- Synthesis of pyrrolo-pyrrolo-pyrazines via the Pd/C-catalyzed cyclization of N-propargyl pyrrolinyl-pyrrole derivatives
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A novel and efficient synthesis of N-substituted dipyrrolo[1,2-a:2′,1′-c]pyrazine derivatives has been developed. The synthetic strategy relies on the synthesis of 4′,5′-dihydro-1H,3′H-2,2′-bipyrrole, followed by the reaction with propargyl bromide. Various substituents were introduced to the alkyne functionality using the Sonogashira coupling reaction. Aromatization of the dihydropyrrole ring followed by an intramolecular cyclization reaction between the alkyne functionality and the pyrrole nitrogen atom was catalyzed by Pd/C at high temperature to furnish the desired dipyrrolo-pyrazine skeleton.
- Aslanoglu, Furgan,Basceken, Sinan,Balci, Metin
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- 18F-Labeled BODIPY Dye: A Potential Prosthetic Group for Brain Hybrid PET/Optical Imaging Agents
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There are few hybrid positron emission tomography (PET)/fluorescence imaging agents available for brain imaging. For this purpose, BODIPY dye is very attractive because one of its fluorine atoms can be readily exchanged with 18F, and it can be modified to produce red-shifted fluorescence. In this study, therefore, we synthesized and investigated a 18F-labeled red-shifted BODIPY dye as a prosthetic group for brain hybrid PET/optical imaging agents and determined the optimal dose of this radioligand for hybrid imaging. The red-shifted BODIPY dye (1) was synthesized, and one of its fluorine atoms was exchanged with 18F using SnCl4 in high yield. Partition coefficients of 18F-labeled BODIPY dye ([18F]1) and 1 were measured using its radioactivity and fluorescence, respectively, which were shown to be suitable for brain penetration. Optimal dose for hybrid imaging was determined by analysis of PET/CT and optical images of Balb/C nude mice injected with [18F]1 and 1, respectively. Hybrid PET/optical images of mice injected with optimal dose of [18F]1 showed strong radioactivity and fluorescence signal in the brain at 2 min after injection, with rapid clearance by 30 min. Tissue distribution data confirmed the in vivo and ex vivo PET/optical imaging data, indicating desirable brain pharmacokinetics of the radioligand. Taken together, the results of this study suggest that [18F]1 can be widely used as a prosthetic group for brain hybrid PET/optical imaging agents.
- Kim, Hyunjung,Kim, Kyul,Son, Sang-Hyun,Choi, Joon Young,Lee, Kyung-Han,Kim, Byung-Tae,Byun, Youngjoo,Choe, Yearn Seong
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- Regioselective bipyrrole coupling of pyrroles and 3-substituted pyrroles using phenyliodine(III) bis(trifluoroacetate)
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A series of electron-rich bipyrroles were prepared by the regioselective, phenyliodine(III) bis(trifluoroacetate) (PIFA) induced oxidative coupling of pyrroles in the presence of bromotrimethylsilane. Using pyrrole and 3,4-disubstituted pyrroles gave exclusively 2,2′-linked bipyrroles without the formation of other bipyrrole regioisomers. The 3-alkyl- or 3-aryl-substituted pyrroles gave unsymmetrical H-T dimers in high yields as the major isolable α-linked bipyrrole products over the symmetrical H-H dimers. The nature of the N-substituent significantly influences the regioselectivity of the reaction, thus regiocontrolled bipyrrole coupling of N-phenyl- and N-benzyl-substituted pyrroles gave 2,3′-bipyrroles. Georg Thieme Verlag Stuttgart.
- Dohi, Toshifumi,Morimoto, Koji,Ito, Motoki,Kita, Yasuyuki
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- Meso-substituted [34]octaphyrin(1.1.1.0.1.1.1.0) and corrole formation in reactions of a dipyrromethanedicarbinol with 2,2′-bipyrrole
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The reaction of a dipyrromethanedicarbinol with 2,2′-bipyrrole leading to meso-substituted [34]octaphyrin(1.1.1.0.1.1.1.0) and/or corrole was investigated to determine the effect of key reaction parameters on the distribution of the two macrocycles. Solve
- Geier III, G. Richard,Grindrod, Scott C.
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- On the Use of N,N'-Dipyrrolylmethane in Heterocyclic Synthesis. Dipyrrol-2H-imidazole and its Aromatic Anion
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The pyrrolate ion (5) is shown to produce N, N'-dipyrrolyl methane (4) when reacted with dichloromethane under conditions of weak counter-ion association. 1-Azoniafulvene ion (13) is sggested to be the key intermediate in this reaction.N,N'-dipyrrolyl methane (4) undergoes intramolecular oxidative coupling when treated with butyllithium and Cu(II)chloride, yielding the novel ring system of dipyrrolo-2H-imidazole (3).The latter upon reaction with methyl lithium forms the Hueckel-aromatic anion 2.Solutions of the lithium salt are stable for several days.Reaction of the dianion of 2,2'-bipyrrole (11) with dichloromethane doesi40 not produce 3, but a pyrrolophane-type dimer (12) having its two anticoplanar N,N'-bipyrrolediyl subunits arranged in a double layer and joined by a methylene group on each side.
- Burger, Ulrich,Dreier, Francine
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- Clean and direct synthesis of α,α′-bithiophenes and bipyrroles by metal-free oxidative coupling using recyclable hypervalent iodine(III) reagents
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The facile and clean oxidative biaryl coupling reaction of thiophenes and pyrroles has been achieved using the recyclable hypervalent iodine(III) reagents having adamantane or methane structures. These iodine(III) reagents could be recovered from the reaction mixtures by a simple solid-liquid separation, i.e., filtration.
- Dohi, Toshifumi,Morimoto, Koji,Ogawa, Chieko,Fujioka, Hiromichi,Kita, Yasuyuki
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- The long and winding road to new porphycenes
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We describe attempts - not always successful - made over the years to improve the efficiency of porphycene synthesis and to produce novel compounds, custom-designed for specific purposes. New porphycenes are reported, some of them obtained rather unexpectedly as by-products of the planned reactions. Structure and energy computations of possible tautomeric forms in porphycenes substituted by one, two, three, and four tert-butyl groups lead to predictions regarding the kinetics and mechanisms of intramolecular double hydrogen transfer. The occurrence of tautomerization in single molecules of tert-butylsubstituted porphycenes is demonstrated by using fluorescence polarization techniques.
- Czerski, Igor,Listkowski, Arkadiusz,Nawrocki, Jan,Urbańska, Natalia,Piwoński, Hubert,Soko?owski, Adam,Pietraszkiewicz, Oksana,Pietraszkiewicz, Marek,Waluk, Jacek
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- Aroylation of Electron-Rich Pyrroles under Minisci Reaction Conditions
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The development of Minisci acylation on electron-rich pyrroles under silver-free neutral conditions has been reported featuring the regioselective monoacylation of (NH)-free pyrroles. Unlike conventional Minisci conditions, the avoidance of any acid that could result in the polymerization of pyrroles was the key to success. The umpolung reactivity of the nucleophilic acyl radical, generated in situ from arylglyoxylic acid, could help explain the mechanism of product formation with electron-rich pyrroles. Alternatively, the nucleophilic substitution of the acyl radical on the electron-deficient pyrrole radical cation is proposed.
- Laha, Joydev K.,Kaur Hunjan, Mandeep,Hegde, Shalakha,Gupta, Anjali
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supporting information
p. 1442 - 1447
(2020/02/22)
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- Synthesis of a meso-Tetraalkylporphycene Bearing Reactive Sites: Toward Porphycene–Polydimethylsiloxane Hybrids with Enhanced Photophysical Properties
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meso-Tetraalkyl porphycenes exhibit unique optical properties with wide potential applications. The very fact that incorporation of porphycenes into polymeric materials is rare, make this approach a particularly attractive one. In this work, meso-tetrakis
- Ono, Toshikazu,Shinjo, Hyuga,Koga, Daiki,Hisaeda, Yoshio
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p. 7578 - 7583
(2019/12/03)
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- Design and synthesis of dye-conjugated hepsin inhibitors
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Hepsin is a type II serine protease that is highly expressed in neoplastic prostate. It is an attractive biomarker for imaging metastatic prostate cancer because of its overexpression in advanced prostate cancer and the location of its active site on the
- Kim, Kyul,Kwon, Hongmok,Choi, Doyoung,Lim, Taehyeong,Minn, Il,Son, Sang-Hyun,Byun, Youngjoo
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- Hypervalent iodine(III): selective and efficient single-electron-transfer (SET) oxidizing agent
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In 1994, we first determined the single-electron-transfer (SET) oxidation ability of phenyliodine(III) bis(trifluoroacetate) (PIFA) toward phenyl ethers, affording the corresponding aromatic cation radicals. Since then, hypervalent iodine(III) has been utilized as a selective and efficient SET oxidizing agent that enables a variety of direct C-H functionalizations of aromatic rings in electron-rich arenes under mild conditions. We have now extended the original method to work in a series of heteroaromatic compounds such as thiophenes, pyrroles, and indoles. The investigations and results obtained since the start of this century are summarized in this article.
- Dohi, Toshifumi,Ito, Motoki,Yamaoka, Nobutaka,Morimoto, Koji,Fujioka, Hiromichi,Kita, Yasuyuki
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experimental part
p. 10797 - 10815
(2010/03/01)
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- A simple synthesis of 2,2′-bipyrroles from pyrrole
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2,2′-Bipyrroles, which are obvious precursors for the synthesis of 2,2′-bipyrrole-based natural products, are synthesized in three steps from pyrrole employing known pyrrolyl ketoalcohols by a sequential alcohol oxidation and Paal-Knorr pyrrole synthesis.
- Fu, Liangfeng,Gribble, Gordon W.
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body text
p. 7352 - 7354
(2009/05/07)
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- Direct synthesis of bipyrroles using phenyliodine bis(trifluoroacetate) with bromotrimethylsilane
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The hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA), mediates the unprecedented, oxidative coupling reaction of pyrroles to give α-linked bipyrroles selectively in the presence of bromotrimethylsilane. This straightforward synthesis could provide 2,3′-bipyrrole by the choice of a N-substituent of pyrrole. Mechanistic consideration of the present reaction is also described.
- Dohi, Toshifumi,Morimoto, Koji,Maruyama, Akinobu,Kita, Yasuyuki
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p. 2007 - 2010
(2007/10/03)
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- Corrole synthesis by dipyrromethane-dicarbinol and 2,2′-bipyrrole condensation
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A3 and trans-A2B tris-aryl corroles 1a-c have been synthesized in up to 12% yield by BF3·Et2O-catalyzed condensation of dipyrromethane-dicarbinol and 2,2′-bipyrrole (1:1 ratio) in acetonitrile at room temperatur
- Decréau, Richard A.,Collman, James P.
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p. 3323 - 3327
(2007/10/03)
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- Heteroaromatic diphosphines as chiral ligands
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Chiral diphosphines constituted by an aromatic pentatomic biheterocyclic system, suitable to act as chiral ligands, complexes between said diphosophines and transition metals, and their utilization as chiral catalysts in sterocontrolled reactions, such as diastereo- and enantioselective reduction reactions. Process for the preparation of said chiral diphosophines and process for the preparation of said complexes and for their utilization as chiral catalysts in sterocontrolled reactions.
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- Long wavelength chemically reactive dipyrrometheneboron difluoride dyes and conjugates
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This invention relates to derivatives of dipyrrometheneboron difluoride fluorescent dyes that have an absorption maximum at wavelengths longer than about 525 nm, and are chemically reactive with nucleic acids, proteins, carbohydrates, and other biologically derived or synthetic chemical materials. The dyes generally have the structure: STR1 wherein at least one of the substituents R1 -R7, is a reactive functional group, and at least one of the substituents R1 -R7 contains a bathochromic moiety. The bathochromic moiety is an unsaturated organic group, preferably heteroaryl or alkenyl. The remaining substituents, which may be the same or different, are hydrogen, halogen, alkyl (containing 1-5 carbon atoms), aryl, arylalkyl, or sulfo. The dyes are used to make novel conjugates with members of specific binding pairs that are ligands or receptors.
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- Long wavelength heteroaryl-substituted dipyrrometheneboron difluoride dyes
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This invention describes novel 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes containing heteroaryl substituents conjugated to the fluorophore and methods for their synthesis. The heteroaryl substituted compounds (heteroaryl dyes) generally have the structure: STR1 wherein any or all of the substituents R1 -R7, but at least one of such substituents, is a heteroaryl group, including 5- or 6-member rings, singly or fused, containing one or more heteroatoms. The new dyes that have spectral properties that are significantly shifted from those of the parent alkyl-substituted dyes, usually accompanied by an increase in photostability and in some cases by an increase in the extinction coefficient relative to the alkyl-substituted dyes. The general method of synthesis includes formation of pyrromethene salt intermediates followed by cyclization with boron trifluoride in the presence of a base to give heteroaryl-substituted dipyrrometheneboron difluoride dyes.
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- Synthesis of Biheteroaromatic Compounds via the Isoxazoline Route
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A number of heteroaromatically substituted furans, thiophenes, pyrroles, pyridines and benzenes have been prepared via the 2-isoxazoline route.N-Acetylnornicotyrine is prepared from N-allylacetamide and 3-pyridinecarboxaldoxime.
- Ghabrial, Sami S.,Thomsen, I.,Torssell, K. B. G.
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p. 426 - 434
(2007/10/02)
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- Dimerization of Pyrroles by Palladium Acetate. New Synthesis of 2,2'-Bipyrroles
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Oxidation of 1-aroylpyrroles by palladium acetate in acetic acid gave the corresponding 1,1'-diaroyl-2,2'-bipyrroles, which were easily hydrolysed in MeOH-H2O containing HCl to give 2,2'-bipyrrole.
- Itahara, Toshio
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