KR102658761B1 - Method of preparing intermediate for synthesizing sphinosine-1-phosphate receptor agonist - Google Patents

Abstract

The present invention relates to a novel method for preparing an intermediate of the following formula (2) that can be usefully used for the synthesis of sphingosine-1-phosphate receptor agonists.
[Formula 2]

Description

Method of preparing intermediate for synthesizing sphinosine-1-phosphate receptor agonist {Method of preparing intermediate for synthesizing sphinosine-1-phosphate receptor agonist}

The present invention relates to a method for preparing key intermediates for the synthesis of sphingosine-1-phosphate receptor agonists.

Sphingosine-1-phosphate (S1P) is produced through the intracellular ceramide pathway, and ceramide, the starting material of this synthetic pathway, is produced through two production pathways: the de novo biosynthetic pathway and the de novo biosynthetic pathway. It is produced within cells through the degradation of sphingomyelin, a cell membrane component. S1P levels in each tissue are regulated by two biosynthetic sphingosine kinases (SphKs) and two biodegradable S1P phosphatases (S1P lyase and lysophospholipid phosphatases). Sphingosine is phosphorylated by sphingosine kinases. The produced substance, S1P, mediates various cellular responses such as cell proliferation, cytoskeletal organization and migration, adherence and tight junction assembly, and morphogenesis. It is known that They exist in high concentrations (100-1000 nM) in plasma bound to albumin and other plasma proteins, while they exist in low concentrations in tissues.

S1P exhibits various biological functions by binding to the S1P receptor, a G-protein coupled receptor. There are five sub-types of S1P receptors known to date, S1P1 to S1P5, each of which has an endothelial differentiation gene (EDG). ) receptor) are named 1, 5, 3, 6, and 8. These S1P receptors are involved in leukocyte recirculation, neural cell proliferation, morphological changes, migration, endothelial function, vasoregulation, and cardiovascular development ( It is known to be involved in various biological functions such as cardiovascular development.

Many recent studies have shown that S1P signaling through these receptors plays an important role in a series of reactions related to multiple sclerosis, including inflammatory responses and repair processes. In fact, non-selective S1P1 agonists have recently been developed. It is approved as a treatment for multiple sclerosis. S1P receptors are equally widely expressed in many cells involved in causing multiple sclerosis, and S1P1 receptors in particular play a very important role in the immune system. The S1P1 receptor is mainly expressed on the surface of lymphocytes such as T cells and B cells, and reacts with S1P to participate in lymphocyte recycling. Under normal conditions, the concentration of S1P is higher in body fluids than in lymphoid tissue, so lymphocytes leave lymphoid tissues and circulate through efferent lymph according to the difference in S1P concentration. However, when the S1P1 receptor on lymphocytes is down-regulated by S1P1 agonists, egress of lymphocytes from lymphoid tissue does not occur, and eventually autoaggressive behavior occurs, causing inflammation and tissue damage to the CNS. The infiltration of lymphocytes is reduced, resulting in a therapeutic effect on multiple sclerosis. In the case of fingolimod, a non-selective S1P1 agonist approved as an oral multiple sclerosis treatment, when it binds to and activates the S1P1 receptor, paradoxically, the receptor is internalized or degraded from the surface of lymphocytes, resulting in functional S1P1. It acts as antagonism.

In relation to these S1P receptor agonists, Republic of Korea Patent Publication No. 10-2014-0104376 discloses a new compound of the following formula (1) that is effective as an S1P receptor agonist.

[Formula 1]

In Formula 1,

X is C or N,

R1 is H or optionally substituted alkyl,

R2 is H, optionally substituted alkyl, halogen, CN, CF ₃ or COCF ₃ ,

W is C, N, C-alkoxy, C-halogen or C-CN,

이고,Q is CH ₂ O or

ego,

S is selected from the following residues:

In the above structural formula

m, n are 0, 1, 2 or 3,

R3 to R10 are each H, alkyl, halogen, halogeno alkyl or alkoxy alkyl,

R11 is H, ego,

R12 is OH, NH ₂ , or am.

In a specific example of the above document, 1-[1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro- Discloses the preparation of naphthalen-2-ylmethyl]piperidine-4-carboxylic acid (in Scheme 1, “SG35” refers to “1-chloro-6-hydroxy-3,4-dihydro-naphthalene- 2-Carbaldehyde”).

[Scheme 1]

In Scheme 1, the step of preparing 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-naphthalene-2-carbaldehyde If we look at it in detail, it is as follows.

(1-1) Synthesis of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol

1H-indazole-5-carboxylic acid methyl ester was dissolved in dimethylformamide, and isopropyl iodide and sodium hydride were slowly added dropwise at 0°C, followed by stirring at 50°C for 8 hours. A 1N hydrochloric acid solution was added and extracted with ethyl acetate. It was washed with brine, dried over anhydrous magnesium sulfate, and the filtered filtrate was distilled under reduced pressure. It was separated by column chromatography to obtain 1-isopropyl-1H-indazole-5-carboxylic acid methyl ester.

The 1-isopropyl-1H-indazole-5-carboxylic acid methyl ester obtained above was dissolved in dimethylformamide, N-chlorosuccinimide (NCS) was added dropwise, and the mixture was stirred at room temperature for 18 hours. Water was added and extracted with ethyl acetate. After washing with brine and drying with anhydrous magnesium sulfate, the filtered filtrate was distilled under reduced pressure. The residue was separated by column chromatography to obtain 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester.

The 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester obtained above was dissolved in tetrahydrofuran, and then lithium aluminum borohydride was added dropwise. After stirring at room temperature for 1 hour, water, 6N aqueous sodium hydroxide solution, and water were sequentially added. Celite was added dropwise, and the filtered filtrate was distilled under reduced pressure. The residue was separated by column chromatography to obtain (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol.

(1-2) Synthesis of 1-chloro-6-hydroxy-3,4-dihydro-naphthalene-2-carbaldehyde

First, N,N-dimethylformamide (DMF) and phosphorous oxychloride (POCl ₃ ) were added to a solution of 6-methoxy-3,4-dihydronaphthalen-1(2H)-one in toluene. It was added dropwise at ℃ and then stirred at 70℃ for 6 hours. The reaction mixture was poured onto ice and extracted with ethyl acetate. The organic layer was washed with brine, dried and concentrated, and the obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate=20:1 to 10:1) to produce 1-chloro-6-methoxy-3,4- Dihydro-2-naphthalenecarbaldehyde was obtained.

Next, aluminum chloride (AlCl ₃ ) was added to a solution of 1-chloro-6-methoxy-3,4-dihydro-2-naphthalenecarbaldehyde in dichloromethane at 0°C, and then incubated at 50°C for 6 hours. It was stirred. The reaction mixture was poured onto ice and extracted with ethyl acetate. The organic layer was dried and concentrated, and the obtained residue was purified by silica gel column chromatography (hexane: tetrahydrofuran = 5:1 to 3:1) to obtain 1-chloro-6-hydroxy-3,4-dihydro-2. -Naphthalenecarbaldehyde was obtained.

(1-3) Synthesis of 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-naphthalene-2-carbaldehyde

(3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol and 1-chloro-6-hydroxy-3,4-dihydro-2-naphthalenecarbaldehyde obtained above were added to toluene. After dissolving, tributylphosphine (PBu ₃ ) and 1,1'-(azodicarbonyl)dipiperidine (ADD) were added dropwise. After stirring at room temperature for 18 hours, an excess amount of hexane was added. After filtration and distillation under reduced pressure, the residue was purified by column chromatography to obtain 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-naphthalene- 2-Carbaldehyde was obtained.

However, the above reaction may have the following problems in producing clinical API.

First, in the process of synthesizing 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester, there may be problems depending on the production rate of the N2 isomer, and (3-chloro-1-isopropyl Lithium aluminum hydride (LAH), used in the synthesis of -1H-indazol-5-yl)-methanol, is very limited in terms of stability for use in large scale synthesis and has the disadvantage of being easily decomposed in moisture. .

In addition, during the Vilsmeier-Haack reaction to obtain 1-chloro-6-methoxy-3,4-dihydro-2-naphthalenecarbaldehyde, a heat generation problem occurs as the reaction is performed at a high temperature of 70°C. It can happen. In addition, in the reaction to obtain 1-chloro-6-hydroxy-3,4-dihydro-2-naphthalenecarbaldehyde, there may be stability problems due to reactor contamination due to use of AlCl ₃ or use of hazardous reagents. In addition, when using AlCl ₃ , there is a stability problem due to batch failure due to reaction stoppage or side reaction, and the total yield is 70%, so there is a need to improve yield.

Additionally, coupling of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol with 1-chloro-6-hydroxy-3,4-dihydro-naphthalene-2-carbaldehyde 1,1'-(azodicarbonyl)dipiperidine (ADD) used in the reaction is undesirable in terms of low yield and cost.

Accordingly, the inventors of the present invention used the 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-naphthalene-2-carbaldehyde and In order to mass produce the same intermediate compound with high yield through a simpler process, a new synthesis method as shown in Scheme 2 below has been designed.

[Scheme 2]

In Scheme 2, the step of preparing 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-6-ylmethoxy)-3,4-dihydro-naphthalene-2-carbaldehyde In detail, it is as follows (“SG26” in Scheme 2 refers to “6-hydroxy-3,4-dihydro-2H-naphthalen-1-one”).

(2-1) Synthesis of 5-bromomethyl-3-chloro-1-isopropyl-1H-indazole

Dichloromethane (DCM), methyl tert-butyl ether (MTBE), and (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol were added to the reactor, and the internal temperature was cooled to 0°C. PBr ₃ was slowly added dropwise to the reaction product over 70 minutes, and the reaction proceeded for 80 minutes. Ion-pair chromatography (IPC) was performed using HPLC, and the reaction was completed (3% > (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol). The reaction was terminated by slowly adding sodium hydroxide over 120 minutes. DCM was added to the reaction mixture and stirred for 30 minutes, the layers were separated to remove the aqueous layer, the organic layer was washed with water, and the organic layer was distilled under reduced pressure to obtain 5-bromomethyl-3-chloro-1-isopropyl-1H-indazole. got it

(2-2) Synthesis of 6-hydroxy-3,4-dihydro-2H-naphthalen-1-one

HBr and 6-methoxy-3,4-dihydro-2H-naphthalen-1-one dissolved in water were added to the reactor and refluxed for 52 hours at an external temperature of 120°C. IPC was performed using HPLC and the reaction was completed (3% > 6-methoxy-3,4-dihydro-2H-naphthalen-1-one), the internal temperature was cooled to 10°C, and the resulting solid was Filtered. After washing with water and drying with nitrogen, 6-hydroxy-3,4-dihydro-2H-naphthalen-1-one (SG26) was obtained.

(2-3) Synthesis of 6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-2H-naphthalen-1-one

Add 5-bromomethyl-3-chloro-1-isopropyl-1H-indazole, 6-hydroxy-3,4-dihydro-2H-naphthalen-1-one, K ₂ CO ₃ and DMF to the reactor. and reacted for 3 hours at an internal temperature of 25°C. IPC was performed using HPLC, and 5% of 6-hydroxy-3,4-dihydro-2H-naphthalen-1-one remained, resulting in 5-bromomethyl-3-chloro-1-isopropyl-1H- Indazole was additionally added to complete the reaction (1% > 6-hydroxy-3,4-dihydro-2H-naphthalen-1-one). Water was added to the reactor, the internal temperature was cooled to 0°C, and the produced solid was filtered. The filtered solid was sequentially washed with water and MTBE and then dried with nitrogen to obtain 6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-2H. -Naphthalen-1-one was obtained.

(2-4) Synthesis of 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-6-ylmethoxy)-3,4-dihydro-naphthalene-2-carbaldehyde

Phosphoryl chloride (POCl ₃ ) was added to the reactor and the internal temperature was cooled to 0°C. DMF was slowly added dropwise, stirred for 2 hours at an internal temperature of 50°C, and then 6-(3-chloro-1-isopropyl-1H-indazol-5-ylmethoxy)-3,4-dihydro-2H-naphthalene. -1-one was added and reacted at an internal temperature of 50°C for 3 hours. Since excessive HCl gas was generated during the reaction, a NaOH trap was installed and a vent line was installed to neutralize it. IPC was performed using HPLC, and the reaction was completed. After cooling the internal temperature to 0°C, cold water, hexane (Hex), and MTBE were added to another reactor, and the above reaction mixture was slowly added dropwise for 90 minutes to generate crystals. . The resulting solid was filtered, washed sequentially with water and MTBE/HEX mixed solvent, and dried to produce 1-chloro-6-(3-chloro-1-isopropyl-1H-indazol-6-ylmethoxy). -3,4-dihydro-naphthalene-2-carbaldehyde was obtained.

According to the above reaction, not only can the generation rate of the N2 isomer be improved and the heat generation problem caused by the Vilsmeyer-nuclear reaction solved, but the coupling reaction can also be performed without using ADD, sphingosine It is expected that the key intermediate in the synthesis of -1-phosphate receptor agonist can be mass-produced through a simpler process while ensuring the stability of the compound and the stability of the manufacturing conditions.

Accordingly, the purpose of the present invention is to provide a suitable method for producing the compound of Formula 2, which is a key intermediate in a new synthesis method of an excellent sphingosine-1-phosphate receptor agonist, in high yield.

[Formula 2]

In Formula 2,

R1 is hydrogen or substituted or unsubstituted alkyl,

R2 is hydrogen, substituted or unsubstituted alkyl, halogen, CN, CF ₃ or COCF ₃ ,

X is C or N,

L is a leaving group.

In order to achieve the above objectives,

One aspect of the present invention provides a method for producing an intermediate compound of Formula 2 below, which includes substituting the alcohol group of the compound of Formula 3 with a leaving group in an ether-based single solvent.

[Formula 2]

[Formula 3]

In Formula 2 and Formula 3,

R1 is hydrogen or substituted or unsubstituted alkyl,

R2 is hydrogen, substituted or unsubstituted alkyl, halogen, CN, CF ₃ or COCF ₃ ,

X is C or N,

L is a leaving group.

When the 'alkyl' is substituted alkyl, there may be one or more substituents, and the substituents are each independently a group consisting of halogen, cyano, hydroxy, alkyloxy, oxo, unsubstituted sulfonyl, and sulfonyl substituted with alkyl. It may be selected from .

According to one embodiment of the present invention, R1 in the above formula is hydrogen, or substituted or unsubstituted alkyl of C ₁ -C ₆ , and R2 is hydrogen, substituted or unsubstituted alkyl of C ₁ -C ₆ , halogen, CN, It may be CF ₃ or COCF ₃ .

According to another embodiment of the present invention, R1 may be substituted or unsubstituted alkyl of C ₁ -C ₄ , and R2 may be halogenyl (F, Cl, Br or I).

According to one embodiment of the present invention, the leaving group (L) is a reactive group that provides a substitution site to the compound of Formula 2 when the compound of Formula 2 undergoes a substitution reaction with an alcohol-based compound, but is not limited thereto, for example, chlorine (Cl), bromine (Br), iodine (I), methanesulfonate (Oms), p-toluenesulfonate (OTs), and trifluoromethanesulfonate (OTf).

According to another embodiment of the present invention, L may be Br.

The present invention provides a compound of Formula 2, which is a key intermediate in the synthesis of a sphingosine-1-phosphate receptor agonist, by replacing the terminal alcohol group of the compound of Formula 3 with a leaving group. Specifically, the step of replacing the alcohol group with a leaving group. '(hereinafter referred to as 'leaving group substitution step') has a technical feature of significantly lowering the production rate of the N2 isomer by performing it in an ether-based single solvent.

In the present invention, the 'single solvent' indicates that only one type of solvent is included in the reactor for the leaving group substitution reaction. At this time, the inclusion of a trace amount of heterogeneous solvent at a level that does not substantially affect the yield of the reaction product in the reactor for the leaving group substitution reaction is not excluded from the single solvent. For example, based on the volume of the total solvent for the leaving group substitution reaction, 5 vol% or less, 4 vol% or less, 3 vol% or less, 2 vol% or less, 1 vol% or less, 0.5 vol% or less, or 0 vol% ( In other words, the inclusion of heterogeneous solvents in an amount of (not included at all) can also be viewed as the use of a single solvent.

The ether-based solvent is not limited thereto, but includes, for example, dialkyl solvents such as diethyl ether, dipropyl ether, dibutyl ether, diisoamyl ether, ethyl methyl ether, methyl propyl ether, methyl butyl ether, and ethyl propyl ether. ether-based solvent; Arylalkyl ether-based solvents such as diphenyl ether and anisole; Or cyclic ether-based solvents such as tetrahydrofuran and tetrahydropyran.

In one embodiment according to the present invention, the ether-based single solvent may be methyl tert-butyl ether (MTBE).

In another embodiment according to the present invention, the compound of Formula 3 may be mixed with MTBE, cooled to 0°C, and then reacted with PBr ₃ to obtain the compound of Formula 2.

In another embodiment according to the present invention, the compound of Formula 3 is mixed with MTBE, cooled to 0°C, reacted with PBr _3, and upon completion of the reaction, washed with water and filtered to obtain the compound of Formula 2. You can.

In another aspect according to the invention, the compound of formula 3 is prepared according to a method comprising the following steps:

1) introducing R1 and R2 substituents into the compound of formula 4 below and crystallizing it with a crystallization solvent containing an alcohol solvent to obtain a compound of formula 5, and

2) Reacting the compound of Formula 5 with a reducing agent to obtain a compound of Formula 3:

[Formula 4]

[Formula 5]

In Formula 4 and Formula 5,

R1, R2 and X are as defined in Formula 2 or Formula 3,

R3 is substituted or unsubstituted alkyl of C ₁ -C ₆ .

According to one embodiment of the present invention, R3 may be substituted or unsubstituted alkyl of C ₁ -C ₄ .

According to another embodiment of the present invention, R3 may be a methyl group.

In step 1), R1 and R2 substituents are introduced into the compound of Formula 4 and crystallized using a crystallization solvent containing an alcohol solvent to prepare the compound of Formula 5.

The alcohol solvent for crystallization is not limited thereto, but may be, for example, one or more solvents selected from methanol, ethanol, isopropyl alcohol, and butanol.

In one embodiment according to the present invention, the solvent for crystallization may be a mixed solvent of an alcohol solvent and water. Using a mixed solvent of alcohol solvent and water as the crystallization solvent may have the effect of reducing the N2 isomer yield.

In another embodiment according to the present invention, the mixed solvent for crystallization has a volume ratio of alcohol solvent and water of 5:1 to 1:5, 4:1 to 1:4, and 3:1 to 3:1 in terms of yield of Chemical Formula 5. It may be used 1:3, 2:1 to 1:2, 2:1 to 1:1, or 1.5:1 to 1:1.

In one embodiment according to the present invention, the solvent for crystallization may be a mixed solvent of ethanol and water. Specifically, the ethanol and water may be used in a volume ratio of EtOH:H ₂ O of 2:1 to 1:2, 2:1 to 1:1, 1.5:1 to 1:1, or 1:1.

In another embodiment according to the present invention, when the crystallization solvent is a mixed solvent of an alcohol solvent and water, the alcohol solvent and water may be added sequentially or simultaneously during crystallization.

In another embodiment according to the present invention, an alcohol solvent, such as EtOH, is added to the reaction product into which the substituent is introduced, cooled to 0° C. to 20° C., and then water is added and crystallized to obtain a compound of Formula 5. It may be.

In one embodiment according to the present invention, the reaction product into which the substituent is introduced may be purified and then crystallized before the crystallization. By purifying the reaction product, unreacted residual compounds used in the reaction can be removed, thereby improving the crystallization yield.

The purification may be performed using, for example, a polar solvent, and the polar solvent may be, for example, a polar organic solvent, water, or a mixed solvent thereof.

The polar organic solvent is not limited thereto, but may be, for example, one or more solvents selected from ethyl acetate, hexane, and dichloromethane.

In another embodiment according to the present invention, the reaction product into which the substituent is introduced may be purified using a mixed solvent of ethyl acetate (EtOAc) and water and then crystallized to obtain the compound of Formula 5.

In another embodiment according to the present invention, the reaction product into which the substituent is introduced is cooled to 25°C to 35°C, and then the aqueous layer is removed using ethyl acetate and water in a volume ratio of 2:1 to 1:2, It may be crystallized after removing polar solvents other than water.

In one embodiment according to the present invention, the reaction product into which the substituent is introduced is purified using a mixed solvent of a polar organic solvent and water and then crystallized, so that K ₂ CO ₃ used in the reaction for introducing the substituent is together during crystallization of the reaction product. This may be to improve the purity of the crystals by preventing precipitation or reducing the amount of precipitation.

In the present invention, the substituents of R1 and R2 may be substituted by R1 and then R2, R2 and then R1, or R1 and R2 may be substituted simultaneously.

In one embodiment according to the present invention, R2 may be substituted before R1 in the compound of Formula 4. In the case where bulky R1 is substituted first in the compound of Formula 4, for example, if bulky R1 is substituted first at position 3 of indazole where It can be.

In step 2), the compound of Formula 5 is reacted with a reducing agent to obtain the compound of Formula 3.

The reducing agent used in step 2) may be a common reducing agent capable of reducing an ester group to alcohol, for example, sodium borohydride (NaBH ₄ ), lithium borohydride (LiBH ₄ ), borane (BH ₃ ) and diisobutylaluminum hydride (DIBAH) may be used, but are not limited thereto.

In one embodiment according to the present invention, during the reduction reaction of the compound of Formula 5, a reducing agent and a solvent may be added together at the beginning of the reaction, and then additional reducing agent may be added as the reaction progresses. Additionally, when adding additional reducing agent, the solvent that was added at the beginning of the reaction can be added together, or only the reducing agent can be added without adding the solvent.

In another embodiment according to the present invention, during the reduction reaction of the compound of Formula 5, a reducing agent and a solvent such as MeOH are added together at the beginning of the reaction, and then, as the reaction progresses, a reducing agent is added to react the remaining compound of Formula 5. It can have the effect of further improving the yield of the compound of Formula 3 obtained by adding methanol.

In one embodiment according to the present invention, after the reduction reaction of the compound of Formula 5 is completed, the reaction product may be purified to obtain the compound of Formula 3. At this time, organic solvents such as dichloromethane (DCM), isopropylacetate, and ethyl acetate, water, or a mixed solvent thereof may be used to purify the reaction product of the reduction reaction.

In another embodiment according to the present invention, after the reduction reaction of the compound of Formula 5 is completed, DCM and water are added to remove the water layer, which can have the effect of further improving the yield of the compound of Formula 3.

The compound prepared according to the present invention can be used as a key intermediate for the synthesis of sphingosine-1-phosphate receptor agonist. The compound prepared according to the present invention can be used as a main intermediate in the known synthesis method of sphingosine-1-phosphate receptor agonist, and can also be used as a main intermediate in a new synthesis method developed after the filing of the present application. , the use of the present invention is not limited to a specific method of synthesizing the sphingosine-1-phosphate receptor agonist.

In addition, the compounds prepared according to the present invention can be used for other purposes other than the synthesis of sphingosine-1-phosphate receptor agonists, and the use of the present invention is not limited to the synthesis of sphingosine-1-phosphate receptor agonists. That is not the case.

Using the production method of the present invention, the compound of Formula 2 can be mass-produced with high yield.

Hereinafter, to aid understanding of the present invention, it will be described in detail through examples. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the following embodiments. Embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the field to which the present invention pertains.

Example 1-1. Synthesis of 3-Chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester

1H-Indazole-5-carboxylic acid methyl ester (6.2 kg, 35.19 mol), N-chlorosuccinimide (NCS, 5.64 kg, 42.2 mol), dimethylform After amide (DMF, 31.0 ml, 5 fold) was added to the reactor, the internal temperature of the reaction mixture was raised to 75°C and reacted for 1.5 hours.

Reactive ion pair chromatography (IPC) was performed using HPLC, and the reaction was completed (1H-indazole-5-carboxylic acid methyl ester: N/D). The external temperature was set to 0°C and cooling was performed for 60 minutes. While maintaining the internal temperature of the reactor at 50℃, add K ₂ CO ₃ (10.7 kg, 77.4 mol) and 2-iodopropane (8.98 kg, 52.8 mol) and proceed with the alkylation reaction at 60℃ for 120 minutes. did.

As a result of the reaction IPC using HPLC, 19.3% of methyl 3-chloro-1H-indazole-5-carboxylate remained, and K ₂ CO ₃ (2.14 kg, 15.5 mol) and 2-iodopropane (1.80 kg, 10.6 mol) was added twice. Since 2.4% of methyl 3-chloro-1H-indazole-5-carboxylate remained, K ₂ CO ₃ (1.08 kg, 7.75 mol) and 2-iodopropane (0.9 kg, 5.3 mol) were added to terminate the reaction. I ordered it. (1% > methyl 3-chloro-1H-indazole-5-carboxylate).

The reaction mixture was cooled to 30°C, water (43.4 L) and EtOAc (43.4 L) were added, stirred for 30 minutes, layers were separated to remove the aqueous layer, and water (31.0 L) was added to further wash the organic layer. After removing EtOAc by reduced pressure distillation, EtOH (24.8 L) was added and the temperature was raised to 40°C to form a clear solution. The reactor was cooled and the internal temperature was maintained at 20°C, and then water (24.8 L) was slowly added dropwise to form crystals. The resulting solid was aged for 30 minutes, the crystals were filtered, washed twice with water (31.0 L), and dried under nitrogen to obtain the title compound (6.56 kg, net yield 64.9%).

^1H NMR (400MHz, CDCl ₃ ): 1.58 (d, 6H), 3.96 (s, 3H), 4.81 (m, 1H), 7.42 (d, 1H), 8.06 (dd, 1H), 8.44 (s, 1H) ).

Example 1-2. (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol Synthesis of ((3-Chloro-1-isopropyl-1H-indazol-5-yl)-methanol)

THF (34.2 L, 6 fold) and 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester (Example 1-1, 5.7 kg, 22.6 mol) were added to the reactor and the internal temperature was adjusted to The temperature was raised to 60°C. NaBH ₄ (1.68 kg, 44.4 mol) and MeOH (5.7 L, 1 fold) were slowly added dropwise to the reaction product over 80 minutes, and the reaction proceeded for 30 minutes. NaBH ₄ (0.44 kg, 11.6 mol) was added at 90-minute intervals, and MeOH (1.69 L, 0.3 fold) was added twice, reacted for 30 minutes, and then IPC was performed using HPLC.

14.3% of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester remained, so only NaBH ₄ (0.22 kg, 5.8 mol) was added and reacted for 120 minutes. With 2.5% of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester remaining, the reaction was terminated and cooling was performed to bring the internal temperature to 10°C.

B-complex (a complex produced by NaBH ₄ in which boron is conjugated to the alcohol of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol) and residual NaBH ₄ To remove 3N HCl (39.3 kg) was slowly added over 60 minutes to maintain the pH of the reaction solution at 3.0 and the solvent was removed by distillation under reduced pressure.

DCM (28.5 L) and water (57.0 L) were added to the residue, the layers were separated, the aqueous layer was removed, and the title compound (4.32 kg, net yield 85%) was obtained by additional washing with water (42.8 L) and distillation under reduced pressure. Obtained.

^1H NMR (400MHz, CDCl ₃ ): 1.5~1.7 (m, 6H), 1.82 (m, 1H), 3.72 (m, 1H), 4.70~5.10 (m, 2H), 7.30~7.50 (m, 2H) , 7.62 (s, 1H).

Example 1-3: Synthesis of 5-Bromomethyl-3-chloro-1-isopropyl-1H-indazole

MTBE (43.3 L, 8 fold) and (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol (Example 1-2, 4.32 kg, 19.3 mol) were added to the reactor and the internal temperature was adjusted to was cooled to 0°C. PBr ₃ (3.64 kg, 13.5 mol) was slowly added to the reaction mixture over 90 minutes, and the reaction proceeded for 180 minutes.

IPC was performed using HPLC, and the reaction was completed (Example 1-2: N/D). 1.5N NaOH (34.7 L) was slowly added over 60 minutes and stirred for 30 minutes to terminate the reaction. Water (21.7 L) was added to the reaction mixture, stirred for 10 minutes, and the layers were separated to remove the aqueous layer, washed additionally with water (17.3 L), and the organic layer was distilled under reduced pressure to synthesize the title compound (4.97 g, Net yield 90.0%). did.

^1H NMR (400MHz, CDCl ₃ ): 1.53 (d, 6H), 4.7 (s, 2H), 4.88 (m, 1H), 7.51-7.6 (m, 2H), 7.68 (s, 1H).

Experimental Example 1. Evaluation of the reaction solvent during the reaction of replacing the alcohol of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol with a leaving group

Reference Synthesis Example 1

During the substitution reaction, a mixed solvent of DCM/MTBE 4:1 was used, and when extracting the reaction product, DCM was used instead of water, and 5-bromomethyl-3-chloro- 1-Isopropyl-1H-indazole was obtained.

When the leaving group substitution reaction was performed under DCM and MTBE during the preparation of Reference Synthesis Example 1, the phenomenon of sticky oil being coated on the reactor wall was continuously observed, and this was confirmed to dissolve and disappear upon completion of the reaction with NaOH. I was able to.

As a result of HPLC analysis to confirm the components of the viscous oil produced during the reaction, it was confirmed that the ratio of N2:N1 isomers was very high, with the ratio of N2 isomers being 1.5:1. In addition, it was confirmed that it was not substituted with a leaving group and remained in the form of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol.

According to these results, using MTBE as a single solvent during the reaction of substituting the alcohol group of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol with a leaving group is effective in removing N2 isomers and improving yield. It was confirmed that it was possible.

During the reaction of substituting the alcohol group of (3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol with a leaving group, the N2 isomer and the title compound ((3-chloro-1- The results of measuring the yield of isopropyl-1H-indazol-5-yl)-methanol) are shown in Table 1 below.

In Table 1 below, “SG15” represents “(3-chloro-1-isopropyl-1H-indazol-5-yl)-methanol” and “SG20” represents “ 5-bromomethyl-3-chloro- It represents “1-isopropyl-1H-indazole”.

Entry Reaction and extraction conditions N2 isomer
HPLC
(%PAR) SG20
HPLC
(%PAR) One SG15 (for entry 2,3,4) 15.6 84.4 2 DCM/MTBE = 4: 1 reaction proceeds, DCM 2 folds are added to dissolve stick oil, DCM is extracted 14.0 86.0 3 DCM/MTBE = 4: 1 reaction proceeds, extract MTBE by adding 3 fold 2.4 97.6 4 MTBE 8 fold reaction progresses, MTBE extraction 1.3 98.7 5 SG15 (for entry 6,7) 20.6 79.4 6 DCM/MTBE = 4: 1 reaction proceeds, extract MTBE by adding 3 fold 3.8 96.2 7 MTBE 8 fold reaction progresses, MTBE extraction 1.7 98.3

As can be seen in Table 1 above, it was confirmed that the N2 isomer could be reduced to less than 2% when the substitution reaction of alcohol with a leaving group was performed in the MTBE single solvent and extracted using MTBE.

Experimental Example 2. Evaluation of crystallization solvents in the synthesis of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester 1

Reference Synthesis Example 2

After completing the alkylation reaction, 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester was prepared in the same manner as in Example 1-1, except that water was added and crystallized without a purification step. Obtained.

Reference Synthesis Example 3

After purifying the reaction mixture and removing EtOAc, 3-chloro-1-isopropyl-1H-indazole-5- was obtained in the same manner as in Example 1-1 except that crystallization was performed by adding an equal amount of n-hexane instead of EtOH. Carboxylic acid methyl ester was obtained.

Reference Synthesis Example 4

After purifying the reaction mixture and removing EtOAc, 3-chloro-1-isopropyl-1H-indazole was prepared in the same manner as in Example 1-1 except that crystallization was performed by adding an equal amount of isopropyl alcohol (IPA) instead of EtOH. -5-Carboxylic acid methyl ester was obtained.

As a result of comparing the content of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester obtained according to Example 1-1 and Reference Synthesis Examples 2 to 4 and the content of N2 isomer, In addition to Reference Synthesis Example 2, which did not use an organic solvent, Examples 1-2 and Reference Synthesis Examples 3 and 4 were all confirmed to be excellent in terms of N2 isomer removal rate.

In particular, in the case of Example 1-2 using a mixed solvent of EtOH and water, it was confirmed that it showed excellent effects in terms of both the removal rate of the N2 isomer and the recovery rate of the title compound.

The results of measuring the yield of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester according to the crystallization solvent after alkylation reaction and purification are shown in Tables 2 and 3 below.

In Tables 2 and 2 below, “SG10” represents “3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester”.

Entry Crystallization method (fold) HPLC ratio N1(%) N2(%) - Use after SG10 purification
(Purification conditions: H ₂ O (10) / EA (10) twice → H ₂ O (3) washed with water and then distilled) 77.6 22.4 One EtOH (5) → H ₂ O (10) slow addition for 1h → aging for 1h → filter 87.4 12.6 2 IPA (5) → H ₂ O (10) slow addition for 1h → aging for 1h → filter 90.6 9.4 3 t-BuOH (5) → H ₂ O (10) slow addition for 1h → aging for 1h → filter 90.4 9.6 4 EA (1) → H ₂ O (10) slow addition for 1h → 5 ℃ → aging for 1h → filter 84.4 15.6 5 t-BuOH (1.5) → H ₂ O (4.5) slow addition for 1h → aging for 1h → filter 83.9 16.1 6 DCM (0.1) → H ₂ O (10) slow addition for 1h → aging for 1h → filter 87.1 12.9 7 EtOH (1.5), DCM (0.1) → H ₂ O (4.5) slow addition for 1h → aging for 1h → filter 87.5 12.5

Entry Scale
(g) crystallization conditions
(Fold) Purity (HPLC % PAR) -288 nm NY
(%) F/C mother liquor N2
Isomer SG10 N2 Isomer SG10 0 - SG10 17.6 82.4 - - - One 2 EtOH (3) →heating 50 ℃ →H ₂ O (5) dropwise, stirring 1 hr, filter 10.3 89.7 59.6 40.4 - 2 2 HEX (3) heating 50 ℃ →H ₂ O (3) dropwise, stirring 1 hr, filter 7.6 92.4 40.3 59.7 - 3 2 IPA (3) heating 50 ℃ →H ₂ O (5) dropwise, stirring 1 hr, filter 9.4 90.6 52.2 47.8 - 4 30 EtOH (3) heating 50 ℃ →H ₂ O (3) dropwise, stirring 1 hr, filter 5.6NMR (4.8) 94.4 53.2 46.8 84.2 5 30 EtOH (3) heating 50 ℃ →H ₂ O (4) dropwise, stirring 1 hr, filter 9.3 NMR (8.0) 90.7 59.8 40.2 86.0 6 30 EtOH (3) heating 50 ℃ →H ₂ O (3) dropwise, 0 ℃, stirring 1 hr, filter 9.3
NMR (9.6) 90.7 - - 88.6 7 30 EtOH (3) heating 50 ℃ →H ₂ O (4) dropwise, 0 ℃, stirring 1 hr, filter 11.3
NMR (11.0) 88.7 69.5 30.5 92.3

In the experiment of Table 2 above, when t-BuOH or DCM was used as the crystallization solvent, aggregation was observed during crystallization, and when IPA was used, in terms of net yield, 3-chloro-1-isopropyl- An increase in the loss of 1H-indazole-5-carboxylic acid methyl ester was observed. In addition, as can be seen in Table 3 above, 3-chloro-1-isopropyl containing about 17% of N2 isomer As a result of crystallization using -1H-indazole-5-carboxylic acid methyl ester using EtOH, IPA, and n-hexane as crystallization solvents, it was confirmed that about 10% of the N2 isomer was removed.

Through Tables 2 and 3 above, it was confirmed that both N2 isomer removal and recovery rate were excellent when EtOH was used as the crystallization solvent. In addition, it was confirmed that the greater the amount of H ₂ O used as an anti-solvent and the lower the aging temperature, the lower the N2 isomer removal effect.

Experimental Example 3. Evaluation of crystallization solvents in the synthesis of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester 2

Reference Synthesis Example 5

3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester was prepared in the same manner as in Example 1-1 except that EtOH:H ₂ O was used in a volume ratio of 3:7 during crystallization. Obtained.

Reference Synthesis Example 6

3-Chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester was prepared in the same manner as Example 1-1 except that EtOH:H ₂ O was used in a volume ratio of 1:1 during crystallization. Obtained.

Reference Synthesis Example 7

3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester was prepared in the same manner as in Example 1-1 except that EtOH:H ₂ O was used in a volume ratio of 7:3 during crystallization. Obtained.

As a result of comparative evaluation of the content of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester obtained according to Reference Synthesis Examples 5 to 7 and the content of N2 isomer, as the amount of EtOH used increases, , it was confirmed that as the amount of H ₂ O used decreased, the content of residual N 2 isomers decreased.

In particular, when the amount of EtOH used increased, a large yield loss phenomenon was observed, and in terms of reduction of N2 properties and recovery of the title compound, EtOH and _H2O were each used in the amount of 4 fold of the reaction product in a ratio of 1:1. It was confirmed that its use was effective.

The results of measuring the yield according to the volume ratio of EtOH and H ₂ O used in the crystallization of 3-chloro-1-isopropyl-1H-indazole-5-carboxylic acid methyl ester are shown in Table 4 below.

Entry EtOH (fold) H ₂ O (fold) N2 isomer
(%PAR) NMR assay
（％） NY
（％） One 3 7 14.7 82.4 62.8+α 2 7 7 2.00 96.8 77.7 3 5 5 4.50 90.6 80.0 4 5 5 5.10 92.9 81.2 5 5 5 4.74 89.3 80.4 6 7 3 1.80 99.8 52.9 7 3 3 5.60 89.6 84.0

Claims (8)

A method for producing an intermediate compound of Formula 2 below, comprising the step of substituting an alcohol group of a compound of Formula 3 with a leaving group in an ether-based single solvent,
The preparation method of the compound of formula 3 is prepared according to a method comprising the following steps:
1) introducing R1 and R2 substituents into the compound of formula 4 below and crystallizing it with a crystallization solvent containing an alcohol solvent to obtain a compound of formula 5, and
2) Reacting the compound of Formula 5 with a reducing agent to obtain a compound of Formula 3:
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 2 to 5,
R1 is hydrogen or substituted or unsubstituted alkyl,
R2 is hydrogen, substituted or unsubstituted alkyl, halogen, CN, CF ₃ or COCF ₃ ,
R3 is substituted or unsubstituted alkyl of C ₁ -C ₆ ,
X is C or N,
L is a leaving group,
The substituted alkyl has at least one substituent selected from the group consisting of halogen, cyano, hydroxy, alkyloxy, oxo, unsubstituted sulfonyl, and sulfonyl substituted with alkyl. In claim 1,
A production method wherein the ether-based single solvent is a dialkyl ether-based solvent, an arylalkyl ether-based solvent, or a cyclic ether-based solvent. In claim 1,
A manufacturing method wherein the ether-based single solvent is methyl tertiary butyl ether (MTBE). In claim 1,
In step 1), the crystallization solvent is a mixed solvent of alcohol solvent and water. In claim 4,
In step 1), the crystallization solvent is a mixed solvent of alcohol solvent and water in a volume ratio of 2:1 to 1:1. In claim 5,
A manufacturing method wherein the alcohol solvent is EtOH. In claim 1,
A production method in which the compound of Formula 3 is obtained by reducing the compound of Formula 5 in step 2) and then purifying it with a mixed solvent of a polar organic solvent and water. In claim 1,
R1 is substituted or unsubstituted alkyl of C ₁ -C ₄ ,
R2 is halogen,
L is a leaving group selected from chlorine (Cl), bromine (Br), iodine (I), methanesulfonate (Oms), p-toluenesulfonate (OTs), and trifluoromethanesulfonate (OTf) Phosphorus manufacturing method.