5-Substituted dipyrranes: synthesis and reactivity

Gryko, Daniel T.,Gryko, Dorota,Lee, Chang-Hee The Royal Society of Chemistry 2012 Chemical Society reviews Vol.41 No.10

<P>Dipyrranes constitute important building blocks in the synthesis of porphyrins, corroles, chlorins, calix[4]pyrroles, porphodimethenes, BODIPY dyes and dipyrrinato complexes. This <I>tutorial review</I> describes the overall progress made in the last twenty years in this field, mainly focusing on the most practical and useful synthetic methodologies and offers a critical comparison of various conditions reported in the literature. This review also deals with the reactivity of 5-substituted dipyrranes presenting the scope of their reactions with electrophiles.</P> <P>Graphic Abstract</P><P>The efficient preparation of dipyrranes (dipyrromethanes) is fundamental for synthesis of porphyrins, corroles, other porphyrinoids and BODIPYs. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cs00003b'> </P>

Photochemical Conversion of Phenanthro[9,10-<i>d</i>]imidazoles into π-Expanded Heterocycles

Skonieczny, Kamil,Gryko, Daniel T. American Chemical Society 2015 Journal of organic chemistry Vol.80 No.11

<P>We discovered that phenanthro[9,10-<I>d</I>]imidazoles bearing a 2-halogenoaryl substituent at position 2 undergo swift photochemically driven direct arylation, leading to barely known phenanthro[9′,10′:4,5]imidazo[1,2-<I>f</I>]phenanthridines. The reaction is high-yielding, and it does not require any sensitizer or base. The discovered process is tolerant of a variety of substituents present both at positions 1 and 2; i.e., strongly electron-donating and electron-withdrawing substituents are tolerated as well as various heterocyclic units. Steric hindrance does not affect this process. The evidence gathered here indicates that S<SUB>RN</SUB>1 mechanism is operating in this case with the formation of radical anion as a critical step, followed by heterolytic cleavage of a carbon–halogen bond. Also TfO groups were shown to undergo cyclization, which allows the use of salicylaldehydes in the construction of heterocyclic systems. Efficiency of this photochemically driven direct arylation has been demonstrated by the synthesis of two systems possessing 13 and 17 conjugated rings, respectively. Phenanthro[9′,10′:4,5]imidazo[1,2-<I>f</I>]phenanthridines are blue-emitters, and they exhibit strong fluorescence in solution and in the solid state in direct contrast to their precursors.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/joceah/2015/joceah.2015.80.issue-11/acs.joc.5b00714/production/images/medium/jo-2015-00714j_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jo5b00714'>ACS Electronic Supporting Info</A></P>

Effect of conformational flexibility on photophysics of bis-coumarins

Kielesiń,ski, Łukasz,Gryko, Daniel T.,Sobolewski, Andrzej L.,Morawski, Olaf W. The Royal Society of Chemistry 2018 Physical chemistry chemical physics Vol.20 No.21

<P>The fluorescence intensity of bis-coumarins linked <I>via</I> CONH and COO functionalities are shown to exhibit a strong dependance on solvent polarity. The presence of the intramolecular hydrogen bond between the CO oxygen atom of coumarin and amide-NH moieties reduces the number of thermodynamically populated conformations in both ground and electronically excited states and an <I>anti</I>-arrangement of coumarin units is favored. Additionally, the rigidity of the linker raises the barrier to the conical intersection with the ground state, and in non-polar solvents strong fluorescence is observed. Although changing the CONH linking position from 3-7′ to 3-6′, does not remarkably affect the photophysics, replacement with a flexible ester linker allows the molecule a greater degree of conformational freedom due to the absence of the intramolecular hydrogen bonding interaction. The photophysical effect of this is the appearance of two fluorescence bands, the relative intensity and spectral positions of which are sensitive to the environment. Theoretical explorations of the excited-state potential energy surfaces performed with the aid of the ADC(2) <I>ab initio</I> electronic structure theory method revealed an exceptional wealth of concomitant photophysical processes. In particular, two channels for radiationless deactivation of the excited state were found; the first is related to the inter-ring twist of the coumarin units, and the second is associated with the excited-state intramolecular proton-transfer (ESIPT) from the CONH linker to the coumarin core.</P>

Recent advances in the synthesis of indolizines and their π-expanded analogues

Sadowski, Bartłomiej,Klajn, Jan,Gryko, Daniel T. The Royal Society of Chemistry 2016 Organic & Biomolecular Chemistry Vol.14 No.33

<P>Indolizine (pyrrolo[1,2-<I>a</I>]pyridine) is one of the five isomers of indole and it serves as a precursor for widespread indolizidine alkaloids. The straightforward synthesis of indolizines based on classical methodologies such as Scholtz or Chichibabin reactions has overshadowed numerous new strategies that have been revealed especially within the last ten years. The desire to achieve substitution patterns which were hard to build sparked the discovery of completely new pathways, <I>e.g.</I> transition metal-catalyzed reactions and approaches based on oxidative coupling. In this review, selected strategies toward indolizines published since 2005 are briefly summarized, commented upon, compared, and illustrated. The literature discussed here involves reactions based on either pyridine or pyrrole scaffolds, as well as selected methodologies leading to π-expanded indolizines.</P> <P>Graphic Abstract</P><P>Synthesis of indolizines developed during the last decade is reviewed, with special emphasis given to densely functionalized architectures, breakthrough strategies, compounds bearing electron-donating and electron-withdrawing substituents and π-expanded systems. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c6ob00985a'> </P>

Synthesis of Chlorins Linked with Pyrazoline by 1,3-Dipolar Diazomethane Cycloaddition Reaction

Jin-Jun Wang,Jia-Zhu Li,Daniel Gryko,Young Key Shim* 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.7

Vertically π-Expanded Coumarins: The Synthesis and Optical Properties

Nazir, Rashid,Stasyuk, Anton J.,Gryko, Daniel T. American Chemical Society 2016 Journal of organic chemistry Vol.81 No.22

<P>A regioselective synthesis of naphtho[2,1,8-<I>def</I>]coumarins has been realized through a concise route that involves the intramolecular Friedel–Crafts reaction of benzo[<I>f</I>]coumarins. Tetracyclic, planar products were prepared starting from assembly of the suitably substituted coumarin via the Pechmann reaction of 2-naphthols with acetone-1,3-dicarboxylates, followed by an intramolecular Friedel–Crafts reaction. In contrast to earlier report, the main product of the condensation reaction performed at 130 °C was the corresponding sulfonic acid and not the phenol itself. The one-pot process afforded the desired phenol in 39% yield. This reaction has been extended to some naphthalenediols. The model 5-hydroxy-naphtho[2,1,8-<I>def</I>]coumarin was transformed into corresponding dimer using various pathways including intermolecular oxidative aromatic coupling. Photophysical studies revealed that 5-hydroxy-naphtho[2,1,8-<I>def</I>]coumarin has the most bathochromically shifted both absorption and emission among all π-expanded coumarins bearing one OH functionality. In general, all prepared coumarin-phenols as well as their hexyl ethers displayed moderate to strong greenish-yellow fluorescence, except of dimer that emits at 552 nm. The fluorescence of these dyes was strongly dependent on polarity of the solvent. Computational studies supported interpretation of optical properties for the selected compounds.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/joceah/2016/joceah.2016.81.issue-22/acs.joc.6b02094/production/images/medium/jo-2016-020947_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jo6b02094'>ACS Electronic Supporting Info</A></P>

Synthesis of Chlorins Linked with Pyrazoline by 1,3-Dipolar Diazomethane Cycloaddition Reaction

Wang, Jin-Jun,Li, Jia-Zhu,Gryko, Daniel,Shim, Young-Key Korean Chemical Society 2006 Bulletin of the Korean Chemical Society Vol.27 No.7

π-Expanded coumarins: synthesis, optical properties and applications

Tasior, Mariusz,Kim, Dokyoung,Singha, Subhankar,Krzeszewski, Maciej,Ahn, Kyo Han,Gryko, Daniel T. The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.7

<P>Coumarins fused with other aromatic units have recently emerged as a hot topic of research. Their synthesis is partly based on classical methodologies such as Pechmann reaction or Knoevenagel condensation, but it also sparked the discovery of completely new pathways. In very recent years so-called vertically expanded coumarins were synthesized, effectively expanding the portfolio of existing architectures. A subtle relationship exists between the structure of fused coumarins and their optical properties. Although absorption of UV-radiation and light is a unifying theme among these π-expanded coumarins, the fluorescence properties strongly depend on the structure. The mode of fusion, the type of additional ring and the presence of electron-donating and electron-withdrawing substituents all influence the photophysical parameters. Recent advances made it possible to modulate their absorption from 300 nm to 550 nm, resulting in new coumarins emitting orange light. This review serves as a guide through both synthesis strategies and structure-property relationship nuances. Strong intramolecular charge-transfer character made it possible to reach suitable values of two-photon absorption cross-section. Photophysical advantages of π-expanded coumarins have been already utilized in fluorescent probes and two-photon excited fluorescence microscopy.</P>

2,5-Bis(azulenyl)pyrrolo[3,2-b]pyrroles - the key influence of the linkage position on the linear and nonlinear optical properties

Poronik, Y.,Mazur, L.,Samoc, M.,Jacquemin, D.,Gryko, D. Royal Society of Chemistry 2017 Journal of materials chemistry. C, Materials for o Vol.5 No.10

Calix[4]pyrroles bearing proximally <i>meso</i>–<i>meso</i> linking straps: synthesis and anion binding properties

Park, Ja-Young,Skonieczny, Kamil,Aratani, Naoki,Osuka, Atsuhiro,Gryko, Daniel T.,Lee, Chang-Hee The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.65

<P>Calix[4]pyrroles bearing two proximally crossing straps on the same or the opposite sides have been synthesized for the first time. The doubly <I>cis</I>-strapped compound exhibited highly cooperative six-point hydrogen bonding interactions with the anion involving both pyrrolic N–Hs and Ar–Hs.</P> <P>Graphic Abstract</P><P>Calix[4]pyrroles bearing two proximally crossing straps on the same side or the opposite side have been synthesized and characterized. The <I>cis</I>-strapped compound encapsulates the fluoride anion strongly by six-point hydrogen bonding interaction while the <I>trans</I>-strapped compound shows very weak binding. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc33537a'> </P>