3264-21-9Relevant academic research and scientific papers
In quest of reversibility of Friedel-Crafts acyl rearrangements in the pyrene series
Agranat, Israel,Mala’bi, Tahani,Oded, Yaacov Netanel,Kraus, Hanna Daniel
, p. 47 - 60 (2019/12/30)
Friedel-Crafts acyl rearrangements in PPA of diacetylpyrenes (80–120 °C), dibenzoylpyrenes (80–200 °C), and bis(4-flurobenzoyl)pyrenes (80–120 °C) and Scholl reactions in AlCl3/NaCl of dibenzoylpyrenes (140–200 °C) have been studied. The substrates were 1-AcPY, 2-AcPY, 1,3-Ac2PY, 1,6-Ac2PY, 1,8-Ac2PY, 2,7-Ac2PY, 1-BzPY, 1,6-Bz2PY, 1,8-Bz2PY, 1-4FBzPY, 1,6-4FBz2PY, 1,8-4FBz2PY. The mixtures of pyrene, 1-AcPY, 2-AcPY, 1,3-Ac2PY, 1,6-Ac2PY, 1,8-Ac2PY, and 2,7-Ac2PY were separated by HPLC. The following reversible intermolecular isomerizations were established: 1,6-Ac2PY ? 1,8-Ac2PY, 1,6-Bz2PY ? 1,8-Bz2PY, and 1,6-4'FBz2PY ? 1,8-4'FBz2PY, albeit not in high yields. The results substantiate Gore’s 1955 proposition that “The Friedel–Crafts acylation reaction of reactive aromatic hydrocarbons is a reversible process.” The isomerizations reported here differ from the few previously reported completely reversible intramolecular Friedel-Crafts acyl rearrangements. At ≥ 140 °C, in PPA and in AlCl3/NaCl, 1,6-Bz2PY and 1,8-Bz2PY underwent a highly regioselective double Scholl reaction to give pyranthrone (3) and deacylations to 1-BzPy (and pyrene), followed by mono-Scholl reactions to give 8H-dibenzo[def,qr]chrysen-8-one (1), and 11H-indeno[2,1-a]pyren-11-one (2). The formation of 3 and not the expected tribenzo[a,ghi,o]perylene-7,16-dione (4) from 1,8-Bz2PY indicates that 1,8-Bz2PY has first undergone isomerization to 1,6-Bz2PY. The present study confirms the linkage between Friedel-Crafts acyl rearrangements and the Scholl reaction.
1-(Hydroxyacetyl)pyrene a new fluorescent phototrigger for cell imaging and caging of alcohols, phenol and adenosine
Jana, Avijit,Saha, Biswajit,Ikbal, Mohammed,Ghosh, Sudip Kumar,Singh, N. D. Pradeep
, p. 1558 - 1566 (2013/02/26)
1-(Hydroxyacetyl)pyrene has been introduced as a new fluorescent phototrigger for alcohols and phenols. Alcohols and phenols were protected as their corresponding carbonate esters by coupling with fluorescent phototrigger, 1-(hydroxyacetyl)pyrene. Photophysical studies of caged carbonates showed that they all exhibited strong fluorescence properties. Irradiation of the caged carbonates by visible light (≥410 nm) in aqueous acetonitrile released the corresponding alcohols or phenols in high chemical (95-97%) and quantum (0.17-0.21) yields. The mechanism for the photorelease was proposed based on Stern-Volmer quenching experiments and solvent effect studies. Importantly, 1-(hydroxyacetyl)pyrene showed as a phototrigger for rapid photorelease of the biologically active molecule adenosine. In vitro biological studies revealed that 1-(hydroxyacetyl)pyrene has good biocompatibility, cellular uptake property and cell imaging ability. The Royal Society of Chemistry and Owner Societies 2012.
Synthesis, photophysical, photochemical, DNA cleavage/binding and cytotoxic properties of pyrene oxime ester conjugates
Chowdhury, Nilanjana,Dutta, Sansa,Dasgupta, Swagata,Singh, N. D. Pradeep,Baidya, Mithu,Ghosh
experimental part, p. 1239 - 1250 (2012/08/29)
A new series of (E)-pyrene oxime ester conjugates of carboxylic acids including amino acids were synthesized by coupling with an environment sensitive fluorophore 1-acetylpyrene. (E)-Pyrene oxime esters exhibited strong fluorescence properties and interestingly their fluorescence properties were found to be highly sensitive to the surrounding environment. Direct irradiation of the (E)-pyrene oxime esters by UV light (≥350 nm) resulted in both the photo-Beckmann rearrangement product and products resulting from N-O bond homolysis. Photoproduct formation and their distribution were found to be solvent dependent. Further, we also showed (E)-pyrene oxime esters intercalated into DNA efficiently and photo-cleaved DNA. Finally we also showed these oxime esters can permeate cells efficiently and may cause cytotoxicity upon irradiation of light. The Royal Society of Chemistry and Owner Societies.
Superacid-catalyzed dimerization/cyclization of isopropenyl-PAHs - Novel pathways to PAH dimers, phenalenes and their stable carbocations
Brule, Cedric,Sultana, Fatima,Hollenstein, Sandro,Okazaki, Takao,Laali, Kenneth K.
experimental part, p. 3700 - 3708 (2009/04/11)
The isopropenyl derivatives of representative classes of polycyclic aromatic hydrocarbons (PAHs) having four and five fused-ring systems, namely pyrene, chrysene, benzo[c]phenanthrene (BcPh), dibenzo[a,c]anthracene (benzo[f]tetraphene) and perylene, were synthesized by Wittig olefination from the corresponding acetyl-PAHs. Under the influence of triflic acid (TfOH), the isopropenyl derivatives were converted to novel PAH dimers and/or phenalenes in a simple one-pot procedure. A plausible mechanism for this process has been outlined, and the synthetic scope of this chemistry has been explored. Structural features in the PAH dimers were examined by DFT. As representative initial and final carbocation intermediates in the reaction sequence, stable carbocations derived from 3-isopropenylperylene and from 4,6,6-trimethyl-6H- dibenzo[a,kl]anthracene were generated and studied directly by NMR spectroscopy. The NMR characteristics and charge delocalization modes in the resulting benzylic carbocations are discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Quantitative Synthesis and Formation of Cyclopentapyrene 3,4-Oxide under Simulated Atmospheric Conditions
Murray, Robert W.,Singh, Megh
, p. 239 - 243 (2007/10/03)
Cyclopentapyrene 3,4-oxide (2) has been synthesized in a one-step, quantitative reaction using dimethyldioxirane. The oxide, or its thermal rearrangement products cyclopentapyren-3(4H)-one and cyclopentapyren-4(3H)-one, is formed from cyclopentapyrene (1) under simulated environmental conditions. In one case these products are formed when 1 is adsorbed on model particulates and then exposed to the reaction products of tetramethylethylene and ozone in the gas phase.
