KR20220146218A - Tracer for PET Specific to beta-adrenergic receptor - Google Patents

Abstract

The present invention relates to a tracer for positron emission tomography (PET) specific to a beta-adrenergic receptor and a preparation method thereof. More specifically, the present invention relates to a tracer for PET specific to a beta-adrenergic receptor, in particular, to a β_1-adrenergic receptor, which includes a compound represented by chemical formula 1, to a preparation method thereof, wherein the tracer selectively targets a β_1-adrenergic receptor and to a composition including a PET tracer for detecting the β_1-adrenergic receptor to diagnose heart disease. When the bisoprolol represented by the chemical formula 1 and radiolabeled by ^18F isotope according to the present invention is used as a PET tracer for detecting a beta-adrenergic receptor, in particular, a β_1-adrenergic receptor (β1-AR) in vivo cells or tissues, the β_1-AR can be selectively targeted in a heart tissue of a patient with heart disease and the β_1-AR can be detected with very high selectivity and sensitivity, so that the PET tracer can be useful for early detection of the heart disease.

Description

Beta-adrenergic receptor-specific tracer for PET {Tracer for PET Specific to beta-adrenergic receptor}

The present invention relates to a tracer for positron emission tomography (PET) specific to beta-adrenergic receptors and a method for preparing the same. More specifically, including the compound represented by Formula 1, beta-adrenergic receptor, in particular, beta 1-adrenergic receptor (β ₁ -adrenergic receptor) that selectively targets beta 1-adrenergic receptor PET tracer for detecting and a method for manufacturing the same, and a composition for diagnosis of heart disease comprising the PET tracer for detecting the beta 1-adrenergic receptor.

Isoforms of protein families share amino acid sequence homology and structural homology. In drug discovery, the clear selectivity of the lead compound for the homologous isoform of the target protein is an important factor for discovering low-toxic candidates. In addition, improving the selectivity of a candidate substance during drug discovery is an essential process for successful clinical development of a candidate substance that presents sufficient safety. Several proteins, including the β-adrenoceptor (β-AR), show different populations of isoforms in tissues, providing the opportunity to engineer selective drugs that discriminate isoforms. However, the evaluation of drug selectivity for one of several isoforms has so far been limited to in vitro approaches, and a technical method to evaluate the isoform selectivity of drug candidates in vivo is required. . Positron Emission Tomography (PET) is a non-invasive technique for in vivo detection of radiolabeled drugs. PET is widely used for diagnostic imaging of various diseases and also provides information on the biodistribution of labeled drugs.

β-adrenergic receptors are G-protein coupled receptors that are prominently present in organs such as the heart, lungs and brain. Of the two main subtypes of β-AR, β ₁ -AR is mainly found in the heart, kidney, and cerebral cortex, whereas β ₂ -AR is mainly found in the lung, gastrointestinal tract, liver, uterus, vascular smooth muscle, skeletal muscle, and cerebellar cortex. (Mineman KP et . al., Mol Pharmacol. , 16(1):21-33, 1979). β ₁ -AR is primarily associated with the pathophysiology of various heart diseases, such as hypertension, heart failure, ischemia, hypertrophic cardiomyopathy, and dilated cardiomyopathy (Michel MC et . al., Hypertension , 16(2):107- 120, 1990). Although non-selective β-blockers such as propranolol are still used to treat cardiovascular disease, selective β ₁ -blockers such as bisoprolol are mainly used in clinical settings because of the predominance of β ₁ -AR in the heart. The selectivity of β-blockers for specific β-AR isoforms has been well established through in vitro investigations (Baker JG. et.al. , Br J Pharmacol. , 160(5):1048-1061, 2010). However, in vivo profiling techniques of β-blocker selectivity for specific β-AR isoforms have not yet been comprehensively reported. PET could be a useful tool to evaluate the interaction between β-AR isoforms and their blockers in vivo due to the different populations of β-AR isoforms in the heart and other peripheral smooth muscle, including the lungs.

On the other hand, bisoprolol is a synthetic β ₁ -AR blocker whose selectivity is about 100 times higher for β ₁ -AR than for β ₂ -AR (Hieble JP et.al. , J Med Chem. , 38 (18). ):3415-3444, 1995). Due to its ideal pharmacokinetic properties, (±)-bisoprolol possesses high β ₁ -AR selectivity, indicating its potential as a ligand for the development of PET imaging agents for β ₁ -AR density measurement. However, studies on the development of imaging radiotracers for selective quantification of intra-cardiac β ₁ -AR density are limited. To date, only one study on the development of a PET imaging agent using bisoprolol as a radioligand has been reported (S)-[ ¹¹ C]bisoprolol ( ¹¹ C, t _1/2 = 20.4 min), which It targets the central β ₁ -AR (Soloviev DV. et . al., Neurochem Int. , 38(2):169-180, 2001).

Against this background, the present inventors sought to develop a novel PET tracer as a validation tool to determine the in vivo selectivity and efficacy of β-blockers against β-AR isoforms, particularly β ₁ -AR. We present a bisoprolol-based PET tracer radiolabeled with an ¹⁸ F isotope (t _1/2 = 109.7 min, shorter mean positron range) with decay properties better than ¹¹ C as a selective β ₁ -AR blocker. Phosphorus (±)-[ ¹⁸ F]bisoprolol (Compound 1) was developed. Selectivity and efficacy of β ₁ -blockers against intracardiac β ₁ -AR by performing ex vivo biodistribution and uptake studies of (±)-[ ¹⁸ F]bisoprolol tracer in Balb/c normal mice. By confirming, the present invention was completed.

Mineman KP et. al., Mol Pharmacol., 16(1):21-33, 1979 Michel M C et. al., Hypertension, 16(2):107-120, 1990 Baker JG. et.al., Br J Pharmacol., 160(5):1048-1061, 2010 Hieble J.P. et. al., J Med Chem., 38(18):3415-3444, 1995 Soloviev DV. et.al., Neurochem Int., 38(2):169-180, 2001

One object of the present invention is to provide a tracer for PET for detecting β-adrenoceptor containing [ ¹⁸ F]bisoprolol compound and a method for preparing the same.

Another object of the present invention is to provide a composition for diagnosis of heart disease comprising the PET tracer.

Another object of the present invention is to provide a method for providing information for the diagnosis of heart disease using the PET tracer.

In order to achieve the above object, the present invention provides a tracer for PET for detecting β-adrenergic receptor containing [ ¹⁸ F]bisoprolol compound and a method for preparing the same.

In addition, the present invention provides a composition for diagnosis of heart disease comprising the PET tracer.

In addition, the present invention provides a method for providing information for the diagnosis of heart disease using the PET tracer.

The bisoprolol compound of Formula 1 radiolabeled with ¹⁸ F isotope according to the present invention was used as a PET tracer for detecting β-adrenergic receptors, particularly β ₁ -adrenergic receptors (β ₁ -AR) in living cells or tissues. If used, it is possible to selectively target β ₁ -AR in the heart tissue of patients with heart disease, which can be used for more effectively diagnosing heart disease.

The tracer for PET containing the compound of Formula 1 according to the present invention can detect β-adrenergic receptors, particularly β ₁ -AR, with very selective and high sensitivity, and can be usefully used for early diagnosis of heart disease. .

1 is a diagram schematically showing the synthesis process of (A) non-radioactive [F] bisoprolol and (B) radiolabeled [ ¹⁸ F] bisoprolol according to an embodiment of the present invention. Here, the reaction conditions and reagents are as follows: A. Synthesis of non-radioactive [F]bisoprolol; (a) Dowex 50WX8 resin, IPA, rt, 69%; (b) K ₂ CO ₃ , epichlorohydrin, CH ₃ CN, reflux, 69%; (c) DL-alaninol, CH ₃ OH, reflux, 97%; (d) Boc ₂ O, CH ₂ Cl ₂ , rt, 93%; (e) TBSCl, imidazole, CH ₂ Cl ₂ , rt, 77%; (f) NaH, toluene, rt, 28%; (g) TBAF, THF, rt 89%; (h) TsCl, TEA, DMAP, CH ₂ Cl ₂ , rt, 92%; (i) 2.2.2-cryptand, KF, CH ₃ CN, 100° C., 61%; (j) LiAlH ₄ , THF, rt, 73%; B. Synthesis of radiolabeled [ ¹⁸ F]bisoprolol; (k) 2.2.2-cryptand, ¹⁸ F, CH ₃ CN, 100° C., 61%; (l) LiAlH ₄ , THF, rt, 73%.
2 is a diagram showing the purification results of (±)-[ ¹⁸ F]bisoprolol after deprotection by LiAlH ₄ in an embodiment of the present invention. Specifically, (A) radioactive-HPLC (high pressure liquid chromatography) chromatogram results for purification of (±)-[ ¹⁸ F]bisoprolol and (B) purification of (±)-[ ¹⁸ F]bisoprolol It is a diagram showing the HPLC chromatogram results for
3 shows (±)-[ ¹⁸ F]bisoprolol (Compound 1) in Balb/c mice at 5, 30, 90, and 120 minutes after injection (±)-[ ¹⁸ F] It is a diagram showing the biodistribution results of bisoprolol (Compound 1). Specifically, (A) bar graphs showing the in vitro distribution results of (±)-[ ¹⁸ F]bisoprolol in various organs and (B) (±)-[ ¹⁸ F] ratios in blood, heart, lung and brain It is a line graph showing the soprorolol distribution.
4 shows (±)-[ ¹⁸ F]bisoprolol (Compound 1) in normal Balb/c mice at 30 and 120 minutes after (±)-[ ¹⁸ F]bisoprolol (Compound 1) injection according to an embodiment of the present invention. It is a diagram showing the results of competition analysis between rollol (Compound 1) and unlabeled (±)-bisoprolol. Specifically, (A) a bar graph showing the in vitro distribution results of (±)-[ ¹⁸ F]bisoprolol in various organs in Balb/c mice pretreated with (±)-bisoprolol, (B) (± )-A graph showing the organ-to-blood ratio of (±)-[ ¹⁸ F]bisoprolol in Balb/c mice not pretreated with )-bisoprolol, and (C) (±) -A graph showing the organ-to-blood ratio of (±)-[ ¹⁸ F]bisoprolol in Balb/c mice pretreated with bisoprolol.

The present invention includes a compound represented by Formula 1, and beta-adrenergic receptor, in particular, beta 1-adrenergic receptor (β ₁ -adrenergic receptor, β ₁ -AR) selectively targeting β ₁ -AR detection PET A tracer, a method for preparing the same, and a composition for diagnosis of heart disease comprising the PET tracer for detecting the β ₁ -AR.

In one aspect, the present invention provides a tracer for PET for detecting β-adrenoceptor containing [ ¹⁸ F]bisoprolol compound represented by the following formula (1):

[Formula 1]

As used herein, the term "β-adrenoceptor (β-AR)" is a G-protein coupled receptor that is distinctly present in organs such as the heart, lungs and brain, β-AR is β ₁ - There are two main subtypes: AR and β ₂ -AR. It is known that β ₁ -AR is mainly found in the heart, kidney and cerebral cortex, whereas β ₂ -AR is mainly found in the lungs, gastrointestinal tract, liver, uterus, vascular smooth muscle, skeletal muscle, and cerebellar cortex. In addition, β ₁ -AR is known to be mainly associated with the pathophysiology of various heart diseases such as hypertension, heart failure, ischemia, hypertrophic cardiomyopathy, and dilated cardiomyopathy.

As used herein, the term "bisoprolol" is a drug that selectively inhibits sympathetic beta-1 adrenergic receptors (β ₁ -adrenoceptor; β ₁ -AR) to reduce myocardial contractility and heart rate. Because it lowers blood pressure and reduces the burden on the heart, it is used in the treatment of hypertension and angina, and is also used in the treatment of chronic heart failure.

In the present invention, the bisoprolol is a compound having the chemical structure of the following formula (1) radiolabeled by ¹⁸ F isotope, β-adrenoceptor (β-AR), particularly β ₁ -adrenergic A PET tracer for the detection of β ₁ -AR that selectively targets the sex receptor (β ₁ -AR) is available:

[Formula 1]

As used herein, the term "Positron Emission Tomography (PET) is one of nuclear medicine examination methods, and is a non-invasive technique for in vivo detection of radioactive isotope-labeled drugs. Specifically, PET is a positron It is to examine the distribution of isotopes in the body by injecting and imaging a drug containing radioactive isotopes that emit It also provides information about

The selectivity of a drug for the various isoforms of the target protein family is often important in terms of toxicity. Typically, drug or candidate selectivity is assessed by in vitro assays, but in vivo investigations are currently lacking. Positron emission tomography (PET) can be used to non-invasively determine the biodistribution of radiolabeled drugs, which can provide in vivo data regarding drug selectivity. After the discovery of propranolol, a non-selective β-blocker that inhibits both β ₁ - and β ₂ -adrenergic receptors (β-AR), to overcome the shortcomings associated with β ₂ -AR inhibition, various selective agents including bisoprolol β ₁ -blockers have been developed. As a proof-of-concept, since cardiac and peripheral smooth muscle show distinct populations of β ₁ -AR and β ₂ -AR in vivo to understand the selectivity and efficacy of bisoprolol as a selective β-blocker for β ₁ -AR A PET study was performed. The biodistribution of ¹⁸ F-labeled bisoprolol (1, [ ¹⁸ F]bisoprolol) showed that absorption was maintained in the heart compared to other β-AR-rich organs at later time points after injection. Competitive blocking assays using unlabeled bisoprolol did not inhibit [ ¹⁸ F]bisoprolol uptake in any organs, but marked significant radioactivity between two different time points in β ₁ -AR-rich organs such as the heart and brain. showed a very rapid loss. Moreover, the organ-to-blood ratio showed a slower excretion and better accumulation of [ ¹⁸ F]bisoprolol inside the heart. Collectively, ex vivo biodistribution and blockade studies provide insightful evidence to better understand the biodistribution pattern of bisoprolol as a selective inhibitor targeting β ₁ -AR in the heart, and to evaluate drug selectivity. The potential of PET as an in vivo technique for

In one embodiment of the present invention, the biodistribution of the [ ¹⁸ F]bisoprolol compound represented by Formula 1, which is a tracer for PET for detecting β-adrenergic receptors, is different from other β-AR-rich organs at a late time point after injection. It was confirmed that absorption was maintained in the heart compared to . In addition, it was confirmed that a better accumulation of [ ¹⁸ F]bisoprolol inside the heart was observed.

의 화합물 용액을 첨가한 반응 혼합물을 90℃ 내지 110℃에서 10분 내지 30분 동안 가열한 다음 실온으로 냉각시는 단계; 및 c) 상기 b) 단계의 반응 혼합물을 질소 가스로 건조하여 용매를 제거한 후, 테트라히드로푸란(THF)에 용해된 리튬 알루미늄 하이드라이드(LiAlH₄)를 첨가하여 실온에서 10분 내지 20분 동안 반응시키는 단계;를 포함하는, 하기 화학식 1로 표시되는 β-아드레날린성 수용체 검출을 위한 PET용 추적자의 제조방법을 제공한다:In another embodiment, the present invention provides a method comprising the steps of: a) drying a mixture of ¹⁸ F-fluorine and [2.2.2]-cryptand in acetonitrile with nitrogen gas at a temperature of 85°C to 95°C; b) Formula 9 in acetonitrile in the mixture of step a)

heating the reaction mixture to which a solution of the compound of and c) drying the reaction mixture in step b) with nitrogen gas to remove the solvent, and then adding lithium aluminum hydride (LiAlH ₄ ) dissolved in tetrahydrofuran (THF) to react at room temperature for 10 to 20 minutes. It provides a method for preparing a tracer for PET for detecting β-adrenergic receptors represented by the following formula (1), including:

[Formula 1]

In the present invention, the PET tracer is a [ ¹⁸ F]bisoprolol-based compound represented by Formula 1 that targets β ₁ -adrenergic receptor (β ₁ -AR), (±)-bisoprolol Using the precursor for ¹⁸ F-labeling (Formula 9), radiolabeled (±)-[ ¹⁸ F]bisoprolol (Compound 1) can be synthesized through a nucleophilic substitution reaction with an ¹⁸ F anion. Subsequent deprotection by nucleophilic substitution with an ¹⁸ F anion and ring opening with LiAlH ₄ can finally yield the final [ ¹⁸ F]-PET tracer (Compound 1).

The final product, [ ¹⁸ F]bisoprolol (Compound 1), was purified by reverse-phase semi-preparative HPLC in a radiochemical yield of 15%, radiochemical purity of >98% and >3.4 GBq/ It showed a specific activity of μmol (see Table 1).

As another aspect, the present invention provides a composition for diagnosis of heart disease comprising the PET tracer.

As described above, the tracer for PET is a [ ¹⁸ F]bisoprolol-based compound represented by Formula 1 that targets the β ₁ -adrenergic receptor (β ₁ -AR), and the biodistribution is different at a late time point after injection. Compared with organs rich in β-AR, it was confirmed that absorption was maintained in the heart and a better accumulation of [ ¹⁸ F]bisoprolol inside the heart was confirmed, which can be useful for heart disease.

In the present invention, the heart disease is not limited thereto, but may be one or more selected from the group consisting of hypertension, heart failure, ischemia, hypertrophic cardiomyopathy, and dilated cardiomyopathy.

As another aspect, the present invention provides a method for providing information for diagnosing heart disease using the PET tracer.

As described above, the PET tracer is a [ ¹⁸ F]bisoprolol-based compound represented by Formula 1 that targets the β ₁ -adrenergic receptor (β ₁ -AR) of the heart, but is not limited thereto, This can be done by measuring the amount of β ₁ -AR inside the heart.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

Reference Example 1. Reagents and laboratory equipment

All reagents used in the synthesis were purchased from Sigma-Aldrich, Combi-Block, Acros, TCI, Alfa Aesar and Daejeong, and were used without further purification. The anhydrous solvent used in the reaction was purified using the PureSolv Micro Multi Unit solvent purification system of Inert Technology (Amesbury, MA, USA), and all reactions were performed under a nitrogen atmosphere. The completion of the reaction was confirmed by thin layer chromatography using a silica gel plate (Kiesegel 60 F ₂₅₄ , Merck). All synthesized compounds were purified by flash column chromatography filled with silica gel (ZEOprep 60 40-63 μm). ¹ H NMR and ¹³ C spectra were measured with a JEOL JNM-ECZ400s/L1 (400 MHz) spectrometer, and CDCl ₃ or DMSO- d ₆ was used as the NMR solvent. Chemical shift was expressed in parts per million (ppm), and coupling constant was expressed in Hz. Chemical shifts were referenced to tetramethylsilane (δ=0 ppm) in CDCl ₃ as internal standard. ¹³ C NMR spectra were obtained using the same NMR spectrometer, and chemical shifts are expressed in ppm relative to the center line for the triplet at 77.0 ppm in CDCl ₃ or 39.5 ppm in DMSO- d ₆ .

Example 1. Synthesis of (±)-[F]bisoprolol

A precursor (9) for ¹⁸ F-labeling of (±)-bisoprolol was synthesized as shown in [Scheme 1] below. The resulting alkylation of benzyl alcohol and phenol alcohol from commercially available 4-(hydroxymethyl)phenol and 2-isopropoxyethanol followed by addition of epichlorohydrin gave Intermediate 4. The ring opening reaction of epoxide 4 was carried out to give amino alcohol intermediate 5 by addition of DL-alaninol, followed by Boc-protection of free-NH followed by tert -butyldimethylsilyl chloride (TBSCl) of the primary alcohol. Selective protection resulted in secondary alcohol 6 . For one-pot deprotection of secondary amines and alcohols after ¹⁸ F-labelling, secondary alcohols were cyclized to form oxazolidinone 7 using sodium hydride. Precursor 9 for the ¹⁸ F-label was generated by deprotection of the TBS group using tetra-n-butylammonium fluoride (TBAF) followed by tosylation of the free hydroxyl group using tosyl chloride. ¹⁸ F-labelling, deprotection of the oxazolidinone group and HPLC purification were established using non-radioactive compounds. Then, precursor 9 was used to synthesize radiolabeled (±)-[ ¹⁸ F]bisoprolol (Compound 1) through a nucleophilic substitution reaction with an ¹⁸ F anion. Subsequent deprotection by nucleophilic substitution with ¹⁸ F anion and ring opening with LiAlH ₄ gave the final [ ¹⁸ F]-PET tracer (Compound 1) (see [Scheme 2] below). The final product, [ ¹⁸ F]bisoprolol (Compound 1), was purified by reverse-phase semi-preparative HPLC ( FIG. 2 ), with a radiochemical yield of 15%, a radiochemical purity of >98% and >3.4 It showed a specific activity of GBq/μmol (see Table 1).

[Scheme 1] Synthesis of non-radioactive [F] bisoprolol

The synthesis process of the compounds shown in [Scheme 1] will be described in more detail below.

Example 1-1. Synthesis of compound 3

4-((2-isopropoxyethoxy)methyl)phenol (3)

Dowex 50WX8 resin (4.02 g, 20.14 mmol) was added to a mixture of 4-(hydroxymethyl)phenol (2.11 g, 16.11 mmol) in 28 mL of isopropoxyethanol, and the reaction mixture was stirred at room temperature for 12 hours. did. After completion of the reaction, the reaction mixture was filtered to remove the resin, and the product was isolated by washing with CH ₂ Cl ₂ . The organic filtrate was washed with water (5×45 mL) and dried over Na ₂ SO ₄ . The dried organic layer was concentrated with a rotary evaporator. The residue was purified by silica gel column chromatography (EA:hexane = 1:4) to give compound 3 (2.346 g, 69%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 9.37 (s, 1H), 7.10 (d, J = 8.2 Hz, 2H), 6.71 (dd, J = 11.4, 2.7 Hz, 2H), 4.32 (s, 2H), 3.49-3.55 (m, 1H), 3.45 (s, 4H), 1.05 (d, J = 5.9 Hz, 6H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 156.78, 129.36, 128.60, 114.91, 71.96, 70.83, 69.01, 66.76, 22.04. ESI-MS: m/z = 209.20 (M - H) ^- .

Example 1-2. Synthesis of compound 4

2-((4-((2-isopropoxyethoxy)methyl)phenoxy)methyl)oxirane (4)

To a solution of compound 3 (2.5 g, 11.89 mmol) and K ₂ CO ₃ (3.3 g, 23.78 mmol) in CH ₃ CN (36 mL) was added epichlorohydrin (2.2 g, 23.777 mmol). The reaction mixture was refluxed at 85° C. for 12 hours. After completion of the reaction, the solvent was removed by evaporation, and the crude material was placed in EtOAc (2×50 mL) and washed with water (2×45 mL). Combined organic layers over Na ₂ SO ₄ dried and concentrated. Compound 4 (2.17 g, 69%) was isolated from the crude residue using silica gel flash column chromatography (CH ₂ Cl ₂ :MeOH = 50:1).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.22-7.28 (m, 2H), 6.91-6.96 (m, 2H), 4.39 (s, 2H), 4.30 (dd, J = 11.9, 3.2 Hz, 1H) ), 3.77-3.84 (m, 1H), 3.52 (q, J = 6.1 Hz, 1H), 3.47 (s, 4H), 3.30 (q, J = 3.1 Hz, 1H), 2.83 (t, J = 4.8 Hz) , 1H), 2.69 (q, J = 2.6 Hz, 1H), 1.06 (d, J = 5.9 Hz, 7H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.42, 130.59, 129.15, 128.99, 114.70, 113.99, 71.43, 70.62, 68.94, 68.72, 66.54, 49.50, 43.54, 21.84. ESI-MS: m/z = 265.23 (M - H) ^- .

Examples 1-3. Synthesis of compound 5

2-((2-hydroxy-3-(4-((2-isopropoxyethoxy)methyl)phenoxy)propyl)amino)propan-1-ol (5)

To a stirred solution of compound 4 (1.5 g, 5.64 mmol) in MeOH (9 mL) was added DL-alaninol (2.89 g, 37.76 mmol). The reaction mixture was refluxed at 72° C. for 2 hours 30 minutes. The solvent was removed under reduced pressure. Silica gel flash column chromatography (CH ₂ Cl ₂ :MeOH = 5:1) was performed to obtain compound 5 (1.85 g, 97%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.21 (d, J = 8.2 Hz, 2H), 6.89 (d, J = 8.7 Hz, 2H), 4.99 (s, 1H), 4.51 (s, J = 12.8 Hz, 1H), 4.38 (s, 2H), 3.89-3.94 (m, 1H), 3.82-3.87 (m, 2H), 3.50-3.56 (m, 1H), 3.48 (s, J = 5.9 Hz, 4H) ), 3.16-3.30 (m, 3H), 2.54-2.65 (m, 2H), 1.06 (d, J = 5.9 Hz, 6H), 0.89 (dd, J = 6.4, 4.6 Hz, 3H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.46, 129.77, 129.29, 114.05, 71.65, 70.94, 68.95, 68.15, 66.71, 28.09, 22.35. ESI-MS: m/z = 364.20 (M + Na) ⁺ .

Examples 1-4. Synthesis of compound 6

Tert -Butyl(1-((tert-butyldimethylsilyl)oxy)propan-2-yl)(2-hydroxy-3-(4-((2-isopropoxyethoxy)methyl)phenoxy)propyl)car Barmate (6)

A solution of BOC ₂ O (4.09 g, 18.74 mmol) in anhydrous CH ₂ Cl ₂ (3 mL) was added to a solution of compound 5 (1.6 g, 4.69 mmol) in anhydrous CH ₂ Cl ₂ (12 mL). The reaction mixture was stirred at room temperature for 4 hours. After completion of the reaction on TLC, the reaction mixture was diluted with CH ₂ Cl ₂ (30 mL) and washed with H ₂ O (2×50 mL). The organic layer was dried over Na ₂ SO ₄ and concentrated under vacuum. Purify the crude residue by silica gel flash column chromatography (CH ₂ Cl ₂ :MeOH = 15:1) to tert -butyl(2-hydroxy-3-(4-((2-isopropoxyethoxy)methyl) Phenoxy)propyl)(1-hydroxypropan-2-yl)carbamate (1.92 mg, 93%) was obtained.

¹ H NMR (400 MHz, DMSO- d ₆ ) δ δ 7.22 (d, J = 8.7 Hz, 2H), 6.87 (dd, J = 8.7, 2.7 Hz, 2H), 5.33-5.14 (m, 1H), 4.77 -4.84 (m, 1H), 4.38 (s, 2H), 3.65-4.04 (m, 4H), 3.44-3.58 (m, 6H), 3.33-3.42 (m, 2H), 2.99-3.17 (m, 1H) , 1.37 (d, J = 2.7 Hz, 9H), 1.09 (d, J = 6.9 Hz, 2H), 1.06 (d, J = 6.4 Hz, 6H), 0.96-1.02 (m, 2H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.46, 129.77, 129.29, 114.05, 71.65, 70.94, 68.95, 68.15, 66.71, 28.09, 22.35. ESI-MS: m/z = 440.05 (M - H) ^- .

A solution of TBSCl (0.7 g, 4.49 mmol) in CH ₂ Cl ₂ (5 mL) was mixed with tert -butyl(2-hydroxy-3-(4-((2-isopropoxy) in anhydrous CH ₂ Cl ₂ (10 mL)) To a mixture of ethoxy)methyl)phenoxy)propyl)(1-hydroxypropan-2-yl)carbamate (1.8 g, 4.08 mmol) and imidazole (0.84 g, 12.24 mmol) was added dropwise under a nitrogen environment. The reaction mixture was stirred at room temperature under nitrogen atmosphere for 12 h, then the reaction was quenched with H ₂ O (20 mL), and the product was extracted with CH ₂ Cl ₂ (2×20 mL). The organic layer was dried over Na ₂ SO ₄ , filtered and concentrated under reduced pressure. For product separation, the residue was purified by silica gel flash column chromatography (EtOAc:hexane = 1:1) to give compound 6 (1.74 g, 77%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.22 (d, J = 8.2 Hz, 2H), 6.85 (dd, J = 8.7, 2.3 Hz, 2H), 5.02 (t, J = 4.6 Hz, 1H) , 4.38 (s, 2H), 3.96 (d, J = 5.0 Hz, 1H), 3.86-3.91 (m, 1H), 3.69-3.82 (m, 3H), 3.48-3.56 (m, 2H), 3.47 (s) , 4H), 3.31 (s, 2H), 1.36 (s, 9H), 1.10 (q, J = 3.2 Hz, 3H), 1.06 (d, J = 5.9 Hz, 6H), 0.83 (s, 9H), - 0.00 (d, J = 3.7 Hz, 6H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 158.14, 130.16, 128.88, 113.99, 71.80, 70.78, 69.18, 68.13, 67.98, 66.71, 49.38, 28.07, 25.70, 21.99, 17.83, -5.40. ESI-MS: m/z = 556.11 (M + H) ⁺ .

Examples 1-5. Synthesis of compound 7

3-(1-(( Tert -Butyldimethylsilyl)oxy)propan-2-yl)-5-((4-((2-isopropoxyethoxy)methyl)phenoxy)methyl)oxazolidin-2-one (7)

Compound 6 (1.5 g, 2.7 mmol) was dissolved in 23 mL of toluene, and NaH (0.23 g, 5.81 mmol) was added under a nitrogen environment. The mixture was stirred at room temperature for 10 minutes and heated to 110° C. for 2 hours. The crude was extracted with EtOAc (2×30 mL) and washed with water (1×30 mL). The organic layer was dried over Na ₂ SO ₄ , filtered, and the product was isolated by silica gel column chromatography (EtOAc:hexane = 1:2) to obtain compound 7 (0.36 g, 28%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.24 (d, J = 8.7 Hz, 2H), 6.89-6.93 (m, 2H), 4.79-4.86 (m, 1H), 4.39 (s, 2H), 4.02-4.18 (m, 2H), 3.80 (m, 1H), 3.56-3.69 (m, 3H), 3.52 (q, J = 6.1 Hz, 1H), 3.47 (s, 4H), 3.34-3.41 (m, 1H), 1.08 (d, J = 6.9 Hz, 3H), 1.06 (d, J = 6.4 Hz, 6H), 0.83-0.86 (m, 9H), 0.02-0.04 (m, 6H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.54, 157.46, 156.61, 156.53, 131.05, 130.99, 129.19, 129.15, 114.20, 114.17, 71.58, 71.55, 71.07, 71.04, 66.82, 69.12, 68.62, 68.45, , 63.82, 49.98, 49.92, 42.19, 42.01, 40.12, 39.91, 39.70, 39.50, 39.29, 39.08, 38.87, 25.70, 22.03, 17.80, 17.76, 13.78, 13.66, -5.44, -5.51, -5.58. ESI-MS: m/z = 504.32 (M + Na) ⁺ .

Example 1-6. Synthesis of compound 8

3-(1-hydroxypropan-2-yl)-5-((4-((2-isopropoxyethoxy)methyl)phenoxy)methyl)oxazolidin-2-one (8)

To a solution of compound 7 (0.11 g, 0.23 mmol) in anhydrous THF (2.5 mL) was added TBAF (0.46 mL, 1.0 M in THF, 0.46 mmol) dropwise at 0° C. under nitrogen. The reaction mixture was stirred at room temperature for 1 h and then quenched with H ₂ O. The reaction solvent was evaporated under vacuum and the residue was taken up in EtOAc (2×5 mL), washed with water (2×10 mL) and dried over Na ₂ SO ₄ . The organic layer was filtered, removed over Na ₂ SO ₄ , concentrated, and the crude material was purified by silica gel flash column chromatography (EtOAc:hexane = 2:1) to give compound 8 (75 mg, 89%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.24 (d, J = 8.7 Hz, 2H), 6.90-6.94 (m, 2H), 4.78-4.86 (m, 2H), 4.41 (d, J = 15.1) Hz, 2H), 4.12-4.18 (m, 1H), 4.07 (q, J = 5.6 Hz, 1H), 3.70-3.80 (m, 1H), 3.65 (td, J = 8.9, 2.9 Hz, 1H), 3.54 (td, J = 12.2, 6.1 Hz, 1H), 3.48 (s, 4H), 3.33-3.42 (m, 2H), 3.31 (s, 2H), 1.05 (t, J = 5.7 Hz, 9H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.55, 156.70, 130.99, 129.17, 114.21, 71.58, 71.02, 70.80, 69.13, 68.73, 66.71, 62.30, 62.28, 50.39, 41.98, 41.56, 13.78, 13.97 . ESI-MS: m/z = 390.27 (M + Na) ⁺ .

Examples 1-7. Synthesis of compound 9

2-(5-((4-((2-isopropoxyethoxy)methyl)phenoxy)methyl)-2-oxooxazolidin-3-yl)propyl 4-methyl benzenesulfonate (9)

To a stirred solution of compound 8 (70 mg, 0.19 mmol) in 3 mL of CH ₂ Cl ₂ was added TEA (39 mg, 0.38 mmol), DMAP (2 mg) and TsCl (56 mg, 0.29 mmol). The mixture was stirred at room temperature for 12 h, then quenched with H ₂ O (10 mL) and extracted with CH ₂ Cl ₂ (2×50 mL). The organic layer was dried over Na ₂ SO ₄ , filtered and concentrated. The crude product was purified by silica gel column chromatography (EtOAc:hexane = 2:1) to give compound 9 (92 mg, 92%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.79 (t, J = 8.5 Hz, 2H), 7.46 (dd, J = 23.1, 8.0 Hz, 2H), 7.24 (q, J = 4.6 Hz, 2H) , 6.90 (d, J = 8.7 Hz, 2H), 4.71-4.86 (m, 1H), 4.40 (d, J = 6.4 Hz, 2H), 3.98-4.16 (m, 5H), 3.40-3.65 (m, 6H) ), 3.34-3.23 (m, 1H), 2.39 (d, J = 16.9 Hz, 3H), 1.05-1.10 (m, 9H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 157.46, 157.44, 156.32, 156.28, 145.11, 145.06, 132.11, 131.05, 131.03, 130.21, 130.18, 129.16, 129.14, 127.59, 127.56, 114.21, 71.14. , 70.80, 70.18, 70.11, 69.13, 68.43, 68.33, 66.71, 47.52, 47.43, 41.84, 41.61, 22.01, 21.08, 21.05, 13.43, 13.27. ESI-MS: m/z = 520.38 (M - H) ^- .

Examples 1-8. Synthesis of compound 2

1-((1-fluoropropan-2-yl)amino)-3-(4-((2-isopropoxyethoxy)methyl)phenoxy)propan-2-ol (2)

Compound 9 (100 mg, 0.19 mmol) was dissolved in 5 mL of CH ₃ CN. Then [2.2.2]-cryptand (81 mg, 0.21 mmol) and KF (56 mg, 0.96 mmol) were added to the solution. The reaction mixture was stirred at 100° C. for 20 min. The crude was extracted with EtOAc (2×10 mL) and washed with water (1×10 mL). The organic layer was dried over Na ₂ SO ₄ , filtered and concentrated. The product was isolated by silica gel column chromatography (EtOAc:hexane = 1:4) to obtain an intermediate (43 mg, 61%). The intermediate (5 mg, 0.014 mmol) was dissolved in anhydrous THF (0.7 mL) and to this solution was added LAH powder (5.4 mg, 0.14 mmol) under nitrogen. The reaction mixture was stirred at room temperature for 5 minutes. After completion of the reaction, LAH was quenched with sodium sulfate decahydrate (25 mg) at 0° C. for 10 minutes. Sodium sulfate decahydrate was removed by filtration and the solvent was evaporated under vacuum. The residue was purified by silica gel column chromatography (CH ₂ Cl ₂ :MeOH = 20:1) to give compound 2 (3.3 mg, 73%).

¹ H NMR (400 MHz, DMSO- d ₆ ) δ 7.21 (d, J = 8.7 Hz, 2H), 6.89 (dd, J = 8.9, 2.5 Hz, 2H), 4.38 (s, 2H), 4.31 (d, J = 5.5 Hz, 1H), 4.19 (d, J = 5.0 Hz, 1H), 3.83-3.94 (m, 2H), 3.50-3.56 (m, 1H), 3.47 (s, 4H), 2.81-2.90 (m) , 1H), 2.61-2.70 (m, 2H), 1.06 (d, J = 5.9 Hz, 6H), 0.98 (dd, J = 6.4, 1.4 Hz, 3H); ¹³ C NMR (100 MHz, DMSO- d ₆ ) δ 163.34, 158.35, 130.40, 129.19, 114.15, 71.89, 71.03, 70.83, 69.31, 68.54, 66.94, 52.64, 52.38, 49.95, 22.24. ESI-MS: m/z = 342.73 (M - H) ^- .

Example 2. (±)-[ ¹⁸ F] Synthesis of bisoprolol

[Scheme 2] Radiofluorination: Synthesis of radiolabeled [ ¹⁸ F]bisoprolol

The synthesis process of the radiolabeled [ ¹⁸ F]bisoprolol shown in [Scheme 2] will be described in more detail below.

Example 2-1. Radiolabeling of compound 9

Step I: 3-(1-fluoropropan-2-yl)-5-((4-((2-isopropoxyethoxy)methyl)phenoxy)methyl)oxazolidin-2-one (intermediate) synthesis of

[2.2.2]-Cryptand (0.81 mg, 0.0021 mmol) and KF (0.6 mg, 0.0095 mmol) were added to a solution of compound 9 (1 mg, 0.0019 mmol) in CH ₃ CN (0.5 mL). The reaction mixture was covered with a screw cap and heated at 100° C. for 20 minutes. The mixture was cooled to room temperature and the solvent was removed under reduced pressure. The crude material was filtered through a syringe filter and washed with MeOH. The solvent was removed under reduced pressure and dissolved in MeOH (5 mL). The RP-HPLC method for crude material purification was performed for 10 minutes at the beginning using CH ₃ CN:H ₂ O (20:80 v/v) containing 0.1% TFA v/v as the eluting mobile phase, and then 0.1 A further 10 min was performed using CH ₃ CN:H ₂ O (80:20 v/v) with % TFA v/v. At this time, RP-HPLC was performed under the conditions of a flow rate of 1 mL/min and a UV wavelength of 225 nm.

Step II: 1-((2-fluoroethyl)amino)-3-(4-((2-isopropoxyethoxy)methyl)phenoxy)propan-2-ol ((±)-[F] ratio soprorol) synthesis

The deprotection reaction for the following final product [ ¹⁸ F]bisoprolol was shown.

The intermediate of the radiolabeling reaction (2 mg, 0.0054 mmol) was dissolved in anhydrous THF (0.5 mL) and LAH powder (2.2 mg, 0.054 mmol) was added under nitrogen. The mixture was covered with a screw cap and stirred at room temperature for 5 minutes. After completion of the reaction, LAH was removed with sodium sulfate decahydrate (10 mg) at 0° C. for 10 minutes. The reaction mixture was filtered and washed with CH ₂ Cl ₂ , and the solvent was removed on a rotary evaporator. The mixture was filtered through a syringe filter and washed with MeOH. The RP-HPLC method for crude material purification was performed for 20 minutes at the beginning using CH ₃ CN:H ₂ O (20:80 v/v) containing 0.1% TFA v/v as the eluting mobile phase, and then 0.1 A further 10 min was performed using CH ₃ CN:H ₂ O (80:20 v/v) with % TFA v/v. At this time, RP-HPLC was performed under the conditions of a flow rate of 1 mL/min and a UV wavelength of 225 nm.

Experimental Example 1. (±)-[ ¹⁸ F] Radiolabeling for bisoprolol

¹⁸ F-fluoride was generated through ¹⁸ O(p,n) ¹⁸ F reaction on PET trace ^TM cyclotron (GE Healthcare) ^at Chonnam National University Hwasun Hospital (Molecular Probe Development Innovation Center). ¹⁸ F-Fluoride Kryptofix in Acetonitrile2.2.2 and dried with nitrogen gas at 90°C. The residue was dried two more times by azeotropic distillation in acetonitrile. To the mixture was added a solution of precursor 9 (4 mg) in acetonitrile (1.0 mL). The reaction mixture was heated at 100° C. for 20 minutes and then cooled. After drying with N ₂ to remove the solvent, 5.4 mg of lithium aluminum hydride dissolved in 0.6 mL of tetrahydrofuran was added to the vial. The reaction mixture was stirred at room temperature for 15 minutes. The solution was evaporated with N ₂ gas and 1 mL of MeOH was added. The solution was passed through a FG filter and eluted with MeOH. The filtrate was purified by injection into a semi-preparative high performance liquid chromatography column system. For identification of radioactive products, the collected HPLC fractions were injected with (±)-[F]bisoprolol ( FIG. 2 ). Mobile phase starts with 80% solvent A (0.1% TFA in water) and 20% solvent B (acetonitrile), forming a concentration gradient with 20% solvent A and 80% solvent B at 10 minutes, and at 20 minutes Transfer was carried out with 80% solvent A and 20% solvent B and held for 40 minutes. At this time, the flow rate was 3 mL/min, and the residence time (R _t ) was 18.16 min.

Table 1 below shows the radiochemical properties of the PET tracer.

PET tracer Dose (MBq) Specific activity (GBq/μmol) radiochemical yield Radiochemical Purity (±)-[ ¹⁸ F]bisoprolol (1) 7.4 3.7 15% > 98%

Experimental Example 2. Evaluation of biodistribution

The concentration-time course of a radiotracer is very important for evaluating a specific distribution in a tissue of interest. In order to evaluate the distribution pattern of the PET tracer according to the present invention in organs with β-AR receptors, an ex vivo biodistribution study of (±)-[ ¹⁸ F]bisoprolol in normal Balb/c mice aged 5-6 weeks was conducted. carried out. Animal care, animal experiments, and euthanasia were performed according to protocols approved by the Chonnam National University Animal Research Committee and the Guide for the Care and Use of Laboratory Animals.

Specifically, the biodistribution study was conducted after iv injection of 7.4 MBq of (±)-[ ¹⁸ F]bisoprolol in Balb/c normal mice (5-6 weeks of age), 5 min, 30 min, 90 min. min and at 120 min. (±)-[ ¹⁸ F]bisoprolol was administered to Balb/c mice by intravenous injection (7.4 MBq), followed by heart, lung, liver, spleen, stomach, intestine, kidney, pancreas, muscle, brain and skin. Uptake signals were detected in various organs including, and harvested at time intervals of 5 min, 30 min, 90 min and 120 min post-injection (pi), as shown in Fig. 3A and Table 2, respectively.

(±)-[ ¹⁸ F]bisoprolol (Compound 1) showed high absorption in organs such as liver, spleen, stomach, intestine, kidney and pancreas, i.e., abdominal region, at an initial time point 5 minutes after injection, and with the exception of , decreased over time. Initially, organs rich in β-adrenergic terminals such as the heart, lungs and brain also showed high signal intensities, but lungs and brains showed decreased radioactivity over time. On the other hand, the radioactivity of the heart decreased initially but was maintained at the last time point from 90 min to 120 min post-injection as shown in the time-activity curve (see Fig. 3B and Table 2). In the heart, absorption was 1.66±0.12% injected dose (ID)/g at 90 min post-injection and remained at 1.68±0.59% ID/g at 120 min post-injection. In bone, the progressively increased radioactivity may be due to absorption of free ¹⁸ F.

In Table 2 below, the radioactivity % ID/g of (±)-[ ¹⁸ F]bisoprolol (Compound 1 ) measured at various organs was calculated and shown.

% ID/g 5 minutes 30 minutes 90 minutes 120 minutes blood 8.16±1.86 6.03±0.37 1.69±0.09 1.12±0.25 heart 12.36±5.82 6.37±0.71 1.66±0.12 1.68±0.59 lung 25.62±12.5 10.13±2.12 2.23±0.54 1.88±0.54 liver 35.56±9.86 32.25±11.66 7.98±3.9 4.92±0.58 spleen 21.06±5.02 9.85±3.66 2.34±0.41 1.76±0.43 stomach 16.17±8 24.94±4.1 6.84±2.59 6.1±5.35 page 16.14±4.58 31.35±10.37 35.72±9.39 28.41±17.48 kidney 36.03±9.22 28.93±2.68 7.28±1.82 3.88±0.73 pancreas 27.97±8.24 12.22±3.1 2.45±0.11 1.69±0.44 normal muscle 9.19±3.81 4.91±0.46 1.83±1.11 1.09±0.4 bone 6.82±1.96 10.74±0.68 19.82±6.05 17.58±2.69 brain 11.09±8.86 3.45±0.7 1.19±0.08 0.84±0.34 skin 8.06±3.1 5.87±0.66 2.54±0.9 1.33±0.28

For blocking studies, biodistribution studies were performed 30 and 120 minutes after bisoprolol (0.75 mg/0.1 mL) injection. Blood and organs were extracted from mice, weighed, and organ radioactivity was calculated using a gamma counter. To obtain % ID/g, radioactivity measurements were normalized to the weight of the tissue and the amount of radioactivity injected.

Specifically, the specific binding of the PET tracer to the receptor can be investigated by performing a blocking study in a competition assay using the unlabeled antagonist (±)-bisoprolol. To determine the absorption capacity of (±)-[ ¹⁸ F]bisoprolol in β-AR-rich organs, Balb/c mice were pretreated with 750 μg of unlabeled (±)-bisoprolol and then (±) -[ ¹⁸ F]bisoprolol was injected. Inhibition of (±)-[ ¹⁸ F]bisoprolol absorption was not observed in any organ in the competitive blockade study at 30 and 120 minutes post injection (see Figure 4 and Table 3). However, surprisingly, radioactivity changes between two different time points (30 min and 120 min) after pretreatment with (±)-bisoprolol showed promising results. At 120 min post-injection, organs rich in β ₁ -AR, including the heart and brain, showed radioactive loss (rapid excretion of tracers) of 6% and 10%, respectively, whereas organs rich in β ₂ -AR exhibited maintained or increased showed radioactivity (slow excretion of tracers). This suggests selective inhibition of β ₁ -AR by bisoprolol in the heart and brain compared to the case of β ₂ -AR.

Organ-to-blood ratios of radioactivity by PET tracers were calculated for both case studies 1) untreated and 2) pretreated with unlabeled (±)-bisoprolol. In the untreated case, the accumulation of (±)-[ ¹⁸ F]bisoprolol was superior in all organs except liver, kidney and pancreas, and the organ-to-blood ratio increased from 30 min to 120 min after injection ( Fig. 4B). Among the organs rich in β ₁ -AR, the heart showed a sharp increase in the organ-to-blood ratio from 30 min to 120 min post-injection compared to other organs such as the lungs and brain, indicating that the heart to blood suggesting that excretion is slower. However, after blockade with (±)-bisoprolol, the organ-to-blood ratio decreased in all organs, including the heart, except for the stomach and intestines. In the case of the heart, the organ-to-blood ratio decreased with pretreatment with unlabeled (±)-bisoprolol and increased with no treatment, which was (±)-[ ¹⁸ F in β ₁ -AR inside the heart. ] Shows the accumulation of bisoprolol.

In Table 3 below, the radioactivity % ID/g of (±)-[ ¹⁸ F]bisoprolol (Compound 1 ) measured in various organs in which β-AR was blocked by (±)-bisoprolol was calculated and shown. .

% ID/g 30 minutes 120 minutes blood 6.88±0.91 1.62±0.09 heart 9.7±1.4 1.99±0.14 lung 17.48±2.54 3.29±0.47 liver 31.43±8.54 7.07±0.91 spleen 15.01±2.61 3.44±0.37 stomach 23.83±5.35 6.43±0.63 page 22.71±3.43 13.31±3.28 kidney 38.88±5.89 7.48±0.14 pancreas 18.8±5.51 3.36±0.48 normal muscle 7.03±0.84 1.16±0.17 goal 5.12±1.19 8.45±2.22 brain 9.41±1.66 1.31±0.47 skin 7.51±0.51 1.58±0.16

Tissue-specific localization of receptor-targeting ligands can be validated by in vivo studies using PET. As a model study, we used PET to verify the selective localization of a radiotracer based on a selective β-blocker, (±)-[ ¹⁸ F]bisoprolol that targets the β ₁ -AR inside the heart. In vivo studies of (±)-[ ¹⁸ F]-bisoprolol, including ex vivo biodistribution and blocking studies, showed that the radiotracer had better distribution and better distribution in organs with β ₁ -AR, mainly in the heart and accumulation was suggested.

In conclusion, the present inventors successfully designed and synthesized a novel ¹⁸ F radiolabeled β ₁ -blocker, (±)-[ ¹⁸ F]bisoprolol, and evaluated the selectivity of bisoprolol targeting β ₁ -AR. The potential for in vivo or ex vivo evaluation was evaluated. In addition, the potential as a selective and efficient PET tracer for β ₁ -AR inside the heart was investigated. Ex vivo biodistribution of Balb/c mice (±)-[ ¹⁸ F]bisoprolol showed radioactivity maintained in the heart from 90 min to 120 min post-injection compared to other organs. Pretreatment with non-radioactive (±)-bisoprolol did not inhibit the absorption of (±)-[ ¹⁸ F]bisoprolol. However, the excretion of (±)-[ ¹⁸ F]bisoprolol was faster in β ₁ -AR dominant organs such as the heart, whereas other β ₂ -AR dominant organs showed slower excretion of the tracer. The difference in organ-to-blood ratios with and without unlabeled (±)-bisoprolol pre-treatment showed that (±)-[ ¹⁸ F]bisoprolol was good for the heart compared to other β ₁ -AR organs. showed accumulation. PET studies of (±)-[ ¹⁸ F]bisoprolol performed in this context will be a promising validation model for in vivo selectivity profiling of specific isoforms of target proteins. In addition, this study may help to design a novel highly selective and efficient PET tracer targeting the β ₁ -AR of the heart.

Claims (8)

A tracer for PET for detecting β-adrenoceptor containing [ ¹⁸ F]bisoprolol compound represented by the following formula (1):
[Formula 1]

The tracer for PET according to claim 1, wherein the β-adrenergic receptor is a β ₁ -adrenergic receptor (β ₁ -AR). A composition for diagnosis of heart disease comprising the tracer for PET according to claim 1 or 2. The composition for diagnosis of heart disease according to claim 3, wherein the heart disease is at least one selected from the group consisting of hypertension, heart failure, ischemia, hypertrophic cardiomyopathy, and dilated cardiomyopathy. A method for providing information for the diagnosis of heart disease using the PET tracer according to claim 1 or 2. The method of claim 5, comprising measuring the amount of β ₁ -AR inside the heart. a) drying a mixture of ¹⁸ F-fluorine and [2.2.2]-cryptand in acetonitrile with nitrogen gas at a temperature of 85°C to 95°C;
b) Formula 9 in acetonitrile in the mixture of step a)

heating the reaction mixture to which a solution of the compound of and
c) After drying the reaction mixture of step b) with nitrogen gas to remove the solvent, lithium aluminum hydride (LiAlH ₄ ) dissolved in tetrahydrofuran (THF) is added to react at room temperature for 10 to 20 minutes step; including
A method for preparing a tracer for PET for detecting β-adrenergic receptors represented by the following formula (1):
[Formula 1]

The preparation of the tracer for PET according to claim 7, wherein the tracer for PET is a [ ¹⁸ F]bisoprolol-based compound represented by Formula 1 that targets β ₁ -adrenergic receptor (β ₁ -AR). Way.

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