- Development of a new fluorescent probe: 1,3,5,7-tetramethyl-8-(4′-aminophenyl)-4,4-difluoro-4-bora-3a, 4a-diaza-s-indacence for the determination of trace nitrite
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A new fluorescent probe, 1,3,5,7-tetramethyl-8-(4′-aminophenyl)-4,4-difluoro-4-bora-3a, 4a-diaza-s-indacence (TMABODIPY) has been developed for the determination of trace nitrite in terms of the reaction of nitrite with TMABODIPY first in acidic solution and then in alkaline solution to form diazotate, a stable and highly fluorescent reagent. The method offered the advantage of specificity, sensitivity and simplicity. The linear calibration range for nitrite was 8-300nmoll-1s with a 3σ detection limit of 0.65nmoll -1. The proposed method has been applied to monitor the trace nitrite in drinking water and vegetable without extraction.
- Li, Mengling,Wang, Hong,Zhang, Xian,Zhang, Hua-Shan
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Read Online
- A near-infrared and lysosomal targeting thiophene-BODIPY photosensitizer: Synthesis and its imaging guided photodynamic therapy of cancer cells
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In this study, a novel NIR and lysosomal targeting thiophene-BODIPY photosensitizer SBOP-Lyso was synthesized to explore its potential applications in photodynamic therapy of A549 cells. In the strategy of designing SBOP-Lyso, S atom in thiophene as well as heavy atom I were introduced to promote ISC efficiency to ensure high singlet oxygen yield. A common lysosome targeted group (M1: 1-(2-morpholinoethyl)-1H-indole-3-carbaldehyde) was linked to SBOP to extend its wavelength to the NIR region. Its absorption peak was at 660 nm (εmax = 5.2 × 104 cm?1 M?1) and its corresponding emission peak was located at 705 nm. Singlet oxygen could be quickly generated by SBOP-Lyso in the presence of 660 nm LED irradiation and the singlet oxygen yield was up to 44.1%. In addition, it also had good biocompatibility and could enter cells or zebrafish in a short time. SBOP-Lyso had negligible dark cytotoxicity (cell survival rate > 80%) and excellent phototoxicity (IC50 = 0.2 μM). DCFH-DA (ROS indicator) proved that SBOP-Lyso could generate singlet oxygen with 660 nm LED irradiation. Singlet oxygen produced by SBOP-Lyso could kill cancer cells in PDT process and it had the ability to effectively inhibit A549 cells migration. Besides that, lysosomal colocalization assay showed that it had good lysosomal localization ability (Pearson colocation coefficient, R = 0.93). Considering the above results, SBOP-Lyso as a unique lysosome-targeted photosensitizer with excellent properties would exhibit positive results in PDT process of cancer cells.
- Bai, Jin,Zhang, Lei,Qian, Ying
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supporting information
(2021/02/16)
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- Novel indole-BODIPY photosensitizers based on iodine promoted intersystem crossing enhancement for lysosome-targeted imaging and photodynamic therapy
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In this work, we report the new lysosome-targeting indole-BODIPY derivatives BDP-Lys, IBDP-Lys, and I2BDP-Lys. BDP-Lys dye was designed for fluorescence imaging through introduction of an indole-containing morpholine moiety to a BODIPY core. Monoiodine and diiodine were incorporated into BDP-Lys dye to develop the photosensitizers IBDP-Lys and I2BDP-Lys. The maximum absorption (λabs) for IBDP-Lys and I2BDP-Lys displayed a redshift at approximately 11 nm and 27 nm, respectively, compared with the BDP-Lys dye (λabs= 504 nm). Similarly, the maximum emission also exhibited a redshift. The fluorescence quantum yield (ΦF) of IBDP-Lys (ΦF= 0.37%) and I2BDP-Lys (ΦF= 0.71%) was much lower than that of BDP-Lys dye (ΦF= 7.48%). The singlet oxygen quantum yields were measured as 43.10% for IBDP-Lys and 71.00% for I2BDP-Lys, which were higher than the iodine-free dye BDP-Lys. The theoretical calculation reasonably explains that iodine atoms promoted the intersystem crossing (ISC) process, and di-iodine further enhanced the ISC in indole-BODIPY dyes. Moreover, monoiodine photosensitizer IBDP-Lys was able to balance the generation of singlet oxygen and biocompatibility in cancer treatment. IBDP-Lys exhibited low dark toxicity (cell viability >90%), satisfactory biocompatibility, and precise lysosome targeting, with a Pearson coefficient of 0.93. The IBDP-Lys photosensitizer also was able to kill tumour cells. Considering the above results, the novel structure of indole-BODIPY photosensitizers could serve as a potential platform for lysosome-targeted imaging and photodynamic therapy.
- Liu, Miao,Qian, Ying,Wang, Chengjun
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supporting information
p. 18082 - 18089
(2021/10/12)
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- Design and synthesis of perfluoroalkyl decorated BODIPY dye for random laser action in a microfluidic device
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New and highly emissive 2,6-diacetynyl and 2,6-bis-(phenylacetynyl) functionalized pentamethyldifluoroboron-dipyrromethane (BODIPY) derivatives (FBDP1-2) with perfluorinated pendant groups at the boron center have been synthesized successfully by the combination of two strategies: extending the π-conjugation and functionalization at the boron centre. The newly synthesized dyes have been characterized unambiguously by using various analytical tools such as multinuclear NMR, MALDI-TOF, and single crystal XRD analysis. The dyes (FBDP1-2) exhibit excellent photophysical properties in the yellow to red spectral region (λabs = 530 nm and 555 nm, and λem = 555 nm and 596 nm, respectively) with relatively good Stokes shifts (849 cm-1 and 1240 cm-1), high quantum efficiency (?F = 0.72 and 0.61) and excellent brightness (2.95 × 104 and 2.38 × 104 M-1 cm-1). Most importantly, under a transverse pumping condition at 532 nm, the dyes show efficient and stable laser action, having a good tunable range (20 nm and 13 nm) with a maximum lasing efficiency of 45% and 38% for FBDP1 and FBDP2, respectively. Moreover, the random lasing behavior of FBDP1 has been investigated in a dye-circulated polydimethylsiloxane (PDMS) based disordered microfluidic device. The appearance of randomly positioned sharp spikes with a full width at half maximum (FWHM) of less than 0.3 nm around 555 nm indicates the random laser (RL) emission. The relationship between input pump energy and output random lasing intensity has also been demonstrated, with the random lasing threshold of 0.5 mJ.
- Maity, Apurba,Sarkar, Anirban,Bhaktha B.n, Shivakiran,Patra, Sanjib K.
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supporting information
p. 14650 - 14661
(2020/10/02)
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- Thermal Behavior Analysis of Two Synthesized Flavor Precursors of N-alkylpyrrole Derivatives
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To expand the library of pyrrole-containing flavor precursors, two new flavor precursors—methyl N-benzyl-2-methyl-5-formylpyrrole-3-carboxylate (NBMF) and methyl N-butyl-2-methyl-5-formylpyrrole-3-carboxylate (NUMF)—were synthesized by cyclization, oxidation, and alkylation reactions. Thermogravimetry (TG), differential scanning calorimeter, and pyrolysis–gas chromatography/mass spectrometry were utilized to analyze the thermal degradation behavior and thermal degradation products of NBMF and NUMF. The TG-DTG curve indicated that the maximum mass loss rates of NBMF and NUMF appear at 310 and 268°C, respectively. The largest peaks of NBMF and NUMF showed by the differential scanning calorimeter curve were 315 and 274°C, respectively. Pyrolysis–gas chromatography/mass spectrometry detected small molecule fragrance compounds appeared during thermal degradation, such as 2-methylpyrrole, 1-methylpyrrole-2-carboxylic acid methyl ester, limonene, and methyl formate. Finally, the thermal degradation mechanism of NBMF and NUMF was discussed, which provided a theoretical basis for their application in tobacco flavoring additives.
- Ai, Lvye,Liu, Mengzhen,Ji, Xiaoming,Lai, Miao,Zhao, Mingqin,Ren, Tianbao
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p. 2389 - 2397
(2019/08/01)
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- A water-soluble BODIPY based ‘OFF/ON' fluorescent probe for the detection of Cd2+ ions with high selectivity and sensitivity
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A water-soluble dilithium salt BODIPY derivative (LiBDP) with appended dicarboxylate pseudo-crown ether [NO4] coordinating sites has been designed, synthesized and characterized successfully for the selective and sensitive recognition of Cd2+ in aqueous media. The chemosensor exhibits a remarkable increase in fluorescence intensity as well as a distinct color change upon the addition of Cd2+ over other environmentally and biologically relevant metal ions in H2O. The fluorometric response of LiBDP is attributed to the metal chelation-enhanced fluorescence (MCHEF) effect which has been confirmed by a strong association constant of 2.57 ± 1.06 × 105 M?1 and Job's plot, indicating 1?:?1 binding stoichiometry between LiBDP and Cd2+. Frontier molecular orbital analysis (obtained from DFT studies) also illustrates the turn-on fluorescence of the probe by blocking photoinduced electron transfer (PET) after coordination to Cd2+. The probe can detect Cd2+ in a competitive environment up to a submicromolar level in a biologically significant pH range. The sensor is proved to be reversible and reusable by the alternative addition of Cd2+ followed by S2?. The OFF/ON/OFF sensing behavior is utilized to construct an INHIBIT molecular logic gate based on the two inputs of Cd2+ and S2? and a fluorescence intensity at 512 nm as an output. The test paper experiment demonstrates the practical utility of LiBDP to monitor Cd2+ in an aqueous sample. Finally, the sensing probe was utilized to monitor Cd2+ in living cells.
- Maity, Apurba,Ghosh, Utsav,Giri, Dipanjan,Mukherjee, Devdeep,Maiti, Tapas Kumar,Patra, Sanjib K.
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supporting information
p. 2108 - 2117
(2019/02/12)
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- Synthesis, photophysical and concentration-dependent tunable lasing behavior of 2,6-diacetylenyl-functionalized BODIPY dyes
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2,6-Diacetylenyl- and 2,6-bis(arylacetylenyl)-functionalized pentamethyl-difluoroborondipyrromethene (BODIPY) derivatives, namely, PBDP1 and PBDP2-4 (aryl = phenyl, 4-methoxyphenyl, or 4-cyanophenyl), respectively, which exhibit extended π-conjugation, were synthesized and characterized by various spectroscopic methods. Significant bathochromic shifts in both absorption and emission were observed upon modifying the structure of the BODIPY core via the strategy of extending its π-conjugation. The derivatives displayed efficient emission in the yellow-to-red spectral region, with a high fluorescence quantum yield and a relatively large Stokes shift. Under conditions of transverse pumping in a cuvette, PBDP1 and PBDP2 exhibited highly efficient and stable laser activity for up to 180 and 110 minutes of continuous irradiation, respectively. Amplified spontaneous emission (FWHM of ca. 2.5 nm) with an efficiency of 41% and 36% was achieved for PBDP1 and PBDP2, respectively, in toluene, which had tunable ranges of 561 to 580 nm and 602 to 617 nm, respectively, on irradiation with a Q-switched Nd:YAG laser at 532 nm. The lasing properties of PBDP3 and PBDP4, which contain electron-donating (-OMe) and electron-withdrawing (-CN) arylacetylenyl moieties, respectively, were also investigated. A corresponding digold(i) diacetylide organometallic complex, namely, (PPh3)Au-C≡C-BODIPY-C≡C-Au(PPh3) (PBDP5) was also synthesized and characterized to study the effect of Au(i). PBDP5 exhibited phosphorescence in the vis-NIR region centered at 751 nm at 77 K owing to heavy-atom-induced intersystem crossing.
- Maity, Apurba,Sarkar, Anirban,Sil, Amit,B. N., Shivakiran Bhaktha,Patra, Sanjib K.
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supporting information
p. 2296 - 2308
(2017/03/22)
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- Synthesis and evaluation of a [18F]BODIPY-labeled caspase-inhibitor
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BODIPYs (boron dipyrromethenes) are fluorescent dyes which show high stability and quantum yields. They feature the possibility of selective 18F-fluorination at the boron-core. Attached to a bioactive molecule and labeled with [18F]fluorine, the resulting compounds are promising tracers for multimodal imaging in vivo and can be used for PET and fluorescence imaging. A BODIPY containing a phenyl and a hydroxy substituent on boron was synthesized and characterized. Fluorinated and hydroxy substituted dyes were coupled to an isatin-based caspase inhibitor via cycloaddition and the resulting compounds were evaluated in vitro in caspase inhibition assays. The metabolic stability and the formed metabolites were investigated by incubation with mouse liver microsomes and LC-MS analysis. Subsequently the fluorophores were labeled with [18F]fluorine and an in vivo biodistribution study using dynamic PET was performed.
- Ortmeyer, Christian Paul,Haufe, Günter,Schwegmann, Katrin,Hermann, Sven,Sch?fers, Michael,B?rgel, Frederik,Wünsch, Bernhard,Wagner, Stefan,Hugenberg, Verena
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supporting information
p. 2167 - 2176
(2017/03/23)
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- A novel triphenylamine-BODIPY dendron: Click synthesis, near-infrared emission and a multi-channel chemodosimeter for Hg2+ and Fe3+
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A novel triphenylamine-BODIPY based Schiff base fluorescent probe (TPA-BODIPY-OH) with an emission in the near-infrared (NIR) region was designed and prepared by click reaction. TPA-BODIPY-OH showed three emission bands at 510 nm, 598 nm and 670 nm, and can detect Fe3+ and Hg2+ ions with remarkable fluorescence enhancement in THF/H2O (v/v, 1:1, buffered with 10 mM HEPES pH = 7.4) based on the hydrolysis reaction of the -CN bond, and naked eye detection was realized with an obvious color change. The stoichiometry between the probe and ions was deduced from a Job's plot, which is 1:3 for TPA-BODIPY-OH/Fe3+ and 1:2 for TPA-BODIPY-OH/Hg2+, respectively. The dissociation constant value was found to be 1.35 × 10-16 M for TPA-BODIPY-OH/Fe3+ and 2.06 × 10-11 M for TPA-BODIPY-OH/Hg2+. The low detection limit was calculated from the titration results with the values of 5.15 × 10-7 M for TPA-BODIPY-OH/Fe3+ and 6.81 × 10-7 M for TPA-BODIPY-OH/Hg2+, respectively. In order to investigate the biological applications of TPA-BODIPY-OH, a living cell imaging experiment was carried out. The results demonstrate that TPA-BODIPY-OH can be successfully applied as a bioimaging agent in living cells. In addition, amino-group-functionalized silica fluorescent nanoparticles (FNPs) encapsulating the TPA-BODIPY-OH dyes were prepared and characterized by transmission electron microscopy. TPA-BODIPY-OH/SiO2 nanoparticles exhibit good dispersibility, and the quantum yield of FNPs at 657 nm was 42.3%.
- Shen, Bao-Xing,Qian, Ying
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supporting information
p. 7549 - 7559
(2016/12/09)
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- A novel BODIPY -Schiff base-based colorimetric and fluorometric dosimeter for Hg2+, Fe3+ and Au3+
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A novel Schiff base-based multi-target dosimeter for Hg2+, Fe3+ and Au3+ has been designed and synthesized. Upon addition of Hg2+, Fe3+ and Au3+ to the aqueous solution of compound BODIPY-TRIA, the dosimeter gave a rapid fluorescence response and displayed an obvious fluorescence enhancement with a blue-shift. Meanwhile, a sharp color change from purple to pale yellow occurred, which was readily detected by the naked eye. The hydrolysis of the Schiff base promoted by Hg2+, Fe3+ and Au3+ has been discussed, and the possible mechanism was confirmed by 1H NMR and MS studies. The dosimeter showed high sensitivity (10 nM for Au3+), good stability, and excellent selectivity for Hg2+, Fe3+ and Au3+ with interference by other metal ions.
- Cheng, Huan-Ren,Qian, Ying
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p. 82887 - 82893
(2015/10/19)
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- Intracellular Distribution of Fluorescent Copper and Zinc Bis(thiosemicarbazonato) Complexes Measured with Fluorescence Lifetime Spectroscopy
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The intracellular distribution of fluorescently labeled copper and zinc bis(thiosemicarbazonato) complexes was investigated in M17 neuroblastoma cells and primary cortical neurons with a view to providing insights into the neuroprotective activity of a copper bis(thiosemicarbazonato) complex known as CuII(atsm). Time-resolved fluorescence measurements allowed the identification of the CuII and ZnII complexes as well as the free ligand inside the cells by virtue of the distinct fluorescence lifetime of each species. Confocal fluorescent microscopy of cells treated with the fluorescent copper(II)bis(thiosemicarbazonato) complex revealed significant fluorescence associated with cytoplasmic puncta that were identified to be lysosomes in primary cortical neurons and both lipid droplets and lysosomes in M17 neuroblastoma cells. Fluorescence lifetime imaging microscopy confirmed that the fluorescence signal emanating from the lipid droplets could be attributed to the copper(II) complex but also that some degree of loss of the metal ion led to diffuse cytosolic fluorescence that could be attributed to the metal-free ligand. The accumulation of the copper(II) complex in lipid droplets could be relevant to the neuroprotective activity of CuII(atsm) in models of amyotrophic lateral sclerosis and Parkinson's disease.
- Hickey, James L.,James, Janine L.,Henderson, Clare A.,Price, Katherine A.,Mot, Alexandra I.,Buncic, Gojko,Crouch, Peter J.,White, Jonathan M.,White, Anthony R.,Smith, Trevor A.,Donnelly, Paul S.
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p. 9556 - 9567
(2015/10/12)
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- Preparation, spectral and thermal properties of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes with iodosubstituted 2,2′-dipyrrolylmethene
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Complexes [ML2] of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with asymmetrically substituted (E)-3-ethyl-5-[(4-iodo-3,5- dimethyl-2H-pyrrol-2-ylidene)methyl]-2,4-dimethyl-1H-pyrrole (HL) have been prepared and characterized for the first time. The spectral properties, stability in solutions and in the solid phase at elevated temperature of the complexes have been studied. The effects of complexing metal ion and the reaction medium on the spectral luminescent properties (absorptivity, quantum yield, fluorescence lifetime, and the radiation constant) and on thermal destruction of the [ML2] complexes have been discussed.
- Guseva,Antina,Beresin,V'Yugin,Nuraneeva
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p. 1571 - 1579
(2013/10/22)
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- Antimalarial activity of natural and synthetic prodiginines
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Prodiginines are a family of linear and cyclic oligopyrrole red-pigmented compounds. Herein we describe the in vitro antimalarial activity of four natural (IC50 = 1.7-8.0 nM) and three sets of synthetic prodiginines against Plasmodium falciparum. Set 1 compounds replaced the terminal nonalkylated pyrrole ring of natural prodiginines and had diminished activity (IC 50 > 2920 nM). Set 2 and set 3 prodiginines were monosubstituted or disubstituted at either the 3 or 5 position of the right-hand terminal pyrrole, respectively. Potent in vitro activity (IC50 = 0.9-16.0 nM) was observed using alkyl or aryl substituents. Metacycloprodiginine and more potent synthetic analogues were evaluated in a P. yoelii murine patent infection using oral administration. Each analogue reduced parasitemia by more than 90% after 25 (mg/kg)/day dosing and in some cases provided a cure. The most favorable profile was 92% parasite reduction at 5 (mg/kg)/day, and 100% reduction at 25 (mg/kg)/day without any evident weight loses or clinical overt toxicity.
- Papireddy, Kancharla,Smilkstein, Martin,Kelly, Jane Xu,Shweta,Salem, Shaimaa M.,Alhamadsheh, Mamoun,Haynes, Stuart W.,Challis, Gregory L.,Reynolds, Kevin A.
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experimental part
p. 5296 - 5306
(2011/10/02)
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- Direct synthesis of chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines via a catalytic asymmetric intramolecular aza-Friedel-Crafts reaction
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The direct asymmetric intramolecular aza-Friedel-Crafts reaction of N-aminoethylpyrroles with aldehydes catalyzed by a chiral phosphoric acid represents the first efficient method for the preparation of medicinally interesting chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines with high yields and high enantioselectivities. This strategy has been shown to be quite general toward various aldehydes and pyrrole derivatives.
- He, Yuwei,Lin, Maohui,Li, Zhongmin,Liang, Xinting,Li, Guilong,Antilla, Jon C.
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supporting information; experimental part
p. 4490 - 4493
(2011/10/09)
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- Synthesis and spectral properties of new 3,3'-bis(dipyrrolylmethene) with acetylene spacer
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Bis(2,4,7,9-tetramethyl-8-ethyldipyrrolylmethen-3-yl)acetylene dihydrobromide (H2L·2HBr), new bis(dipyrrolylmethene), in whose molecule dipyrrolylmethene domains were connected through 3,3'-carbon atoms of internal pyrrole nuclei by acetylene spacer, were synthesized by original procedure. The compound was characterized by element analysis, IR, 1H NMR, and electronic spectroscopy. The comparative analysis of spectral properties shows the reduction of the basicity of H2L ligand in comparison with the structural analogs, which contain internal methylene spacer. The quantum-chemical simulation showed that the rigid acetylene spacer gives linear structure to the H2L molecule in contrast to the spiral-shaped geometry of structural analogs with-CH2-spacer. Pleiades Publishing, Ltd., 2010.
- Antina,Guseva,Loginova,Semeikin,V'Yugin
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experimental part
p. 2374 - 2381
(2011/04/14)
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- Boradiazaindacene dyes for technology of biological microchips
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A number of boradiazaindacene dyes containing a carboxyl group separated from a fluorophore by two methylene units were synthesized. The compounds have narrow spectral bands with absorption maxima at 480-530 nm and fluorescence maxima at 500-550 nm. Succinimide esters of these compounds and the corresponding fluorescent-labeled oligonucleotides were also prepared. Boradiazaindacene dyes can be used as fluorescent labels for oligonucleotides for analysis of melting curves of duplexes on microchips either by themselves or in combination with Texas Red. They can also be applied for labeling primers for polymerase chain reaction.
- Belobritskaya,Neunylova,Vasiliskov,Rumyantseva,Chudinov,Zasedatelev
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p. 617 - 619
(2008/03/27)
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- Synthesis of a Chiral 3,3′-Di-tert-butyl-2,2′-bipyrrole
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Diethyl 3,3′-di-tert-butyl-4,4′-dimethyl-2,2′-bipyrrole- 5,5′-dicarboxylate was synthesized in four steps from ethyl 3,5-dimethyl-1H-pyrrole-2-carboxylate. The CH2 hydrogens of the ethyl ester groups of the former are diastereotopic in the 1H-NMR, consistent with axial chirality of the bipyrrole and restricted rotation about the 2,2′-bipyrrole bond, due to the tert-butyl groups. An X-ray structure of the crystalline target compound shows the pyrrole rings are twisted out of coplanarity by 84.5°.
- Skowronek, Pawel,Lightner, David A.
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p. 889 - 899
(2007/10/03)
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- Novel aminophenyl ketone derivatives
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Novel heteroaryl aminophenyl ketone derivatives which are inhibitors of MAP kinases, in particular the p38 MAP kinase, are useful as anti-inflammatory agents in the prophylaxis or treatment of inflammatory diseases or conditions.
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- A novel facile synthesis of 2,5-di- and 2,3,5-trisubstituted pyrroles
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Heterocyclization of ketoximes with propyne or allene in superbase systems MOR/DMSO (M = K, Cs; R = H, t-Bu), which leads to 2-alkyl(aryl, hetaryl)-5-methyl- and 2,3-dialkyl-5-methylpyrroles or 2-methyl-4,5,6,7-tetrahydroindole in yields of up to 63%, has been accomplished for the first time. The reaction is mostly regioselective affording mainly or exclusively 2,5-di- and 2,3,5-trisubstituted pyrroles. The minor isomers in most cases are the corresponding 2,4-di- and 2,3,4-trisubstituted pyrroles, only in the case of acetoxime the isomer ratio is ca 1:1. For oximes of methyl isopropyl ketone and pinacolone, the 4-methyl-isomers become predominant (78, 83%, respectively).
- Trofimov,Tarasova,Mikhaleva,Kalinina,Sinegovskaya,Henkelmann
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p. 1585 - 1590
(2007/10/03)
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- Boron difluoride compounds useful in photodynamic therapy and production of laser light
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A new group of fluorescent organic compounds having a variety of uses are described. They are especially useful as dye compounds in dye laser systems, and as photochemical agents in the treatment of diseased tissues using photodynamic therapy techniques. The compounds include a tri-cyclic compound having the following structure: STR1 Preferably R1 -R5 =R9 -R12 =C; R7 =B; R6 and R8 =N; R14 =lower n-alkyl or an electron withdrawing group such as CN- ; R16 and R19 are independently selected from the group consisting of lower n-alkyl, a sulfate or an acid or salt thereof, or hydrogen; and R20 =R21 =F. Other compounds include compounds of the formula STR2
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- New Efficient and Flexible Synthesis of Polysubstituted Pyrroles
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The Lewis acid mediated reaction of readily available 2-acetoxypropanal-N,N-dimethylhydrazone 1 with various open chain and cyclic silyl enol ethers 2 leads directly or via 4-oxoaldehyde-N,N-dimethylhydrazones 3 to N-(dimethylamino)-pyrroles 4.The subsequent reductive N-N bond cleavage provides an efficient and flexible method for the preparation of alkyl-aryl-di- and trisubstituted pyrroles 5.
- Enders, Dieter,Han, Sin-Ho,Maassen, Ralf
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p. 8007 - 8010
(2007/10/02)
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- Aminosilanes in Organic Synthesis. Addition of Organocopper Reagents on γ-Bis(trimethylsilyl)amino-α-Acetylenic Amides, Esters and Ketones. Stereochemistry und Some Synthetic Uses
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The stereochemical outcome of the carbocupration of γ-bis(trimethylsilyl)amino-α-acetylenic amide, esters and ketone was studied.A judicious choice of substrate, reagent and(or) reaction conditions allows to perform highly stereoselective cis or trans addition.The intermediate vinylic copper adducts, with (E) or (Z) configuration, react with electrophilic reagents to provide short routes to substituted pyrrolinones and pyrroles.Keywords: Silylamines, propargylamines, organocopper regaents, stereochemistry, nitrogen heterocycles.
- Corriu, Robert J. P.,Bolin, Geng,Iqbal, Javed,Moreau, Joel J. E.,Vernhet, Claude
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p. 4603 - 4618
(2007/10/02)
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- Synthesis and flash vacuum thermolysis of 1,2-dihydro-1,2-azaphosphinine 2-oxide-dichlorocarbene adducts
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The reaction of dichlorocarbene with 1,2-dihydro-1,2-azaphophinine 2-oxides follows a regioselective addition on the C5-C6 double bond and yields 3-oxo-2-aza-3-phosphabicycloheptenes 2.The X-ray crystal structure of the major isomer 2aA was determined and shows that the cyclopropane ring and the phenyl group are on opposite sides of the six membered ring.Flash vacuum thermolysis of dihydroazaphosphinine 2-oxide-dichlorocarbene adducts gave 2-oxo-2H-1,2-azaphosphepine 5 and substituted 3-chloropyridines 4.Key Words: 1,2-azaphosphinine 2-oxides / cyclopropanation / X-ray analysis / flash vacuum thermolysis
- Tan, W.H-L. Wai,Bourdieu, C.,Foucaud, A.,Bedel, C.
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- Lasing compositions and methods for using the same
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A new group of flourescent organic materials having a variety of uses are described. They are especially useful as dye comounds in dye laser systems, and as photochemical agents in the treatment of diseased tissues using photodynamic therapy techniques. The materials involve a tri-cyclic compound having the following structure: In this structure, R1 - R21 represent a variety of organic and inorganic groups.
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- 4-Alkylideneisoxazol-5-ones. Synthesis, Tautomerism, and Rearrangement to Pyrroles
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The synthesis of several 4-alkylidene- and 4-cycloalkylideneisoxazol-5-ones is described and their tautomerism is investigated by 13C NMR, 1H NMR and IR spectroscopy.Through hydrogen shifts involving the exocyclic substituent (2-propylidene, cyclopentylidene, or 2-indanylidene) these compounds can exist in CH, NH, or OH forms (Scheme II).The CH form is favored in solvents of low polarity (CDCl3) and in the absence of special enthalpic and conjugative effects stabilizing the NH form.The NH form is favored in polar solvents (Me2SO), and its dominance is accentuated when the vinylic substituent is stabilized thermodynamically and conjugationally.The OH form is not observed directly, but the ionized O- form is present in the morpholinium salts of 15, 16, and 17.In the 2-propylidene derivative 12 only the CH form was spectroscopically detectable, but H/D exchange experiments on this and other isoxazolones showed that tautomerism does take place (12 * 24).The alkylideneisoxazolones rearrange to pyrrolecarboxylic acids on flash vacuum pyrolysis.Of two possible mechanisms, a vinylnitrene mechanism (Scheme IV) and a nitrile ylide mechanism (Scheme V), the former is shown to apply.The pyrrolecarboxylic acids often decarboxylate under the reaction conditions.
- Wollweber, Hans-Joachim,Wentrup, Curt
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p. 2041 - 2047
(2007/10/02)
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- Deacylation of Pyrrole and other Aromatic Ketones
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Ethyl 4-acetyl-3,5-dimethyl-1H-pyrrole-2-carboxylate (1a) reacts rapidly with ethylene glycol in refluxing benzene with p-toluenesulfonic acid or perchloric acid as a catalyst to give ethyl 3,5-dimethyl-1H-pyrrole-2-carboxylate (3) in high yield (96 percent).Various 2- and 3-acylpyrroles can be efficiently deacylated by using this procedure.Other ketones which undergo deacylation include phenyl(2-phenylindol-3-yl)methanone (19), 1-(5-methyl-1-phenylpyrazol-4-yl)ethanone (20), and 2,4-dimethoxybenzophenone.Certain pyrrole ketones where the acyl group is flanked by two ring methyl groups are also cleaved under acidic conditions by using ethanedithiol.
- Moon, M. W.,Wade, R. A.
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p. 2663 - 2669
(2007/10/02)
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- Structurel Analysis of Tetrapyrroles by Hydrogen Chemical Ionization Mass Spectrometry
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The H2 chemical ionization mass spectra of several standard porphyrins have been determined.Fragmentation proceeds via hydrogenation yielding porphyrinogens, followed by cleavage at the meso (bridge) positions to produce mono-, di-, and tripyrrolic ions.Secondary fragmentation by cleavage of substituent groups attached to the pyrrole rings may then occur.Identification of these fragments and the corresponding molecular ions produces considerable structural information on the parent molecule.In certain cases these data are sufficient to distinguish porphyrin type (positional) isomers.In addition information of substituents at meso positions may be retained.
- Shaw, George J.,Eglinton, Geoffrey,Quirke, J. Martin E.
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p. 2014 - 2020
(2007/10/02)
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