76.9, 74.1, 70.9, 68.9,45.1, 41.1, 41.0, 37.1, 36.4, 28.3, 27.2, 26.0, 25.9, 18.2, 18.1, 17.3, 12.5,12.0, 11.6, -4.1, -4.2, -4.6.

[0142] Example 6:

[0143]

[0144] Compound 4 (151 mg, 0.223 mmol) was dissolved in anhydrous DCM (10 mL), and Fmoc-glycine (200 mg, 3.0 eq.), DCC (231 mg, 5 eq.) and DMAP (13.6 mg, 0.5 eq.) were added to the system under argon protection, and the reaction was carried out in an oil bath at 30°C for 15 h. After the reaction, the solvent was removed by rotary evaporation under reduced pressure, and the product was purified by column chromatography (1.6% ~ 5% EtOAc / hexanes) to obtain compound 17 (136 mg, 64%).

[0145] Rf= 0.35 (10% EtOAc / hexanes), PMA stain. = +4 (c 0.25, CHCl3)HRMS(ESI, m / z) for C 48 H 74 Cl3NO8Si2Na + [M + Na] + : Calcd. 976.3911; Found 976.3914.IR(KBr) ν max 3394, 2958, 2927, 2858, 1728, 1506, 1450, 1377, 1259, 1201, 1097,1051, 802, 740cm −1 . 1 H NMR (400 MHz, CDCl3) δ 7.76 (d, J = 7.5 Hz, 2H), 7.61 (d, J =7.5 Hz, 2H), 7.40 (t, J = 7.4 Hz, 2H), 7.31 (td, J = 7.5, 1.2 Hz, 2H), 5.42 (dt, J = 15.2, 6.5 Hz, 1H), 5.33 (t, J = 5.4 Hz, 1H), 5.26 (dd, J = 15.3, 8.7 Hz, 1H),4.82 (dd, J = 6.9, 5.1 Hz, 1H), 4.71 (dd, J = 13.6, 11.7 Hz, 2H), 4.44 – 4.33 (m,2H), 4.23 (t, J= 7.2 Hz, 1H), 4.08 (dt, J = 7.6, 4.9 Hz, 1H), 4.04 – 3.92 (m,2H), 3.91 – 3.76 (m, 1H), 2.85 (qd, J = 7.1, 4.2 Hz, 1H), 2.42 (dt, J = 8.4, 6.6Hz, 1H), 2.18 – 1.88 (m, 1H), 1.77 – 1.49 (m, 6H), 1.45 – 1.31 (m, 2H), 1.27(d, J = 12.5 Hz, 2H), 1.21 (d, J = 7.1 Hz, 3H), 0.96 (d, J = 6.8 Hz, 3H), 0.93 –0.82 (m, 24H), 0.06 (dd, J = 6.0, 3.4 Hz, 12H). 13 C NMR(101 MHz, CDCl3) δ 172.4,170.0, 156.3, 144.0, 141.4, 131.6, 127.8, 127.2, 125.3, 120.1, 95.1, 81.2,74.1, 70.9, 69.0, 67.3, 47.3, 45.1, 42.9, 40.9, 39.3, 37.1, 35.9, 28.1, 26.3,26.0, 25.9, 18.2, 18.1, 17.9, 13.7, 11.6, 11.6, -4.1, -4.2, -4.6.

[0146] Example 7:

[0147]

[0148] Troc-Thr-OH (568.5 mg, 1.93 mmol) was dissolved in DCM (30 mL), and HATU (811.4 mg, 1.5 eq.), HOAt (394.1 mg, 1.5 eq.) and DIPEA (748.3 mg, 3 eq.) were added thereto under argon protection at 0°C. Glycine hydrochloride (266.6 mg, 1.1 eq.) was then added and the reaction was allowed to proceed overnight at room temperature. The reaction was quenched with ammonium chloride solution and extracted with ethyl acetate three times. The organic phases were combined and washed with ammonium chloride solution, sodium bicarbonate solution, and saturated brine, and then dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure, and the product was purified by column chromatography (30% ~ 70% EtOAc / hexanes) to obtain compound 17 (649.1 mg, 92%).

[0149] LiOH·H2O (210 mg, 5 eq.) was added to a THF-water solution (10 mL each) of compound 15 (365 mg, 1.00 mmol) at 0°C and reacted for 30 minutes. After the reaction, the mixture was diluted with ethyl acetate and water and acidified to pH = 3 with 1N hydrochloric acid. The mixture was extracted three times with ethyl acetate. The organic phases were combined and washed with brine, dried over anhydrous sodium sulfate, and impurities were removed by rotary evaporation under reduced pressure to obtain Troc-Thr-Gly-OH (6,350 mg), which was used in subsequent reactions without further purification.

[0150] Rf= 0.3 (66% EtOAc / hexanes), PMA stain. = -27 (c 1, CHCl3)HRMS(ESI, m / z) for C 10 H 15 Cl3N2O6Na + [M + Na] + : Calcd. 386.9888; Found 386.9889.IR(KBr) ν max 3645, 3350, 3057, 2954, 2916, 2849, 1828, 1737, 1660, 1586, 1435,1373, 1215, 1114, 1045, 975, 819, 734, 570cm −1 . 1 H NMR(400 MHz, CDCl3) δ 7.14(t, J = 5.7 Hz, 1H), 6.29 (d, J= 8.0 Hz, 1H), 4.83 – 4.68 (m, 2H), 4.40 (qd, J =6.5, 2.7 Hz, 1H), 4.25 (dd, J = 8.0, 2.6 Hz, 1H), 4.06 (dd, J = 5.7, 1.7 Hz, 2H), 3.75 (s, 3H), 1.22 (d, J = 6.4 Hz, 2H). 13 C NMR (101 MHz, CDCl3) δ 171.0, 170.5, 155.3, 95.4, 74.9, 59.3, 52.7, 41.4, 18.3.

[0151] Embodiment 8:

[0152]

[0153] Compound 17 (88.9 mg, 0.093 mmol) was dissolved in DCM (10 mL), and DBU (14.2 mg, 1.0 eq.) was added at 0°C. The mixture was stirred at 0°C for 30 minutes, and then stirred for another 30 minutes after warming to room temperature. After TLC detection showed that the reaction raw material spot disappeared, the mixture was cooled to 0°C, and a DCM solution of 6 (49.1 mg, 1.5 eq.) was added to the system, followed by HOAt (38.0 mg, 3.0 eq.), and HATU (106.1 mg, 3.0 eq.) was added 5 minutes later. The reaction was stirred at room temperature overnight. The reaction solution was diluted with ethyl acetate, washed with saturated ammonium chloride solution, saturated sodium bicarbonate solution and saturated saline solution, extracted with ethyl acetate, and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure and then purified by column chromatography (30% - 40% EtOAc / hexanes) to give compound 18 (73.4 mg, 74%).

[0154] Rf= 0.15 (67% EtOAc / hexanes), PMA stain. = -28 (c 1, CHCl3)HRMS(ESI, m / z) for C 32 H 71 N3O 18 Si2Na + [M + Na] + : Calcd. 764.4672; Found 764.4673.IR(KBr) ν max3408, 3339, 2956, 2926, 2854, 1739, 1647, 1525, 1464, 1377, 1258,1207, 1080, 1053, 970, 837, 559cm −1 . 1 H NMR(400 MHz, CDCl3) δ 7.08 (t, J = 5.9Hz, 1H), 6.75 (t, J = 5.1 Hz, 1H), 6.12 (d, J = 7.9 Hz, 1H), 5.39 (dt, J = 15.3,6.6 Hz, 1H), 5.23 (dd, J = 15.3, 8.7 Hz, 1H), 4.88 – 4.65 (m, 5H), 4.44 (qd, J =6.5, 2.3 Hz, 1H), 4.24 (dd, J = 7.9, 2.4 Hz, 1H), 4.14 – 4.02 (m, 3H), 4.01 –3.90 (m, 2H), 3.83 (p, J = 6.2 Hz, 1H), 2.84 (qd, J = 7.0, 4.1 Hz, 1H), 2.41 (dt, J = 8.6, 6.6 Hz, 1H), 2.10 – 1.87 (m, 1H), 1.78 – 1.66 (m, 1H), 1.66 – 1.61(m, 1H), 1.61 – 1.56 (m, 1H), 1.56 – 1.44 (m, 1H), 1.41 – 1.31 (m, 1H), 1.29– 1.19 (m, 8H), 1.18 – 1.07 (m, 1H), 0.93 (d, J = 6.8 Hz, 3H), 0.88 (d, J = 1.4Hz, 21H), 0.84 (d, J = 6.8 Hz, 4H), 0.06 (dd, J = 6.0, 4.4 Hz, 12H). 13C NMR(101MHz, CDCl3) δ 172.5, 171.3, 170.1, 168.9, 155.1, 131.7, 131.4, 95.4, 95.1,81.9, 74.9, 74.2, 70.9, 69.0, 67.3, 59.8, 45.2, 43.1, 41.4, 40.9, 39.3, 37.1,35.9, 28.3, 26.2, 26.1, 25.9, 18.8, 18.2, 18.1, 17.9, 13.8, 11.5, -4.1, -4.2,-4.6.

[0155] Embodiment 9:

[0156]

[0157] The zinc powder was activated with 1N hydrochloric acid for 5 minutes, washed with water and ethanol, and then dried under vacuum for later use. 18 (73.4 mg, 0.069 mmol) was dissolved in THF and 1N KH2PO4aq. (1:1 v / v, 20 mL in total), and an excess (~100 mg) of activated zinc powder was added under argon protection, and stirred vigorously until TLC showed that the raw material disappeared completely. The mixture was filtered and washed with water and ethyl acetate, and the filtrate was extracted three times with ethyl acetate. The aqueous phase was adjusted to pH = 7 with sodium bicarbonate solution and then extracted three times with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, and evaporated under reduced pressure to obtain a crude product.

[0158] The crude product was dissolved in anhydrous DCM (70 mL, 0.001 N), HOAt (47.0 mg, 5 eq.) and DIPEA (89.2 mg, 10 eq.) were added thereto under argon protection at 0 ° C, and HATU (131.2 mg, 5 eq.) was added 5 minutes later. The reaction system was gradually warmed to room temperature and reacted for 24 hours. After the reaction was completed, it was quenched with saturated ammonium chloride solution and diluted with ethyl acetate and water. After separation, the aqueous phase was extracted three times with ethyl acetate. The organic phases were combined and washed with 5% citric acid aqueous solution, ammonium chloride solution, sodium bicarbonate solution, and saturated brine, and dried over anhydrous sodium sulfate. After the solvent was removed by vacuum rotary evaporation, it was purified by column chromatography (30% ~ 70% EtOAc / hexanes) to obtain compound 19 (29.7 mg, 58%).

[0159] Rf= 0.15 (67% EtOAc / hexanes), PMA stain. = -28 (c 1, CHCl3)HRMS(ESI, m / z) for C 32H 71 N3O 18 Si2Na + [M + Na] + : Calcd. 764.4672; Found 764.4673.IR(KBr) ν max 3408, 3339, 2956, 2926, 2854, 1739, 1647, 1525, 1464, 1377, 1258,1207, 1080, 1053, 970, 837, 559cm −1 . 1 H NMR(400 MHz, CDCl3) δ 7.71 (d, J = 8.4Hz, 1H), 7.51 (d, J = 6.1 Hz, 1H), 6.20 (s, 1H), 5.33 (ddd, J = 15.2, 8.8, 4.1Hz, 1H), 5.14 (dd, J = 14.9, 9.4 Hz, 1H), 4.82 (dd, J = 10.3, 2.1 Hz, 1H), 4.53 –4.42 (m, 1H), 4.41 – 4.33 (m, 1H), 4.31 (dd, J = 8.3, 1.6 Hz, 1H), 4.24 (dd, J =17.0, 6.1 Hz, 1H), 3.98 – 3.86 (m, 2H), 3.76 (dd, J = 17.0, 3.2 Hz, 1H), 3.62 –3.52 (m, 1H), 2.72 – 2.62 (m, 1H), 2.36 (td, J = 9.6, 6.6 Hz, 1H), 2.22 – 2.00(m, 1H), 1.89 – 1.72 (m, 2H), 1.70 – 1.46 (m, 4H), 1.31 (d, J = 7.3 Hz, 3H),1.29 – 1.16 (m, 2H), 1.14 (d, J = 6.5 Hz, 3H), 0.96 – 0.86 (m, 28H), 0.12 (d, J =3.2 Hz, 6H), 0.05 (d, J= 10.6 Hz, 6H). 13 C NMR(101 MHz, CDCl3) δ 177.1, 172.5,170.0, 167.9, 132.3, 132.2, 80.5, 72.0, 68.5, 65.9, 56.4, 44.6, 42.4, 41.9,40.8, 40.3, 37.0, 35.2, 27.3, 26.1, 26.0, 25.5, 18.8, 18.2, 18.2, 17.5, 17.3,12.5, 12.0, -3.9, -4.1, -4.6, -4.7.

[0160] Embodiment 10:

[0161]

[0162] Compound 19 (12.2 mg, 0.0164 mmol) was dissolved in anhydrous THF (10 mL), and TBAF (1 N solution in THF, 0.33 mL, 20 eq.) was added dropwise at 0°C under argon protection. The reaction was carried out at room temperature for 6 h. After complete conversion, the reaction was diluted with ethyl acetate and quenched with ammonium chloride solution. The organic phase was washed three times with water and then with saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation under reduced pressure and purified by column chromatography (0% ~ 10% MeOH / DCM) to obtain compound 1 (6.0 mg, 72%).

[0163] Rf= 0.4 (10% MeOH / DCM), PMA stain. = -18 (c 0.6, CHCl3)HRMS(ESI,m / z) for C 25 H 42 N3O8 - [M - H] - : Calcd. 512.2977; Found 512.2974.IR(KBr) ν max 3490,3438, 3339, 2966, 2936, 2854, 1677, 1657, 1525, 1464, 1207, 1078, 970, 836,560cm −1 . 1 H NMR (400 MHz, CDCl3) δ 7.70 – 7.60 (m, 2H), 7.30 (s, 1H), 5.44 (ddd, J= 15.1, 8.6, 4.7 Hz, 1H), 5.17 (dd, J = 15.2, 9.0 Hz, 1H), 4.79 (dd, J = 10.3,2.0 Hz, 1H), 4.54 (qd, J = 6.4, 1.7 Hz, 1H), 4.42 (dd, J = 9.0, 1.6 Hz, 1H), 4.34(dd, J = 18.4, 7.6 Hz, 1H), 4.07 – 3.90 (m, 3H), 3.79 – 3.70 (m, 1H), 3.61 (dd, J = 18.4, 3.6 Hz, 1H), 2.46 (qd, J = 7.2, 2.7 Hz, 1H), 2.35 (td, J = 9.4, 6.7 Hz,1H), 2.13 (td, J = 15.1, 6.7 Hz, 1H), 2.04 – 1.90 (m, 1H), 1.75 (dt, J = 14.7,10.4 Hz, 1H), 1.71 – 1.59 (m, 2H), 1.56 (t, J = 12.8 Hz, 1H), 1.50 – 1.39 (m,1H), 1.38 (d, J = 7.3 Hz, 3H), 1.17 (d, J = 6.4 Hz, 4H), 1.12 (dd, J = 13.8, 7.1Hz, 1H), 0.94 (d, J = 6.8 Hz, 3H), 0.88 (d, J = 6.9 Hz, 3H), 0.88 (t, J = 7.4 Hz,3H). 13 C NMR(101 MHz, CDCl3) δ 176.4, 172.1, 170.5, 168.8, 132.7, 130.8, 80.7,74.3, 73.5, 66.1, 57.2, 48.1, 42.5, 41.5, 40.9, 39.6, 37.7, 35.3, 28.5, 27.1,19.3, 16.9, 16.3, 12.2, 11.9.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing Eucalactam B, characterized in that the steps include: S1, subjecting compound 9 and compound 11 to a multi-step reaction to generate compound 7; The step S1 comprises: S1.1, converting compound 2 into compound 9 through a multi-step reaction, and oxidizing compound 9; The step S1.1 comprises: placing the compound 2 in an alkaline environment, adding tert-butyloxycarbonyl anhydride to react, and introducing a tert-butyloxycarbonyl group into the compound 2; adding lithium aluminum hydride to carry out a reduction reaction to reduce the carboxyl group on the compound 2 to an alcohol group; Pyridine chlorochromate is added to carry out oxidation reaction to oxidize the alcohol group into aldehyde group; Methylenetriphenylphosphine is added in a weak acid environment to react, an allyl group is introduced into the compound 2, and the aldehyde group is oxidized to an allyl alcohol; Add tert-butyldimethylsilyl chloride and imidazole to introduce tert-butyldimethylsilyl to protect allyl alcohol; Trifluoroacetic acid is added to remove the tert-butyloxycarbonyl group, and then an oxidant is added to oxidize the alcohol group at the end of the allyl group to an aldehyde to obtain the compound 9; S1.2, the oxidized compound 9 undergoes an aldol condensation reaction with the compound 11 to generate a compound 12; S1.3, converting the compound 12 into a compound 14, and then subjecting the compound 14 to an esterification reaction to obtain the compound 7; The step S1.3 comprises: The compound 12 is dissolved and placed in an inert atmosphere, and 2,6-lutidine is first added, and then tri-tert-butylsilyl trifluoromethanesulfonate is added to obtain compound 13; The compound 13 is dissolved and placed in an inert atmosphere, sodium borohydride is first added to heat the reaction, and then anhydrous potassium carbonate is added to reduce the temperature to obtain a pre-product; dissolving the pre-product in a weak acid buffer, adding sodium periodate to react, and extracting to obtain an aldehyde product; The aldehyde product is dissolved and placed in an inert atmosphere, and sodium dihydrogen phosphate, 2-methyl-2-butene and sodium chlorite are added to react. After the reaction is completed, the compound 14 is obtained by extraction, drying and evaporation. The compound 14 is dissolved and placed in an inert atmosphere, and 2,2,2-trichloroethanol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine are added to react, and after the reaction is completed, the compound 7 is obtained by washing, extracting, drying and evaporating in sequence; S2, the compound 7 and the compound 8 undergo olefin metathesis reaction to generate compound 4; S3, subjecting the compound 4 to a macrocyclic lactamization reaction to obtain a product 1, wherein the product 1 is Eucalactam B; The step S3 comprises: S3.1, dissolving the compound 4 and placing it in an inert atmosphere, adding compound 5, dicyclohexylcarbodiimide and 4-dimethylaminopyridine to react to obtain compound 17; S3.2, converting the compound 17 into compound 18 by reacting with compound 6, and introducing a protecting group; The step S3.2 comprises: 2,2,2-trichloroethoxycarbonyl-L-threonine was dissolved and placed in an inert atmosphere, HATU, HOAt and DIPEA were first added, and then glycine hydrochloride was added to react to obtain compound 15; The compound 15 is dissolved in a weak acid solution, lithium hydroxide is added to react, the solution after the reaction is acidified to pH=3, and extraction, drying and evaporation are performed in sequence to obtain the compound 6; The compound 17 is dissolved and then an organic basic compound is added. After the reaction is completed, a solution of the compound 6 and HOAt are added, and then HATU is added for reaction. The compound 18 is obtained by washing, extraction, drying and evaporation. S3.3, removing the protecting group of the compound 18 in a weak acid environment, and then adding HATU catalyst to carry out macrolactamization reaction to obtain the product 1; Wherein, the structural formula of the above compound is as follows: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 2. The preparation method of Eucalactam B according to claim 1, characterized in that, The step S3.3 comprises: The compound 18 is dissolved in a weak acid environment, activated zinc powder is added, and then filtered, washed, extracted, and dried in sequence to obtain a crude product; The crude product is dissolved in an anhydrous organic solvent, HOAT and DIPEA are first added in an inert atmosphere, and then HATU is added, followed by extraction, drying and evaporation to obtain compound 19; The compound 19 is dissolved in a weak acid environment, and TBAF is added dropwise in an inert atmosphere, and after the conversion is completed, the compound 1 is obtained; Wherein, the structural formula of the above compound is as follows: 。 3. The preparation method of Eucalactam B according to claim 2, characterized in that, The steps of obtaining the crude product include: The zinc powder is activated in an acidic solvent and then dried; Adding activated zinc powder to the acidic solution of compound 18, stirring vigorously, and then filtering and washing; The filtrate is subjected to preliminary extraction, and the obtained aqueous phase is adjusted to a neutral solution; The neutral aqueous phase is subjected to deep extraction again, and the organic phases obtained by the preliminary extraction and the deep extraction are mixed, dried and evaporated to obtain the crude product.

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