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• 102-52-3 malonaldehydebis(dimethylacetal) 
• 62-53-3 aniline 
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• 2581-87-5 N,N’-diphenyl-1,5-diazapenta-1,3-dienium perchlorate 

Downstream Products

• 40367-69-9 [4-(1,3,3-trimethyl-indolin-2-ylidene)-but-2-enyliden]-aniline; perchlorate 
• 71467-45-3 2-((1E,3E)-4-(acetyl)-4-(phenyl)aminobuta-1,3-dienyl)-3-methyl-benzothiazolium iodide 
• 63468-67-7 2-[4-(N-acetyl-anilino)-buta-1,3-dienyl]-1-ethyl-quinolinium; iodide 
• 116081-83-5 2-[4-(N-acetyl-anilino)-buta-1,3-dienyl]-1,3-dimethyl-benzimidazolium; iodide 
• 67492-39-1 4-(4-anilino-buta-1,3-dienyl)-1-methyl-quinolinium; iodide 
• 18371-33-0 1,5-bis-[3-(2-hydroxy-ethyl)-benzothiazol-2-yl]-pentamethinium ; bromide 
• 110441-23-1 N-[3-(5-oxo-3-phenyl-isoxazol-4-ylidene)-propenyl]-acetanilide 
• 1202554-83-3 C₂₆H₂₃N₂O⁽¹⁺⁾*I^(1-) 
• 59360-11-1 C₁₇H₁₆N₂O 
• 1377967-72-0 1-butyl-3,3-dimethyl-2-((1E,3E)-4-(N-phenylacetamido)buta-1,3-dienyl)-3H-indolium bromide 
• 170965-06-7 1-methyl-3,3-dimethyl-2-((1E,3E)-4-(N-phenylacetamido)buta-1,3-dienyl)-3H-indolium iodide 
• 53213-98-2 C₃₁H₃₉N₂⁽¹⁺⁾*I^(1-) 

Relevant academic research and scientific papers

Polymethine-Based Semiconducting Polymer Dots with Narrow-Band Emission and Absorption/Emission Maxima at NIR-II for Bioimaging

Deep-penetration fluorescence imaging in the second near-infrared (NIR-II) window heralds a new era of clinical surgery, in which high-resolution vascular/lymphatic anatomy and detailed cancerous tissues can be visualized in real time. Described here is a series of polymethine-based semiconducting polymers with intrinsic emission maxima in the NIR-IIa (1300–1400 nm) window and absorption maxima ranging from 1082 to 1290 nm. These polymers were prepared as semiconducting polymer dots (Pdots) in aqueous solutions with fluorescence quantum yields of 0.05–0.18 %, and they demonstrate promising applications in noninvasive through-skull brain imaging in live mice with remarkable spatial resolution as well as signal-to-background contrast. This study offers a platform for future design of NIR-IIa or even NIR-IIb emitting Pdots.

Unsymmetrical pentamethine cyanines for visualizing physiological acidities from the whole-animal to the cellular scale with pH-responsive deep-red fluorescence

Acidity plays an important role in numerous physiological and pathological events. Non-invasively monitoring pH dynamics would be valuable for understanding pathological processes and optimizing therapeutic strategies. Although numerous near-infrared (NIR) fluorophores have been developed to monitor acidification in vivo, the experimental results are difficult to verify at the molecular or cellular level using a fluorescence microscope or flow cytometer due to the lack of lasers with excitation wavelengths in the NIR wavelength range. This work presents a sequential condensation strategy for obtaining unsymmetrical pentamethine cyanines with fine-tuned pKa values and improved yields. These deep-red fluorophores with pH responsiveness can not only be used to monitor acidification in live cells using confocal microscopic imaging and flow cytometry, but they can also be used to non-invasively identify infected tissue with a low pH value in live mouse models. In addition, the acidity in infected tissue slices was verified under a conventional confocal microscope. Overall, this work demonstrates a new synthetic method with improved yields for unsymmetrical pentamethine cyanines that can report acidity. These pH-responsive deep-red fluorophores not only provide new tools for accessing pH-associated physiological and pathological events, but they can also help in understanding in vivo imaging results at the molecular or cellular level due to their detectability by multiple imaging instruments.

Cell-Permeable Fluorogenic Probes for Identification and Imaging Nitroreductases in Live Bacterial Cells

Enzyme-activated fluorogenic probes, which invoke enzymatic catalysis to trigger the generation of fluorescence, provide a versatile platform for monitoring biological processes. The development of fluorogenic probes that can readily penetrate the cell envelopes of bacteria are essential to examine intracellular targets of live bacterial cells. Herein, we present the design, synthesis, properties, and biological applications of two series of fluorogenic probes based on cyanine 5 for identification of bacterial nitroreductase (NTR). The selected fluorogenic probe 3 generates a rapid 10-fold fluorescence response after being catalytically reduced by NTR to the intermediate para-aminobenzyl substituted which then underwent a rearrangement elimination reaction. Moreover, probe 3 is cell permeable for both Gram-positive and Gram-negative bacterial cell envelopes and is selective for NTR over other biological analytes, thus minimizing the background signal and enabling the real-time intracellular imaging of NTR in live bacterial cells.

Ratiometric fluorescent probes for selective and sensitive visualization of bacterial microenvironment protease activity

The extracellular SspA protease of the human pathogen S. aureus is essential for evading the host immune defence system. Two novel FRET probes for selective real-time ratiometric imaging of SspA activity in live S. aureus cells are reported.

Polymethine Thiopyrylium Fluorophores with Absorption beyond 1000 nm for Biological Imaging in the Second Near-Infrared Subwindow

Small-molecule fluorescence imaging in the second near-infrared (NIR-II, 1000-1700 nm) window has gained increasing interest in clinical application. Till now, very few studies have been exploited in the small-molecule fluorophores with both excitation and emission in the NIR-II window. Inspired by the indocyanine green structure, a series of polymethine dyes with both absorption and emission in the NIR-II window have been developed for NIR-II imaging, providing the feasibility to directly compare optical imaging in the NIR-IIa (1300-1400 nm) subwindow under 1064 nm excitation with that in the NIR-II window under 808 nm excitation. The signal-background ratio and the tumor-normal tissue ratio achieved great improvement under 1064 nm excitation in the imaging of mouse blood pool and U87 glioma tumors. Our study not only introduces a broadband emission fluorophore for both NIR-II and NIR-IIa imaging, but also reveals the advantages of NIR-II excitation over NIR-I in in vivo imaging.

Easily-modified near-infrared region II organic small molecule dye and synthetic method and application thereof

The invention provides an easily-modified near-infrared region II organic small molecule dye and a synthetic method and application of the easily-modified near-infrared region II organic small molecule dye. The near-infrared region II fluorescent dye belongs to polymethenyl pyran or polymethenyl thiapyran salt organic small molecules, and is prepared by a condensation reaction of polymethenyl aniline salt with pyran or thiopyran salt. The synthetic raw materials are easy to obtain, the cost is low, the preparation process is simple, the yield is high, and large-amount synthesis can be achieved. The purpose of adjusting the fluorescence emission spectrum is achieved by changing an intramolecular polymethenyl chain and hetero atom species. The small molecule dye has the maximum emission wavelength range of 1000-1200 nm, and is high in fluorescence quantum yield, good in light stability and quite applicable to living imaging. The small molecule dye can be linked to groups with specific functions by click chemistry for a variety of bioimaging application. Near-infrared region II fluorescent living imaging achieves low background noise, strong fluorescence signal and high signal-to-noise ratio.

Aminoglycoside-based novel probes for bacterial diagnostic and therapeutic applications

Specific detection of pathogens has long been recognized as a vital strategy in the control of infectious diseases. Two novel theranostic neomycin analogs exhibit efficient targeting, labelling and killing of broad spectrum bacteria while not damaging macrophage-like cells. Furthermore, lipidated probe 2 clearly showed antibacterial activity against methicillin-resistant S. aureus.

Real time detection of ESKAPE pathogens by a nitroreductase-triggered fluorescence turn-on probe

The identification of bacterial pathogens is the critical first step in conquering infection diseases. A novel turn-on fluorescent probe for the selective sensing of nitroreductase (NTR) activity and its initial applications in rapid, real-time detection and identification of ESKAPE pathogens have been reported.

NOVEL KLK4 INHIBITORS

The present invention relates to novel compounds and probes which have a common chemical structure necessary to obtain potent inhibitory activity against KLK4 and/or may be used for the detection of KLK4 peptides and their activity. It further relates to the use of these compounds and methods for inhibiting and/or detecting KLK4 activity in vitro and in vivo by making use of said probes or inhibitors. The compounds of the invention differ from prior art compounds at least in the presence of phenyl guanidine (instead of e.g. benzyl guanidine) and/or the presence of a heteroatom in the tail group, their combined presence unexpectedly leading to potent and selective KLK4 inhibitory activity.

Targeting tumor hypoxia: A third generation 2-nitroimidazole-indocyanine dye-conjugate with improved fluorescent yield

Tumor hypoxia is associated with the rapid proliferation and growth of malignant tumors, and the ability to detect tumor hypoxia is important for predicting tumor response to anti-cancer treatments. We have developed a class of dye-conjugates that are related to indocyanine green (ICG, 1) to target tumor hypoxia, based on in vivo infrared fluorescence imaging using nitroimidazole moieties linked to indocyanine fluorescent dyes. We previously reported that linking 2-nitroimidazole to an indocyanine dicarboxylic acid dye derivative (2) using an ethanolamine linker (ethanolamine-2-nitroimidazole-ICG, 3), led to a dye-conjugate that gave promising results for targeting cancer hypoxia in vivo. Structural modification of the dye conjugate replaced the ethanolamine unit with a piperazineacetyl unit and led a second generation dye conjugate, piperzine-2-nitroimidazole-ICG (4). This second generation dye-conjugate showed improved targeting of tumor hypoxia when compared with 3. Based on the hypothesis that molecules with more planar and rigid structures have a higher fluorescence yield, as they could release less absorbed energy through molecular vibration or collision, we have developed a new 2-nitroimidazole ICG conjugate, 12, with two carbon atoms less in the polyene linker. Dye-conjugate 12 was prepared from our new dye (8), and coupled to 2-nitroimidazole using a piperazine linker to produce this third-generation dye-conjugate. Spectral measurements showed that the absorption/emission wavelengths of 657/670 were shifted ～100 nm from the second-generation hypoxia dye of 755/780 nm. Its fluorescence quantum yield was measured to be 0.467, which is about 5 times higher than that of 4 (0.083). In vivo experiments were conducted with balb/c mice and 12 showed more than twice the average in vivo fluorescence intensity in the tumor beyond two hours post retro-orbital injection as compared with 4. These initial results suggest that 12 may significantly improve in vivo tumor hypoxia targeting.