- A general strategy to optimize the performance of aza-BODIPY-based probes for enhanced photoacoustic properties
-
In this chapter, we describe a generalizable strategy to obtain a high PA output platform that is optimized for ratiometric imaging. Our approach entails conformationally restricting pendant aryl rings on the aza-BODIPY core to enhance orbital overlap which consequently increases the extinction coefficient. This strategy can potentially be applied to other dye platforms to enhance their signal intensity. We provide detailed protocols for the synthesis, in vitro characterization, and in vivo application.
- Yadav, Anuj K.,Tapia Hernandez, Rodrigo,Chan, Jefferson
-
p. 415 - 441
(2021/07/26)
-
- BIOREDUCIBLE N-OXIDE-BASED PROBES FOR IMAGING OF HYPOXIA
-
Hypoxia occurs when limited oxygen supply impairs physiological functions and is a pathological hallmark of many diseases including cancer and ischemia. Thus, detection of hypoxia can guide treatment planning and serve as a predictor of patient prognosis. Current methods suffer from invasiveness, poor resolution and low specificity. To address these limitations, various hypoxia-responsive probes (HyPs) for photoacoustic imaging are disclosed. The emerging modality converts safe, non-ionizing light to ultrasound waves, enabling acquisition of high-resolution 3D images in deep tissue. The HyPs feature an N-oxide trigger that is reduced in the absence of oxygen by haem proteins such as CYP450 enzymes. Reduction of HyPs produce a spectrally distinct product, facilitating identification via photoacoustic imaging. HyPs exhibit selectivity for hypoxic activation in vitro, in living cells and in multiple disease models in vivo. HyPs are also compatible with NIR fluorescence imaging, establishing its versatility as a multimodal imaging agent.
- -
-
Paragraph 0145; 0198
(2020/03/09)
-
- A Conformationally Restricted Aza-BODIPY Platform for Stimulus-Responsive Probes with Enhanced Photoacoustic Properties
-
Photoacoustic (PA) dyes, which absorb near-infrared (NIR) light to generate an ultrasonic signal, can be detected at centimeter depths in tissues with significantly higher resolution than dyes imaged with fluorescence-based methods. As such, PA agents show great promise as research tools for the study of live-animal disease models. However, the development of activatable PA probes has been hampered by the relative scarcity of appropriate PA-active molecular platforms with properties that can be manipulated in a rational manner. Herein we synthesized and evaluated six modifications to the aza-BODIPY dye platform with respect to their absorbance, fluorescence, and PA properties. We identified a promising conformationally restricted aza-BODIPY (CRaB) scaffold that prioritizes three criteria necessary for the design of stimulus-responsive dyes with optimal ratiometric PA response: absorbance at NIR wavelengths, strong PA intensity, and large Δλ upon interaction with the desired stimulus. Using this scaffold, we synthesized three chemically diverse stimulus-responsive PA probes and demonstrated between 2- and 8-fold improvements in theoretical ratiometric response in vitro. This suggests that improvements in PA parameters are generalizable. Finally, we validated the in vitro turnover of each CRaB PA probe and demonstrated the in vivo potential of the CRaB scaffold by direct comparison to an established hypoxia-responsive probe for the detection of tumor hypoxia.
- Zhou, Effie Y.,Knox, Hailey J.,Liu, Chang,Zhao, Weili,Chan, Jefferson
-
supporting information
p. 17601 - 17609
(2019/11/11)
-
- Exploring Tandem Ruthenium-Catalyzed Hydrogen Transfer and SNAr Chemistry
-
A hydrogen-transfer strategy for the catalytic functionalization of benzylic alcohols via electronic arene activation, accessing a diverse range of bespoke diaryl ethers and aryl amines in excellent isolated yields (38 examples, 70% average yield), is reported. Taking advantage of the hydrogen-transfer approach, the oxidation level of the functionalized products can be selected by judicious choice of simple and inexpensive additives.
- Polidano, Kurt,Reed-Berendt, Benjamin G.,Basset, Ana?s,Watson, Andrew J. A.,Williams, Jonathan M. J.,Morrill, Louis C.
-
p. 6716 - 6719
(2017/12/26)
-
- CuI/DMPAO-catalyzed N-arylation of acyclic secondary amines
-
DMPAO has been found to be a powerful ligand to enable copper-catalyzed coupling of aryl halides with aliphatic acyclic secondary amines take place under relatively mild conditions, and coupling of aryl halides with primary amines and cyclic secondary amines proceeds at low catalyst loading.
- Zhang, Yu,Yang, Xinye,Yao, Qizheng,Ma, Dawei
-
supporting information; experimental part
p. 3056 - 3059
(2012/07/28)
-
- Synthesis of 5-aryl-5′-formyl-2,2′-bithiophenes as new precursors for nonlinear optical (NLO) materials
-
A series of formyl-substituted 5-aryl-2,2′-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized arylboronic acids 7 and the 5-bromo-5′-formyl-2,2′-bithiophene 6 gave compounds 5 in good yields in only one step.
- Herbivo, Cyril,Comel, Alain,Kirsch,Raposo, M. Manuela M.
-
experimental part
p. 2079 - 2086
(2009/07/18)
-
- Structure-activity relationship study of a novel necroptosis inhibitor, necrostatin-7
-
Necroptosis is a regulated caspase-independent cell death mechanism characterized by morphological features resembling non-regulated necrosis. Necrotatin-7 (Nec-7), a novel potent small-molecule inhibitor of necroptosis, is structurally distinct from previously described necrostatins (Nec-1, Nec-3, Nec-4 and Nec-5). Here, we describe a series of structural modifications and the structure-activity relationship (SAR) of the Nec-7 series for inhibiting necroptosis.
- Zheng, Weihong,Degterev, Alexei,Hsu, Emily,Yuan, Junying,Yuan, Chengye
-
body text
p. 4932 - 4935
(2009/05/26)
-
- Diarylamino groups as photostable auxofluors in 2-benzoxazolylfluorene, 2,5-diphenyloxazoles, 1,3,5-hexatrienes, 1,4-distyrylbenzenes, and 2,7-distyrylfluorenes
-
The relationship of structure to optical spectral properties was determined for five types of fluors in a search for an optimum-wavelength shifter to be used as part of the detection systems for high-energy particles from accelerators. In a search for photostable fluors to serve as waveshifters in plastic fibers it was found that the wavelengths of interest, absorption max 410 ± 10 nm and fluorescence emission max 480 ± 20 nm, along with other properties, such as high solubility and short fluorescence decay time, could be obtained from fluorophors composed of aromatic rings and vinyl groups only by using amino groups as auxochromes to give bathochromic shifts of wavelengths. Since primary, monoalkyl, and dialkylamino groups were not sufficiently photostable, a number of fluorophores bearing diarylamino groups were investigated. Syntheses of the fluors made use of the Buchwald amination, an improved version of the Emmons-Horner reaction, and other common reactions. The fluor types were the following: a 2-benzoxazolyl-7-(4-diarylamino)fluorene 7, 2-(4-cyanophenyl)-5-(4-aminophenyl)oxazoles 14 and 20, 1,3,5-hexatrienes 24a-d and 26a-c, 1,4-distyrylbenzenes 31d-g and 32a-e, and 2,7-distyrylfluorenes 40a,d-e. The unsymmetrical fluors 7, 14, and 20 were not as bright as the best hexatrienes, distyrylbenzenes, and distyrylfluorenes, which were all symmetrical. Where the 1,6-diaryl-1,3,5-hexatrienes 24a-d had high fluorescence quantum yield (Φf), the 1,1,6,6-tetraryl-1,3,5-hexatrienes 26a-c had both lower ε and Φf. Where the 1,4-distyrylbenzenes 31d-g had high Φf, the 1,4-bis(2-phenylstyryl)benzenes 32a-e had (Φf = 0. Diarylamino groups as auxofluors conferred higher photochemical stability than dialkylamino groups on similar fluorophores. The 1,4-distyrylbenzenes 31d,e and the 2,7-distyrylfluorenes 40d,e had the most desirable properties overall, which included fast decay times of 2 ns. Computer simulations predicted absorption and emission wavelengths fairly well, but were of little help for the prediction of brightness, stability, Φf, or decay time.
- Kauffman, Joel M.,Moyna, Guillermo
-
p. 839 - 853
(2007/10/03)
-
- Amination of aryl bromides catalysed by supported palladium
-
Palladium particles immobilised onto a metal oxide support or Pd(0), Pd(II) and [Pd(NH3)4]2+ in NaY zeolite have been prepared and characterised. They exhibit a good activity towards the amination of aryl bromides using secondary amines such as piperidine and diethyl amine with a good regio-selectivity for these reactions. Low Pd concentrations (1 mol%) are required to observe a reasonable regio-selectivity. The catalysts can easily be separated from the reaction mixture (filtration) and reused without loss of activity and selectivity. The electronic nature of the aryl halides plays an important role for both the reaction yields and the regio-control of the reaction. It depends on the relation of the direct amination via a benzyne intermediate versus the Pd-catalysed route.
- Djakovitch, Laurent,Wagner, Michael,Koehler, Klaus
-
p. 225 - 234
(2007/10/03)
-
- PALLADIUM-CATALYZED AROMATIC AMINATION OF ARYL BROMIDES WITH N,N-DIETHYLAMINO-TRIBUTYLTIN
-
The reaction of N,N-diethylamino-tributyltin with aryl bromides in the presence of a catalytic amount of PdCl2(o-tolyl3P)2 gave N,N-diethylaminobenzene derivatives.The reaction is a new kind of amination different from ones through aryne or SRN1 mechanism.
- Kosugi, Masanori,Kameyama,Masayuki,Migita, Toshihiko
-
p. 927 - 928
(2007/10/02)
-
