WO2023202568A1 - Quaternary ammonium salt compound, and preparation method therefor and application thereof - Google Patents

Abstract

Disclosed in the present invention are a quaternary ammonium salt compound, and a preparation method therefor and an application thereof. The general formula of the quaternary ammonium salt compound in the present invention is as follows: formula. According to the quaternary ammonium salt compound in the present invention, existing nitro labeling precursors are further improved, and aromatic amines are selectively quaternized, so that a labeling precursor having high stability and high labeling efficiency is prepared. By means of the labeling precursor, specific ligands targeting biological macromolecules in the body, especially targeting α7nAChR, can be prepared, and thus can be used as a radioactive or non-radioactive imaging agent for the diagnosis or treatment of Alzheimer's disease or other related diseases.

Description

A kind of quaternary ammonium salt compound and its preparation method and application Technical field

The present invention relates to the technical field of labeling precursor compounds, and in particular to a quaternary ammonium salt compound and its preparation method and application.

Background technique

Nicotinic acetylcholine receptor (nAChR) is a type of gated transmitter ion channel that is widely distributed in the central and peripheral nervous systems and is related to a variety of physiological functions. Among them, the function, distribution and quantity of α7 nicotinic acetylcholine receptor (α7nAChR) are closely related to a variety of degenerative diseases, and it is a popular target for early diagnosis and evaluation of Alzheimer's disease (AD). Imaging techniques such as PET/SPECT can quantitatively study α7nAChR in the human brain.

Although a variety of ¹⁸ F or ¹¹ C-labeled α7nAChR radioligands have been reported in the literature, there is still no commercially available α7nAChR radioactive imaging agent. Our research team has been engaged in the research of α7nAChR for a long time, and has successively reported a variety of single-photon ¹²⁵ I and positron ¹⁸ F-labeled α7nAChR radioactive ligands. Among them, the radioactive ligand [ ^18F ]YLF (shown in Figure 1) has suitable radiochemical properties, strong α7nAChR affinity (K _i = (2.98±1.14) nmol/L), and high selectivity. , excellent stability and suitable intra-brain dynamic properties. At the same time, [ ¹⁸ F]YLF has excellent safety profile and is expected to be successfully developed into an α7nAChR PET imaging agent for the market.

The existing labeling precursors and labeling conditions of [ ^18F ]YLF are shown in Figure 1: the labeling precursor is a nitro compound; the labeling method is 18F ^- as a nucleophile, K ₂ C ₂ O ₄ as a base, DMSO As solvent, Kryptofix222 as phase transfer catalyst, reaction at 120℃～160℃ for 10～30min. In the study, it was found that this kind of nitro labeling precursor has the following shortcomings: the nitro labeling precursor is unstable at room temperature, the labeling conditions are harsh, and the labeling efficiency is not high. This limits [ ¹⁸ F]YLF to a certain extent. clinical promotion.

Therefore, it is necessary to prepare a labeling precursor with high stability and high labeling efficiency.

Contents of the invention

In view of the limitations of the above-mentioned prior art, the present invention provides a quaternary ammonium salt compound and its preparation method and application. The quaternary ammonium salt compound of the present invention further improves the existing nitro labeling precursor and selectively quaternizes the aromatic amine, thereby preparing a labeling precursor with high stability and high labeling efficiency. The labeled precursor can be used to prepare specific ligands that target biological macromolecules in the body, especially α7nAChR; thus, they can be used as radioactive or non-radioactive ligands for the diagnosis or treatment of Alzheimer's disease or other related diseases. .

In order to achieve the above objects, the present invention adopts the following technical solutions:

One of the objects of the present invention is to provide a quaternary ammonium salt compound, the general formula of the quaternary ammonium salt compound is as shown in Formula I:

or its stereoisomers, tautomers or pharmaceutically acceptable salts, prodrugs, hydrates, solvates, isotopically labeled derivatives,

Wherein, M is selected from C=O or

Among R ₁ and R ₂ , one is selected from hydrogen and the other is selected from R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted, saturated or unsaturated C1 to C20 hydrocarbon groups;

R ₇ includes at least one tertiary amine group;

Z is selected from anions.

Formula I can be

Preferably, R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted, saturated or unsaturated C1 to C10 hydrocarbon groups; more preferably, R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted. substituted, saturated or unsaturated C1～C5 hydrocarbon group; further preferably, R ₃ , R ₄ and R ₅ are all unsubstituted hydrocarbon groups;

The substituents in the C1-C20 hydrocarbon group, C1-C10 hydrocarbon group or C1-C5 hydrocarbon group are selected from nitro, cyano, hydroxyl, halogenated or unhalogenated alkyl, halogenated or unhalogenated alkoxy , halogen, aryl, heteroaryl, -OCOR ₆ , -COR ₆ , -COOR _6;

Preferably, R ₆ is selected from C1 to C8 alkyl; more preferably, it is C1 to C5 alkyl;

The alkyl group in the halogenated or unhalogenated alkyl group is C1-C8 alkyl; more preferably, it is C1-C5 alkyl;

The alkyl group in the halogenated or unhalogenated alkoxy group is a C1-C8 alkyl group; more preferably, it is a C1-C5 alkyl group;

More preferably,

Selected from

Preferably, R ₇ is an aliphatic heterocyclic ring with at least one tertiary amine, and the nitrogen atom is on the skeleton of the aliphatic ring; preferably R ₇ is

Preferably, Z is selected from bromide ion, chloride ion, acetate ion, trifluoroacetate ion, sulfate ion, citrate ion, sulfonate ion, trifluoromethanesulfonate ion or p-toluenesulfonate ion.

Preferably, the quaternary ammonium salt compounds include the following compounds:

In the present invention, "stereoisomers" refer to isomers produced by different spatial arrangements of atoms in the molecule, including cis-trans isomers, enantiomers and conformational isomers.

"Solvate" refers to a compound of the invention or a salt thereof, which also includes stoichiometric or non-stoichiometric solvents bound by non-covalent intermolecular forces. When the solvent is water, it is a hydrate.

"Isotope markers" refer to compounds in which one or more atoms in a compound are replaced by their corresponding isotopes. For example, hydrogen in a compound is replaced by protium, deuterium or tritium.

The second object of the present invention is to provide a preparation method of the quaternary ammonium salt compound described in one of the objects of the present invention. The preparation method includes the following steps:

In step a, intermediate 1 and R ₇ -H react under the protection of inert gas to generate intermediate 2; R ₇ includes at least one tertiary amine group;

In step b, intermediate 2 reacts with R ₈ -X to generate intermediate 3; said R ₈ is selected from

In step c, intermediate 3 and HY react to generate intermediate 4; the Y ion is selected from Cl ^- _, , Br ^- or CF ₃ COO ^- ;

In step d, intermediate 4 reacts with the general formula CH ₃ -Z ₁ to generate intermediate 5; the Z ₁ ion is selected from ^I- _, ^Br- _, Cl- ^{, F-} _;

In step e, intermediate 5 undergoes a reaction to remove the R ₈ protecting group to generate the compound of formula I.

Preferably, step a also includes raw material palladium catalyst, catalyst ligand, base, benzene solvent and alcohol solvent;

Further preferably, the palladium catalyst and catalyst ligand are first dissolved in a benzene solvent, and then intermediate 1, R ₇ -H, a base and alcohol solvent are added for reaction;

More preferably, the ratio of the palladium catalyst, catalyst ligand and benzene solvent is 1 mmol: 1-3 mmol: 5-10 mL;

The ratio of the palladium catalyst, intermediate 1, R ₇ -H, base and alcohol solvent is 1mmol: 8-12mmol: 14-16mmol: 20-26mmol: 0.4-1mL;

The palladium catalyst is selected from tris(dibenzylideneacetone)dipalladium;

The catalyst ligand is selected from (±)-BINAP;

The benzene solvent is selected from toluene, xylene or chlorobenzene;

The alcohol solvent is selected from tert-butyl alcohol, isopropyl alcohol, and pivalid alcohol;

The base is selected from cesium carbonate;

The reaction temperature is 80-100°C, and the reaction time is 5-24h;

and / or,

In step b, the raw material organic weak base and alcohol solvent are also included;

Further preferably, intermediate 2 is first dissolved in an alcoholic solvent, and then R ₈ -X and an organic weak base are added;

More preferably, the ratio of intermediate 2, R ₈ -X, organic weak base and alcohol solvent is 1 mmol: 1.5-3 mmol: 1.3-1.6 mmol: 8-12 mL;

The organic weak base is selected from N, N-diisopropylethylamine;

The alcohol solvent is selected from methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol;

The reaction temperature is 30-60°C, and the reaction time is 2-5h;

and / or,

In the step c, the raw material halogenated alkane solvent is also included,

Further preferably, the ratio of intermediate 3, HY and haloalkane solvent is 1 mmol: 2-5 mL: 5-10 mL;

The halogenated alkane solvent is selected from dichloromethane, chloroform, and 1,2-dichloroethane; the reaction temperature is room temperature, and the reaction time is 1-4h;

and / or,

In the step d, raw material nitrile solvents and carbonates are also included,

Further preferably,

The ratio of the intermediate 4, carbonate, CH ₃ -Z ₁ and nitrile solvent is 1mmol: 3-5mmol: 4-6mmol: 15-25mL;

The carbonate is selected from potassium carbonate, sodium carbonate, and cesium carbonate;

The nitrile solvent is selected from acetonitrile;

The reaction temperature is 40-60°C, and the reaction time is 6-20h;

and / or,

In the step e, the raw material halogenated alkyl acid solvent is also included,

Further preferably,

The ratio of the intermediate 5 and the haloalkyl acid solvent is 1mmol:10-15mL;

The haloalkyl acid solvent is selected from trifluoroacetic acid.

The reaction temperature is 80-100°C, and the reaction time is 5-15h.

The second object of the present invention is to provide the quaternary ammonium salt compound described in one of the objects of the present invention as a standard The use of the precursor is preferably as a radioactive labeling precursor. The present invention uses radioactive or non-radioactive ligands obtained from quaternary ammonium salt compounds to treat related diseases or to diagnose, stage or evaluate their efficacy. Preferably, the quaternary ammonium salt compound can be F-substituted or ¹⁸ F-labeled.

Preferably, the labeling method using quaternary ammonium salt compounds as labeling precursors includes the following steps:

The quaternary ammonium salt compound described in one of the objects of the present invention is dissolved in an anhydrous solvent, and then the phase transfer catalyst and nucleophile reagent from which water has been removed are added.

Preferably,

The phase transfer catalyst is selected from Kryptofix222, tetrabutylammonium halide, crown ether 18-crown 6, tetrabutylammonium bisulfate, tetrabutylammonium bicarbonate, preferably tetrabutylammonium bicarbonate; and/or,

The nucleophile includes halogen, preferably the nucleophile is the negative ion of halogen, and more preferably the nucleophile is F ^- or ¹⁸ F ^- ; and/or,

The anhydrous solvent is selected from at least one of methanol, ethanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide; preferably, it is selected from dimethyl sulfoxide; and/or,

The ratio of the quaternary ammonium salt compound to the anhydrous solvent is 1 mg: 0.05 mL to 0.5 mL; and/or,

The molar mass ratio of the quaternary ammonium salt compound and the phase transfer catalyst is 1 mmol: 0.1 mL ~ 5 mL; and/or,

The molar ratio of the quaternary ammonium salt compound to the nucleophile is 1:1 to 5; and/or,

The reaction temperature is 70~120℃; the reaction time is 5~15min.

Compared with the nitro compounds reported by this research team, the labeling conditions of the quaternary ammonium salt labeling precursor of the present invention are significantly milder, and the labeling efficiency is significantly improved. According to the consensus of scientific researchers in this field, the quaternary ammonium salt compounds prepared by the present invention have strong stability. The present invention can greatly promote the clinical promotion of the above-mentioned [ ^18F ]YLF.

The quaternary ammonium salt compounds provided by the invention can obtain radioactive or non-radioactive ligands after labeling, and can be used to prepare radioactive or non-radioactive imaging agents for Alzheimer's disease or other related diseases. Related conditions include mild cognitive impairment, age-related and other cognitive disorders, schizophrenia, attention deficit disorder, attention deficit hyperactivity disorder (ADHD), dementia due to injection or metabolic disorders, dementia with Lewy bodies, seizures Such as epilepsy, multiple cerebral infarctions, mood disorders, compulsive and addictive behaviors, inflammatory diseases, Cognitive dysfunction related to cardiovascular disease, etc.

Compared with the prior art, the present invention at least has the following advantages:

The quaternary ammonium salt compound of the present invention is an aromatic quaternary ammonium salt compound. Compared with nitro compounds, the aromatic quaternary ammonium salt compound has the advantages of mild labeling conditions and high labeling efficiency.

The nitro compounds reported by this research team have poor stability and will deteriorate if left at room temperature for a long time. It is the consensus of scientific researchers in this field that salt compounds have good stability. The quaternary ammonium salt compounds prepared by the present invention can be left at room temperature for a long time and have strong stability. The present invention can greatly promote the clinical promotion of the above-mentioned [ ^18F ]YLF.

The quaternary ammonium salt compound of the present invention is an aromatic quaternary ammonium salt compound. The quaternization activity of the aliphatic amine in the aromatic quaternary ammonium salt compound is much higher than that of the aromatic amine. When the molecule contains an aliphatic amine, it is difficult to selectively quaternize the aromatic amine. Not only that, due to the strong electron-withdrawing effect of the quaternary ammonium group and its relatively easy to leave property, the substitution reaction at other positions on the aromatic ring where it is located is also very difficult.

The preparation method of the quaternary ammonium salt compound of the present invention is simple, the solvents and reagents used are simple and common materials, the preparation conditions are mild, and they are all conventional laboratory and industrial production conditions. The reaction yield of each step is more than 63%, and the total yield of the 6-step reaction can reach more than 41%, which is suitable for large-scale/industrial production.

When the quaternary ammonium salt compounds (shown in Figure 2) of the present invention are used as labeling precursors to prepare radioactive ligands, the reaction temperature is greatly reduced, and the yield is significantly improved, while the nitro compounds require high-temperature substitution, and the yield is low, and Nitro compounds of this type are also inherently unstable.

Description of the drawings

Figure 1 is a schematic diagram of the labeling process of nitro labeling precursors in the prior art;

Figure 2 is the general structural formula of the quaternary ammonium salt compound of the present invention.

Detailed ways

The present invention will be described in detail below with reference to specific drawings and examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the protection scope of the present invention. Limitation, some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

Source of raw materials:

The raw materials used in the present invention can be purchased directly.

Example 1

Synthesis of aromatic quaternary ammonium salts:

The synthetic route of compound 1 is as follows:

(1) Synthesis of intermediate 2

Under argon protection, tris(dibenzylideneacetone)dipalladium (Pd ₂ (dba) ₃ ) (148 mg, 0.160 mmol) and (±) 1,1'-binaphthyl-2,2'-bisdi Benzene phosphine ((±)-BINAP) (200 mg, 0.320 mmol) was dissolved in 5 mL of redistilled anhydrous toluene, stirred at 90°C for 15 min (the reaction liquid changed from dark purple turbid liquid to orange clear liquid), and cooled to room temperature. Then, intermediate 1 (600 mg, 1.604 mmol), 1,4-diazabicyclo[3.2.2]nonane (303 mg, 2.406 mmol), cesium carbonate (1.045 g, 3.208 mmol) and 0.5 mL were added to the reaction system. Tert-butanol, protected by argon, stirred for 12 hours at 90°C, then cooled to At room temperature, add 10 mL of water to quench the reaction, extract with dichloromethane, collect the organic phase, dry with anhydrous sodium sulfate, filter, remove the solvent by rotary evaporation under reduced pressure, and purify by silica gel column chromatography (CH ₂ Cl ₂ : CH ₃ OH =20:1), deep red solid intermediate 2 (590 mg, 87.8%) was obtained. ¹ H NMR (600MHz, DMSO-d ₆ ) δ9.15 (s, 1H), 7.72 (d, J = 8.4Hz, 1H), 7.44 (d, J = 8.3Hz, 1H), 7.38 (dd, J = 8.5,7.3Hz,1H),7.10(d,J＝7.2Hz,1H),6.91(d,J＝2.6Hz,1H),6.87(dd,J＝8.4,2.6Hz,1H),4.08–4.06( m,1H),3.56(t,J＝5.6Hz,2H),2.95(s,4H),2.87(s,2H),1.97(d,J＝13.3Hz,2H),1.72–1.61(m,2H ),1.46(s,9H); Ms(ESI ⁺ ):m/z calcd for C ₂₅ H ₂₉ N ₃ O ₃ ,419.2209; found,420.2285(M+H ⁺ ).

(2) Synthesis of intermediate 3

Intermediate 2 (590 mg, 1.404 mmol) was dissolved in 10 mL of methanol, and N, N-diisopropylethylamine (271 mg, 2.809 mmol) and 4-methoxybenzyl chloride (328 mg, 2.106 mmol) were added. Stir for 3 hours at 40°C, remove the solvent by rotary evaporation under reduced pressure, and purify by silica gel column chromatography (CH ₂ Cl ₂ : CH ₃ OH = 10:1) to obtain dark red solid intermediate 3 (760 mg, 94%). ¹ H NMR(600MHz,Chloroform-d)δ9.22(s,1H),7.99(d,J＝8.5Hz,1H),7.59(d,J＝8.2Hz,2H),7.36–7.29(m,2H ),6.97–6.88(m,4H),6.77(d,J＝9.1Hz,1H),5.10(s,2H),4.26–4.15(m,1H),4.12–3.88(m,6H),3.87– 3.81(m,2H),3.80(s,3H),2.35–2.26(m,4H),1.54(s,9H).Ms(ESI ⁺ ):m/z calcd for C ₃₃ H ₃₈ N ₃ O ₄ ⁺ ,540.2857; found,540.2852(M ⁺ ).

(3) Synthesis of intermediate 4

Intermediate 3 (760 mg, 1.319 mmol) was dissolved in 10 mL of methylene chloride, and 2 mL of trifluoroacetic acid was added. Stir at room temperature for 2 h, and then evaporate the solvent under reduced pressure to obtain 1.2 g of deep red oily intermediate 4. The crude product is used directly in the next step. Ms(ESI ⁺ ):m/z calcd for C ₂₈ H ₃₀ N ₃ O ₂ ⁺ ,440.2333; found, 440.2341(M ⁺ ).

(4) Synthesis of intermediate 5

Dissolve intermediate 4 (1.2g crude product, 1.319mmol) in 20mL acetonitrile, add potassium carbonate (733mg, 5.276mmol) and methyl trifluoromethanesulfonate (1.018g, 6.595mmol), and stir for 12h at 50°C. (The reaction solution changed from dark red to dark purple), cooled to room temperature, filtered under reduced pressure, washed the filter cake with acetonitrile, the filtrate was rotary evaporated under reduced pressure to remove the solvent, the residue was redissolved with ethyl acetate, and extracted with water (3X 20 mL), collect the aqueous phase, concentrate by rotary evaporation under reduced pressure, and purify through C18 column (H ₂ O: CH ₃ OH = 1/3) to obtain deep purple solid intermediate 5 (820 mg, 78.6%). ¹ H NMR (600MHz, DMSO-d ₆ ) δ7.83 (d, J = 7.5 Hz, 1H), 7.73 (t, J = 7.9 Hz, 1H), 7.65 (d, J = 8.3 Hz, 1H), 7.53 (d,J＝8.4Hz,1H),7.48–7.43(m,2H),7.08–7.00(m,4H),4.52(s,2H),4.36–4.31(m,1H),3.85–3.82(m ,2H),3.77(s,3H),3.68(s,9H),3.54–3.50(m,2H),3.28–3.23(m,4H),2.15–2.11(m,4H).Ms(ESI ⁺ ) :m/z calcd for C ₃₁ H ₃₇ N ₃ O ₂ ²⁺ ,483.2875; found, 362.2232(M ²⁺ -PMB ⁺ ).

(5) Synthesis of compound 1 (i.e. compound of formula I)

In a glass sealed tube, intermediate 5 (820 mg, 0.823 mmol) was dissolved in trifluoroacetic acid. After reacting at 90°C for 10 hours, it was cooled to room temperature, and the trifluoroacetic acid was removed by rotary evaporation under reduced pressure. Re-dissolve the remaining residue in ethyl acetate, extract with water (3×20mL), collect the aqueous phase, concentrate by rotary evaporation under reduced pressure, and purify through C18 reverse-phase column (H2O: CH3OH=1/5) to remove impurities to obtain a dark purple solid compound. 1 (390mg, 63.3%). ¹ H NMR (600MHz, DMSO-d ₆ ) δ7.84 (d, J = 7.5 Hz, 1H), 7.74 (t, J = 8.0 Hz, 1H), 7.66 (d, J = 8.3 Hz, 1H), 7.53 (d,J＝8.5Hz,1H),7.14–7.07(m,2H),4.36(s,1H),3.81(t,J＝5.5Hz,2H),3.69(s,9H),3.43(t, ¹³ CNMR (600MHz, DMSO-d ₆ )δ192.15,150.31,150.20,145.07,138.48,134.32,131.08,125.05,123.29,122.83,120.02,119.95,110.31,56.06,55.26,49.16 ,49.13,46.02,22.57; Ms(ESI ⁺ ):m/z calcd for C ₂₃ H ₂₈ N ₃ O ⁺ ,362.2227; found,362.2222(M ⁺ ).

Example 2

Synthesis of non-radioactive ligand (i.e. [F] compound 1).

The path to F substitution for compound 1 is as follows:

Dissolve compound 1 (50 mg, 0.105 mmol) in 3 mL of anhydrous DMF, add Kryptofix 222 (40 mg, 0.105 mmol), potassium fluoride (9 mg, 0.158 mmol), and react at 90°C for 10 min (the reaction solution changes from bright blue to dark red). Add 20 mL of ethyl acetate to dilute the reaction solution, wash with saturated brine (3×10 mL), dry and concentrate the organic phase, and purify by silica gel column chromatography (CH ₂ Cl ₂ : CH ₃ OH = 20:1) to obtain a red solid [F ] Compound 1 (21 mg, 64%). 1H NMR(400MHz,)δ7.41–7.35(m,1H),7.33(d,J＝8.3Hz,1H),7.11(d,J＝7.4Hz,1H),7.10–7.05(m,1H), 6.85–6.70(m,2H),4.17–4.02(m,1H),3.64–3.54(m,2H),3.21–3.09(m,4H),3.07–2.94(m,2H),2.20–2.05(m ,2H),1.87–1.71(m,2H).Ms(ESI ⁺ ):m/z calcd for C ₂₀ H ₁₉ FN ₂ O,322.1481; found,323.1550(M+H ⁺ ). Confirmed by NMR and mass spectrometry, It is the same compound as YLF previously reported by our research group.

Example 3

Synthesis of radioactive ligand (i.e. [ ¹⁸ F] compound 1). The route for ^18F labeling of compound 1 is as follows:

Dissolve 10 mg tetrabutylammonium bicarbonate in 1 mL of a mixed solvent of acetonitrile and water (7/3) to prepare a ¹⁸ F ^- eluent; use this eluent to elute ^{the 18} F ^- eluent captured on the QMA column into the reaction bottle, blow dry the solvent in the reaction bottle with _N2 at 100°C, then add 0.5 mL anhydrous acetonitrile to it, and blow dry again. This process is repeated three times to ensure that the water in the reaction bottle is fully removed; Quickly add the anhydrous DMSO solution (0.5 mL) of labeled precursor compound 1 (2 mg) into the above reaction bottle, seal it, and react at 90°C for 10 minutes; after the reaction is completed, add distilled water (10 mL) and use a syringe to draw the reaction solution Pass through the Sep-Pak C18 solid-phase extraction column that was activated in advance; then, use 2 mL of acetonitrile to elute the reaction product from the C18 cartridge. Collect the eluate, concentrate under reduced pressure to remove the solvent, add an appropriate amount of acetonitrile to dissolve it, and then use acetonitrile to : Water (containing 0.2% trifluoroacetic acid and 0.3% ammonium acetate) = 32:68 is the mobile phase for radio-HPLC separation and purification, the flow rate is 2mL/min, the wavelength is 254nm, and the semi-preparative column is Type C18 reversed-phase semi-preparative column (Waters Instruments, Inc. 10 μm 10 mm × 250 mm).

After radio-HPLC separation and purification, the radioactive labeling rate without decay correction was about 34%. The labeled product was co-injected with the stable fluorinated compound (ie, the product YLF in Example 2). The mobile phase composition was acetonitrile:water ( Containing 0.2% trifluoroacetic acid and 0.3% ammonium acetate) = 28:72, the flow rate is 2mL/min, the wavelength is 254nm, and the analytical column is Type C18 reversed-phase semi-preparative column (Waters Instruments, Inc. 10 μm 10 mm × 250 mm); the retention times of ¹⁸ F-YLF and F-YLF are 11.882 minutes and 11.763 minutes respectively. The retention times of the two matched, confirming the accuracy of the radioligand.

Compound 2 to Compound 8 shown in the present invention can also be synthesized according to the method shown in Example 1. The only difference is that the corresponding reaction raw materials can be replaced according to the groups of the corresponding compounds of Compound 2 to Compound 8. As follows:

Compounds 2 to 4: Compare the route of compound 1, only need to replace trifluoroacetic acid with the corresponding trifluoromethanesulfonic acid, p-toluenesulfonic acid, and hydrochloric acid in the last step.

For example, compound 2, intermediate 1 is coupled with the nitrogen heterocycle to form intermediate 2, and then forms a quaternary ammonium salt (intermediate 3) with p-methoxybenzyl chloride, which plays the role of occupying the active reaction site; next, three Fluoroacetic acid removes the protective group of aliphatic amine (Intermediate 4), and then uses methyl trifluoromethanesulfonate to quaternize the aromatic amine to obtain Intermediate 5. Finally, trifluoromethanesulfonic acid is used to remove the p-methoxy group. The benzyl group simultaneously forms trifluoromethanesulfonate with the cation.

For example, compound 3, intermediate 1 is coupled with the nitrogen heterocycle to form intermediate 2, and then forms a quaternary ammonium salt (intermediate 3) with p-methoxybenzyl chloride, which plays the role of occupying the active reaction site; next, three Fluoroacetic acid removes the protective group of aliphatic amine (Intermediate 4), and then uses methyl trifluoromethanesulfonate to quaternize the aromatic amine to obtain Intermediate 5. Finally, p-toluenesulfonic acid is used to remove p-methoxybenzyl. The base simultaneously forms p-toluenesulfonate with cations.

For example, compound 4, intermediate 1 is coupled with the nitrogen heterocycle to form intermediate 2, which is then combined with p-methoxybenzyl chloride to form Quaternary ammonium salt (Intermediate 3) plays the role of occupying the active reaction site; next, trifluoroacetic acid is used to remove the protective group of aliphatic amine (Intermediate 4), and then methyl trifluoromethanesulfonate is used to treat the aromatic amine. After quaternization to obtain intermediate 5, hydrochloric acid is finally used to remove the p-methoxybenzyl group and form a chloride salt with the cation.

Although the salts formed by different anions and quaternary ammonium cations in compounds 1 to 4 are different compounds, in subsequent practical applications, it is the quaternary ammonium cations that play a role, and different anions do not affect radioactive labeling.

Compound 5:

When synthesizing compound 5, follow the route of compound 1, only need to replace intermediate 1 of compound 1 with intermediate 1 of compound 5, and other steps are exactly the same as those of compound 1.

Intermediate 1 is obtained from 2-amino-7-bromo-9H-fluoren-9-one (Cas:58557-63-4) through the reaction of a protecting group commonly used in organic synthesis:

Under argon protection, 2-amino-7-bromo-9H-fluoren-9-one (1.0g, 3.649mmol) was dissolved in 10mL of tert-butanol, and di-tert-butyl dicarbonate (795mg, 4.379mmol) was added ) and triethylamine (737 mg, 7.298 mmol), reflux at 90°C overnight, the reaction is basically complete, concentrate the reaction solution under reduced pressure, extract with ethyl acetate and water, collect the organic phase, dry over anhydrous sodium sulfate, filter, and evaporate under reduced pressure Remove the solvent and purify by silica gel column chromatography Intermediate 1 is obtained.

Compound 6

Comparing the synthetic route of compound 1, when synthesizing compound 6, we only need to replace the nitrogen heterocycle that reacts with intermediate 1 with the nitrogen heterocycle required in compound 6 when synthesizing intermediate 2. The other steps are the same as those in compound 6. The steps in 1 are exactly the same.

Compounds 7 and 8 are similar to compound 6, except that the nitrogen heterocycle reacting with intermediate 1 is changed.

Compound 9

When synthesizing compound 9, follow the route of compound 1, only need to replace intermediate 1 of compound 1 with intermediate 1 of compound 9, and other steps are exactly the same as those of compound 1.

Intermediate 1 is composed of 6-amino-3-bromodibenzo[b,d]thiophene 5,5-dioxide (4-Dibenzothiophenamine,7-bromo-,5,5-dioxide, Cas: 2871771-72-9 ) is obtained through the upper protecting group reaction commonly used in organic synthesis:

Under argon protection conditions, dissolve 6-amino-3-bromodibenzo[b,d]thiophene 5,5-dioxide (1.0g, 3.247mmol) in 10mL tert-butanol, add dicarbonate Tert-butyl ester (849 mg, 3.896 mmol) and triethylamine (656 mg, 6.494 mmol) were refluxed at 90°C overnight. The reaction was basically complete. The reaction solution was concentrated under reduced pressure, extracted with ethyl acetate and water, and the organic phase was collected and treated with anhydrous sodium sulfate. Dry, filter, and rotary evaporate under reduced pressure to remove the solvent, and purify through silica gel column chromatography to obtain intermediate 1.

Comparative example 1

The existing labeling precursors and labeling conditions of [ ¹⁸ F]YLF are shown in Figure 1: the labeling precursor is nitro-based Compound; labeling method is ¹⁸ F ^- as nucleophile, K ₂ C ₂ O ₄ as base, DMSO as solvent, Kryptofix222 as phase transfer catalyst, precursor: K ₂ C ₂ O ₄ : DMSO: Kryptofix222=2mg: 2mg :0.3mL:15mg. React at 160°C for 30 minutes. The labeling efficiency of the nitro compound shown in Figure 1 is 13.1% (without decay correction).

If the above compounds are labeled using the same labeling conditions as in Example 3, they will hardly react.

Comparative example 2

The above compounds were labeled using the same labeling conditions as in Example 3, and they hardly reacted.

Comparative example 3

The above compounds were labeled using the same labeling conditions as in Example 3, and they hardly reacted.

Comparative Example 2 and Comparative Example 3 listed in the present invention are used as non-radioactive α7nAChR ligands in the prior art, rather than as radioactive labeling precursors. At present, there are only non-radioactive F substitution methods for the amino group of this type of compound, and there are no research reports on ¹⁸ F substitution. Our team's previous research also first oxidized the amino group to nitro group and then performed radioactive labeling. The corresponding labeling conditions were the labeling conditions for the nitro compounds in Comparative Example 1 above.

Comparative example 4

This compound cannot be directly labeled with ¹⁸ F.

The corresponding nitro compounds of this compound are as follows:

The reaction equation of the labeling process is as follows:

Labeling conditions are ¹⁸ F ^- as nucleophile, K ₂ C ₂ O ₄ as base, DMSO as solvent, Kryptofix222 as phase transfer catalyst, precursor: K ₂ C ₂ O ₄ : DMSO: Kryptofix222=2mg: 2mg: 0.8mL :20mg. React at 160°C for 12 minutes. The labeling rate is 22% (not corrected for decay).

If this compound is labeled using the same labeling conditions as in Example 3, it will hardly react.

Subsequent literature also reported another specific labeling condition for this type of compound: ¹⁸ F ^- as a nucleophile, KHCO ₃ as a base, DMSO as a solvent, Kryptofix222 as a phase transfer catalyst, precursor: KHCO ₃ : DMSO: Kryptofix222=1.5mg:8mg:0.4mL:27mg. The microwave radiation power is 50W and the radiation time is 150s. Its marking rate is 29%. Obviously this condition is more stringent than the marking conditions of the present invention.

It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (25)

A quaternary ammonium salt compound characterized by: The general formula of the quaternary ammonium salt compound is shown in Formula I:
or its stereoisomers, tautomers or pharmaceutically acceptable salts, prodrugs, hydrates, solvates, isotopically labeled derivatives, Wherein, M is selected from C=O or Among R ₁ and R ₂ , one is selected from hydrogen and the other is selected from R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted, saturated or unsaturated C1 to C20 hydrocarbon groups; R ₇ includes at least one tertiary amine group; Z is selected from anions. The quaternary ammonium salt compound according to claim 1, characterized in that: R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted, saturated or unsaturated C1 to C10 hydrocarbon groups; more preferably, R ₃ , R ₄ , and R ₅ are each independently selected from substituted or unsubstituted, saturated Or unsaturated C1～C5 hydrocarbon group; The substituents in the C1-C20 hydrocarbon group, C1-C10 hydrocarbon group or C1-C5 hydrocarbon group are selected from nitro, cyano, hydroxyl, halogenated or unhalogenated alkyl, halogenated or unhalogenated alkoxy , halogen, aryl, heteroaryl, -OCOR ₆ , -COR ₆ , -COOR ₆ ; R ₆ is selected from C1～C8 alkyl; The alkyl group in the halogenated or unhalogenated alkyl group is C1 to C8 alkyl; The alkyl group in the halogenated or unhalogenated alkoxy group is C1 to C8 alkyl; More preferably, Selected from The quaternary ammonium salt compound according to claim 1, characterized in that: The R ₇ is an aliphatic heterocyclic ring with at least one tertiary amine, and the nitrogen atom is on the skeleton of the aliphatic ring; preferably R ₇ is The quaternary ammonium salt compound according to claim 1, characterized in that: The Z is selected from bromide ion, chloride ion, acetate ion, trifluoroacetate ion, sulfate ion, citrate ion, sulfonate ion, trifluoromethanesulfonate ion or p-toluenesulfonate ion. The quaternary ammonium salt compound according to claim 1, characterized in that: The quaternary ammonium salt compounds include the following compounds:
The preparation method of quaternary ammonium salt compounds according to any one of claims 1 to 5, characterized in that the preparation method includes the following steps:
In step a, intermediate 1 and R ₇ -H react under the protection of inert gas to generate intermediate 2; R ₇ includes at least one tertiary amine group; In step b, intermediate 2 reacts with R ₈ -X to generate intermediate 3; said R ₈ is selected from In step c, intermediate 3 and HY react to generate intermediate 4; the Y ion is selected from Cl ^- , Br ^- or CF ₃ COO ^- ; In step d, intermediate 4 reacts with the general formula CH ₃ -Z ₁ to generate intermediate 5; the Z ₁ ion is selected from I ^- , Br ^- , Cl ^- , F ^- ; In step e, intermediate 5 undergoes a reaction to remove the R ₈ protecting group to generate the compound of formula I. The preparation method of quaternary ammonium salt compounds according to claim 6, characterized in that: In step a, raw material palladium catalyst, catalyst ligand, base, benzene solvent and alcohol solvent are also included. The preparation method of quaternary ammonium salt compounds according to claim 7, characterized in that first the palladium catalyst and catalyst ligand are dissolved in a benzene solvent, and then intermediate 1, R ₇ -H, alkali and alcohol are added Solvent-like reaction. The method for preparing quaternary ammonium salt compounds according to claim 8, wherein the ratio of the palladium catalyst, catalyst ligand and benzene solvent is 1 mmol: 1-3 mmol: 5-10 mL; The ratio of the palladium catalyst, intermediate 1, R ₇ -H, base and alcohol solvent is 1mmol: 8-12mmol: 14-16mmol: 20-26mmol: 0.4-1mL. The preparation method of quaternary ammonium salt compounds according to claim 8, characterized in that the palladium catalyst is selected from tris(dibenzylideneacetone)dipalladium; The catalyst ligand is selected from (±)-BINAP; The benzene solvent is selected from toluene, xylene or chlorobenzene; The alcohol solvent is selected from tert-butyl alcohol, isopropyl alcohol, and pivalid alcohol; The base is selected from cesium carbonate; The reaction temperature is 80-100°C, and the reaction time is 5-24h. The preparation method of quaternary ammonium salt compounds according to claim 6, characterized in that: In the step b, the raw material organic weak base and alcohol solvent are also included. The method for preparing quaternary ammonium salt compounds according to claim 11, characterized in that intermediate 2 is first dissolved in an alcohol solvent, and then R ₈ -X and an organic weak base are added. The preparation method of quaternary ammonium salt compounds according to claim 12, characterized in that the ratio of the intermediate 2, R ₈ -X, organic weak base and alcohol solvent is 1mmol: 1.5-3mmol: 1.3-1.6 mmol: 8-12mL. The preparation method of quaternary ammonium salt compounds according to claim 12, characterized in that the organic weak base is selected from N, N-diisopropylethylamine; The alcohol solvent is selected from methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol; The reaction temperature is 30-60°C, and the reaction time is 2-5h. The preparation method of quaternary ammonium salt compounds according to claim 6, characterized in that: In step c, the raw material halogenated alkane solvent is also included. The preparation method of quaternary ammonium salt compounds according to claim 15, characterized in that the ratio of the intermediate 3, HY and haloalkane solvent is 1 mmol: 2-5 mL: 5-10 mL. The method for preparing quaternary ammonium salt compounds according to claim 15, wherein the halogenated alkane solvent is selected from dichloromethane, chloroform, and 1,2-dichloroethane; The reaction temperature is room temperature, and the reaction time is 1-4h. The preparation method of quaternary ammonium salt compounds according to claim 6, characterized in that: In the step d, the raw materials nitrile solvent and carbonate are also included. The preparation method of quaternary ammonium salt compounds according to claim 18, characterized in that, The ratio of the intermediate 4, carbonate, CH ₃ -Z ₁ and nitrile solvent is 1 mmol: 3-5 mmol: 4-6 mmol: 15-25 mL. The preparation method of quaternary ammonium salt compounds according to claim 18, characterized in that the carbonate is selected from potassium carbonate, sodium carbonate, and cesium carbonate; The nitrile solvent is selected from acetonitrile; The reaction temperature is 40-60°C, and the reaction time is 6-20h. The preparation method of quaternary ammonium salt compounds according to claim 6, characterized in that: In step e, the raw material halogenated alkyl acid solvent is also included. The preparation method of quaternary ammonium salt compounds according to claim 21, characterized in that, The ratio of the intermediate 5 and the haloalkyl acid solvent is 1mmol:10-15mL; The haloalkyl acid solvent is selected from trifluoroacetic acid. The reaction temperature is 80-100°C, and the reaction time is 5-15h. The application of the quaternary ammonium salt compound according to any one of claims 1 to 5 as a labeling precursor is preferably used as a radioactive labeling precursor. The application according to claim 23, characterized in that the labeling method using quaternary ammonium salt compounds as labeling precursors includes the following steps: The quaternary ammonium salt compound described in any one of claims 1 to 5 is dissolved in an anhydrous solvent, and then the phase transfer catalyst and nucleophile reagent from which water has been removed are added. The application according to claim 24, characterized in that: The phase transfer catalyst is selected from Kryptofix222, tetrabutylammonium halide, crown ether 18-crown 6, tetrabutylammonium bisulfate, tetrabutylammonium bicarbonate, preferably tetrabutylammonium bicarbonate; and/or, The nucleophile includes halogen, preferably the nucleophile is the negative ion of halogen, and more preferably the nucleophile is F ^- or ¹⁸ F ^- ; and/or, The anhydrous solvent is selected from at least one of methanol, ethanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide; preferably dimethyl sulfoxide; and/or, The ratio of the quaternary ammonium salt compound to the anhydrous solvent is 1 mg: 0.05 mL to 0.5 mL; and/or, The molar mass ratio of the quaternary ammonium salt compound and the phase transfer catalyst is 1 mmol: 0.1 mL ~ 5 mL; and/or, The molar ratio of the quaternary ammonium salt compound to the nucleophile is 1:1 to 5; and/or, The reaction temperature is 70~120℃; the reaction time is 5~15min.