JP3877754B2 - Amyloid affinity compounds - Google Patents

Description

  The present invention relates to a novel compound that belongs to the technical field of in vivo testing and is particularly useful for the detection of amyloid, which has an affinity for the onset and progress of Alzheimer's disease.

  The number of Alzheimer's disease patients is currently said to be more than 1.5 million in Japan, and it is predicted that one out of 10 elderly people will develop in 20 years, and the economic burden of the public will increase as the population ages. ing. The disease is about 10% hereditary and the remaining 90% is sporadic, and everyone has a risk of onset, but the risk of onset increases with age. It is characterized by the formation of senile plaques, neurofibrillary tangles, and brain atrophy, and these organic changes are said to have progressed well before clinical manifestations.

At present, the definitive diagnosis of Alzheimer's disease is based on histopathological examination of the postmortem brain of patients (ZS Khachaturian, Arch. Neurol., 1985, 42, 1097: Non-Patent Document 1), and Congo Red as a tissue stain therefor (Congo Red) has been widely used. Since Congo Red has a high affinity for amyloid β (sometimes abbreviated as Aβ) protein, which is a component of senile plaques, selective staining is possible. On the other hand, in order to capture the formation of senile plaque, which is the earliest neuropathological change, in advance, probes for diagnostic imaging of brain amyloid in vivo have recently appeared. Congo red is a fluorescent molecule that has an affinity for Aβ protein. Since it has a sulfone group in the molecule and is highly hydrophilic, it cannot cross the blood-brain barrier and cannot be used in vivo. For this reason, hydrophobic low molecular weight compounds with improved migration to the brain are labeled with radionuclides (especially ¹¹ C, ¹³ N, ¹⁵ O, ¹⁸ F), and PET (positron emission tomography) or SPECT (simple An approach for detection using photon emitting nuclide (computed tomography) has been studied. As a probe for in vivo imaging, a thioflavine derivative (for example, CA Mathis, et al., Bioorg. Med. Chem, Lett., 2002, 12, 295: Non-Patent Document 2; MP Kung, et al) , J. Mol. Neurosci., 2003, 20, 15: Non-patent document 3; Z.-P. Zhuang, et al., J. Med. Chem, 2003, 46, 237: Non-patent document 4) and the like. However, both detections require large-scale nuclear medicine facilities.

The recently developed compound BSB [(trans, trans) -1-bromo-2,5-bis- (3-hydroxycarbonyl-4-hydroxy) styrylbenzene] recognizes the β-sheet structure of the protein and thus against the Aβ protein. High affinity (Km = 0.4 μM) and fluorescent staining of Aβ protein are expected as a selective probe for imaging Alzheimer's disease (DM Skovronsky et al., Proc. Natl. Acad. Sci., 2000, 97, 7609: Non-patent document 5). According to this report by Non-Patent Document 5, BSB was intravenously administered to a model mouse of Alzheimer's disease, and the mouse specimen was sacrificed, and then the postmortem brain specimen was stained, and a good transition to the brain was confirmed. However, when performing prenatal diagnosis, radiolabeling for detection by PET or SPECT is still necessary. In addition, BSB has obtained excellent staining results as a fluorescent stain for systemic amyloidosis (Y. Ando et al., Lab. Invest., 2003, in press .: Non-patent document 6).
Z. S. Khachaturian, Arch. Neurol. , 1985, 42, 1097 C. A. Mathis, et al. Bioorg. Med. Chem, Lett. , 2002, 12, 295 M.M. P. Kung, et al. , J .; Mol. Neurosci. , 2003, 20, 15 Z. -P. Zhang, et al. , J .; Med. Chem. , 2003, 46, 237 D. M.M. Skovronsky et al. , Proc. Natl. Acad. Sci. 2000, 97, 7609 Y. Ando et al. Lab. Invest. , 2003, in press.

  An object of the present invention is to establish a new technique that enables detection of amyloid such as Aβ protein in Alzheimer's disease without requiring special equipment.

As a result of repeated research, the present inventor succeeded in developing a novel compound having BSB as a basic skeleton and having affinity for amyloid, and derived the present invention.
Thus, according to the present invention, a styrylbenzene compound represented by the following general formula (I) is provided.

In formula (I), R ₁ and R ₂ are each independently a hydroxyl group or a carboxyl group. R ₃ is a fluorine atom or a bromine atom. When R ₃ is a bromine atom, whenever R ₃ is a fluorine atom, the carbon atoms constituting the α-position, β-position, γ-position and δ-position carbon atoms and the carboxyl groups of R ₁ and R ₂ are At least one of which is carbon-13.

Preferable specific examples of the compound represented by the formula (I) according to the present invention include a styrylbenzene compound in which R ₁ is a hydroxyl group, R ₂ is a carboxyl group, and R ₃ is a fluorine atom in the formula (I), Alternatively, in the formula (I), a styrylbenzene compound in which R ₁ is a hydroxyl group, R ₂ is a carboxyl group, R ₃ is a bromine atom, and carbon atoms at the α-position and the β-position are carbon 13 can be given. However, it is not limited to these.

  The compound of the above general formula (I) can fluorescently stain amyloid. Therefore, according to the present invention, a fluorescent stain of amyloid comprising the compound represented by the general formula (I) is provided.

Furthermore, the compound of the above general formula (I) can also be an MRI contrast agent having specificity for amyloid. Therefore, according to the present invention, the amyloid-specific compound comprising the compound represented by the general formula (I) can be used. An MRI contrast agent is provided.
As is well known, the term amyloid used in connection with the present invention is a depositing protein comprising a secondary structure of β sheet structure (β folding structure) that causes systemic amyloidosis or local amyloidosis. The representative example belonging to the latter topical amyloidosis is due to the Aβ protein deposited in the brain of Alzheimer's disease patients as described above.

  The compound of the present invention represented by the formula (I) has a high affinity for amyloid and can be fluorescently stained for the protein as in the case of the conventionally known BSB. It also functions as an MRI contrast agent.

FIG. 1 shows a reaction scheme for synthesizing Example compounds of the present invention (Compounds 1 and 9).
FIG. 2 shows a ¹⁹ F-NMR spectrum (A) of Compound 1 and a ¹³ C-NMR spectrum (B) of Compound 9.
FIG. 3 shows fluorescence spectra of Compound 1, Compound 9, and BSB.
[FIG. 4] Stained images of temporal cortical sections (ethanol fixed) of postmortem brains of Alzheimer's disease patients, (A) stained with compound 1, (B) stained with compound 9, and (C) stained with BSB. Show the case.
[FIG. 5] Stained images of frontal cortex sections (ethanol fixed) of postmortem brains of Alzheimer's disease patients, (A) shows compound 1 and (B) stained with compound 9.
FIG. 6 shows an in vivo ¹⁹ F-MR brain image when Compound 1 according to the present invention is administered to amyloid precursor protein transgenic mice.
FIG. 7 shows a ¹ H-MR brain image after removing and fixing a mouse brain measured by ¹⁹ F-MRI.

The styrylbenzene compound of the present invention represented by the formula (I) can be synthesized by devising various reactions. FIG. 1 illustrates a preferred reaction scheme for synthesizing the styrylbenzene compounds of the present invention. Briefly, as shown, the 3- and 4-positions are —OMe or —CO ₂ Me (Me Is a methyl group) and a benzaldehyde substituted with fluorine or bromine and a phosphonic acid derivative group —P (O) (OEt) ₂ (Et is an ethyl group) at both ends. ) Is reacted with the introduced p-xylene-α, α′-diyl compound to form a distyrylbenzene structure as a skeleton (step indicated by d in FIG. 1), and then demethylation is sequentially performed. By doing so, a compound of formula (I) is obtained.

In the formula (I), when R ₃ is a bromine atom, at least one of carbon atoms at the α-position, β-position, γ-position, and δ-position and the carboxyl groups of R ₁ and R ₂ is carbon 13 ( ¹³ C). On the other hand, when R ₃ is a fluorine atom, at least one of those carbon atoms may not necessarily be carbon 13, that is, carbon atoms at the α-position, β-position, γ-position and δ-position, and R ₁ and R _2. The carbon atom constituting the carboxyl group may be ordinary carbon 12. The compound of the present invention represented by the formula (I) thus obtained has a fluorine and / or carbon 13 in the molecule and becomes an MRI (magnetic resonance imaging) contrast agent having specificity for amyloid. In this respect, it has a characteristic not found in the BSB known in the art.

Furthermore, the compound of the present invention represented by the formula (I) has a high affinity for brain amyloid (Aβ protein) and amyloid caused by systemic amyloidosis, as in BSB, and can also fluorescently stain these amyloids. In this case, the formula (I) in which R ₃ is a fluorine atom has particularly high fluorescence intensity, and it has also been found that the fluorescence intensity is increased by about 2 times compared to BSB. This is understood because the compound (I) having a fluorine atom in the molecule loses fluorescence quenching due to the heavy atom effect as compared with BSB.
Examples are given below to illustrate the features of the present invention more specifically, but the present invention is not limited to these examples.

Synthesis Example 1: As an example of the compound of the present invention represented by the formula (I), a compound _{1 in} which R ₁ is a hydroxyl group, R ₂ is a carboxyl group, and R ₃ is a fluorine atom in FIG. It was synthesized according to the scheme shown below. Operation in each step and identification data of the obtained product are sequentially shown below.
<Synthesis of Intermediate 3>
2,5-Dimethylaniline (10 g, 82 mmol) was suspended in water (30 ml), and concentrated hydrochloric acid (17 ml) was added little by little. After cooling to about 5 ° C., an aqueous sodium nitrite solution (a solution of 7.0 g dissolved in 10 ml of water; 101 mmol) was added dropwise. The mixture was stirred as it was for 1 hour, insoluble matter was filtered off, sodium borofluoride (11.0 g, 101 mmol) was added to the filtrate, and the precipitated diazonium salt was collected by filtration. This was thermally decomposed and the separated oil was purified by silica gel column (hexane) to obtain 1.51 g of the desired product (yield 15%). Colorless oil. ¹ H NMR (CDCl ₃ ): δ 2.22 (s, 3H), 2.30 (s, 3H), 6.79-6.83 (m, 2H), 7.03 (t, J = 8.0 Hz) , 1H); ¹⁹ F-NMR (CDCl ₃ ): -118.5 ppm.

<Synthesis of Intermediate 4>
Intermediate 3 (1.02 g, 8.2 mmol) was dissolved in chloroform (100 ml), and N-bromosuccinimide (3.1 g, 17.4 mmol) and 2,2′-azobis (isobutyronitrile) (10 mg, 0.06 mmol) was added and heated to reflux for 100 minutes. After cooling, the chloroform layer was washed with water, dried (MgSO ₄ ) and concentrated under reduced pressure. Hexane was added to the residue for crystallization. Yield 0.99 g (43% yield). White crystalline powder. ¹ H NMR (CDCl ₃ ): δ 4.43 (s, 2H), 4.49 (s, 2H), 7.08-7.41 (m, 3H); ¹⁹ F-NMR (CDCl ₃ ): −115 .9 ppm; MS: m / z 281 (M + 1).

<Synthesis of Intermediate 5>
Intermediate 4 (0.99 g, 3.5 mmol) and triethyl phosphite (1.16 g, 7.0 mmol) were mixed and heated at 160 ° C. for 4 hours. After completion of the reaction, the oil obtained by concentration under reduced pressure was purified on a silica gel column (methylene chloride: methanol = 95: 5 (v / v)) to obtain 1.18 g (yield 85%) of the desired product. Colorless oil. ¹ H NMR (CDCl ₃ ): δ 1.23-1.29 (m, 12H), 3.11 (d, J = 20.3 Hz, 2H), 3.17 (d, J = 20.6 Hz, 2H) 3.98-4.10 (m, 8H), 7.04 (d, J = 9.9 Hz, 1H), 7.27-7.34 (m, 2H); ¹⁹ F-NMR (CDCI ₃ ) : -117.1 ppm; MS: m / z 397 (M + 1).

<Synthesis of Intermediate 6>
Intermediate 5 (1.18 g, 3.0 mmol) was dissolved in anhydrous methanol (5 ml) and compound 8 (1.16 g, 6.0 mmol) was added. The mixture was cooled to 0 ° C., 28% sodium methoxide methanol solution (2 ml) was added dropwise, and the mixture was heated to reflux overnight. After allowing to cool, the precipitate was collected by filtration. The obtained yellow solid was suspended in water (100 ml) and adjusted to pH 3 with 1M hydrochloric acid. The mixture was extracted with chloroform, and the chloroform layer was washed with water, dried (MgSO ₄ ), and concentrated to dryness. After silica gel column purification (chloroform: ethyl acetate = 9: 1 (v / v)), 0.42 g (yield 30%) of the desired product was obtained. Yellow powder. ¹ H NMR (CDCl ₃ ): δ 3.93 (s, 6H), 3.94 (s, 6H), 6.94-7.26 (m, 8H), 7.55 (t, J = 7.9 Hz) , 1H), 7.61 (dd, J = 9.1, 2.2 Hz, 1H), 7.64 (dd, J = 9.3, 2.2 Hz, 1H), 7.97 (d, J = 2.2 Hz, 1H), 7.98 (d, J = 2.2 Hz, 1H); ¹⁹ F-NMR (CDCl ₃ ): −118.1 ppm; MS: m / z 476 (M ⁺ ).

<Synthesis of Intermediate 7>
Intermediate 6 (0.42 g, 0.87 mmol) was dissolved in methylene chloride (50 ml) and cooled to -78 ° C. A 1.0 M boron tribromide-dichloromethane solution (9 ml, 9.0 mmol) was added dropwise, and the mixture was stirred at room temperature overnight. The mixture was cooled in an ice bath, water (30 ml) was added, about 10% methanol was further added, and the methylene chloride layer was separated. Further, the aqueous layer was extracted with methylene chloride. The methylene chloride layers were combined, dried (MgSO ₄ ), and concentrated under reduced pressure to obtain 0.39 g (yield 100%) of the desired product. Yellow powder. ¹ H NMR (DMSO ₆ -d): δ 3.93 (s, 6H), 7.03 (d, J = 8.7 Hz, 1H), 7.04 (d, J = 8.5 Hz, 1H), 7 .15 (d, J = 16.5 Hz, 1H), 7.16 (d, J = 16.5 Hz, 1H), 7.36 (d, J = 16.5 Hz, 1H), 7.37 (d, J = 16.5 Hz, 1H), 7.43-7.52 (m, 2H), 7.75-7.89 (m, 3H), 7.98 (s, 2H), 10.59 (s, 2H); ¹⁹ F-NMR (DMSO-d ₆ ): -118.6 ppm.

<Synthesis of Compound 1>
Intermediate 7 (0.42 g, 0.94 mmol) was suspended in 0.06 M aqueous potassium hydroxide solution (150 ml, 9.3 mmol) and heated to reflux for 4 hours. 6M hydrochloric acid (10 ml) was added little by little to adjust the pH to about 2. After cooling, the precipitate was collected by filtration to obtain 0.23 g of the desired product (yield from intermediate 6: 64%). Yellow powder.
mp 294 ° C (decomp.); ¹ H NMR (DMSO-d ₆ ): δ 6.95 (d, J = 8.5 Hz, 1H), 6.96 (d, J = 8.5 Hz, 1H), 7. 12 (d, J = 16.2 Hz, 1H), 7.13 (d, J = 16.5 Hz, 1H), 7.33 (d, J = 16.5 Hz, 1H), 7.34 (d, J = 16.2 Hz, 1H), 7.42-7.49 (m, 2H), 7.74-7.76 (m, 1H), 7.79 (d, J = 8.8 Hz, 1H), 7 .80 (d, J = 8.8 Hz, 1H), 7.98 (d, J = 2.2 Hz, 1H), 8.00 (d, J = 2.2 Hz, 1H); ¹⁹ F NMR (DMSO- _{d 6): - 118.7ppm (s} ); MS: m / z419 (M-1); IR (KBr): 3430 (OH), 3025 (CO 2 H) 1670 (C═O), 1210, 1190, 955 cm ⁻¹ .

As shown in A of the above data and Figure 2, Compound ^1, is expressed a single large peak at -118.5ppm in 19 ^F-NMR, allows the contrast by 19 F-NMR (imaging) It was confirmed that.

Synthesis Example 2: As an example of the compound of the present invention represented by the formula (I), in the formula (I), R ₁ is a hydroxyl group, R ₂ is a carboxyl group, R ₃ is a bromine atom, and α-position and β Compound 9 in which the carbon atom at the position was carbon 13 was synthesized according to the ski pole shown in FIG. Operation in each step and identification data of the obtained product are sequentially shown below.

<Synthesis of Intermediate 8>
5-Formylsalicylic acid (22.0 g, 132.4 mmol) was dissolved in acetone (1.1 L) by heating, potassium carbonate (36.5 g, 264.1 mmol) was added, and methyl iodide (253.4 g, 1. 78 mol) was added every 2 hours and stirred at 50 ° C. for 12 hours. After allowing to cool, the solvent was distilled off, water (200 ml) was added, and the insoluble material was collected by filtration. After recrystallization from ethanol (300 ml), 16.59 g (yield 65%) of the desired product was obtained. White needle crystal. ¹ H NMR (CDCl ₃ ): δ 3.93 (s, 3H), 4.06 (s, 3H), 7.12 (d, J = 8.7 Hz, 1H), 8.03 (dd, J = 8 .5, 2.2 Hz, 1H), 8.33 (d, J = 2.1 Hz, 1H), 9.92 (s, 1H).

<Synthesis of Intermediate 11>
The synthesis of the complex ferrocenium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate is carried out by the method described in the literature (H. Kitagawa et al., Bull. Chem. Soc. Jpn., 2002, 75, 339). Was synthesized from ferrocenium tetrafluoroborate in a yield of 64%. Ferrocenium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (0.49 g, 0.46 mmol) and zinc oxide (0.84 g, 10.3 mmol) were dissolved in methylene chloride (5 ml) and bromine ( 1.65 g, 10.3 mmol) was added, and the mixture was stirred at room temperature for about 1 hour. p-Xylene-α, α′- ¹³ C ₂ (1.0 g, 9.2 mmol) was dissolved in methylene chloride (10 ml), cooled to −50 ° C., and the above solution was added dropwise. The mixture was changed to an ice bath and stirred for 1.5 hours. Ethyl acetate was added and washed with saturated sodium thiosulfate. The ethyl acetate layer was washed with water and dried (MgSO ₄ ), and the solvent was evaporated. The residue was purified by silica gel column (hexane) to obtain 1.03 g (yield 59%) of the desired product. Colorless oil. ¹ H NMR (CDCl) ₃ : δ 2.28 (d, J = 127.0 Hz, 3H), 2.33 (d, J = 127.0 Hz, 3H), 6.99 (dd, J = 7.7, 4.1 Hz, 1H), 7.09 (dd, J = 7.7, 4.7 Hz, 1H), 7.34 (d, J = 4.4 Hz, 1H).

<Synthesis of Intermediate 12>
It was synthesized from intermediate 11 in the same manner as intermediate 4 (yield 43%). White crystalline powder. ¹ H NMR (CDCl ₃ ): δ 4.41 (d, J = 154.0 Hz, 2H), 4.58 (d, J = 154.0 Hz, 2H), 7.32 (ddd, J = 7.7, 4.7, 1.7 Hz, 1H), 7.43 (dd, J = 7.7, 4.7 Hz, 1H), 7.61 (dd, J = 5.5, 1.7 Hz, 1H).

<Synthesis of Intermediate 13>
It was synthesized from intermediate 12 in the same manner as intermediate 5 (yield 94%). Yellow oil. ¹ H NMR (CDCl ₃ ): δ1.25 (t, J = 7.1 Hz, 12H), 3.08 (dd, J = 18.0, 21.0 Hz, 2H), 3.37 (dd, J = 128.0, 21.0 Hz, 2H), 3.98-4.09 (m, 8H), 7.20-7.26 (m, 1H), 7.39-7.43 (m, 1H), 7.50-7.52 (m, 1H).

<Synthesis of Intermediate 14>
It was synthesized from intermediate 13 in the same manner as intermediate 6 (yield 50%). Yellow powder. ¹ H NMR (CDCl ₃ ): δ 3.93 (s, 6H), 3.94 (s, 6H), 6.94 (dd, J = 154.0, 16.0 Hz, 1H), 6.98-7 .14 (m, 4H), 7.43-7.45 (m, 1H), 7.60-7.72 (m, 5H), 7.97 (s, 1H), 7.98 (s, 1H) ).
As shown in the above data and FIG. 2B, Compound 9 expresses large peaks at 134.8 ppm and 125.5 ppm in ¹³ C-NMR, and can be imaged by ¹³ C-MRI. It was confirmed that. Note that the peak near 40 ppm in B of FIG. 2 is the peak of the solvent (DMSO ₆ -d).

Measurement of fluorescence characteristics: Fluorescence spectra were measured for Compound 1 synthesized in Example 1, Compound 9 synthesized in Example 2, and BSB for comparison. The equipment used for the measurement is
F-4500 manufactured by HITACHI. The measurement concentration is 1 μM (in DMSO), and the wavelength of the excitation light is 390 nm.
FIG. 3 shows the measurement results. As shown in FIG. 3, the compounds 1 and 9 of the present invention express strong fluorescence at 511 nm and 521 nm, similarly to BSB. In particular, Compound 1 having fluorine in the molecule has an approximately 2-fold increase in fluorescence intensity compared to BSB.

Brain amyloid staining: Brain amyloid was stained using Compound 1 synthesized in Example 1, Compound 9 synthesized in Example 2, and BSB for comparison.
Staining was performed according to the method described in Non-Patent Document 5 (DM Skovronsky et al., Proc. Natl. Acad. Sci., 2000, 97, 7609). That is, postmortem brains (4 cases) of Alzheimer's disease patients were fixed with 150% NaCl-containing 70% ethanol or 10% neutral buffered formalin (NBF), and 6-μm paraffin sections were prepared by a conventional method. The section was immersed in a 50% ethanol solution of 0.01% Compound 1, Compound 9 or BSB for 30 minutes, and then immersed in a saturated aqueous lithium carbonate solution. The sample was washed with 50% ethanol and observed with a fluorescence microscope (V excitation UV light).
4 and 5 show stained images (photographs) observed with a fluorescence microscope. FIG. 4 shows a stained image of a temporal cortex section fixed with ethanol, and FIG. 5 shows a stained image of a frontal cortex section (quasi-adjacent section) fixed with ethanol. The images shown in FIGS. 4 and 5 are actually color images, and in order to clearly show the characteristics of the images, a trace of the fluorescent region is shown below each photographic image. It is understood that Compounds 1 and 9 of the present invention have an affinity for Aβ protein constituting senile plaques and selectively fluorescently stain the protein. In addition, FIG. 5 dye | stains the same sample using the compounds 1 and 9, and has shown that the same number in a figure originates in the senile plaque of the same place.

This example demonstrates that the compounds of the present invention represented by formula (I) function as amyloid-specific MRI contrast agents. Using the compound 1 synthesized in Example 1 (hereinafter referred to as FSB in this example), MRI measurement was performed as follows.
An amyloid precursor protein transgenic mouse (Tg2576, described in K. Hsiao et al., Science, 274, 99 (1996)) is anesthetized and 0.2% FSB at a dose of 20 mg / kg, 500 μl of PBS containing 10% DMSO was administered from the tail vein over 150 minutes. Three hours later, a ¹⁹ F-MRI scan of the mouse head was performed in vivo (the mouse was alive). ¹⁹ F-MR brain images were obtained by 3D-RARE (3D spin echo Rapid acquisition Relaxation Enhancement). The MRI apparatus used was a Bruker AVANCE 400WB imaging spectrometer (manufactured by Bruker BioSpin GmbH).
The obtained brain image photograph of ¹⁹ F-MR is shown in FIG. Spots presumed to be senile groups were detected as high-signal areas in the ¹⁹ F-MR image (white spots in FIG. 6 (1)). Note that FIG. 6A is actually a color image, and the spotted portion is observed as a clear red light emitting portion. FIG. 6 (2) shows the photograph of FIG. 6 (1) traced by hand in order to facilitate understanding of FIG. 6 (1).

Further, as described above, the brains of ¹⁹ F-MRI scanned mice were removed, fixed overnight with 4% paraformaldehyde, and then embedded in 3% aqueous agarose gel to obtain T2-weighted RARE ¹ H-MR images. It was. The obtained brain image of ¹ H-MR is shown in FIG. FIG. 7 (2) shows the photograph of FIG. 7 (1) traced by hand in order to facilitate understanding of FIG. 7 (1). As shown in FIG. 7, the T2-weighted image signal is obtained in the portion corresponding to FIG. 6 (the portion indicated by the arrowhead in FIGS. 6 and 7) by ¹ H-MRI, and the spots shown in FIG. It is understood that the stigma is senile plaque. Furthermore, it was shown that in vivo ¹⁹ F-MRI can detect senile plaques with higher sensitivity than post-mortem ¹ H-MRI in some brain regions (for example, the part in the circle in FIG. 6). In addition, the brain subjected to MRI measurement as described above was frozen, a frozen section having a thickness of 40 μm was prepared, and when the FSB brain distribution was observed with a fluorescence microscope, it was observed with ¹⁹ F-MRI as shown in FIG. It was clarified that the abnormal portion (spotted portion) was detected as a result of accumulation of FSB in a lesion that was morphologically identifiable as senile plaque.

The compound of the present invention can be used as a fluorescent staining agent for amyloid derived from systemic amyloidosis and local amyloidosis for histopathological examination of diseases associated with amyloid represented by Alzheimer's disease.
Furthermore, since the compound of the present invention also functions as an MRI contrast agent having specificity for amyloid, as a simple method using MRI widely spread in medical institutions, amyloid-related diseases such as Alzheimer's disease can be used. It can also be used for prenatal diagnosis.

Claims (4)

A styrylbenzene compound represented by the following general formula (I):

[In the formula (I), R ₁ and R ₂ are each independently a hydroxyl group or a carboxyl group (except when R ₁ and R ₂ are both a hydroxyl group or a carboxyl group), and R ₃ is fluorine An atom or a bromine atom, and when R ₃ is a bromine atom, and whenever R ₃ is a fluorine atom, the α-position, β-position, γ-position, and δ-position carbon atoms and R ₁ and R ₂ At least one of the carbon atoms constituting the carboxyl group is carbon-13. ] The styrylbenzene compound according to claim 1, wherein in formula (I), R ₁ is a hydroxyl group, R ₂ is a carboxyl group, and R ₃ is a fluorine atom. The styrylbenzene compound according to claim 1, wherein in formula (I), R ₁ is a hydroxyl group, R ₂ is a carboxyl group, R ₃ is a bromine atom, and carbon atoms at the α-position and β-position are carbon 13. An amyloid-specific MRI contrast agent comprising the compound represented by the general formula (I) of claim 1.

Images