- Phototoxicity of some bromine-substituted rhodamine dyes: synthesis, photophysical properties and application as photosensitizers.
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The synthesis of some bromine-substituted rhodamine derivatives viz., 4,5-dibromorhodamine methyl ester (dye 2) and 4,5-dibromorhodamine n-butyl ester (dye 3) are reported. These dyes were synthesized to promote a more efficient cancer cell photosensitizer for potential use in in vitro bone marrow purging in preparation for autologous bone marrow transplantation. Spectroscopic and photophysical characterization of these dyes together with rhodamine 123 (dye 1) are reported in water, methanol, ethanol and also in a microheterogeneous system, sodium dodecyl sulfate. The possible mechanism of photosensitization is characterized in terms of singlet oxygen efficiency of these dyes. Singlet oxygen quantum yields for bromine-substituted dyes are in the range of 0.3-0.5 depending on the solvent. For dye 1 no singlet oxygen production is found. The photodynamic actions of these dyes in different cell lines are tested. It was found that dye 2 and dye 3 are efficient photosensitizers and mediate eradication of K562, EM2, myeloid cell lines (CML) and the SMF-AI rhabdomyosarcoma line.
- Pal,Zeng,Durocher,Girard,Li,Gupta,Giasson,Blanchard,Gaboury,Balassy,Turmel,Laperriere,Villeneuve
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- Facile synthesis of rhodamine esters using acetyl chloride in alcohol solution
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The rhodamines are a highly fluorescent class of compound used in many different fields of research, from the lasing medium in dye lasers to biological stains and markers for cellular drug resistance. In this study, esters (2-7) of rhodamine 110 (1) were conveniently prepared via the addition of acetyl chloride to a solution of the free acid (1) in the appropriate alcohol. This method conferred several advantages over previous preparations, namely that for low boiling alcohols, simple evaporation of the solution afforded the ester in quantitative yield with no need for purification. For higher boiling point alcohols, a method has been developed which allows the separation of longer chain esters from the alcohol solvent. Copyright Taylor & Francis Group, LLC.
- Ross, Justin A.,Ross, Benjamin P.,Rubinsztein-Dunlop, Halina,McGeary, Ross P.
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- Does Perthionitrite (SSNO-) Account for Sustained Bioactivity of NO? A (Bio)chemical Characterization
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Hydrogen sulfide (H2S) and nitric oxide (NO) are important signaling molecules that regulate several physiological functions. Understanding the chemistry behind their interplay is important for explaining these functions. The reaction of H2S with S-nitrosothiols to form the smallest S-nitrosothiol, thionitrous acid (HSNO), is one example of physiologically relevant cross-talk between H2S and nitrogen species. Perthionitrite (SSNO-) has recently been considered as an important biological source of NO that is far more stable and longer living than HSNO. In order to experimentally address this issue here, we prepared SSNO- by two different approaches, which lead to two distinct species: SSNO- and dithionitric acid [HON(S)S/HSN(O)S]. (H)S2NO species and their reactivity were studied by 15N NMR, IR, electron paramagnetic resonance and high-resolution electrospray ionization time-of-flight mass spectrometry, as well as by X-ray structure analysis and cyclic voltammetry. The obtained results pointed toward the inherent instability of SSNO- in water solutions. SSNO- decomposed readily in the presence of light, water, or acid, with concomitant formation of elemental sulfur and HNO. Furthermore, SSNO- reacted with H2S to generate HSNO. Computational studies on (H)SSNO provided additional explanations for its instability. Thus, on the basis of our data, it seems to be less probable that SSNO- can serve as a signaling molecule and biological source of NO. SSNO- salts could, however, be used as fast generators of HNO in water solutions.
- Wedmann, Rudolf,Zahl, Achim,Shubina, Tatyana E.,Dürr, Maximilian,Heinemann, Frank W.,Bugenhagen, Bernhard Eberhard Christian,Burger, Peter,Ivanovic-Burmazovic, Ivana,Filipovic, Milos R.
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- 1H and 13C NMR spectra of commercial rhodamine ester derivatives
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Ethyl and methyl esters of commercial rhodamines B, 19, 101 and 110 and propyl and butyl esters of commercial rhodamine B were synthesized and isolated with different counterions (yields 70-98%). The 1H and 13C NMR spectral data for these compounds were fully assigned by a combination of one-and two-dimensional experiments. The Fourier transform IR and UV-visible spectra were also recorded and the main bands were identified. Copyright
- Ramos,Vilhena,Santos,Almeida
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p. 475 - 478
(2007/10/03)
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