Method for producing diphenylmethane derivative

Abstract

To provide an improved method for producing a diphenylmethane derivative which is effective as a sodium-dependent glucose cotransporter (SGLT) inhibitor.SOLUTION: The present invention relates to a method for producing a compound of the formula Ia implemented by a convergent synthesis method. The method comprises: reacting a compound of the formula 2 with a compound of the formula 3, and subjecting the resultant to a cyclization reaction to obtain a compound of the formula 4; subjecting the resultant to dehydration or amidation, reacting the resultant with a compound of the formula 5, and performing reduction to obtain a compound of the formula 6; and reacting the resultant with a compound of the formula 7 and performing deprotection and reduction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing diphenylmethane derivatives, and more particularly to an improved method for producing diphenylmethane derivatives useful as inhibitors of sodium-dependent glucose cotransporters (SGLTs). [Background technology]

[0002] Sodium-dependent glucose cotransporters (SGLTs) follow the concentration gradient. + It enables the transport of glucose while simultaneously allowing the transport of glucose against the concentration gradient. Currently, two important SGLT isoforms, known as SGLT1 and SGLT2, have been cloned. SGLT1 is present in the intestines, kidneys, and heart, and its expression regulates cardiac glucose transport. As a high-affinity, low-volume transporter, SGLT1 is responsible for only a portion of renal glucose reabsorption. In contrast, SGLT2 is a low-affinity, high-volume transporter, primarily present in the apical region of epithelial cells in the early proximal tubules. In healthy individuals, more than 99% of filtered plasma glucose is reabsorbed in the renal glomeruli, and less than 1% of total filtered glucose is excreted in the urine. It is estimated that 90% of renal glucose reabsorption is facilitated by SGLT2, and the remaining 10% is mediated by SGLT1 in the late proximal straight tubules. Genetic mutations in SGLT2 do not have any particular adverse effects on carbohydrate metabolism. However, the mutation increases renal glucose secretion by approximately 140 g / day. Human mutation studies suggest that SGLT2 is responsible for most of the renal glucose reabsorption, making it a target for therapeutic research.

[0003] U.S. Patent Publication No. 2015 / 0152075 discloses a compound having a diphenylmethane moiety that has inhibitory activity against SGLT2 and a method for producing the same. This document discloses that diphenylmethane derivative compounds are effective in treating diabetes, as they exhibit superior inhibitory effects on human SGLT2 activity compared to dapagliflozin, a known SGLT2 inhibitor, and significantly reduce urinary glucose excretion in animals. Furthermore, U.S. Patent Publication No. 2014 / 0274918 discloses a diphenylmethane derivative that is effective as a dual inhibitor of sodium-dependent glucose cotransporter 1 (SGLT1) and sodium-dependent glucose cotransporter 2 (SGLT2).

[0004] Examples such as in U.S. Patent Publication No. 2015 / 0152075 disclose a method for producing diphenylmethane compound c28 in the same manner as in Reaction Scheme 1 below.

[0005] [Reaction Scheme 1] [ka] [ka] [ka] [ka]

[0006] However, conventional methods for producing compound C28 employ linear synthesis methods, such as coupling with a glucose group and then forming a pentagonal ring on the aglycone group. In such linear synthesis, the final yield is low due to the complexity of the pathway. Furthermore, if the synthesis of the substituents on the glucose group or cyclopropylbenzyl group bonded to dihydrobenzofuran fails midway, or if it is intended to change the substituent or cyclopropylbenzyl group to another group, the synthesis must be restarted from the beginning, which is inconvenient. In addition, in the step of synthesizing the cyclopropyl group of compound C28, the yield varies greatly depending on the state of the reagents (diethylzinc, solvent) (purity, anhydride, etc.) and the reaction concentration. The method is carried out by cyclizing the olefin by a Simon-Smith reaction at the end of the synthesis pathway.

[0007] Therefore, the inventors discovered that diphenylmethane derivatives can be efficiently produced by a convergent synthesis method, in which the main groups are synthesized separately and then combined, rather than by the conventional linear synthesis method, and thus completed the present invention. [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, the object of the present invention is to provide an improved method for producing diphenylmethane derivatives useful as SGLT inhibitors. [Means for solving the problem]

[0009] According to one aspect of the present invention, a method for producing the compound of the following formula 1a, (1) A step of reacting the compound of formula 2 below with the compound of formula 3 below, and then cyclizing the resulting mixture to obtain the compound of formula 4 below; (2) A step of dehydrating or amidating the compound of formula 4, reacting it with the compound of formula 5 below, and reducing it to obtain the compound of formula 6 below; and (3) A step of reacting the compound of formula 6 with the compound of formula 7 below to perform deprotection and reduction; [Chemical formula] [In the formula, A is oxygen (O) or sulfur (S); n is 1 or 2; PG is a protecting group; X' is halogen or C 1-7 alkyl; X, Y, and Hal are each independently halogen; B is (B-1) [Chemical formula] or (B-2) [Chemical formula] ; Here, Ra, Rb, Rc, and Rd are each independently hydrogen, halogen, hydroxy, mercapto, cyano, nitro, amino, carboxy, oxo, C 1-7 alkyl, C 1-7 alkylthio, C 2-7 alkenyl, C 2-7 alkynyl, C 1-7 alkoxy, C 1-7 alkoxy-C 1-7 alkyl, C 2-7 alkenyl-C 1-7 alkyloxy, C 2-7 alkynyl-C 1-7 alkyloxy, C 3-10 cycloalkyl, C 3-7 cycloalkylthio, C 5-10 cycloalkenyl, C 3-10 cycloalkyloxy, C 3-10 cycloalkyloxy-C 1-7 alkoxy, phenyl-C 1-7 alkyl, C 1-7 alkylthio-phenyl, phenyl-C 1-7 alkyloxy, mono- or di-C 1-7 alkylamino, mono- or di-C 1-7Alkylamino-C 1-7 Alkyl, C 1-7 Alkanoyl, C 1-7 Alkanoylamino, C 1-7 Alkylcarbonyl, C 1-7 Alkoxycarbonyl, carbamoyl, mono- or di-C 1-7 Alkylcarbamoyl, C 1-7 Alkyl sulfonylamino, phenylsulfonylamino, C 1-7 Alkyl sulfinyl, C 6-14 Aryl sulfanyl, C 6-14 Aryl sulfonyl, C 6-14 Aryl, 5-13 member heteroaryl, 5-10 member heterocycloalkyl, 5-10 member heterocycloalkyl-C 1-7 Alkyl, or 5-10 member heterocycloalkyl-C 1-7 It is an alkoxy; Ring C is C 3-10 Cycloalkyl, C 5-10 Cycloalkenyl, C 6-14 They are aryl, 5-13 member heteroaryl, or 5-10 member heterocycloalkyl; Alkyl, alkenyl, alkynyl, and alkoxy elements are each independently unsubstituted or halogenated, hydroxy, cyano, nitro, amino, mercapto, C 1-7 Alkyl, and C 2-7 Having one or more substituents selected from the group consisting of alkynyls; Cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocycloalkyl are each independently unsubstituted or halogenated, hydroxy, cyano, nitro, amino, mercapto, C 1-4 Alkyl, and C 1-4 Having one or more substituents selected from the group consisting of alkoxys; and Heteroaryls and heterocycloalkyls each independently contain one or more heteroatoms selected from the group consisting of N, S, and O. A method including this is provided.

[0010] According to another aspect of the present invention, a method for producing the compound of the following formula 1b, (1) A step of reacting the compound of formula 2 below with the compound of formula 3 below, and then cyclizing the resulting mixture to obtain the compound of formula 4 below; (2) A step of dehydrating or amidating the compound of formula 4, reacting it with the compound of formula 5, and reducing it to obtain the compound of formula 6 below; and (3) A step of reacting the compound of formula 6 with the compound of formula 8 below, and performing reduction to obtain the compound of formula 9 below; (4) Under acidic conditions, the furanose ring of the compound of formula 9 is converted to a pyranose ring, and then a protecting group is introduced to obtain the compound of formula 10 below; and (5) The compound of formula 10 is treated with thiourea, and the obtained product is C 1-7 A step of reacting with an alkyl halide, followed by reduction; [ka] [ka] [ka] [In the formula, R is C 1-7 It is alkylthio; B, n, PG, X', X, Y, and Hal are as defined above in Equation 1. A method including this is provided.

[0011] According to yet another aspect of the present invention, a crystalline form of a compound produced by the above method, specifically, a crystalline form of the compound of the following formula c28, is provided.

[0012] [Formula c28] [ka] [Effects of the Invention]

[0013] The present invention provides a method for producing diphenylmethane derivatives by a convergent synthesis method in which the main groups are synthesized separately and then bonded together. Therefore, compared to linear synthesis methods disclosed in prior art literature, a simpler synthesis route and high yield are achieved, and reproducibility is improved by reducing the risk factors inherent in linear synthesis routes (such as returning to the beginning of the route and repeating the synthesis at the point of failure in the middle of the synthesis).

[0014] In particular, according to the methods disclosed in prior art documents, even after coupling the glucose group and the aglycone group, the residues of the aglycone group must be synthesized. On the other hand, according to the present invention, all the residues of the aglycone group can be formed before bonding with the glucose group. Furthermore, the aryl group attached to the terminal group of the aglycone can be easily synthesized, and a variety of terminal group designs are possible.

[0015] Furthermore, the crystalline form of the compound produced by the above method has excellent physicochemical properties and can be effectively utilized in fields such as pharmaceutical manufacturing. [Brief explanation of the drawing]

[0016] [Figure 1-2] The XRD and DSC spectra of crystal form A obtained in Experimental Example 4 are shown below. [Figure 3-4] The XRD and DSC spectra of crystal form B obtained in Experimental Example 4 are shown below. [Figure 5-6] The XRD and DSC spectra of crystal form C obtained in Experimental Example 4 are shown below. [Figure 7-8] The XRD and DSC spectra of crystal form D obtained in Experimental Example 4 are shown below. [Modes for carrying out the invention]

[0017] Best mode for carrying out the invention The present invention relates to formula 1: [Formula 1] [ka] This relates to a method for producing the compound.

[0018] During the ceremony, A is either oxygen (O) or sulfur (S); R is hydroxymethyl or C 1-7 It is alkylthio; n is either 1 or 2; X' is a halogen (e.g., F, Cl, Br, or I) or C 1-7 It is alkyl; B is (B-1) [ka] or (B-2) [ka] is; Here, Ra, Rb, Rc, and Rd are independently hydrogen, halogen, hydroxyl, mercapto, cyano, nitro, amino, carboxyl, oxo, and C. 1-7 Alkyl, C 1-7 Alkylthio, C 2-7 Alkenil, C 2-7 Alkinyl, C 1-7 Alkoxy, C 1-7 Alkoxy-C 1-7 Alkyl, C 2-7 Alkenil-C 1-7 Alkyloxy, C 2-7 Alkinyl-C 1-7 Alkyloxy, C 3-10 Cycloalkyl, C 3-7 Cycloalkylthio, C 5-10 Cycloalkenyl, C 3-10 Cycloalkyloxy, C 3-10 Cycloalkyloxy-C 1-7 Alkoxy, Phenyl-C 1-7 Alkyl, C 1-7 Alkylthiophenyl, Phenylen-C 1-7 Alkoxy, mono- or di-C 1-7Alkylamino, mono- or di-C 1-7 Alkylamino-C 1-7 Alkyl, C 1-7 Alkanoyl, C 1-7 Alkanoylamino, C 1-7 Alkylcarbonyl, C 1-7 Alkoxycarbonyl, carbamoyl, mono- or di-C 1-7 Alkylcarbamoyl, C 1-7 Alkylsulfonylamino, phenylsulfonylamino, C 1-7 Alkylsulfinyl, C 6-14 Arylsulfanyl, C 6-14 Arylsulfonyl, C 6-14 Aryl, 5- to 13-membered heteroaryl, 5- to 10-membered heterocycloalkyl, 5- to 10-membered heterocycloalkyl-C 1-7 Alkyl, or 5- to 10-membered heterocycloalkyl-C 1-7 Is alkoxy; Ring C is C 3-10 Cycloalkyl, C 5-10 Cycloalkenyl, C 6-14 Aryl, 5- to 13-membered heteroaryl, or 5- to 10-membered heterocycloalkyl; Alkyl, alkenyl, alkynyl, and alkoxy are each independently unsubstituted or have one or more substituents selected from the group consisting of halogen, hydroxy, cyano, nitro, amino, mercapto, C 1-7 Alkyl, and C 2-7 Alkynyl; Cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocycloalkyl are each independently unsubstituted or have one or more substituents selected from the group consisting of halogen, hydroxy, cyano, nitro, amino, mercapto, C 1-4 Alkyl, and C 1-4 Alkoxy; and Heteroaryl and heterocycloalkyl each independently contain one or more heteroatoms selected from the group consisting of N, S, and O.

[0019] As a specific example, ring B-1 may be selected from the group consisting of [Chemical formula] .

[0020] In the above formula, R7 is hydrogen or C[[ID=**12**]] 1-7 alkyl; R[[ID=**14**]] 8a and R[[ID=**16**]] 8b are each independently C[[ID=**18**]] 1-7 alkyl or are joined to each other to form a 5- to 10-member heterocycloalkyl containing at least one heteroatom selected from the group consisting of N, S, and O.

[0021] As another specific example, ring B-2 may be selected from the group consisting of [Chemical formula] .

[0022] Preferably, the compound of formula 1 is a compound represented by the following formula 1a or may be a compound represented by the following formula 1b. [Chemical formula] In the formula, A, B, R, X', and n are as defined above in formula 1.

[0023] According to a preferred example of the compound of formula 1a, A may be oxygen; n may be 1; X' may be halogen; and B may be unsubstituted phenyl or phenyl substituted with one or two substituents selected from the group consisting of halogen, hydroxy, cyano, nitro, amino, mercapto, C[[ID=**46**]] 1-7 alkyl, C[[ID=**48**]] 3-10 cycloalkyl, and C[[ID=**50**]] 1-7 alkoxy.

[0024] Furthermore, the compounds of formulas 1a and 1b may be compounds in which glucose is in the α-form, β-form, or a racemic form thereof.

[0025] Preferably, the compounds of formulas 1a and 1b may be compounds in which glucose is in the β form.

[0026] Method for producing the compound of formula 1a (formula 1, where R = hydroxymethyl) According to one aspect of the present invention, a method for producing a compound of formula 1a (formula 1, where R = hydroxymethyl) is provided, comprising the following steps: (1) A step of reacting the compound of formula 2 below with the compound of formula 3 below, and then cyclizing the resulting mixture to obtain the compound of formula 4 below; (2) A step of dehydrating or amidating the compound of formula 4, reacting it with the compound of formula 5 below, and reducing it to obtain the compound of formula 6 below; and (3) A step of reacting the compound of formula 6 with the compound of formula 7 below to perform deprotection and reduction; A method including this is provided. [ka]

[0027] [In the formula, A is either oxygen (O) or sulfur (S); n is either 1 or 2; PG is a protecting group; X' is a halogen or C 1-7 It is alkyl; X, Y, and Hal are, independently, halogens; B is defined in Equation 1 as described above.

[0028] The compound of formula 2 used as a starting material in the above manufacturing method can be produced by the synthesis route described in the prior art document (U.S. Patent Publication No. 2015 / 0152075). For example, the compound of formula 2 is produced by the following steps: (i) A step of subjecting a carboxylic acid compound of formula 2a below to an esterification reaction to obtain a methyl ester compound of formula 2b below; (ii) A step of reducing the nitro group of the compound of formula 2b by hydrogenation to obtain the amine compound of formula 2c below; (iii) A step of reacting the compound of formula 2c with a halogenated reagent to obtain the halogenated compound of formula 2d below; and (iv) The step of subjecting the compound of formula 2d to the Sandmeyer reaction; [ka] It can be manufactured by including [a certain substance].

[0029] In the formula, Y is a halogen.

[0030] As used herein, the term "halogen" means fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0031] Process (1) In step (1), the compound of formula 2 is reacted with the compound of formula 3, and the resulting mixture is subjected to a cyclization reaction to obtain the compound of formula 4.

[0032] Therefore, a pentagonal or hexagonal ring containing oxygen can be pre-formed within the aglycone group before it binds to the glucose group and before it forms the terminal residue of the aglycone group (i.e., ring B).

[0033] As a specific example, step (1) is the following step: (i) A step of reacting the compound of formula 2 with the compound of formula 3 to obtain the compound of formula 3a below; (ii) The allyl group of the compound of formula 3a is subjected to a rearrangement reaction, the obtained product is subjected to an oxidation or ozonation reaction, and then reduced to obtain the compound of formula 3d below; and (iii) A step of subjecting the compound of formula 3d to a cyclization reaction to obtain the compound of formula 4; [ka] It can include...

[0034] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0035] In step (i), the compound of formula 2 may be subjected to a demethylation step before reacting with the compound of formula 3. For example, the compound of formula 2 may be demethylated to obtain the compound of formula 2e, and the compound of formula 2e may be reacted with the compound of formula 3: [Formula 2e] [ka]

[0036] In the formula, X and Y are halogens, independently of each other.

[0037] The rearrangement reaction in step (ii) may be carried out, for example, by a Claisen rearrangement reaction.

[0038] The rearrangement reaction may be carried out by adding a Lewis acid. The Lewis acid may be at least one selected from the group consisting of diisobutylaluminum chloride, diethylaluminum chloride, aluminum chloride, and boron trichloride.

[0039] Furthermore, the rearrangement reaction may be carried out in a solvent-free reaction or in diethylamine under heating conditions at high temperatures (e.g., 150°C to 170°C).

[0040] After the rearrangement reaction in step (ii), the compound of formula 3a is subjected to the following formula 3b: [Formula 3b] [ka] It can be obtained as a compound.

[0041] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0042] The oxidation or ozonation reaction in step (ii) may be carried out by adding osmium tetroxide (OsO4), potassium osmite (VI) dihydrate, or ozone (O3).

[0043] After being subjected to oxidation or ozonation in step (ii), the following formula (3c): [Formula 3c] [ka] As a compound, the compound of formula (3b) can be obtained.

[0044] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0045] Next, the compound of formula 3c can be reduced to obtain the compound of formula 3d.

[0046] In step (iii), the compound of formula 3d is subjected to a cyclization reaction to obtain the compound of formula 4. This method can improve the yield compared to the cyclization method disclosed in the prior art document (U.S. Patent Application Publication No. 2015 / 0152075).

[0047] The cyclization reaction may be a cyclization reaction using a Vilsmeyer reagent, a cyclization reaction using a leaving group, a cyclization reaction using a halide, or a cyclization reaction using the Mitsunobu reaction.

[0048] In one example, the cyclization reaction may be carried out by adding a Vilsmeyer reagent to the compound of formula 3d. This reaction may be carried out at a temperature of 0°C to room temperature. The Vilsmeyer reagent described above is preferably prepared and used rapidly during synthesis for the sake of yield, and for example, a Vilsmeyer reagent prepared by the reaction of dimethylformamide (DMF) with SOCl2 or POCl3 may be used.

[0049] In another example, the cyclization reaction may be carried out by introducing a tosyl or mesyl group as a leaving group. In yet another example, the cyclization reaction may be carried out using halides such as I2 and PBr3. In yet another example, the cyclization reaction may also be carried out by the Mitsunobu reaction using diisopropyl azodicarboxylate (DIAD).

[0050] These reactions involve the substitution of a primary alcohol group with a group that can act as a leaving group, and the substituent acts as a nucleophile for the phenol group, resulting in a cyclization reaction.

[0051] Process (2) In step (2), the compound of formula 4 is subjected to aldehyde or amidation, and then reacted with the compound of formula 5. The resulting mixture is reduced to obtain the compound of formula 6.

[0052] As one example, step (2) involves aldehyde conversion of the compound of formula 4 to obtain the compound of formula 4a, and then formula 4a: [Formula 4a] [ka] This may include reacting the compound with the compound of formula 5.

[0053] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0054] Specifically, the compound of formula 4 can be reduced to obtain the compound of formula 4c below, and then the compound of formula 4 can be reacted with pyridinium chlorochromate (PCC), magnesium dioxide, sulfur trioxide-pyridine complex, etc., to carry out the aldehyde reaction. As a result, formula 4a: [Formula 4c] [ka] This allows us to obtain the compound.

[0055] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0056] At this point, reducing agents such as NaBH4 and LiBH4 may be used when reducing the compound of formula 4. Furthermore, alcohol, tetrahydrofuran (THF), or a mixture thereof may be used as a solvent during reduction. A preferred example is the use of a mixed solvent of ethanol and THF during reduction, with a mixing volume ratio of 1:1 to 1:3. Furthermore, Lewis acids may also be used during reduction; examples of Lewis acids that can be used include LiCl and CaCl2.

[0057] Next, the compound of formula 4a is reacted with the compound of formula 5 to obtain the following formula 6a: [Formula 6a] [ka] This allows us to obtain the compound.

[0058] In the formula, n is either 1 or 2, X and Y are each independently halogens, and B is as defined above in Equation 1.

[0059] By reducing the compound of formula 6a, the compound of formula 6 can be obtained.

[0060] As another example, step (2) involves amidating the compound of formula 4 to obtain the compound of formula 4b, and then formula 4b: [Formula 4b] [ka] This may include reacting the compound with the compound of formula 5.

[0061] In the formula, n is either 1 or 2; and X and Y are, independently, halogens.

[0062] Specifically, the compound of formula 4 can be subjected to hydrolysis, and the resulting product can be reacted with N,O-dimethylhydroxyamine hydrochloride (such as MeO(Me)NH·HCl) to carry out the amidation reaction. As a result, a winelevamide such as formula 4b can be obtained.

[0063] Next, the compound of formula 4b is reacted with the compound of formula 5 to obtain the following formula 6b: [Formula 6b] [ka] This allows us to obtain the compound.

[0064] In the formula, n is either 1 or 2; X and Y are, independently, halogens; and B is as defined above in Equation 1.

[0065] Next, the compound of formula 6b can be reduced to obtain the compound of formula 6.

[0066] The compound in formula 5 may also be a Grignard reagent.

[0067] According to the general method for preparing Grignard reagents, the following formula 5a: [Formula 5a] [ka] The compound shown in formula 5 can be produced by reacting the compound with metallic magnesium (Mg).

[0068] In the formula, B is as defined above in Formula 1, and Hal is a halogen.

[0069] As described above, according to the present invention, the B group of the final compound (compound of formula 1a) can be easily introduced in advance by following a method for producing a Grignard reagent before coupling the aglycone group and the glucose group. This not only enables various derivatizations but also improves the final yield.

[0070] On the other hand, according to prior art documents (U.S. Patent Publication No. 2015 / 0152075A1), in order to complete the final compound group B, a complex synthetic process is required at the end of the synthetic route after coupling with a glucose group, and therefore, there is a problem that the reaction yield and reaction reproducibility change significantly due to the long process.

[0071] Process (3) In step (3), the compound of formula 6 is reacted with the compound of formula 7, followed by deprotection and reduction.

[0072] The reaction between the compound of formula 6 and the compound of formula 7 may be carried out in the presence of n-butyllithium, sec-butyllithium, t-butyllithium, isopropylmagnesium chloride (i-PrMgCl), etc.

[0073] The compound of formula 6 is reacted with the compound of formula 7 to obtain the following formula 7a: [Formula 7a] [ka] This allows us to obtain the compound.

[0074] In the formula, A is oxygen or sulfur; n is 1 or 2; X is a halogen; PG is a protecting group; and B is as defined above in Formula 1.

[0075] The protecting group may be, for example, a trimethylsilyl (TMS) group, a benzyl group, or an acetyl group.

[0076] Next, the compound of formula 7a can be deprotected to obtain the compound of formula 1a. For example, if the protecting group is a trimethylsilyl (TMS) group, methanesulfonic acid (CH3SO3H) or trimethylsilyl trifluoromethanesulfonate (TMSOTf) can be added to the compound of formula 7a to obtain the compound of formula 1a.

[0077] Furthermore, after deprotection, the compound of formula 1a can be obtained by further reduction. At this point, dichloromethane (CH2Cl2) and acetonitrile (CH2Cl2) may be used as solvents in combination.

[0078] The compound of formula 1a obtained through the above process may be a compound containing a mixture of α- and β-forms of glucose.

[0079] In this way, further separation can be performed to obtain only the desired α- or β-form. That is, after the deprotection and reduction steps, only compounds in which glucose is in the β-form can be further isolated.

[0080] For example, a protecting group is introduced into the compound obtained by deprotection and reduction. The resulting product is then heated in alcohol, ethyl acetate, or dichloromethane, the resulting precipitate is isolated, and then deprotected to obtain only the β-form.

[0081] Specifically, the hydroxyl groups of glucose in the compound obtained by deprotection and reduction are protected with acetyl groups or the like. Then, the resulting product is C 1-6 By heating and stirring in an alcoholic solvent (ethanol, isopropanol, etc.) and isolating the resulting precipitate, it can be determined that glucose is in the β form as shown in formula 7b below: [Formula 7b] [ka] This allows us to obtain the compound.

[0082] In the formula, A is oxygen or sulfur; n is 1 or 2; X is a halogen; PG is a protecting group; and B is as defined above in Formula 1.

[0083] Next, the compound of formula 7b is deprotected, and finally, formula 7c: [Formula 7c] [ka] Only the β type, which can be represented by this formula, can be obtained.

[0084] In the formula, A, B, n, and X' are as defined above in Equation 1.

[0085] As a preferred example, step (3) may be the following step: (3a-1) A step of reacting the compound of formula 6 with the compound of formula 7 in the presence of n-butyllithium, sec-butyllithium, t-butyllithium, or isopropylmagnesium chloride to obtain the compound of formula 7a shown below; (3a-2) A step of subjecting the compound of formula 7a to a deprotection and methylation reaction in the presence of methanol under acidic conditions to obtain the compound of formula 7d below; (3b) A step of reducing the compound of formula 7b to obtain the compound of formula 7e below; and (3c) A step in which a protecting group is introduced to the compound of formula 7e, the resulting product is heated in alcohol, ethyl acetate, or dichloromethane, and the resulting precipitate is isolated and deprotected to obtain only the β form; [ka] This can be done by a method that includes [a specific method].

[0086] In the formula, PG is a protecting group; and A, B, n, and X are as defined above in formula 1a.

[0087] After the reaction in step (3a-1), it is preferable to further perform evaporation, extraction, drying, filtration, etc., to obtain the compound of formula 7a, which is then used in the next step (3a-2).

[0088] The acid used in step (3a-2) may be hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrogen chloride gas, etc.

[0089] In another preferred example, step (3) is replaced with the following step: (3a') In the presence of n-butyllithium, sec-butyllithium, t-butyllithium, or isopropylmagnesium chloride, the compound of formula 6 is reacted with the compound of formula 7, and without separation or purification, the resulting mixture is subjected to deprotection and methylation reactions in the presence of methanol under acidic conditions to obtain the compound of formula 7d below; (3b') A step of reducing the compound of formula 7d to obtain the compound of formula 7e below; and (3c') A step of introducing a protecting group to the compound of formula 7e, isolating only the β form, and then deprotecting it; [ka] This can be carried out by methods including the following.

[0090] In the formula, A, B, n, and X are as defined above in formula 1a.

[0091] In step (3a'), firstly, a bonding reaction is carried out, at which point each of the compounds of formula 7 and the reaction reagent (i.e., n-butyllithium, sec-butyllithium, t-butyllithium, or isopropylmagnesium chloride) may be used in amounts of 1.5 to 2.5 equivalents, more preferably 1.7 to 2.3 equivalents, and especially 2.0 equivalents, per equivalent of one equivalent of the compound of formula 6. The reaction at this point may be carried out at -80°C to -10°C, more preferably -70°C to -60°C, for 1 to 12 hours, or 1 to 3 hours. Furthermore, as the reaction solvent, a single solvent such as tetrahydrofuran or ether, or a mixed solvent such as tetrahydrofuran / toluene (1:1) may be used.

[0092] Furthermore, in step (3a'), a deprotection reaction and a methylation reaction are carried out under acidic conditions. Acids that can be used at this stage include hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and hydrogen chloride gas. The acid can be used in an amount of 2 to 5 equivalents, more preferably 3 equivalents, per 1 equivalent of the compound of formula 6. The reaction at this stage can be carried out at 0°C to 40°C, more preferably 20°C to 30°C, for 6 to 24 hours, or 6 to 12 hours. Methanol may be used as the reaction solvent.

[0093] Next, a reduction reaction is carried out in step (3b'), at which point a reducing agent and an acid may be used. Examples of reducing agents include triethylsilane, triisopropylsilane, t-butyldimethylsilane, and sodium borohydride. Examples of acids include diethyl boron trifluoride, trimethylsilyl trifluoromethanesulfonate, aluminum chloride, trifluoroacetic acid, and trifluoromethanesulfonic acid. The amount of reducing agent used is 2 to 5 equivalents, more preferably about 3 equivalents, and the amount of acid used is 1.5 to 3 equivalents, more preferably about 2 equivalents. The reaction at this point may be carried out at -50°C to 0°C, more preferably -20°C to -10°C, for 2 to 12 hours, or 2 to 5 hours. Furthermore, as the reaction solvent, single solvents such as dichloromethane, 1,2-dichloroethane, or acetonitrile, or mixed solvents such as dichloromethane / acetonitrile (1:1) and 1,2-dichloromethane / acetonitrile (1:1) may be used.

[0094] Next, a protecting group may be introduced in step (3c'), at which point a reaction using an acetylating agent and a base may be carried out. Examples of acetylating agents include acetyl chloride, acetyl bromide, and acetic anhydride, and examples of bases include sodium hydroxide, sodium carbonate, triethylamine, diisopropylethylamine, pyridine, lutidine, and 4-dimethylaminopyridine. The acetylating agent can be used in amounts of 4 to 12 equivalents, more preferably about 8 equivalents, and the base can be used in amounts of 1 to 4 equivalents, more preferably about 1.5 equivalents. The reaction at this point may be carried out at 0°C to 50°C, more preferably -0°C to 30°C, for 1 to 12 hours, or 1 to 3 hours. As a reaction solvent, acetone, ethyl acetate, tetrahydrofuran, dimethylformamide, dimethylacetamide, dichloromethane, 1,2-dichloroethane, chloroform, etc. may be used.

[0095] Finally, in step (3c'), a deprotection reaction is carried out, at which point reagents such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methoxide, and sodium ethoxide can be used in amounts of 2 to 12 equivalents, more preferably about 5 equivalents. The reaction at this point can be carried out at a temperature of 0°C to 50°C, more preferably 20°C to 30°C, for 1 to 12 hours, or 1 to 3 hours. As solvents, methanol / water (1:1 to 3:1), dichloromethane / methanol (1:1 to 1:2), dichloromethane / ethanol (1:1 to 1:2), tetrahydrofuran / methanol (1:1 to 1:2), tetrahydrofuran / methanol / ethanol (1:1 to 1:2), tetrahydrofuran / methanol / water (1:1:3 to 2:1:3), tetrahydrofuran / ethanol / water (1:1:3 to 2:1:3), etc. can be used.

[0096] In yet another preferred example, step (3) is the following step: (3a'') In the presence of n-butyllithium, sec-butyllithium, t-butyllithium, or isopropylmagnesium chloride, the compound of formula 6 is reacted with the compound of formula 7, and without separation or purification, the resulting mixture is subjected to deprotection and methylation reactions in the presence of methanol under acidic conditions to obtain the compound of formula 7d below; (3b'') The step of introducing a protecting group to the compound of formula 7d to obtain the compound of formula 7f below; and (3c'') The process of isolating only the β-form of the compound of formula 7f, reducing it, and then deprotecting it; [ka] This can be carried out by methods including the following.

[0097] In the formula, PG is a protecting group; and A, B, n, and X are as defined above in formula 1a.

[0098] In step (3a''), the bonding reaction, deprotection, and methylation take place. Preferred conditions at this point, such as the equivalent ratio, reaction temperature, and solvent, are as exemplified in step (3a').

[0099] Next, in step (3b''), a protecting group may be introduced, and at this point, a reaction using an acetylating agent and a base may be carried out. Preferred conditions such as the type of acetylating agent, the type of base, the equivalent ratio, the reaction temperature, and the solvent are as exemplified in step (3c') above.

[0100] Next, a reduction reaction is carried out in step (3c''). At this point, a reducing agent and an acid may be used, and preferred conditions such as the type of reducing agent, the type of acid, the equivalent ratio, the reaction temperature, and the solvent are as exemplified in step (3b') above.

[0101] Furthermore, a deprotection reaction is carried out in step (3c''), and the preferred conditions at this point, such as the type of reagent, equivalent ratio, reaction temperature, and solvent, are as exemplified in step (3c') above.

[0102] As shown in the preferred example above, the process for obtaining the compound of formula 7d can be carried out in two steps or as an in-situ reaction in one step, further improving the final yield. Furthermore, when carried out as an in-situ reaction in one step, a crude concentrated residue containing the compound of formula 7b can be obtained, or the compound of formula 7d can be obtained as a solid content by crystallizing it, which can then be used in the next step. In the latter case, quality improvement by removing reaction by-products and control of moisture content can be easily achieved.

[0103] Furthermore, the compound of formula 7d can be used in the next step after purification following synthesis. For example, (i) after synthesis, the compound of formula 7d may be made into an azeotrope with an organic solvent such as toluene, and the residue obtained by repeatedly performing a concentration step to remove the remaining water may be used in the next step, or (ii) after synthesis, the compound of formula 7d may be crystallized, and the solid obtained by removing the remaining water by vacuum drying may be used in the next step.

[0104] Alkylation process Furthermore, according to the present invention, it is possible to further enclose the alkylation reaction after step (3), and as a result, X' in formula 1 becomes C 1-7 Alkyl is also acceptable.

[0105] For example, the product after step (4) can be reacted with methylboronic acid to obtain the compound of formula 1a in which X' is substituted with methyl.

[0106] Crystallization process The compound of formula 1a can be produced in crystalline form, amorphous form, or a mixture thereof. However, the crystalline form of the compound of formula 1a is preferred in terms of stability, non-hygroscopicity, and physicochemical properties that facilitate formulation.

[0107] Therefore, the method of the present invention may further include a step of crystallizing the compound of formula 1a after step (3). Crystallization can be carried out using various solvents, and thus various crystalline forms can be obtained.

[0108] For example, the solvent used for crystallization can be selected from toluene; ethyl acetate; dichloromethane; acetone; acetonitrile; a mixture of 2-propanol, tetrahydrofuran, and dichloromethane; and a mixture of tetrahydrofuran and n-hexane, and as a result, crystalline form A can be produced.

[0109] As another example, the solvent used for crystallization can be selected from a mixture of methanol and distilled water; a mixture of methanol and n-hexane; and a mixture of methanol, dichloromethane, and n-hexane, and as a result, crystalline form B can be produced.

[0110] As yet another example, the solvent used for crystallization can be selected from a mixture of ethanol, distilled water, and n-hexane; as well as a mixture of tetrahydrofuran and toluene, and as a result, crystalline form C can be produced.

[0111] As yet another example, the solvent used for crystallization may be a mixture of ethanol and hexane, which can result in the production of crystalline form D.

[0112] As a preferred example, the solvent used for crystallization may be selected from the group consisting of toluene, ethyl acetate, dichloromethane, tetrahydrofuran and a mixture of dichloromethane, and a mixture of tetrahydrofuran and n-hexane.

[0113] Method for producing compounds of formula 1b (formula 1, where R = alkylthio and A = oxygen) According to another aspect of the present invention, a method for producing a compound of formula 1b (formula 1, where R = alkylthio and A = oxygen), (1) A step of reacting the compound of formula 2 below with the compound of formula 3 below, and then cyclizing the resulting mixture to obtain the compound of formula 4 below; (2) A step of dehydrating or amidating the compound of formula 4, reacting it with the compound of formula 5, and reducing it to obtain the compound of formula 6 below; and (3) A step of reacting the compound of formula 6 with the compound of formula 8 below, and performing reduction to obtain the compound of formula 9 below; (4) Under acidic conditions, the furanose ring of the compound of formula 9 is converted to a pyranose ring, and then a protecting group is introduced to obtain the compound of formula 10 below; and (5) The compound of formula 10 is treated with thiourea, and the obtained product is C 1-7 A step of reacting with an alkyl halide, followed by reduction; A method including this is provided.

[0114] [ka] [ka] [ka]

[0115] During the ceremony, R is C 1-7 It is alkylthio; n is either 1 or 2; PG is a protecting group; X' is a halogen or C 1-7 It is alkyl; X, Y, and Hal are, independently, halogens; and B is defined in Equation 1 as described above.

[0116] In the above process, steps (1) and (2) can be carried out in the same manner as steps (1) and (2) of the method for producing the compound of formula 1a (formula 1, where R = hydroxymethyl).

[0117] The following will explain steps (3) to (5) in detail.

[0118] Process (3) In step (3), the compound of formula 6 is reacted with the compound of formula 8 to obtain the compound of formula 9.

[0119] The compound of formula 8 can be produced according to a known method, for example, the method disclosed in International Publication No. 2009 / 014970. Specifically, the compound of formula 8 can be produced according to the method disclosed in International Publication No. 2009 / 014970 starting from L-xylose.

[0120] According to one example, the compound of formula 6 can be reacted with the compound of formula 8 to obtain the compound of the following formula 9a. [Formula 9a]

Chemical formula

[0121] In the formula, B, n, and X are as defined above in formula 1.

[0122] Next, the compound of formula 9a can be reduced to obtain the compound of formula 9.

[0123] Process (4) In step (4), the furanose ring of the compound of formula 9 is formed into a pyranose ring under acidic conditions, and then a protecting group is introduced to obtain the compound of formula 10. By this step, the pyranose ring constituting the glucose group can be completed.

[0124] The protecting group may be, for example, an acetyl group.

[0125] Process (5) In step (5), the compound of formula 10 is treated with thiourea, and C 1-7The alkyl halide is reacted with the alkyl thio group, and then reduced. This step allows the alkylthio group to be introduced into the final compound (compound of formula 1b).

[0126] C 1-7 Alkyl halides are, for example, C 1-7 Alkyl iodides may also be used.

[0127] Furthermore, after step (5), an alkylation reaction can be carried out, and as a result, X' becomes C 1-7 A compound of formula 1b, which is alkyl, can be obtained.

[0128] Crystal form According to yet another aspect of the present invention, a crystalline form of the compound produced by the above production method is provided.

[0129] As one example, the present invention provides a crystalline form of the compound of formula 1a.

[0130] As a specific example, the present invention provides a crystalline form of the compound of formula 1a, in which A is O, B is cyclopropylphenyl, n is 1, and X' is Cl, and is β-type.

[0131] In other words, the present invention provides a crystalline form of the compound of the following formula c28. [Formula c28] [ka]

[0132] The compound of formula c28 can be produced by the method for producing formula 1a described above.

[0133] According to the present invention, the compound of formula c28 can exist in various crystalline forms, and each crystalline form will be described in detail below.

[0134] In the following, the term "approximately" may mean within 5%, preferably within 2%, of a given value or range. For example, "approximately 10%" may mean 9.5 to 10.5%, preferably 9.8 to 10.2%. As another example, "approximately 100°C" may mean 95°C to 105°C, preferably 98°C to 102°C.

[0135] Firstly, the present invention provides crystalline form A of the compound of formula c28. Crystalline form A is Cu-K α When irradiated using a light source, the XRD spectrum exhibits peaks at diffraction angles (2θ) of 6.2°±0.2°, 7.2°±0.2°, 8.8°±0.2°, 17.6°±0.2°, 19.0°±0.2°, 22.5°±0.2°, and 25.1°±0.2°. These peaks correspond to relative intensities (I / I). o ) may have a peak of about 5% or more, preferably about 10% or more.

[0136] The XRD spectrum of crystal form A may further include peaks at diffraction angles (2θ) of 15.4°±0.2°, 18.6°±0.2°, 21.6°±0.2°, and 23.8°±0.2°.

[0137] Furthermore, this crystal form may have an endothermic peak with a starting point of approximately 157°C and a minimum point of approximately 159°C when measured by DSC (10°C / min).

[0138] Furthermore, the present invention provides crystalline form B of the compound of formula c28. Crystalline form B is Cu-K α When irradiated using a light source, the XRD spectrum exhibits peaks at diffraction angles (2θ) of 7.0°±0.2°, 14.9°±0.2°, 17.7°±0.2°, 18.8°±0.2°, 20.6°±0.2°, 21.8°±0.2°, and 23.5°±0.2°. These peaks correspond to relative intensities (I / I). o ) may have a peak of about 5% or more, preferably about 10% or more.

[0139] The XRD spectrum of crystalline form B can further include peaks at diffraction angles (2θ) of 5.6° ± 0.2°, 9.4° ± 0.2°, and 11.0° ± 0.2°.

[0140] Furthermore, this crystalline form may have endothermic peaks in DSC (10 °C / min) with a starting point at about 79 °C and a lowest point at about 88 °C, as well as an endothermic peak with a starting point at about 103 °C and a lowest point at about 111 °C.

[0141] Furthermore, the present invention provides crystalline form C of the compound of formula c28. Crystalline form C has an XRD spectrum including peaks at diffraction angles (2θ) of 5.6° ± 0.2°, 7.3° ± 0.2°, 15.7° ± 0.2°, 17.2° ± 0.2°, 18.9° ± 0.2°, 21.2° ± 0.2°, and 21.9° ± 0.2° when irradiated with a Cu - K α light source. These peaks may be peaks with a relative intensity (I / I o ) of about 5% or more, preferably about 10% or more.

[0142] The XRD spectrum of crystalline form C can further include peaks at diffraction angles (2θ) of 19.9° ± 0.2° and 23.1° ± 0.2°.

[0143] Furthermore, this crystalline form may have an endothermic peak in DSC (10 °C / min) with a starting point at about 157 °C and a lowest point at about 159 °C.

[0144] Furthermore, the present invention provides crystalline form D of the compound of formula c28. Crystalline form D has an XRD spectrum including peaks at diffraction angles (2θ) of 5.5° ± 0.2°, 7.2° ± 0.2°, 15.3° ± 0.2°, 17.2° ± 0.2°, 17.6° ± 0.2°, 18.9° ± 0.2°, and 21.1° ± 0.2° when irradiated with a Cu - K α light source. These peaks may be peaks with a relative intensity (I / I o ) of about 5% or more.

[0145] The XRD spectrum of crystal form D may further include peaks at diffraction angles (2θ) of 0.0°±0.2°, 22.5°±0.2°, and 25.1°±0.2°.

[0146] Furthermore, this crystal form may have an endothermic peak with a starting point of approximately 157°C and a minimum point of approximately 160°C when measured by DSC (10°C / min).

[0147] Compound C28 in this crystalline form exhibits excellent physicochemical properties (e.g., hygroscopicity and chemical stability), and therefore can be easily handled in various fields (e.g., pharmaceutical manufacturing).

[0148] Modes for carrying out the invention The present invention will be described in more detail below with reference to examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited to these examples.

[0149] The meanings of the abbreviations shown in the following examples are as follows: Acetic acid (TOH) ACN: Acetonitrile Ac2O: Acetic anhydride BF3·OEt2: Boron trifluoride etherate DIPEA: N,N-diisopropylethylamine DCM: Dichloromethane DMAP: 4-dimethylaminopyridine DMF: N,N-dimethylformamide æ:ethyl acetate EtOH: Ethanol Et3SiH: Triethylsilane HBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate Hex: Hexane i-PrOH: Isopropyl alcohol MeI: Iodomethane MeOH: methanol MsCl: Mesyl chloride NaOMe: Sodium Methoxyde NBS: N-bromosuccinimide PCC: Pyridinium chlorochromate Pd(PPh3)4: Tetrakis(triphenylphosphine)palladium(0) TEA: Triethylamine TEMPO:(2,2,6,6-tetramethylpiperidine-1-yl)oxazinyl THF: Tetrahydrofuran TMSOTf: Trimethylsilyl trifluoromethanesulfonate RT or rt: Room temperature [Examples]

[0150] Comparative Example 1: Synthesis of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

[0151] The compound in question was prepared by the method disclosed in U.S. Patent Publication No. 2015 / 0152075. For the specific synthesis steps of Comparative Example 1, refer to Scheme 1 as described above in the Background Art section.

[0152] Step 1: Methyl 3-methoxy-2-nitrobenzoate (compound c2) A mixture of 3-methoxy-2-nitrobenzoic acid (25.0 g, 126 mmol) and K2CO3 (35.0 g, 253 mmol) in DMF (126 mL) was mixed with MeI (15.8 mL, 253 mmol) at room temperature. The mixture was stirred at room temperature for 2 hours. Water (200 mL) was added to the mixture, and the mixture was stirred at 5°C for 30 minutes. The precipitated solid was collected by filtration and washed with water and hexane. The solid was vacuum-dried to obtain the labeled compound as a crude white solid (26.2 g, 98%). 1 H NMR(400 MHz, CDCl3) δ 7.60(dd, J = 8.2, 1.2 Hz, 1H), 7.50(t, J = 8.2 Hz, 1H), 7.26(dd, J = 8.2, 1.2 Hz, 1H), 3.39(s, 3H), 3.99(s, 3H);[M+Na] + 235.

[0153] Step 2: Methyl 2-amino-3-methoxybenzoate (compound C3) A suspension of methyl 3-methoxy-2-nitrobenzoate (26.2 g, 124 mmol) and Pd / C (10 wt%, 6.0 g) in THF (400 mL) and MeOH (200 mL) was stirred at room temperature under an H2 atmosphere for 18 hours. SiO (300 mL) was added to the mixture, and the mixture was filtered through a Celite pad. The filtrate was concentrated under vacuum to obtain the labeled compound as a colorless oil (22.4 g, 99%). 1 H NMR (400 MHz, CDCl3) δ 7.47(dd, J = 8.2, 1.2 Hz, 1H), 6.85(dd, J = 8.2, 1.2 Hz, 1H), 6.58(t, J = 8.2 Hz, 1H), 6.00(brs, 2H), 3.87(s, 3H); [M+H] + 182.

[0154] Step 3: Methyl 2-amino-5-bromo-3-methoxybenzoate (compound C4) To a solution of methyl 2-amino-3-methoxybenzoate (22.4 g, 123 mmol) in DMF (250 mL), N-bromosuccinimide (21.9 g, 123 mmol) was gradually added at 0°C. The mixture was stirred at 0°C for 0.5 hours. Water was added to the mixture, and it was extracted with ELISA (500 mL x 2). The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography to obtain the labeled compound as a white solid (27.5 g, 86%). 1 H NMR(400 MHz, CDCl3) δ 7.60(d, J = 2.2 Hz, 1H), 6.90(d, J = 2.2 Hz, 1H), 6.03(brs, 1H), 3.87(s, 3H); [M+H] + 260.

[0155] Step 4: 5-Brom-2-chloro-3-methoxybenzoate methyl (compound C5) To a solution of methyl 2-amino-5-bromo-3-methoxybenzoate (27.0 g, 103 mmol) in H2O (70 mL) and concentrated HCl (70 mL), a solution of NaNO2 (21.5 g, 311 mmol) in H2O (50 mL) was added dropwise at 0°C. After stirring for 1 hour, a solution of Cu(I)Cl in concentrated HCl (80 mL) was added dropwise to the reaction mixture at 0°C. The mixture was stirred at room temperature for 18 hours. Water (300 mL) was added to the mixture, and it was extracted with SiO2 (500 mL). The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude labeled compound was dried under high vacuum and used as a white solid in the next step without further purification (29.0 g, 100%). 1 H NMR(400 MHz, CDCl3) δ 7.49(d, J = 2.4 Hz, 1H), 7.16(d, J = 2.4 Hz, 1H), 3.93(s, 36H), 3.92(s, 3H);[M+H] + 278

[0156] Step 5: 5-Bromo-2-chloro-3-methoxybenzoic acid (compound C6) A solution of methyl 5-bromo-2-chloro-3-methoxybenzoate (25.0 g, 89.4 mmol) in THF (100 mL), H2O (100 mL), and MeOH (100 mL) was to be added dropwise to an aqueous 5 N NaOH solution at 0°C. The mixture was stirred at room temperature for 1 hour. Concentrated HCl was added to the mixture to acidify it, and the mixture was extracted with ELISA (500 mL x 2). The combined organic layer was dried over MgSO4, filtered, and concentrated under vacuum to obtain the labeled compound as an orange solid (22.6 g, 96%). 1 H NMR (400 MHz, CDCl3) δ 7.55(s, 1H), 7.13(s, 1H), 3.89(s, 3H);[M+H] + 265.

[0157] Step 6: 5-Bromo-2-chloro-3-methoxybenzoyl chloride (compound c7) To a suspension of 5-bromo-2-chloro-3-methoxybenzoic acid (6.0 g, 22.6 mmol) in CH2Cl2 (100 mL), oxalyl chloride (2.4 mL, 27.1 mmol) and a catalytic amount of DMF were added at room temperature. The mixture was stirred at room temperature for 2 hours. The mixture was evaporated under vacuum and dried under vacuum to obtain the crude labeled compound. 1 H NMR (400 MHz, CDCl3) δ 7.49(d, J = 2.4 Hz, 1H), 7.16(d, J = 2.4 Hz, 1H), 3.93(s, 3H), 3.92(s, 3H).

[0158] Step 7: (5-bromo-2-chloro-3-hydroxyphenyl)(phenyl)methanone (compound C8) Crude 5-bromo-2-chloro-3-methoxybenzoyl chloride was dissolved in benzene (100 mL) and cooled to 0°C. AlCl3 (6.9 g, 52.0 mmol) was gradually added to the reaction mixture at 0°C. The mixture was stirred at 90°C for 15 hours. The mixture was cooled to room temperature and evaporated under vacuum. The residue was cooled to 0°C and 1N HCl aqueous solution was added. The mixture was extracted with toluene (150 mL x 1). The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography to obtain the labeled compound (7.33 g, quantitative yield). 1 H NMR (400 MHz, CDCl3) δ 7.85-7.82(m, 2H), 7.70-7.64(m, 1H), 7.55-7.49(m, 2H), 7.37(d, J = 2.2 Hz, 1H), 7.13(d, J = 2.2 Hz, 1H), 5.94(s, 1H).

[0159] Step 8: 3-benzyl-5-bromo-2-chlorophenol (compound C9) A mixture of (5-bromo-2-chloro-3-hydroxyphenyl)(phenyl)methanone (362 mg, 1.16 mmol) in trifluoroacetic acid (3 mL) was mixed with triethylsilane (0.37 mL, 2.32 mmol) and the catalyst triflic acid at 0°C. The mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with saturated NaHCO3 solution at 0°C and extracted with ethylethanol. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethylethanol / Hex) to obtain the labeled compound (267 mg, 77%). 1 H NMR (400 MHz, CDCl3) δ 7.37-7.32(m, 2H), 7.30-7.27(m, 1H), 7.22-7.19(m, 2H), 7.13(d, J = 2.4 Hz, 1H), 6.92(d, J = 2.0 Hz, 1H), 4.07(s, 2H). [M+H] + 297.

[0160] Step 9: 1-(allyloxy)-3-benzyl-5-bromo-2-chlorobenzene (compound C10) A mixture of 3-benzyl-5-bromo-2-chlorophenol (1.72 g, 5.78 mmol) and K2CO3 (1.6 g, 11.56 mmol) in acetone (35 mL) was mixed with allyl bromide (0.73 mL, 8.67 mmol) at room temperature. The reaction mixture was stirred at 65°C for 12 hours. The resulting mixture was filtered to remove inorganic substances. The filtrate was concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, Â1 / Hex) to obtain the labeled compound (1.96 g, 100%). 1H NMR (400 MHz, CDCl3) δ 7.32-7.27(m, 2H), 7.25-7.22(m, 1H), 7.21-7.17(m, 2H), 6.92(d, J = 2.4 Hz, 1H), 6.92(d, J = 2.0 Hz, 1H), 6.10-6.00(m, 1H), 5.48(dq, J = 17.2 Hz, 1.6 Hz, 1H), 5.33(dq, J = 12.4, 1.6 Hz, 1H), 4.59(dt, J = 4.4 Hz, 1.6 Hz, 2H), 4.08(s, 2H). [M+H] + 337.

[0161] Step 10: (3R,4S,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (compound c12) To a solution of 1-(allyloxy)-3-benzyl-5-bromo-2-chlorobenzene (1.96 g, 5.82 mmol) in tetrahydrofuran (5.5 mL) / toluene (11 mL), n-butyllithium (2.5 M hexane solution, 2.6 mL, 6.41 mmol) was added dropwise under a nitrogen atmosphere at -78°C. After stirring for 1 hour, a solution of (3R,4S,5R,6R)-3,4,5-tris((trimethylsilyl)oxy)-6-(((trimethylsilyl)oxy)methyl)tetrahydro-2H-pyran-2-one (c11; 3.54 g, 7.58 mmol) in tetrahydrofuran (6.6 mL) was added dropwise to the mixture via cannula at -78°C for 20 minutes. The reaction mixture was stirred at -78°C for 3 hours. CH3SO3H (0.6 mL, 9.25 mmol) in MeOH (15 mL) was added dropwise to the mixture at 0°C. The mixture was warmed to room temperature for 18 hours and then quenched with saturated NaHCO3 at 0°C. The mixture was evaporated under reduced pressure to remove volatiles. The aqueous residue was extracted with ELISA (100 mL x 2). The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled product as a yellow solid. [M+Na] + 473.

[0162] Step 11: (3R,4R,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c13) To a mixture of (3R,4S,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (2.55 g, 5.65 mmol) in CH2Cl2 (30 mL) and CH3CN (30 mL), Et3SiH (1.82 mL, 11.3 mmol) and BF3·Et2O (1.07 mL, 8.48 mmol) were added dropwise at 0°C. The reaction mixture was stirred at room temperature for 5 hours. The resulting mixture was quenched with saturated NaHCO3 solution, extracted with ethyl acetate, the organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was used in the next step without further purification.

[0163] Step 12: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(3-(allyloxy)-5-benzyl-4-chlorophenyl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c14) A mixture of (3R,4R,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (c13) in CH2Cl2 (12 mL) was mixed with Ac2O (4.7 mL, 49.72 mmol), pyridine (4.0 mL, 49.45 mmol), and DMAP (35 mg, 0.28 mmol) at room temperature. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was diluted with ethyl acetate and washed with 1N HCl solution. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (1.55 g, 47%). 1H NMR (400 MHz, DMSO-d6) δ 7.31-7.27(m, 2H), 7.22-7.21(m, 1H), 7.19-7.16(m, 2H), 7.09(d, J = 1.6 Hz, 1H), 6.88(d, J = 1.6 Hz, 1H), 6.12-6.03(m, 1H), 5.47(dq, J = 17.6, 2.0 Hz, 1H), 5.35(t, J = 9.6 Hz, 1H), 5.30(dq, J = 10.4, 1.6 Hz, 1H), 5.12(t, J = 9.6 Hz, 1H), 5.06(t, J = 9.6 [M+Na] + 611.

[0164] Step 13: (2S,3R,4R,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c15) A mixture of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(3-(allyloxy)-5-benzyl-4-chlorophenyl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (1.55 g, 2.63 mmol) in MeOH (50 mL) was mixed with NaOMe (25 wt%, in MeOH, 2.34 mL) at room temperature. The mixture was stirred at room temperature for 12 hours. The resulting mixture was neutralized with ice AcOH. The mixture was diluted with ELISA and washed with saturated NaHCO3 solution. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was used in the next step without further purification. [M+Na] + 443.

[0165] Step 14: (2S,3S,4R,5R,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran (compound c16) To a mixture of (2S,3R,4R,5S,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol in DMF (26 mL), NaH (60% mineral oil dispersion, 842 mg, 21.0 mmol) was added at 0°C and the mixture was stirred at room temperature for 1 hour. Benzyl bromide (2.5 mL, 21.0 mmol) was added dropwise to the reaction mixture at 0°C. The mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with water and extracted with ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (1.80 g, 88%). 1 H NMR (400 MHz, CDCl3) δ 7.36-7.31(m, 13H), 7.26-7.19(m, 10H), 6.94(d, J = 1.6 Hz, 2H), 6.91(dd, J = 14.8, 2.0 Hz, 2H), 6.10-6.00(m, 1H), 5.46(dq, J = 17.2, 1.6 Hz, 1H), 5.31(dq, J = 10.8, 1.6 Hz, 1H), 4.94(ABq, J AB = 15.2 Hz, 2H), 4.90(d, J = 10.8 Hz, 1H), 4.70-4.64(m, 2H), 4.57(d, J = 12.4 Hz, 1H), 4.52-4.49(m, 2H), 4.46(d, J = 10.8 [M+Na] + 803.

[0166] Step 15: 3-benzyl-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenol (compound c17) A mixture of ((2S,3S,4R,5R,6R)-2-(3-(allyloxy)-5-benzyl-4-chlorophenyl)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran (1.80 g, 2.30 mmol) in THF (25 mL) was mixed with NaBH4 (700 mg, 18.4 mmol) and Pd(PPh3)4 (266 mg, 0.23 mmol) at room temperature. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with saturated NaHCO3 solution and extracted with ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (1.62 g, 95%). 1 H NMR (400 MHz, CDCl3) δ 7.37-7.31(m, 13H), 7.27-7.21(m, 8H), 7.18-7.16(m, 2H), 7.08(d, J = 2.0 Hz, 1H), 6.98(dd, J = 7.6, 2.0 Hz, 2H), 6.89(d, J = 2.0 Hz, 1H), 4.93(ABq, J AB = 16.0 Hz, 2H), 4.89(d, J = 10.8 Hz, 1H), 4.67(d, J = 4.8 Hz, 1H), 4.64(d, J = 6.0 Hz, 1H), 4.57(d, J = 12.4 Hz, 1H), 4.46(d, J = 10.4 [M+Na] + 763.

[0167] Step 16: 3-Benzyl-6-bromo-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenol (compound c18) A mixture of 3-benzyl-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenol (1.62 g, 2.18 mmol) in AcOH (11 mL) was mixed with triethylamine (0.46 mL, 3.27 mmol) and bromine (0.11 mL, 2.18 mmol) at 0°C. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with saturated NaHCO3 solution and extracted with ethylethanol. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethylethanol / Hex) to obtain the labeled compound (1.04 g, 58%). [M+Na] + 841.

[0168] Step 17: 3-(3-benzyl-6-bromo-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenoxy)propan-1-ol (compound c19) 3-benzyl-6-bromo-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenol (1.04 g, 1.27 mmol) and K2CO3 (0.35 g, 2.54 mmol) were mixed in acetone (13 mL), to which 2-bromoethanol (0.14 mL, 1.90 mmol) was added at room temperature. The reaction mixture was stirred at 50°C for 12 hours. The resulting mixture was filtered to remove inorganic substances. The filtrate was concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, siRNA / Hex) to obtain compound c19 (1.10 g, 100%). [M+Na] + 899.

[0169] Step 18: (2S,3S,4R,5R,6R)-2-(5-benzyl-2-bromo-4-chloro-3-(2-chloroethoxy)phenyl)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran(compound c20) To a mixture of 3-(3-benzyl-6-bromo-2-chloro-5-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)phenoxy)propan-1-ol (1.09 g, 1.25 mmol) and triphenylphosphine (1.64 g, 6.28 mmol) in CH3CN (12 mL), carbon tetrachloride (12 mL, 134 mmol) was added at room temperature. The reaction mixture was stirred at 55°C for 12 hours. The resulting mixture was evaporated to remove the solvent. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, RINKAN / Hex) to obtain the labeled compound (0.61 g, 55%). [M+Na] + 903.

[0170] Step 19: 6-benzyl-7-chloro-4-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)-2,3-dihydrobenzofuran (compound c21) To a mixture of (2S,3S,4R,5R,6R)-2-(5-benzyl-2-bromo-4-chloro-3-(2-chloroethoxy)phenyl)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran (10.02 g, 11.4 mmol) in THF (114 mL), n-butyllithium (2.5 M hexane solution, 6.8 mL, 17.0 mmol) was added dropwise at -78°C. The reaction mixture was stirred at -78°C for 3 hours. The resulting mixture was quenched with 1N HCl solution (100 mL) and extracted with ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (6.0 g, 69%). [M+Na] + 789.

[0171] Step 20: (2S,3R,4R,5S,6R)-2-(6-benzyl-7-chloro-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c22) A mixture of 6-benzyl-7-chloro-4-((2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-yl)-2,3-dihydrobenzofuran (6.0 g, 7.82 mmol) and Pd / C (0.35 g, 2.54 mmol) in MeOH (220 mL) / THF (220 mL) was stirred under H2 at room temperature for 5 hours. The resulting mixture was filtered through Celite to remove inorganic substances. The filtrate was concentrated under vacuum to obtain the labeled compound (quantitative yield). The crude product was used in the next step without further purification. 1 H NMR (400 MHz, CD3OD) δ 7.28-7.14(m, 5H), 6.89(s, 1H), 4.65(t, J = 8.6 Hz, 2H), 4.17(d, J = 8.8 Hz, 1H), ), 4.07(ABq, Δν AB = 18.0 Hz, J AB [M+Na] + 507.

[0172] Step 21: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(6-benzyl-7-chloro-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c23) A mixture of (2S,3R,4R,5S,6R)-2-(6-benzyl-7-chloro-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol in CH2Cl2 (78 mL) was mixed with Ac2O (5.9 mL, 62.6 mmol), pyridine (5.0 mL, 62.6 mmol), and DMAP (48 mg, 0.39 mmol) at room temperature. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was diluted with ethyl acetate and washed with 1N HCl solution. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (4.54 g, 100%). 1 H NMR (400 MHz, CDCl3) δ 7.32-7.28(m, 2H), 7.25-7.18(m, 3H), 6.59(s, 1H), 5.30(t, J = 9.2 Hz, 2H), 5.19(t, J = 9.6 Hz, 1H), 4.77-4.68(m, 2H), 4.35-4.32(m, 1H), 4.31-4.26(m, 1H), 4.21-4.14(m, 1H), 4.11(m, 1H), 4.02(d, J = 15.6 Hz, 1H), 3.83-3.79(m, 1H), 3.42(td, J = 8.8, 1.6 Hz, 2H), 2.10(s, 3H), 2.09(s, 3H), 2.03(s, 3H), 1.70(s, 3H); [M+Na] + 597.

[0173] Step 22: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(6-(4-acetylbenzyl)-7-chloro-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c24) To a mixture of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(6-benzyl-7-chloro-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (3.75 g, 6.52 mmol) in CH2Cl2 (78 mL), acetyl chloride (3.71 mL, 52.16 mmol) and aluminum chloride (6.95 mg, 52.16 mmol) were added dropwise at 0°C. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with ice-water and extracted with CH2Cl2. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, siRNA / Hex) to obtain the labeled compound (3.73 g, 93%). 11H NMR (400 MHz, CDCl3) δ 7.92-7.89(m, 2H), 7.29-7.28(m, 2H), 6.63(s, 1H), 5.34-5.31(m, 1H) , 5.24-5.18(m, 2H), 4.78-4.68(m, 2H), 4.37-4.27(m, 2H), 4.19-4.16 (m, 1H), 4.16-4.08(m, 2H), 3.84-3.77(m, 1H), 3.45-3.40(m, 2H), 2.61(s, 3H), 2.10(s, 3H), 2.09(s, 3H), 2.03(s, 3H), 1.70(s, 3H); [M+Na] + 639.

[0174] Step 23: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-(1-hydroxyethyl)benzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c25) To a mixture of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(6-(4-acetylbenzyl)-7-chloro-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (1.0 g, 1.62 mmol) in THF (7 mL), sodium borohydride (0.12 g, 3.24 mmol) was slowly added at -20°C, and then MeOH (0.24 mL) was added dropwise to the mixture. The mixture was stirred at room temperature for 3 hours. The resulting mixture was quenched with saturated NaHCO3 and extracted with ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ethyl acetate / Hex) to obtain the labeled compound (0.52 g, 52%). 1H NMR (400 MHz, CDCl3) δ 7.29-7.27(m, 2H), 7.15-7.12(m, 2H), 6.54(d, J = 5.2 Hz, 1H), 5.29-5.26(m, 1H), 5.18-5.13(m, 2H), 4.89-4.84(m, 2H), 4.71-4.66(m, 2H), 4.32-4.29(m, 1H), 4.27-4.22(m, 1H), 4.15-4 .11(m, 1H), 4.04-3.96(m, 2H), 3.80-3.75(m, 1H), 3.40-3.35(m, 2H), 2.06(s, 3H), 2.05(s, 3H), 1.99(s, 3H), 1.68(s, 3H), 1.47(d, J = 6.4 Hz, 3H);[M+Na] + 641.

[0175] Step 24: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-vinylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c26) A mixture of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-(1-hydroxyethyl)benzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (520 mg, 0.84 mmol) and p-toluenesulfonic acid monohydrate (16 mg, 0.084 mmol) in toluene (10 mL) was stirred at 120°C for 2 hours. The resulting mixture was diluted with siRNA and washed with water. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, siRNA / Hex) to obtain the labeled compound (407 mg, 81%). 1H NMR (400 MHz, CDCl3) δ 7.32-7.30(m, 2H), 7.12-7.10(m, 2H), 6.71-6.63(m, 1H), 6.55(s, 1H), 5.71-5.6 6(m, 1H), 5.29-5.25(m, 1H), 5.25-5.13(m, 3H), 4.71-4.66(m, 2H), 4.33-4.29(m , 1H), 4.28-4.22(m, 1H), 4.15-4.11(m, 1H), 4.08-3.96(m, 2H), 3.79-3.75(m, 1H) ), 3.41-3.35(m, 2H), 2.06(s, 3H), 2.05(s, 3H), 1.99(s, 3H), 1.68(s, 3H); [M+Na] + 623.

[0176] Step 25: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c27) To a solution of diethylzinc (1.74 mL, 1.91 mmol, 1.1 M toluene solution) in CH2Cl2 (3 mL), trifluoroacetic acid (0.15 mL, 1.91 mmol, 1.5 mL) was added dropwise at 0°C. After 1 hour, diiodomethane (0.16 mL, 1.91 mmol, 1.5 mL) was added dropwise to the mixture at 0°C. After 1 hour, (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-vinylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (460 mg, 0.77 mmol, 1.5 mL) was slowly added to the mixture at 0°C. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with saturated NH4Cl solution and extracted with ÃO. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system, ÃO / Hex) to obtain the labeled compound (285 mg, 60%). 1H NMR (400 MHz, CDCl3) δ 7.04-7.02(m, 2H), 6.98-6.95(m, 2H), 6.53(s, 1H), 5.29-5.24(m, 1H), 5.18-5.12(m, 2H), 4.71-4.65(m, 2H), 4.31-4.26(m, 1H), 4.25-4.22(m, 1H), 4.15-4.11(m, 1H), 4.0 5-3.91(m, 2H), 3.79-3.74(m, 1H), 3.40-3.35(m, 2H), 2.06(s, 3H), 2.05(s, 3H), 1.99 (s, 3H), 1.88-1.81(m, 1H), 1.66(s, 3H), 0.94-0.89(m, 2H), 0.66-0.61(m, 2H); [M+Na] + 637.

[0177] Step 26: (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) A mixture of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (298 mg, 0.48 mmol) and K2CO3 (536 mg, 3.88 mmol) in MeOH (20 mL) was stirred for 12 hours. The resulting mixture was filtered to remove inorganic substances. The filtrate was concentrated under vacuum. The crude product was purified by preparative HPLC (Gilson system, CH3CN / H2O) to obtain the labeled compound (101 mg, 47%).

[0178] According to the synthesis route described in steps 1 to 26 above, the total yield of the final compound in Comparative Example 1 was calculated to be less than 1%. 1 H NMR (400 MHz, CD3OD) δ 7.02(d, J = 8.0 Hz, 2H), 6.92(d, J = 8.0 Hz, 2H), 6.81(s, 1H), 4.59(t, J = 8.8 Hz, 2H), 4.11(d, J = 9.2 Hz, 1H), 3.96(ABq, Δν AB = 19.0 Hz, J AB= 15.2 Hz, 2H), 3.87-3.84(m, 1H), 3.67-3.63(m, 1H), 3.47-3.37(m, 3H), 3.35-3. 33(m, 3H), 1.85-1.79(m, 1H), 0.91-0.86(m, 2H), 0.61-0.57(m, 2H); [M+Na] + 469.

[0179] Example 1: Synthesis of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol [ka] [ka]

[0180] Step 1: 5-Bromo-2-chloro-3-hydroxybenzoate methyl (compound C29) ) To a solution of methyl 5-bromo-2-chloro-3-methoxybenzoate (compound c5; 30.0 g, 107.3 mmol) in CH2Cl2 (300 mL), BBr3 (25.9 mL, 268.3 mmol) was slowly added at 0°C under a nitrogen atmosphere. The mixture was slowly warmed to room temperature and stirred at room temperature for 15 hours. The reaction mixture was quenched by adding MeOH (100 mL) at 0°C. The mixture was evaporated under reduced pressure to remove CH2Cl2, and then MeOH (150 mL) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was concentrated under vacuum to obtain the marked compound (29.4 g, 110.8 mmol, 103%). 1 H NMR (400 MHz, CDCl3) δ 7.60(d, J = 2.4 Hz, 1H), 7.36(d, J = 2.4 Hz, 1H), 6.00(s, 1H), 3.94(s, 1H); [M+H] + 265.

[0181] Step 2: 3-(allyloxy)-5-bromo-2-chlorobenzoate methyl (compound C30) To a solution of methyl 5-bromo-2-chloro-3-hydroxybenzoate (38.2 g, 143.9 mmol) in acetone (700 mL), allyl bromide (14.9 mL, 172.7 mmol) and K2CO3 (29.8 g, 215.9 mmol) were added at room temperature. The mixture was stirred at 60°C for 12 hours and then cooled to room temperature. After filtering off the insoluble salts with Celite, the filtrate was evaporated under reduced pressure, and the residue was dissolved in siRNA (500 mL). The organic solution was washed with saline solution, dried over MgSO4, filtered, and vacuum concentrated (44.1 g, 144.3 mmol, 100%). The crude residue was used in the next step without further purification. 1 H NMR (400 MHz, CDCl3) δ 7.49(d, J = 2.4 Hz, 1H), 7.16(d, J = 2.4 Hz, 1H), 6.09-6.00(m, 1H), 5.48(dd, J = 17.2 Hz, 1.2 Hz, 1H), 5.35(dd, J = 10.6 Hz, 1.4 Hz, 1H), 4.63-4.61(m, 2H), 3.93(s, 3H); [M+H] + 305.

[0182] Step 3: 4-Allyl-5-bromo-2-chloro-3-hydroxybenzoate methyl (compound C31) To a solution of methyl 3-(allyloxy)-5-bromo-2-chlorobenzoate (10.0 g, 32.7 mmol) in CH2Cl2 (150 mL), diisobutylaluminum chloride (25% hexane solution, 64.0 mL) was added dropwise at 0°C under a nitrogen atmosphere (0.5-1 hour). The mixture was slowly warmed to room temperature and stirred at room temperature for a further 12 hours. The reaction mixture was cooled to 0°C, quenched with 1 M HCl (50 mL), and then extracted with RINKAN (150 mL x 2). The combined organic layer was dried over MgSO4, filtered, and concentrated under vacuum (9.9 g, 32.3 mmol, 99%). The crude residue was used in the next step without further purification to obtain the labeled compound. 1H NMR(400 MHz, CDCl3) δ 7.23(s, 1H), 6.20(s, 1H), 5.96-5.86(m, 1H), 5.11-5.07(m, 2H), 3.92(s, 3H), 3.65(dt, J = 5.4 Hz, 1.4 Hz, 2H);[M+H] + 305.

[0183] Step 4: 5-Bromo-2-chloro-3-hydroxy-4-(2-hydroxyethyl)methyl benzoate (compound C33) Method A) Synthesis by reduction of aldehydes To a mixture of methyl 4-allyl-5-bromo-2-chloro-3-hydroxybenzoate (9.9 g, 32.3 mmol) in THF / H2O (100 mL / 100 mL), NaIO4 (20.8 g, 97.0 mmol) and OsO4 (82 mg, 0.32 mmol) were added at 0°C. After stirring at 0°C for 1 hour, the reaction mixture was warmed to room temperature and stirred at room temperature for 2 hours. The mixture was filtered to remove insoluble substances. The filtrate was poured into a saturated solution of Na2S2O3 (100 mL), and the mixture was extracted with ELISA (200 mL x 2). The organic layer was dried over MgSO4, filtered, and vacuum concentrated (9.0 g, 29.4 mmol, 91%). The crude residue was used in the next step without further purification to obtain methyl 5-bromo-2-chloro-3-hydroxy-4-(2-oxoethyl)benzoate (compound c32). [M+H] + 307.

[0184] To a solution of methyl 5-bromo-2-chloro-3-hydroxy-4-(2-oxoethyl)benzoate (20.1 g, 65.3 mmol) in THF (200 mL), NaBH4 (2.72 g, 71.8 mmol) was added under a nitrogen atmosphere at 0°C. The reaction mixture was stirred at 0°C for 2 hours. The mixture was quenched with saturated NH4Cl (100 mL) and extracted with siRNA (100 mL x 2) [a single extraction was insufficient]. The combined organic layer was dried over MgSO4, filtered, and vacuum concentrated (19.9 g). Hexane (10-20 mL) was added to the suspension of the residue in siRNA (20 mL). The resulting precipitate was collected by filtration and washed with hexane (50 mL). The precipitate was vacuum dried to obtain the labeled compound (14.3 g, 72%). 1 H NMR (400 MHz, CDCl3) δ 7.68(s, 1H), 7.35(s, 1H), 3.97-3.93(m, 2H), 3.92(s, 3H), 3.21(t, J = 6.2 Hz, 2H);[M+H] + 309.

[0185] Method B) Synthesis by ozonation and subsequent reduction Ozone gas was bubbling methyl 4-allyl-5-bromo-2-chloro-3-hydroxybenzoate (10.2 g, 33.4 mmol, 80% purity) in CH2Cl2 / MeOH (150 mL / 35 mL) at -78°C for 4 hours (the solution changed color from yellow to pale green). After stopping the ozone addition, the reaction solution was purged with nitrogen until the green color disappeared (the solution returned to yellow). Sodium borohydride (2.5 g, 66.8 mmol) was added gradually at -78°C. The resulting mixture was slowly warmed to room temperature for 2 hours, concentrated, suspended in ethyl acetate, and concentrated again. 1N aqueous HCl solution (200 ml) was added to the residue and stirred for 30 minutes. The precipitate was collected by filtration (quantitative, 80% purity). The precipitate was suspended in ethyl acetate and stirred. Hexane was slowly added to the resulting mixture. A precipitate was obtained by filtration, yielding the labeled compound (7.9 g, 76.4%, purity 92%). 1H NMR (400 MHz, MeOD) δ 7.57(s, 1H), 3.93(s, 3H), 3.76(t, J = 7.24 Hz, 2H), 3.20(t, J = 7.28 Hz, 2H);[M+H] + 309.

[0186] Step 5: 4-Bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate methyl (compound C34) Preparation of Vilsmeyer's reagent: SOCl2 (7.5 ml, 102.2 mmol) was added to a solution of N,N-dimethylformamide (7.9 ml, 102.2 mmol) at room temperature. The reaction mixture was stirred at 40°C for 2 hours. The resulting mixture was concentrated under vacuum to obtain a hydrated white solid.

[0187] To a mixture of Vilsmeyer's reagent (13.08 g, 102.2 mmol) in DMF (100 mL), methyl 5-bromo-2-chloro-3-hydroxy-4-(2-hydroxyethyl)benzoate (21.08 g, 68.10 mmol) in DMF (130 mL) was slowly added at 0°C. The mixture was stirred at 0°C to 15°C (stepwise heating) for 1 hour. Triethylamine (38 ml, 272.4 mmol) in DMF (38 mL) was added to the reaction mixture at 0°C and quenched. After stirring for 10 minutes, water (1400 ml) was poured into the mixture at 0°C and stirred at room temperature for 2 hours. The resulting precipitate was collected by filtration, washed with water, and concentrated by vacuum drying to obtain the marked compound as a pale yellow solid (13.0 g, 44.6 mmol, 65%). 1 H NMR(400 MHz, CDCl3) δ 7.53(s, 1H), 4.75(t, J = 8.8 Hz, 2H), 3.91(s, 3H), 3.33(t, J = 8.8 Hz, 2H);[M+H] + 291.

[0188] Step 6: (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)methanol (compound C35) To a mixture of methyl 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate (13.0 g, 44.7 mmol) in THF / EtOH (150 mL / 75 mL), sodium borohydride (5.07 g, 133.98 mmol) was slowly added at room temperature. The mixture was stirred at room temperature for 12 hours. The resulting mixture was quenched with saturated NH4Cl at 0°C and extracted with ELISA (aqueous solution, pH ~7.0). The organic layer was dried over MgSO4, filtered, and concentrated under vacuum to obtain the marked compound as a white solid (11.7 g, 44.4 mmol, 99%). The crude product was used in the next step without further purification. 1 H NMR (400 MHz, CDCl3) δ 7.15(s, 1H), 4.73(m, 4H), 3.29(t, J = 8.8 Hz, 2H), 1.91(t, J = 6.4 Hz, 1H); [M-H2O] + 245.

[0189] Step 7: 4-Bromo-7-chloro-2,3-dihydrobenzofuran-6-carboaldehyde (compound C36) To a solution of (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)methanol (11.7 g, 44.4 mmol) in CH2Cl2 (450 ml), PCC (14.4 g, 66.6 mmol, pyridinium chlorochromate) was slowly added at room temperature. After stirring for 8 hours, the precipitate was filtered off using a silica gel pad and washed with CH2Cl2. The filtrate was concentrated under vacuum to obtain the marked compound as a white solid (10.4 g, 39.8 mmol, 90%). The crude product was used in the next step without further purification. 1 H NMR(400 MHz, CDCl3) δ 10.33(s, 1H), 7.59(s, 1H), 4.79(t, J = 8.8 Hz, 2H), 3.35(t, J = 8.8 Hz, 2H);[M+H] + 261.

[0190] Step 8: (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)(4-cyclopropylphenyl)methanol (compound C39) Preparation of (4-cyclopropylphenyl)magnesium bromide (compound c38): A 250 mL three-neck flask containing magnesium (shavings, 1.1 g, 46.6 mmol) was dried by heat. Under a nitrogen atmosphere, a condenser and an additive funnel were attached to the flask. 4-cyclopropylphenyl bromide (PepTech, USA) (6.0 ml, 42.4 mmol) in anhydrous THF (32.4 mL) was transferred to the additive funnel. The Grignard reaction was started with approximately 5 mL of 4-cyclopropylphenyl bromide solution. The remaining bromide solution was added at room temperature for 4 hours. The resulting solution was used directly in the next step.

[0191] To a solution of 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboaldehyde (4.6 g, 17.6 mmol) in anhydrous THF (170 mL), a freshly prepared solution of (4-cyclopropylphenyl)magnesium bromide (compound c38) (30.0 mL of 0.85 M THF solution, 26.4 mmol) was added under a nitrogen atmosphere at 0°C. The reaction mixture was stirred at 0°C for 30 minutes. Water (100 mL) was added to the reaction mixture to quench it, and the mixture was extracted with HCl (100 mL). The organic layer was dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled product (7.6 g, 20.0 mmol, 114%). The crude residue was used in the next step without further purification to obtain the crude labeled compound. [M-H2O] + 361.

[0192] Step 9: 4-Bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (compound C40) To a solution of (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)(4-cyclopropylphenyl)methanol (7.6 g, 20.0 mmol) in CH2Cl2 / CH3CN (100 mL / 100 mL), triethylsilane (4.6 mL, 40 mmol) and boron trifluoride diethyl etherate (3.8 mL, 30 mmol) were added under a nitrogen atmosphere at -20°C. The mixture was gradually warmed to room temperature and stirred at room temperature for a further 50 minutes. The reaction mixture was slowly quenched by adding saturated NaHCO3 solution (200 mL) and extracted with siRNA (100 mL). The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography to obtain the labeled product (4.4 g, 12.1 mmol, 85% in two steps). 1 H NMR (400 MHz, CDCl3) δ 7.07(d, J = 8.0 Hz, 2H), 6.99(d, J = 8.0 Hz, 2H), 6.80(s, 1H), 4.70(t, J = 8.8 Hz, 2H), 3.97(s, 2H), 3.26(t, J = 8.8 Hz, 2H), 1.88-1.84(m, 1H), 0.95-0.90(m, 2H), 0.68-0.64(m, 2H).

[0193] Step 10: (3R,4S,5R,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyran-2-ol (compound c41) To a solution of 4-bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (5.16 g, 14.2 mmol) in tetrahydrofuran (80 mL), n-butyllithium (2.5 M hexane solution, 7.38 mL, 18.4 mmol) was added dropwise under a nitrogen atmosphere at -78°C. After stirring at the same temperature for 40-60 minutes (yellowish solution), a pre-cooled solution (compound c11; 8.6 g, 18.4 mmol) of (3R,4S,5R,6R)-3,4,5-tris((trimethylsilyl)oxy)-6-(((trimethylsilyl)oxy)methyl)tetrahydro-2H-pyran-2-one (compound c11; 8.6 g, 18.4 mmol) in tetrahydrofuran (20 mL) was added dropwise through a cannula for 20 minutes. The reaction mixture was stirred at the same temperature for 2-3 hours (yellowish solution).

[0194] The reaction mixture was quenched with 1% acetic acid (20 mL) at -78°C, and then evaporated under reduced pressure to remove volatiles. The aqueous residue was extracted with phenylethylamine (150 mL x 2). The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled compound as a pale yellow oil (11.8 g, quantitative). The crude residue was used in the next step without further purification.

[0195] Step 11: (3R,4S,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (compound c42) To a solution of (3R,4S,5R,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyran-2-ol; 11.8 g) in MeOH (150 mL), CH3SO3H (1.5 mL, 23.5 mmol) was added dropwise at 0°C. The mixture was warmed to room temperature over 18 hours and then quenched with saturated NaHCO3 at 0°C. The mixture was evaporated under reduced pressure to remove volatiles. The aqueous residue was extracted with siRNA (100 mL x 2). The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled compound as a yellow solid (6.0 g, 88% in 2 steps). [M+Na] + 499 and [M-OMe] + 445.

[0196] Step 12: (3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c43) (3R,4S,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (6.0 g, 12.6 mmol) in CH2Cl2 / CH3CN (v:v=1:1, 120 mL) is stirred, then Et3SiH (6.0 mL, 37.8 mmol) is added, followed by BF3 .OEt2 (3.2 mL, 25.2 mmol) was added dropwise at -50 to -45°C. The reaction mixture was warmed to -10 to 0°C for 3 to 3.5 hours, then quenched with saturated NaHCO3 (130 mL). The mixture was evaporated under reduced pressure to remove volatiles, and the resulting residue was extracted with toluene (150 mL x 2). The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled compound as a yellow solid (5.8 g, 12.9 mmol, 102%). [M+Na] + 469.

[0197] Step 13: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c27) To a solution of (3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (5.8 g, 12.9 mmol) in CH2Cl2 (120 mL), DMAP (1.9 g, 15.5 mmol) and Ac2O (9.7 mL, 103.76 mmol) were added at room temperature. After stirring at room temperature for 18 hours, the reaction was stopped by adding water (120 mL). The resulting mixture was extracted with CH2Cl2 (100 mL x 2). After washing with 1 M HCl and saline solution, the combined organic layers were dried over MgSO4, filtered, and evaporated under reduced pressure (7.0 g, crude). The residue, slurryed with EtOH (45 mL), was heated under reflux at 80°C for 1 hour. The mixture was cooled to room temperature while being stirred for 18 hours. The resulting precipitate was filtered, washed with EtOH, and vacuum-dried to obtain the labeled compound as a white solid (4.7 g, 7.6 mmol, 59%). 1H NMR (400 MHz, CDCl3) δ 7.04-7.02(m, 2H), 6.98-6.95(m, 2H), 6.53(s, 1H), 5.29-5.24(m, 1H), 5.18-5.12( m, 2H), 4.71-4.65(m, 2H), 4.31-4.26(m, 1H), 4.25-4.22(m, 1H), 4.15-4.11(m, 1H), 4.05-3.91(m, 2H), 3.79-3.74(m, 1H), 3.40-3.35(m, 2H), 2.06(s, 3H), 2.05(s, 3H), 1.99(s, 3H), 1.88-1.81(m, 1H), 1.66(s, 3H), 0.94-0.89(m, 2H), 0.66-0.61(m, 2H); [M+Na] + 637.

[0198] Step 14: (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) To a solution of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (1.5 g, 2.44 mmol) in THF / MeOH (5.4 mL / 10.8 mL; 0.15 M), 4 M NaOH aqueous solution (2.8 mL) was added. The reaction mixture was stirred at room temperature for 1.5 hours. After cooling the solution to 0°C, it was neutralized with 1N HCl. The reaction solution was diluted with ELISA and water. The organic layers were separated, and the aqueous layer was extracted twice with ELISA. The combined organic layers were dried over MgSO4, filtered, and concentrated under vacuum to obtain the crude labeled compound.

[0199] A suspension of the crude labeled compound in toluene (8 mL) was heated at 40°C for 30 minutes (forming a viscous solution → clear solution → white solid) and cooled to room temperature. The slurry was filtered through a filtration funnel, and the cake was washed with twice its volume of toluene. The moist cake was vacuum-dried to obtain 1.0 g (2.24 mmol, quantitative) of the labeled compound.

[0200] According to the synthesis route described in steps 1 to 14 above, the total yield of the final compound in Example 1 was calculated to be approximately 12%. 1H NMR (400 MHz, CD3OD) δ 7.02(d, J = 8.0 Hz, 2H), 6.92(d, J = 8.0 Hz, 2H), 6.81(s, 1H), 4.59(t, J = 8.8 Hz, 2H), 4.11(d, J = 9.2 Hz, 1H), 3.96(ABq, Δν AB = 19.0 Hz, J AB = 15.2 Hz, 2H), 3.87-3.84(m, 1H), 3.67-3.63(m, 1H), 3.47-3.37(m, 3H), 3.35-3. 33(m, 3H), 1.85-1.79(m, 1H), 0.91-0.86(m, 2H), 0.61-0.57(m, 2H); [M+Na] + 469.

[0201] Example 2: Synthesis of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol [ka]

[0202] Step 1: (3R,4S,5R,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyran-2-ol (compound c41) To a solution of 4-bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (compound c40, 5.00 g, 13.8 mmol) in tetrahydrofuran (140 mL), n-butyllithium (2.5 M hexane solution, 8.28 mL, 20.7 mmol) was added dropwise under a nitrogen atmosphere at -78°C. After stirring at the same temperature for 5 minutes, a solution of TMS-protected lactone (compound c11; 7.70 g, 16.6 mmol) in tetrahydrofuran was added dropwise for 30 minutes. The reaction mixture was stirred at the same temperature for 1 hour. The reaction mixture was quenched with saturated aqueous NH4Cl (300 mL) at 0°C and extracted with ethyl acetate. The organic layer was dried over Na2SO4, filtered, and concentrated under vacuum to obtain the crude labeled compound as a yellow oil (10.3 g, quantitative). The crude residue was used in the next step without further purification.

[0203] Step 2: (3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c43) Crude (3R,4S,5R,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyran-2-ol (10.3 g) was added to CH2Cl2 (70 mL) and CH3CN (70 mL) at -78°C with triethylsilane (8.8 mL, 55.2 mmol) and TMSOTf (10 mL, 55.2 mmol). After stirring at -78°C for 1 hour, the reaction mixture was quenched with water (200 mL) at 0°C and extracted with CH2Cl2 (300 mL). The organic layer was dried over Na2SO4, filtered, and concentrated under vacuum to obtain the crude labeled compound as a yellow oil (6.3 g, quantitative). The crude residue was used in the next process without further purification.

[0204] Step 3: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c27) To a solution of (3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (6.3 g, 13.8 mmol) in CH2Cl2 (140 mL), DMAP (0.84 g, 6.9 mmol) and Ac2O (13.0 mL, 13.8 mmol) were added at room temperature. After stirring at room temperature for 18 hours, the reaction mixture was quenched with water (120 mL) and extracted with DCM (200 mL). The organic layer was washed with aqueous NaHCO3 solution (100 mL), dried over Na2SO4, filtered, and concentrated under vacuum. The slurry residue in isopropyl alcohol (20 mL) was heated at 80°C for 10 minutes and cooled to room temperature. Next, the resulting precipitate was filtered and concentrated under vacuum to obtain the labeled compound as a β-type white solid (4.52 g, 7.35 mmol, 53%). 1H NMR (400 MHz, CDCl3) δ 7.04-7.02(m, 2H), 6.98-6.95(m, 2H), 6.53(s, 1H), 5.29-5.24(m, 1H), 5.18-5.12( m, 2H), 4.71-4.65(m, 2H), 4.31-4.26(m, 1H), 4.25-4.22(m, 1H), 4.15-4.11(m, 1H), 4.05-3.91(m, 2H), 3.79-3.74(m, 1H), 3.40-3.35(m, 2H), 2.06(s, 3H), 2.05(s, 3H), 1.99(s, 3H), 1.88-1.81(m, 1H), 1.66(s, 3H), 0.94-0.89(m, 2H), 0.66-0.61(m, 2H); [M+Na]+ 637.

[0205] Step 4: (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) To a solution of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (4.52 g, 7.35 mmol) in MeOH (70 mL), NaOMe (25 wt%, 0.35 mL) was added. After stirring at room temperature for 18 hours, the reaction mixture was concentrated under vacuum, diluted with water (200 mL), and extracted with siRNA (300 mL). The organic layer was dried over Na2SO4, filtered, and concentrated under vacuum. The residue was purified by recrystallization in toluene to obtain the β-form of the labeled compound as a yellow solid (3.16 g, 96%). 1 H NMR (400 MHz, CD3OD) δ 7.02(d, J = 8.0 Hz, 2H), 6.92(d, J = 8.0 Hz, 2H), 6.81(s, 1H), 4.59(t, J = 8.8 Hz, 2H), 4.11(d, J = 9.2 Hz, 1H), 3.96(ABq, ΔνAB = 19.0 Hz, JAB = 15.2 Hz, 2H), 3.87-3.84(m, 1H), 3.67-3.63(m, 1H), 3.47-3.37(m, 3H), 3.35-3.3 3(m, 3H), 1.85-1.79(m, 1H), 0.91-0.86(m, 2H), 0.61-0.57(m, 2H);[M+Na]+ 469.

[0206] Example 3: Synthesis of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-thiopyran-3,4,5-triol [ka]

[0207] Step 1: (3R,4S,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)-2-(7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-thiopyran-2-ol (compound c52) Except for using 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboaldehyde as a starting material and (4-methoxyphenyl)magnesium bromide (compound c48) as a Grignard reagent, the synthesis procedure of step 8 of Example 4 was repeated to obtain (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)(4-methoxyphenyl)methanol (compound c49). Then, except for using (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)(4-methoxyphenyl)methanol (compound c49) as a starting material, the synthesis procedure of step 9 of Example 4 was repeated to obtain 4-bromo-7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran (compound c50).

[0208] To a solution of 4-bromo-7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran (compound c50, 859 mg, 2.43 mmol) in tetrahydrofuran (8 mL), n-butyllithium (2.5 M hexane solution, 1.3 mL, 3.24 mmol) was added dropwise under a nitrogen atmosphere at -78°C, and the mixture was stirred at the same temperature for 1.5 hours. Next, a solution of (3R,4S,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-thiopyran-2-one (compound c51, 898 mg, 1.62 mmol, synthesized with reference to H. Driguez and B. Henrissat, Tetrahedron Lett. 1981, 22, 5061-5062, Kakinuma, H., et al., J. Med. Chem. 2010, 53, 3247-3261) was added dropwise in tetrahydrofuran (4 mL), and the mixture was stirred at the same temperature for 1.5 hours. The reaction mixture was quenched by adding a saturated ammonium chloride solution. After the addition was complete, the solution was gradually raised to room temperature. The organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with saline solution, dried over magnesium sulfate, filtered, and concentrated under vacuum to obtain the crude compound (3R,4S,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)-2-(7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-thiopyran-2-ol (quantitative yield).

[0209] Step 2: 7-Chloro-6-(4-methoxybenzyl)-4-((2S,3R,4R,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-thiopyran-2-yl)-2,3-dihydrobenzofuran (compound c53) To a solution of lactol (C52) in dichloromethane (16 mL) stirred at -20°C, triethylsilane (1.6 mL, 9.72 mmol) and then boron trifluoride diethyl etherate (0.8 mL, 6.48 mmol) were added at a rate that maintained the temperature between -20°C and 0°C. The solution was warmed to 0°C over 1.5 hours and then quenched with saturated sodium bicarbonate solution. After removing organic volatiles under reduced pressure, the residue was partitioned into ethyl acetate and water. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were washed with brine, dried over sodium sulfate, filtered, and concentrated under vacuum. The crude residue was purified by silica gel column chromatography (silica gel, hexane solution of 3-25% ethyl acetate) to obtain the crude compound 7-chloro-6-(4-methoxybenzyl)-4-((2S,3R,4R,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-thiopyran-2-yl)-2,3-dihydrobenzofuran as a white solid (603 mg, 46% in two steps). [M+Na] + 835.

[0210] Step 3: (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-methoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-thiopyran-3,4,5-triol (compound c47) To a solution of 7-chloro-6-(4-methoxybenzyl)-4-((2S,3R,4R,5S,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-thiopyran-2-yl)-2,3-dihydrobenzofuran (c53, 570 mg, 0.70 mmol) in dichloromethane (8 mL), BCl3 (1.0 M in dichloromethane solution, 2.8 mL) was added at 0°C. The reaction mixture was stirred at 0°C for 1 hour. After quenching the reaction with methanol, the solvent was evaporated under reduced pressure. The compound was purified by reverse-phase preparative HPLC (Gilson, SunFire® Prep, 5-50% acetonitrile / water gradient) to obtain the marked compound as a white solid (18 mg, 6%). 1H NMR (400 MHz, CD3OD) δ 7.07(d, J = 8.4 Hz, 2H), 6.79(d, J = 8.8 Hz, 2H), 6.76(s, 1H), 4.63(td, J = 8.0, 1.6 Hz, 2H), 3.95(s, 2H), 3.92(d, J = 3.6 Hz, 1H), 3.79-3.75(m, 3H), 3.74(s, 3H), 3.71(d, J = 6.4 Hz, 1H), 3.56(dd, J = 10.0, 8.8 Hz, 1H), 3.42-3.35(m, 2H), 3.24-3.20(m, 1H), 3.01-2.96(m, 1H), 0.90(t, J = 7.2 Hz, 3H); [M+Na] + 475.

[0211] Example 4: Preparation of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol [ka]

[0212] Step 1: ((3aS,5S,6R,6aS)-5-(Hydroxymethyl)-2,2-dimethyltetrahydrofl[3,2-d][1,3]dioxol-6-ol A suspension of L-(-)-xylose (19.15 g, 127.5 mmol) and MgSO4 (30.72 g, 255.0 mmol) in acetone (190 mL) was to be mixed with concentrated H2SO4 (1.9 mL) at room temperature. After 12 hours, the reaction mixture (all L-(-)-xylose consumed) was filtered, and the combined solid was washed twice with acetone (20 mL per wash). The yellow filtrate was neutralized to approximately pH 9 with NH4OH solution while stirring. The suspended solid was filtered off. The filtrate was concentrated to obtain the bisacetonide intermediate as a yellow oil. The yellow oil was suspended in water (5 mL), and then the pH was adjusted from 9 to 2 with 1N HCl aqueous solution. The reaction mixture was stirred at room temperature for 12 hours. The resulting mixture was neutralized to approximately pH 7 by adding 25% (w / w) K3PO4 aqueous solution. The mixture was extracted with ELISA. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel chromatography to obtain the labeled compound as a yellow oil (12.63 g, 52%). 1H NMR (400 MHz, CD3OD) δ 5.88(d, J = 4.0 Hz, 1H), 4.47(d, J = 4.0 Hz, 1H), 4.18-4.14(m, 1H), 4.11(d, J = 2.8 Hz, 1H), 3.83-3.71(m, 2H), 1.45(s, 3H), 1.29(s, 3H).

[0213] Step 2: (3aS,5R,6S,6aS)-6-Hydroxy-2,2-dimethyltetrahydrofl[3,2-d][1,3]dioxol-5-carboxylic acid To a solution of ((3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofluoro[3,2-d][1,3]dioxol-6-ol (14.6 g, 76.7 mmol), NaHCO3 (19.3 g, 230.3 mmol), and NaBr (1.6 g, 15.4 mmol) in acetone / water (120 mL / 40 mL), TEMPO (0.24 g, 1.5 mmol) was added at room temperature. The mixture was cooled to 0°C, and then trichloroisocyanuric acid (17.8 g, 76.7 mmol) was added little by little. The suspension was stirred at room temperature for 12 hours. Methanol (2.0 mL) was added, and the mixture was stirred at room temperature for 2 hours. The mixture was filtered and washed with acetone (twice, 20 ml per wash). (mL). The organic solvent was removed by vacuum, the aqueous layer was extracted with pharmaceutically acceptable ammonium compounds, and the organic layer was concentrated by vacuum. Acetone was added, and the mixture was filtered. The filtrate was concentrated to obtain the desired acid as a pale yellow solid (9.0 g, 58%). 1 H NMR (400 MHz, CD3OD) δ 5.98(d, J = 3.6 Hz, 1H), 4.71(d, J = 3.2 Hz, 1H), 4.51(d, J = 3.6 Hz, 1H), 4.36(d, J = 3.6 Hz, 1H), 1.45(s, 3H), 1.31(s, 3H).

[0214] Step 3: ((3aS,5R,6S,6aS)-6-Hydroxy-2,2-dimethyltetrahydrofluor[3,2-d][1,3]dioxol-2-yl)(morpholino)methanone (compound c56) To a suspension of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydroflo[3,2-d][1,3]dioxol-5-carboxylic acid (9.0 g, 44.2 mmol) and HBTU (25.1 g, 66.3 mmol, hexafluorophosphate N,N,N',N'-tetramethyl-O-(1H-benzotriazole-1-yl)uronium) in tetrahydrofuran, 4-methylmorpholine (7.3 mL, 66.3 mmol) was added at room temperature. After 1 hour, morpholine (5.8 mL, 66.3 mmol) was added to the mixture at room temperature. After 12 hours, the resulting mixture was filtered, and the filter cake was washed with tetrahydrofuran. The filtrate was concentrated under vacuum, and the crude substance was purified by silica gel chromatography to obtain the labeled compound as a yellow solid (5.8 g, 48%). 1 H NMR (400 MHz, CD3OD) δ 6.01(d, J = 3.6 Hz, 1H), 5.10(s, 1H), 4.59(d, J = 2.4 Hz, 1H), 4.57(d, J = 3.6 Hz, 1H), 4.47(d, J = 2.4 Hz, 1H), 3.85-3.62(m, 6H), 3.53-3.49(m, 2H), 1.49(s, 3H), 1.33(s, 3H). [M+H] + 274.

[0215] Step 4: (7-Chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofluor[2,3-d][1,3]dioxol-5-yl)methanone (compound c58) To a solution of 4-bromo-7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran (compound c57, 0.7 g, 1.90 mmol) in THF (17.5 mL), n-BuLi (2.5 M hexane solution, 0.9 mL, 2.28 mmol) was added at -78°C. After 1 hour, ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofluor[3,2-d][1,3]dioxol-5-yl)(morpholino)methanone (compound c56, 0.17 g, 0.63 mmol) in THF (8.0 mL) was added dropwise at -78°C. After 4 hours, the resulting mixture was quenched with saturated NH4Cl solution and extracted with ELISA. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude product was purified by silica gel column chromatography (Biotage Isolera® FLASH purification system) to obtain the marked compound (0.13 g, 43%); [M + H] + 475.

[0216] Step 5: (3aS,5S,6R,6aS)-5-((S)-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)(hydroxyl)methyl)-2,2-dimethyltetrahydroflo[2,3-d][1,3]dioxol-6-ol (compound c59) To a solution of (7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuran[2,3-d][1,3]dioxol-5-yl)methanone (0.13 g, 0.27 mmol) in methanol (18 mL), CeCl3.7H2O (0.12 g, 0.32 mmol) was added, and the mixture was stirred at room temperature until all solids were dissolved. The mixture was then cooled to -78°C, and NaBH4 (0.012 g, 0.32 mmol) was added gradually. The mixture was stirred at -78°C for 2 hours, slowly warmed to 0°C, and quenched with saturated NH4Cl solution. The mixture was concentrated under reduced pressure to remove CH3OH, extracted with siRNA, and washed with saturated NaCl solution. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude labeled compound was dried under high vacuum and used in the next step as a white solid (0.13 g) without purification. [M + Na] + 499.

[0217] Step 6: (3S,4R,5S,6S)-6-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-2,3,4,5-tetrayl tetraacetate (compound c60) A solution of (3aS,5S,6R,6aS)-5-((S)-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)(hydroxyl)methyl]-2,2-dimethyltetrahydrofl[2,3-d][1,3]dioxol-6-ol (0.13 g, 0.27 mmol) in AcOH / water (4.0 / 2.5 mL) was stirred at 100°C for 12 hours. The resulting mixture was cooled to room temperature and concentrated under reduced pressure. The crude oil was treated with acetic anhydride (0.2 mL, 2.16 mmol) in pyridine (0.7 mL) at 0°C. The mixture was stirred at room temperature for 8 hours. The resulting mixture was quenched with water, extracted with ethyl acetate, and washed with brine. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography to obtain the marked compound as a white solid (0.16 g, 96%). + Na] + 627.

[0218] Step 7: (2S,3S,4R,5S,6R)-2-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c61) To a solution of (3S,4R,5S,6S)-6-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-2,3,4,5-tetrayl tetraacetate (160 mg, 0.26 mmol) and thiourea (39 mg, 0.52 mmol) in 1,4-dioxane (3.1 mL), TMSOTf (70 μl, 0.39 mmol) was added, and the reaction mixture was heated at 80°C for 4 hours. The mixture was cooled to room temperature, and MeI (40 μl, 0.65 mmol) and DIPEA (452 ​​μl, 2.60 mmol) were added, and the mixture was stirred for 3 hours. The resulting mixture was diluted with ethyl acetate and washed with water. The organic layer was dried over MgSO4, filtered, and concentrated under vacuum. The crude labeled compound was dried under high vacuum and used in the next step without purification as a white solid (150 mg, 48%). [M + Na] + 615.

[0219] Step 8: (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol (compound c54) A suspension of (2S,3S,4R,5S,6R)-2-(7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (150 mg, 0.25 mmol) in CH3OH (0.7 mL) was to be to which NaOMe (catalytic amount, 25% CH3OH solution) was added at room temperature. After 20 hours, the resulting mixture was concentrated under vacuum. The crude product was diluted with siRNA and filtered through a membrane. The crude product was purified by preparative HPLC (Gilson system, CH3CN / H2O) to obtain the labeled compound (41 mg, 35%). 1 H NMR (400 MHz, CDCl3) δ 7.09(d, J = 8.4 Hz, 2H), 6.80(d, J = 8.8 Hz, 2H), 6.68(s, 1H), 4.69-4.64(m, 2H), 4.35(d, J = 10.0 Hz, 1H), 4.20(d, J = 9.2 Hz, 1H), 4.02-3.88(m, 4H), 3.67-3.65(m, 2H), 3.61-3.58(m, 1H), 3.56-3 .52(m, 1H), 3.42-3.40(m, 2H), 3.29-3.27(m, 2H), 2.17(s, 3H), 1.40(t, J = 7.0 Hz, 3H); [M+Na] + 489.

[0220] Example 5: Preparation of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-ethylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol The synthetic procedure of Example 4 was repeated, except that 4-bromo-7-chloro-6-(4-ethylbenzyl)-2,3-dihydrobenzofuran was used instead of 4-bromo-7-chloro-6-(4-ethoxybenzyl)-2,3-dihydrobenzofuran in step 4, to obtain the marked compound. 1H NMR (400 MHz, CDCl3) δ 7.10-7.90(m, 4H), 6.71(s, 1H), 4.68-4.62(m, 2H), 4.33(d, J = 9.6 Hz, 1H), 4.18(d, J = 9.2 Hz, 1H), 4.07-4.00(m, 2H), 3.63-3.57(m, 3H), 3.52-3.49(m, 1H), 3.39-3.37(m, 2H), 3.27-3.25(m, 2H), 2.60(q, J = 7.4 Hz, 2H), 2.15(s, 3H), 1.20(t, J = 7.6 Hz, 3H); [M+Na] + 473.

[0221] Example 6: Preparation of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol [ka]

[0222] Step 1: (3R,4S,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl])-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (compound c42) The indicated compound was synthesized via either route 1a or 1b described below.

[0223] (1a) In a reaction vessel, 4-bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (250 g, 0.687 mol), (3R,4S,5R,6R)-3,4,5-tris((trimethylsilyl)oxy)-6-(((trimethylsilyl)oxy)methyl)tetrahydro-2H-pyran-2-one (642 g, 1.38 mol), and anhydrous tetrahydrofuran (2.00 L) were added dropwise under nitrogen at room temperature until the mixture was completely dissolved. After cooling the reaction vessel to -78°C, n-butyllithium (550 mL, 2.0 M hexane solution, 1.38 mol) was added dropwise for 1 hour while maintaining the internal temperature below -60°C. Once the addition of n-butyllithium was complete, the mixture was further stirred at -78°C for 40 minutes. While maintaining the internal temperature below -30°C, concentrated hydrochloric acid / methanol (152 mL / 1,750 mL) solution was added dropwise to the reaction mixture over 20 minutes. Once the addition was complete, the reaction vessel was brought to room temperature and stirred for 18 hours. After confirming the completion of the reaction, the reaction vessel was cooled to 0°C, saturated NaHCO3 aqueous solution (2.5 L) was added, and the pH was adjusted to 9-10 using a pH meter. The reaction solvent was then removed using a vacuum concentrator. The concentrate was diluted with RINKAN (2.5 L), distilled water (1.25 L), and brine (1.25 L) to form layers. The organic layers were then pooled, and the aqueous layer was extracted with RINKAN (2 x 1.25 L). The organic layers were combined and rinsed with distilled water (2.5 L) and brine (2.5 L). The organic layers were dried over MgSO4 (50 g) and filtered. The filtrate was then concentrated under reduced pressure to remove the solvent. The residue was diluted with toluene (500 mL) and removed by distillation under reduced pressure, and this process was repeated twice to obtain the labeled compound as a yellow liquid (328 g). The crude residue was used in the next step without further purification.

[0224] (1b) In a reaction vessel, 4-bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (10.0 g, 27.5 mol), (3R,4S,5R,6R)-3,4,5-tris((trimethylsilyl)oxy)-6-(((trimethylsilyl)oxy)methyl)tetrahydro-2H-pyran-2-one (25.7 g, 54.9 mol), and anhydrous tetrahydrofuran (80 mL) were added dropwise under nitrogen at room temperature until the mixture was completely dissolved. After cooling the reaction vessel to -78°C, n-butyllithium (22.1 mL, 2.5 M hexane solution, 54.9 mmol) was added dropwise for 15 minutes while maintaining the internal temperature below -60°C. Once the addition of n-butyllithium was complete, the mixture was stirred further at -78°C for 30 minutes. While maintaining the internal temperature below -30°C, concentrated hydrochloric acid / methanol (7.01 mL / 70 mL) solution was added dropwise to the reaction mixture for 10 minutes. Once the addition was complete, the reaction vessel was brought to room temperature and stirred for 18 hours. After confirming the completion of the reaction, the reaction vessel was cooled to 0°C, saturated NaHCO3 aqueous solution (60 L) was added, and the pH was adjusted to 9-10 using a pH meter. Then, the reaction solvent was removed using a vacuum concentrator. The concentrate was diluted with toluene (60 mL), distilled water (60 mL), and brine (60 mL) to form layers. The organic layers were then pooled, and the aqueous layer was extracted with toluene (2 x 30 mL). The organic layers were combined and rinsed with distilled water (60 mL) and brine (60 mL). The organic layers were dried over MgSO4 (5 g), filtered, and the filtrate was concentrated under reduced pressure to remove the solvent. The residue was diluted with toluene (50 mL), and the toluene solution was then slowly added dropwise to hexane (200 mL) at room temperature while stirring. The resulting suspension was stirred at the same temperature for 1 hour and then filtered under vacuum. The resulting filtrate was washed with hexane (10 mL) and then dried in a vacuum oven (40°C) until its water content was less than 1% by Karl Fischer analysis, yielding the marked compound as a yellow solid (12.6 g, 96%). 1H NMR (500 MHz, CDCl3): δ 7.02(d, J = 8.0 Hz, 2H), 6.92(d, J = 8.0 Hz, 2H), 6.81(s, 1H), 4.64(m, 1H), 4.57(m, 1H), 4.05(d, J = 15.0 Hz, 1H), 3.96(d, J = 15.0 Hz, 1H), 3.93(dd, J = 11.8, 3.0 Hz, 1H), 3.87(m, 2H), 3.65(m, 2H), 3.51(m, 1H), 3.30(d, J = 9.5 Hz, 1H), 3.14(s, 3H), 1.83(m, 1H), 0.91(m, 2H), 0.63(m, 2H);LC-MS:[M-OMe] + 445.

[0225] Step 2: (3R,4R,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c43) In the reaction vessel, the crude residue (328 g, 0.687 mol) obtained by reaction pathway 1a of step 1 was completely dissolved in a CH2Cl2 / CH3CN (= v / v, 1:1, 5.00 L) solution under nitrogen at room temperature with stirring. The reaction vessel was cooled to -50°C, and then Et3SiH (329 mL, 2.08 mol) and BF3-OEt2 (170 mL, 1.37 mol) were added dropwise for 10 minutes while maintaining the internal temperature below -45°C. The reaction mixture was slowly warmed to -10°C for 1 hour, and the resulting mixture was warmed to 0°C. After stirring at 0°C for 3 hours, saturated NaHCO3 aqueous solution (5.5 L) was added to the reaction mixture, and the pH was adjusted to 7.0-7.5 using a pH meter. The organic solvent was removed from the mixture using a vacuum concentrator, and the concentrate was diluted with ELISA (2.5 L). The organic layer was then isolated. The aqueous layer was diluted with SiO2 (2 x 125 L) and extracted. All organic layers were combined, dried over anhydrous MgSO4 (50 g), filtered, and the filtrate was concentrated under reduced pressure to remove the solvent. The residue was vacuum-dried to obtain the labeled compound as a yellow liquid (307 g). The crude residue thus obtained was used in the next step without further purification. 1H NMR (500 MHz, CD3OD): δ 7.04(d, J = 8.0 Hz, 2H), 6.93(d, J = 8.0 Hz, 2H), 6.83(s, 1H), 4.61(t, J = 9.0 Hz, 2H), 4.13(d, J = 9.0 Hz, 1H), 3.99(d, J = 15.0 Hz, 1H), 3.94(d, J = 15.0 Hz, 1H), 3.87(d, J = 12.0 Hz, 1H), 3.66(m, 1H), 3.44(m, 1H), 3.41(t, J = 9.0 Hz, 2H), 3.36(m, 2H), 3.31(m, 1H), 1.83(m, 1H), 0.91(m, 2H), 0.63(m, 2H);LC-MS:[M+Na] + 469.

[0226] Step 3: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c27) In a reaction vessel, while stirring a CH2Cl2 (5.00 L) solution of the crude residue from step 2 (307 g, 0.687 mol), DMAP (101 g, 0.825 mol) and Ac2O (520 mL, 5.50 mol) were continuously added dropwise at room temperature. The resulting yellow reaction mixture was stirred at room temperature for 2 hours. Distilled water (500 mL) was added to the reaction mixture to quench it. The mixture was layered. The organic layers were stored, and the aqueous layers were extracted with dichloromethane (2 x 1.25 L). All the organic layers were combined and rinsed with 1N HCl aqueous solution (2.5 L) and brine (2.5 L). The organic layers were dried over MgSO4 (50 g), filtered, and the filtrate was concentrated under reduced pressure. The residue was diluted with MeOH (2.5 L) and stirred at room temperature for 30 minutes. The resulting solid was filtered under reduced pressure, and the filtrate was rinsed with MeOH (500 mL). The filtered solid was dried to obtain the labeled compound as a white solid (357 g, yield: 84%, purity: >97.6%). 1H NMR (500 MHz, CDCl3): δ 7.04 (d, J = 8.0 Hz, 2H), 6.95 (d, J = 8.0 Hz, 2H), 6.53 (s, 1H), 5.24 (dd, J = 9.5, 9.5 Hz, 1H), 5.12(m, 2H), 4.67(m, 2H), 4.29(d, J = 10.0 Hz, 1H), 4.24(dd, J = 12.5, 4.5 Hz, 1H), 4.13(dd, J = 12.5, 1.5 Hz, 1H), 4.02(d, J = 15.0 Hz, 1H), 3.92(d, J = 15.0 Hz, 1H), 3.77(m, 1H), 3.38(m, 2H), 2.07(s, 3H), 2.06(s, 3H), 1.99(s, 3H), 1.84(m, 1H), 1.66(s, 3H), 0.92(m, 2H), 0.63(m, 2H);LC-MS:[M+Na] + 637.

[0227] Step 4: (2S,3R,4R,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) To a suspension of (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (357 g, 0.580 mol) in THF / MeOH (= v / v, 1:2, 4.28 L), 4M aqueous NaOH (668 mL, 2.67 mol) was added dropwise at room temperature for 20 minutes while stirring the suspension. The resulting suspension was further stirred at room temperature for 2 hours. After cooling the reaction vessel to 0°C, 1N aqueous HCl (1.18 L) was slowly added dropwise to the reaction mixture, and the pH was adjusted to 6.5-7.0 using a pH meter. The reaction solvent was removed using a vacuum concentrator, and the concentrate was diluted with ELISA (5.36 L) and distilled water (5.36 L). The mixture was layered. The organic layers were stored, and the aqueous layer was extracted with SiO2 (2 x 1.79 L). All the organic layers were combined and rinsed with distilled water (1.79 L). The organic layers were dried over MgSO4 (710 g), filtered, and the filtrate was concentrated under reduced pressure to obtain the crude compound.

[0228] The crude labeled compound was diluted with SiO2 (3.89 L) and then stirred under reflux for 30 minutes to completely dissolve the solid. The resulting mixture was then cooled to room temperature. Isopropyl ether (1.29 L) was added dropwise to the resulting suspension over 10 minutes, and stirred for 30 minutes (including the addition time). The step of adding isopropyl ether was repeated twice. The reaction vessel was then cooled to 0°C and stirred for 30 minutes. The resulting solid was filtered under reduced pressure, and the filtrate was rinsed with a mixture of SiO2 / isopropyl ether (= v / v, 1:1, 357 mL). The filtered solid was dried in a vacuum oven (40°C, 18 hours) to obtain the labeled compound as a white solid (236 g, yield: 92%, purity: > 99.7%). Furthermore, according to the synthesis route of steps 1-4 above, the total yield of the final compound of Example 6 was calculated to be approximately 77%. 1 H NMR (500 MHz, CD3OD): δ 7.04(d, J = 8.0 Hz, 2H), 6.93(d, J = 8.0 Hz, 2H), 6.83(s, 1H), 4.61(t, J = 9.0 Hz, 2H), 4.13(d, J = 9.0 Hz, 1H), 3.99(d, J = 15.0 Hz, 1H), 3.94(d, J = 15.0 Hz, 1H), 3.87(d, J = 12.0 Hz, 1H), 3.66(m, 1H), 3.44(m, 1H), 3.41(t, J = 9.0 Hz, 2H), 3.36(m, 2H), 3.31(m, 1H), 1.83(m, 1H), 0.91(m, 2H), 0.63(m, 2H);LC-MS:[M+Na] + 469.

[0229] Example 7: Preparation of (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol [ka]

[0230] Step 1: (3R,4S,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (compound c42) According to the synthesis route of Step 1, 1b of Example 6, the marked compound was obtained as a pale yellow solid (26.2 g, 93%) using 4-bromo-7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran (21.6 g).

[0231] Step 2: (3R,4S,5R,6R)-6-(acetoxymethyl)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-2-methoxytetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c44) In a reaction vessel, DMAP (8.06 g, 66.0 mmol) and Ac2O (51.8 mL, 550 mol) were continuously added dropwise at room temperature while stirring, using a solution of (3R,4S,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol (26.2 g, 55.0 mmol) in CH2Cl2 (65.5 L). The resulting yellow reaction mixture was stirred at room temperature for 6 hours. Distilled water (50 mL) was added to the reaction mixture to quench it. The mixture was layered. The organic layers were stored, and the aqueous layers were extracted with CH2Cl2 (2 x 30 mL). All organic layers were combined and rinsed with 1N HCl aqueous solution (50 mL) and saline solution (30 mL). The organic layer was dried over MgSO4 (6 g), filtered, and the filtrate was concentrated under reduced pressure. The residue was diluted with MeOH (100 mL) and stirred at room temperature for 12 hours. The resulting solid was filtered under reduced pressure, and the filtrate was rinsed with MeOH (30 mL). The filtered solid was dried to obtain the labeled compound as a white solid (29.2 g, 71% total from the two steps). 1 H NMR (500 MHz, CDCl3): δ 7.01(d, J = 8.5 Hz, 2H), 6.95(d, J = 8.5 Hz, 2H), 6.65(s, 1H), 5.53(dd, J = 10.0, 9.5 Hz, 1H), 5.19(dd, J = 10.0, 9.5 Hz, 1H), 4.99(d, j = 10.0 Hz, 1H), 4.63(m, 2H), 4.34(dd, J = 12.0, 4.5 Hz, 1H), 4.14(dd, J = 12.0, 2.0 Hz, 1H), 4.05(d, J = 15.5 Hz, 1H), 4.01(m, 1H), 3.99(d, J = 15.5 Hz, 1H), 3.49(m, 1H), 3.33(m, 1H), 3.17(s, 3H), 2.08(s, 3H), 2.05(s, 3H), 1.94(s, 3H), 1.83(m, 1H), 1.61(s, 3H), 0.90(m, 2H), 0.62(m, 2H).

[0232] Step 3: (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]tetrahydro-2H-pyran-3,4,5-triyl triacetate (compound c27) In a reaction vessel, f(3R,4S,5R,6R)-6-(acetoxymethyl)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-2-methoxytetrahydro-2H-pyran-3,4,5-triyl triacetate (5.00 g, 7.75 mmol) was completely dissolved in a CH2Cl2 / CH3CN (= v / v, 1:10, 550 mL) solution at room temperature while stirring. After cooling the reaction vessel to 0°C, Et3SiH (9.89 mL, 62.0 mmol) and BF3-OEt2 (4.96 mL, 40.3 mmol) were added dropwise for 10 minutes while maintaining the internal temperature below 5°C. The reaction mixture was stirred below 5°C for 1 hour. Then, the reaction mixture was warmed to 10°C and stirred for a further 2 hours. A saturated aqueous solution of NaHCO3 was added to the reaction mixture, and the pH was checked using a pH meter to ensure it was between 7.0 and 7.5. The organic solvent was then removed using a vacuum concentrator. The concentrate was diluted with ELISA (50 mL), and the organic layer was isolated. The aqueous layer was extracted with ELISA (2 x 30 mL). All the organic layers were combined, dried over MgSO4 (5 g), filtered, and the filtrate was concentrated under reduced pressure. The residue was dissolved in CH2Cl2 (5 mL), hexane (10 mL) was added, and the mixture was stirred at room temperature for 5 minutes. Isopropyl ether (20 mL) was added to the mixture and the mixture was stirred for 30 minutes. Isopropyl ether (20 mL) was further added to the resulting suspension. The reaction vessel was cooled to 0°C and stirred for 2 hours. The resulting solid was filtered under reduced pressure, and the filtrate was rinsed with isopropyl ether (10 mL). The filtered solid was vacuum dried to obtain the labeled compound as a white solid (4.38 g, 92%).

[0233] Step 4: (2S,3R,4R,5S,6R)-2-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) According to the synthesis method described in step 4 of Example 1 above, the crude compound was obtained using (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-[7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl]tetrahydro-2H-pyran-3,4,5-triyl triacetate (4.38 g, 7.12 mmol). The residue was diluted with ELISA (45.3 mL), and then stirred under reflux for 10 minutes to completely dissolve the solid. The resulting mixture was cooled to room temperature. Isopropyl ether (15.1 mL) was added dropwise to the resulting suspension for 10 minutes, and the mixture was stirred for 30 minutes (including the addition time). The step of adding isopropyl ether was repeated twice. The reaction vessel was then cooled to 0°C and stirred for 30 minutes. The resulting solid was filtered under reduced pressure, and the filtrate was rinsed with isopropyl ether (10 mL). The filtered solid was dried in a vacuum oven (40°C, 18 hours) to obtain the labeled compound as a white solid (2.93 g, yield: 92%, purity: > 99.5%). According to the synthesis route of steps 1-4 described above, the total yield of the final compound in Example 2 was calculated to be approximately 60%.

[0234] Experimental Example 1: Evaluation of Yield under Rearrangement Reaction Conditions [ka]

[0235] (1) Reactions using amine solvents or reactions without solvents Methyl 3-(allyloxy)-5-bromo-2-chlorobenzoate (compound c30) was subjected to a rearrangement reaction at 160°C to obtain methyl 4-allyl-5-bromo-2-chloro-3-hydroxybenzoate (compound c31), and its yield was calculated.

[0236] At this point, the amounts of starting materials and reaction conditions were adjusted as shown in Table 1 below. The reaction was carried out either using 5M diethylamine (DEA) as the reaction solvent or without using any solvent.

[0237] As a result, the yield reached a maximum of 67% and did not increase beyond that. [Table 1]

[0238] (2) Reaction by addition of Lewis acid Methyl 3-(allyloxy)-5-bromo-2-chlorobenzoic acid (compound C30) was dissolved in a solvent as a starting material and subjected to a rearrangement reaction. The residue was then purified by silica gel chromatography to obtain methyl 4-allyl-5-bromo-2-chloro-3-hydroxybenzoate (compound C31), and its yield was calculated.

[0239] At this point, the reaction solvent, reaction temperature, and Lewis acid were adjusted as shown in Table 2 below, and the reaction was carried out with or without the Lewis acid.

[0240] As a result, the yield increased to 80% when a Lewis acid, such as diisobutylaluminum chloride ((i-Bu)2AlCl) or diethylaluminum chloride (Et2AlCl), was added. [Table 2]

[0241] Experimental Example 2: Evaluation of Yield under Cyclization Reaction Conditions (1) Cyclization using Vilsmeyer reagent [ka]

[0242] Preparation of Vilsmeyer's reagent (Reagent A): SOCl2 (5.3 mL, 72.24 mmol) was added to a solution of N,N-dimethylformamide (5.6 mL, 74.24 mmol) at room temperature. The mixture was stirred at 40°C for 2 hours, and then concentrated under vacuum to obtain Vilsmeyer's reagent, a hygroscopic white solid.

[0243] Preparation of Vilsmeyer's reagent (Reagent B): SOCl2 (2.7 mL, 37.07 mmol) was added to a solution of N,N-dimethylformamide (2.9 mL, 37.07 mmol) at room temperature. The mixture was stirred at 40°C for 2 hours, and then concentrated under vacuum to obtain Vilsmeyer's reagent, a hygroscopic white solid.

[0244] Next, methyl 5-bromo-2-chloro-3-hydroxy-4-(2-hydroxyethyl)benzoate (compound c33) in DMF was slowly added to the mixture of Vilsmeyer reagents in DMF. The mixture was subjected to a cyclization reaction for 1 hour with stirring to obtain methyl 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate (compound c34), and its yield was calculated.

[0245] At this point, the starting materials, reaction temperature, etc., were adjusted as shown in Table 3 below, and the reaction was carried out.

[0246] As a result, the cyclization product was obtained in generally high yields. However, when the starting material was impure, the product was recovered in low yields. [Table 3]

[0247] (2) Cyclization using leaving groups [ka]

[0248] Methyl 5-bromo-2-chloro-3-hydroxy-4-(2-hydroxyethyl)benzoate (compound c33) was added to the starting material with mesyl chloride (MsCl) as a solvent. The mixture was subjected to a cyclization reaction to obtain methyl 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate (compound c34), and its yield was calculated.

[0249] At this point, the amount of reagents used, the method of addition, and the reaction conditions were adjusted as shown in Table 4 below, and the reaction was carried out.

[0250] As a result, the desired compound could sometimes be obtained in high yield. However, there were drawbacks due to the equivalent control of MsCl and its addition.

[0251] [Table 4]

[0252] (3) Cyclization using halide or Mitsunobu reaction Methyl 5-bromo-2-chloro-3-hydroxy-4-(2-hydroxyethyl)benzoate (compound C33) was subjected to a cyclization reaction using a halide or Mitsunobu reaction to obtain methyl 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate (compound C34), and its yield was calculated.

[0253] At this point, a reagent consisting of triphenylphosphine (PPh3), imidazole, iodine (I2), and toluene was used for the halide cyclization, and a reagent consisting of triphenylphosphine (PPh3), diisopropyl azodicarboxylate (DIAD), and tetrahydrofuran (THF) was used for the Mitsunobu reaction.

[0254] As a result, a maximum yield of approximately 60% was obtained. However, there was a drawback: the by-product triphenylphosphine oxide had to be removed after the reaction.

[0255] Experimental Example 3: Evaluation of Yield under Reduction Reaction Conditions [ka]

[0256] 4-bromo-7-chloro-2,3-dihydrobenzofuran-6-carboxylate methyl (compound c34) was used as a starting material, to which NaBH4 (3 equivalents) was added, and a Lewis acid was either added or omitted. The mixture was then subjected to a reduction reaction in a solvent at room temperature to obtain (4-bromo-7-chloro-2,3-dihydrobenzofuran-6-yl)methanol (compound c35), and its yield was calculated. Furthermore, the amount of by-product 1 (compound c35-1) was also measured.

[0257] (1) The reaction was carried out by adjusting the amount of reaction solvent and Lewis acid added as shown in Table 5 below. As a result, when THF / EtOH (1:1) was used as the reaction solvent, it was possible to obtain the product in the highest yield, and even when NaBH4 alone was used without Lewis acid, a good yield of 95% was obtained. [Table 5]

[0258] (2) The reaction was carried out without the addition of Lewis acid, by adjusting the reaction solvent and the amount of NaBH4 added as shown in Table 6 below. As a result, a good yield of 95% without byproducts was obtained when 3 equivalents of NaBH4 were added under conditions of THF / EtOH (1:1) or THF / EtOH (2:1) as the reaction solvent. [Table 6]

[0259] (3) The reaction was carried out by adjusting the reaction solvent, the amount of NaBH4 added, and the amount of Lewis acid added as shown in Table 7 below. As a result, the reaction did not proceed when THF alone or THF / i-PrOH was used as the reaction solvent. On the other hand, when THF / ethanol was used as the reaction solvent, a good yield of 95% or more was obtained by using NaBH4 alone without a Lewis acid. [Table 7]

[0260] Experimental Example 4: Production and Analysis of Crystal Forms The compounds produced according to the method of the present invention, in particular crude (2S,3R,4R,5S,6R)-2-(7-chloro-6-(4-cyclopropylbenzyl)-2,3-dihydrobenzofuran-4-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (compound c28) obtained according to steps 1 to 14 of Example 1, were crystallized in various solvents and analyzed.

[0261] For the XRD spectrum, we used an X-ray diffractometer according to the standard procedure to obtain the Cu-K spectrum. α Powder X-ray diffraction was measured by irradiating the sample with a line (wavelength λ = 1.54056 Å).

[0262] For differential scanning calorimetry (DSC), measurements were performed using a differential scanning calorimeter at a rate of +1°C / min.

[0263] (1) Production of crystals using toluene solvent Crystallization using toluene is the same as described in the latter half of step 14 of Example 1. Specifically, crude compound C28 was dissolved by heating a toluene solution (8 times the weight of C28) at 40°C for 30 minutes, and then cooled to room temperature. After a suspension was formed at room temperature, it was stirred for a further 30 minutes. The resulting precipitate was filtered, washed with toluene (2 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 91.8%).

[0264] The XRD spectrum of the generated crystal showed the crystal form (crystal form A) as shown in Figure 1, and the diffraction angle (2θ), interplanar spacing (d), and relative intensity (I / I 0×100) of the characteristic peaks are summarized in Table 8. [Table 8]

[0265] As shown in Figure 2, the endothermic melting peak of the crystal was confirmed by DSC spectroscopy.

[0266] (2) Preparation of crystals using ethyl acetate solvent Crystallization using ethyl acetate is the same as described in the latter half of step 14 of Example 6. Specifically, crude compound c28 was dissolved in a solution of ethyl acetate (15 times the weight of c28) by reflux stirring, and then cooled to room temperature. After a suspension was formed at room temperature, it was stirred for a further 30 minutes. To the resulting mixture, isopropyl ether (15 times the weight of c28) was added dropwise over 30 minutes, and the mixture was stirred for a further 30 minutes at room temperature. The resulting precipitate was filtered, washed with ethyl acetate (2 times the weight of c28) at 0°C, and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 88.3%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0267] (3) Production of crystals using dichloromethane solvent A solution of crude compound c28 in dichloromethane (17 times the weight of c28) was dissolved by heating at 40°C and then cooled to room temperature. The mixture was stirred at room temperature for 30 minutes. Compound c28 (10 mg, seed) obtained in step 4 of Example 6 was added to the reaction mixture and then stirred for 12 hours. The resulting precipitate was filtered, washed with dichloromethane (2 times the weight of c28), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 50.1%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0268] (4) Production of crystals using acetone solvent Crude compound c28 was dissolved in acetone (35 times the weight of c28) by reflux stirring, and then cooled to room temperature. After a suspension formed at room temperature, it was stirred for a further 3 hours. The resulting precipitate was filtered, washed with acetone (twice the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 38.2%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0269] (5) Production of crystals using acetonitrile solvent A solution of crude compound c28 in acetonitrile (10 times the weight of c28) was dissolved by heating at 60°C and then cooled to room temperature. After a suspension formed at room temperature, the mixture was stirred for a further 1 hour. The resulting precipitate was filtered, washed with acetonitrile (twice the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 39.4%). XRD spectral analysis of the resulting crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0270] (6) Preparation of crystals using 2-propanol solvent A solution of crude compound c28 in 2-propanol (10 times the weight of c28) was dissolved by heating at 60°C and then cooled to room temperature. After a suspension formed at room temperature, the mixture was stirred for a further 30 minutes. 2-propanol (5 times the weight of c28) was added dropwise to the reaction mixture and stirred for 30 minutes. The resulting precipitate was filtered, washed with 2-propanol (twice the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 9.5%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0271] (7) Preparation of crystals using tetrahydrofuran / dichloromethane solvent Crude compound c28 was dissolved in tetrahydrofuran (5 times the weight of c28) by stirring at room temperature for 30 minutes. The reaction mixture was concentrated under reduced pressure to remove the organic solvent. The concentrated residue was diluted with dichloromethane (30 times the weight of c28) and stirred at room temperature. After a suspension formed at room temperature, it was stirred for a further 30 minutes. The resulting precipitate was filtered, washed with dichloromethane (2 times the weight of c28), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 65.3%). XRD spectral analysis of the resulting crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0272] (8) Preparation of crystals using tetrahydrofuran / n-hexane solvent Crude compound c28 was dissolved in tetrahydrofuran (5 times the weight of c28) by stirring at room temperature for 30 minutes. N-hexane (10 times the weight of c28) was added dropwise to the reaction mixture and stirred for 1 hour. To the resulting suspension, n-hexane (10 times the weight of c28) was added dropwise again and stirred for 30 minutes. N-hexane (5 times the weight of c28) was repeatedly added dropwise to the reaction suspension and stirred for 30 minutes. The resulting precipitate was filtered, washed with n-hexane (5 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 99.6%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form A) as in Experimental Example 4 (1).

[0273] (9) Methanol / distilled water solvent Crude compound C28 was dissolved in methanol (5 times the weight of C28) by stirring at room temperature for 30 minutes. Distilled water (10 times the weight of C28) was added dropwise to the reaction mixture, and the mixture was stirred for 30 minutes. Distilled water (10 times the weight of C28) was added dropwise to the resulting suspension, and the mixture was stirred for 1 hour. The resulting precipitate was filtered, washed with distilled water (2 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 100%).

[0274] The XRD spectrum of the generated crystals showed the crystal form (crystal form B) as shown in Figure 3, and the diffraction angle (2θ), interplanar spacing (d), and relative intensity (I / I 0×100) of the characteristic peaks are summarized in Table 9. [Table 9]

[0275] As shown in Figure 4, the endothermic melting peak of the crystal was confirmed by DSC spectroscopy.

[0276] (10) Preparation of crystals using methanol / n-hexane solvent Crude compound c28 was dissolved in methanol (5 times the weight of c28) by stirring at room temperature for 30 minutes. N-hexane (15 times the weight of c28) was added dropwise to the reaction mixture and stirred for 30 minutes. To the resulting suspension, n-hexane (10 times the weight of c28) was added dropwise and stirred for 1 hour. The resulting precipitate was filtered, washed with n-hexane (5 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 97.1%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form B) as in Experimental Example 4 (9).

[0277] (11) Preparation of crystals using methanol / dichloromethane / n-hexane solvent Crude compound c28 was dissolved in a dichloromethane / methanol solution (20:1 times the weight of c28) by stirring at room temperature for 30 minutes. N-hexane (10 times the weight of c28) was added dropwise to the reaction mixture and stirred for 30 minutes. N-hexane (5 times the weight of c28) was repeatedly added dropwise to the reaction suspension and stirred for 30 minutes. The resulting precipitate was filtered, washed with n-hexane (5 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 99.2%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form B) as in Experimental Example 4 (9).

[0278] (12) Preparation of crystals using tetrahydrofuran / toluene solvent Crude compound C28 was dissolved in tetrahydrofuran (5 times the weight of C28) by stirring at room temperature for 30 minutes. The reaction mixture was concentrated under reduced pressure to remove the organic solvent. The concentrated residue was diluted with toluene (30 times the weight of C28) and stirred at room temperature for 1 hour. The resulting precipitate was filtered, washed with toluene (5 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 76.1%).

[0279] The XRD spectra of the generated crystals showed the crystal form (crystal form C) as shown in Figure 5, and the diffraction angles (2θ), interplanar spacing (d), and relative intensity (I / I 0×100) of characteristic peaks are summarized in Table 10. [Table 10]

[0280] As shown in Figure 6, the endothermic melting peak of the crystal was confirmed by DSC spectroscopy.

[0281] (13) Preparation of crystals using ethanol / distilled water / n-hexane solvent A solution of crude compound c28 in ethanol (5 times the weight of c28) was dissolved by heating at 50°C and then cooled to room temperature. Distilled water (10 times the weight of c28) was added dropwise to the reaction mixture and the mixture was stirred for 1 hour. Distilled water (10 times the weight of c28) was added dropwise to the resulting suspension and the mixture was stirred for 30 minutes. N-hexane (1 time the weight of c28) was added dropwise to the reaction suspension and the mixture was stirred for 1 hour. The resulting precipitate was filtered, washed with distilled water (2 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 95.8%). XRD spectral analysis of the generated crystals showed the same crystal form (crystal form C) as in Experimental Example 4 (12).

[0282] (14) Preparation of crystals using ethanol / n-hexane solvent Crude compound C28 was dissolved in ethanol (5 times the weight of C28) by heating at 50°C, and then cooled to room temperature. N-hexane (5 times the weight of C28) was added dropwise to the reaction mixture and stirred for 30 minutes. To the resulting suspension, N-hexane (10 times the weight of 10-fold C28) was added dropwise and stirred for 30 minutes. N-hexane (5 times the weight of C28) was repeatedly added dropwise to the reaction suspension and stirred for 30 minutes. The resulting precipitate was filtered, washed with N-hexane (5 times the volume of the filtrate), and then dried in a vacuum oven (50°C, 12 hours) to obtain a white solid (yield: 96.5%).

[0283] The XRD spectra of the generated crystals showed the crystal form (crystal form D) as shown in Figure 7, and the diffraction angles (2θ), interplanar spacing (d), and relative intensities (I / I 0×100) of characteristic peaks are summarized in Table 11.

[0284] [Table 11]

[0285] As shown in Figure 8, the endothermic melting peak of the crystal was confirmed by DSC spectroscopy.

[0286] Experimental Example 5: Confirmation of Crystal Form Stability Using the crystal form produced in Experimental Example 4 (2), stability confirmation tests regarding properties, identification, water content, specific rotation, related substances, and content were conducted for 3 months under accelerated testing conditions (temperature: 40±2℃, relative humidity: 75±5%) and long-term testing conditions (temperature: 25±2℃, relative humidity: 60±5%). The results of the stability confirmation tests are shown in Table 12.

[0287] [Table 12]

[0288] (1) Property tests confirmed that there was no change in the properties of the crystal form under accelerated and long-term conditions.

[0289] (2) Identification tests were performed using infrared spectrophotometrics and liquid chromatography, which are among the general test methods specified in the Korean Pharmacopoeia, and it was confirmed that the crystal form showed the same spectrum as the standard product in both test methods. <Analysis conditions> - Column: Capcdell-pak C18 MG (USPL1), 250 x 4.6 mm, 5 μm - Temperature: 35℃ - Detector: Photodiode array (PDA) detector (measurement wavelength: 225 nm) - Flow rate: 1.0 mL / min - Mobile phase: Buffer / methanol (25:75) - Buffer solution: A buffer solution obtained by dissolving 1.36 g of potassium dihydrogen phosphate in 1,000 mL of distilled water, and then adjusting the pH to 3.0 with phosphoric acid.

[0290] (3) In the case of XRD spectroscopy, it was confirmed that there was no change in crystal form under accelerated and long-term conditions.

[0291] (4) When measured according to the moisture content measurement method, one of the general test methods specified in the Korean Pharmacopoeia, the water content test confirmed that the crystalline form showed almost no water content under accelerated and long-term conditions.

[0292] (5) The specific rotation confirmation test was able to confirm the structural stability of the crystal form under accelerated and long-term conditions.

[0293] (6) Of the general test methods specified in the Korean Pharmacopoeia, stability confirmation tests for the relevant substances were performed by liquid chromatography. The analysis time of the sample solution was measured to three times the retention time of the main peak. The peak areas of the standard solution (0.05 mg / mL) and sample solution (1 mg / mL), excluding all peaks that appeared in the blank test solution, were calculated using a formula. As a result, the stability of the crystalline form of the relevant substances under accelerated and long-term conditions was confirmed. - Analytical conditions: Liquid chromatography analytical conditions for the confirmation test in Experimental Example 5 (2) - Calculation formula: Other individual related substances (%) = (Peak area of ​​each related substance in the test sample × Amount of standard product used × Purity of standard product) / (Peak area of ​​the main peak of the standard solution × Amount of sample used × Dilution ratio)

[0294] (7) For confirmation testing, a methanol solution of the standard product was used as the standard solution (0.2 mg / mL), and a methanol solution of the crystalline form was used as the sample solution (1 mg / mL). The sample solution and standard solution were tested by liquid chromatography, a general test method specified in the Korean Pharmacopoeia, and the peak areas of the standard solution and sample solution were used to calculate the content using the following formula. As a result, there was almost no change in content under accelerated and long-term conditions, confirming the stability of the crystalline form. - Analytical conditions: Liquid chromatography analytical conditions for the confirmation test in Experimental Example 5 (2) - Calculation formula: Other individual related substances (%) = (Peak area of ​​the main peak of the test sample × Amount of standard product used × Purity of the standard product) / [Peak area of ​​the main peak of the standard solution × Amount of sample used × (100 - Water content of the sample)]

Claims

1. When irradiated with a Cu-Kα light source, the compound has an X-ray diffraction (XRD) spectrum including peaks at diffraction angles (2θ) of 5.6°±0.2°, 7.3°±0.2°, 15.7°±0.2°, 17.2°±0.2°, 18.9°±0.2°, 21.2°±0.2°, and 21.9°±0.2° of the following formula (c28): Crystals of the compound.

2. When irradiated with a Cu-Kα light source, the compound has an X-ray diffraction (XRD) spectrum including peaks at diffraction angles (2θ) of 5.5°±0.2°, 7.2°±0.2°, 15.3°±0.2°, 17.2°±0.2°, 17.6°±0.2°, 18.9°±0.2°, and 21.1°±0.2° of the following formula (c28): Crystals of the compound.

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