7651-86-7Relevant academic research and scientific papers
Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation
Jiang, Bo,Chen, Yating,Xing, Yi,Lian, Luning,Shen, Yaoxin,Zhang, Baogang,Zhang, Han,Sun, Guangdong,Li, Junyi,Wang, Xinzi,Zhang, Dayi
, (2021/09/24)
Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs), but suffers from unsatisfactory performance in engineering practices, which is hypothetically explained by the complicated interactions between indigenous microbes and introduced degraders. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium (Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira) by magnetic-nanoparticle mediated isolation (MMI) from soils. Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, whilst increased by 30.17% by the active pyrene degrading consortium. Pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP) were enriched in MMI isolates and positively correlated with pyrene degradation efficiency. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas both phthalate and salicylate pathways were observed in the active pyrene degrading consortium. The results indicated that the uncultivable pyrene degraders were suitable for bioaugmentation, rather than cultivable Sphingomonas sp. YT1005. The negative correlations between Sphingomonas sp. YT1005 and the active-yet-uncultivable pyrene degraders were the underlying mechanisms of bioaugmentation postpone in engineering practices.
Could London Dispersion Force Control Regioselective (2 + 2) Cyclodimerizations of Benzynes? YES: Application to the Synthesis of Helical Biphenylenes
Akai, Shuji,Aoyama, Hiroshi,Fukumoto, Yutaka,Heguri, Akito,Ikawa, Takashi,Masuda, Yuto,Murakami, Tomonari,Shigeta, Yasuteru,Takagi, Akira,Tokiwa, Hiroaki,Yahata, Kenzo,Yamamoto, Yuta
supporting information, p. 10853 - 10859 (2021/07/26)
In recent years, London dispersion interactions, which are the attractive component of the van der Waals potential, have been found to play an important role in controlling the regio- and/or stereoselectivity of various reactions. Particularly, the dispersion interactions between substrates and catalysts (or ligands) are dominant in various selective catalyzes. In contrast, repulsive steric interactions, rather than the attractive dispersion interactions, between bulky substituents are predominant in most of the noncatalytic reactions. Herein, we demonstrate the first example of London dispersion-controlled noncatalytic (2 + 2) cyclodimerization of substituted benzynes to selectively afford proximal biphenylenes in high yields and regioselectivities, depending on the extent of dispersion interactions in the substituents. This method can be applied for the synthesis of novel helical biphenylenes, which would be fascinating for chemists as these compounds are potential skeletons for ligands, catalysts, and medicines.
Modular Synthesis of Organoboron Helically Chiral Compounds: Cutouts from Extended Helices
Full, Julian,Panchal, Santosh P.,G?tz, Julian,Krause, Ana-Maria,Nowak-Król, Agnieszka
supporting information, p. 4350 - 4357 (2021/01/29)
Two types of helically chiral compounds bearing one and two boron atoms were synthesized by a modular approach. Formation of the helical scaffolds was executed by the introduction of boron to flexible biaryl and triaryl derived from small achiral building blocks. All-ortho-fused azabora[7]helicenes feature exceptional configurational stability, blue or green fluorescence with quantum yields (Φfl) of 18–24 % in solution, green or yellow solid-state emission (Φfl up to 23 %), and strong chiroptical response with large dissymmetry factors of up to 1.12×10?2. Azabora[9]helicenes consisting of angularly and linearly fused rings are blue emitters exhibiting Φfl of up to 47 % in CH2Cl2 and 25 % in the solid state. As revealed by the DFT calculations, their P–M interconversion pathway is more complex than that of H1. Single-crystal X-ray analysis shows clear differences in the packing arrangement of methyl and phenyl derivatives. These molecules are proposed as primary structures of extended helices.
Modular Design of Fluorescent Dibenzo- and Naphtho-Fluoranthenes: Structural Rearrangements and Electronic Properties
Mohammad-Pour, Gavin S.,Ly, Richard T.,Fairchild, David C.,Burnstine-Townley, Alex,Vazquez-Molina, Demetrius A.,Trieu, Khang D.,Campiglia, Andres D.,Harper, James K.,Uribe-Romo, Fernando J.
supporting information, p. 8036 - 8053 (2018/05/31)
A library of 12 dibenzo- and naphtho-fluoranthene polycyclic aromatic hydrocarbons (PAHs) with MW = 302 (C24H14) was synthesized via a Pd-catalyzed fluoranthene ring-closing reaction. By understanding the various modes by which the palladium migrates during the transformation, structural rearrangements were bypassed, obtaining pure PAHs in high yields. Spectroscopic and electrochemical characterization demonstrated the profound diversity in the electronic structures between isomers. Highlighting the significant differences in emission of visible light, this library of PAHs will enable their standardization for toxicological assessment and potential use as optoelectronic materials.
Synthesis and Evaluation of Sterically Demanding Ruthenium Dithiolate Catalysts for Stereoretentive Olefin Metathesis
Montgomery, T. Patrick,Grandner, Jessica M.,Houk,Grubbs, Robert H.
, p. 3940 - 3953 (2017/10/31)
Dithiolate ligands have recently been used in ruthenium-catalyzed olefin metathesis and have provided access to a kinetically E selective pathway through stereoretentive olefin metathesis. The typical dithiolate used is relatively simple with low steric demands imparted on the catalyst. We have developed a synthetic route that allows access to sterically demanding dithiolate ligands. The catalysts generated provided a pathway to study the intricate structure-activity relationships in olefin metathesis. It was found that DFT calculations can predict the ligand arrangement around the ruthenium center with remarkable accuracy. These dithiolate catalysts proved resistant to ligand isomerization and were stable even under forcing conditions. Additionally, catalyst initiation and olefin metathesis studies delivered a better understanding to the interplay between dithiolate ligand structure and catalyst activity and selectivity.
Synthesis of phenanthrenol derivatives through polar Diels-Alder reactions employing nitronaphthalenes and (E)-1-(trimethylsilyloxy)-1,3-butadiene. Theoretical calculations
Kneeteman, Maria N.,Rosa, Claudia D. Della,Ormachea, Carla M.,Gimenez, Paula,Baena, Anna F. Lopez,Mancini, Pedro M. E.
, p. 333 - 337 (2014/05/20)
The cycloaddition reactions between dinitronaphthalenes and (E)-1-trimethylsilyloxy-1,3-butadiene produce nitrophenanthrenol derivatives as principal products. The primary adducts suffer the irreversible lost of nitrous acid and, consequently, the aromatization. In these reactions it is frequent to observe the presence of naphthalenyl-1H-pyrrole derivatives as a result of a hetero Diels-Alder process, which is competitive with the normal way. The global electrophilic character of the dienophile is responsible of these results. Other dienes (or dienophiles/electrophiles) with electron donor substitution in C-1 show a different behavior in which the hetero Diels-Alder products prevail. In the series explored only the substrate 1-cyano-4-nitronaphthalene produces the naphthalenyl-1H-pyrrole derivative as principal product, probably as a consequence of its charge distribution. A combination between stereoelectronic effects in the electrophile and the type of substitution joint to the nucleophilicity of the diene is responsible of the results and regioselectivity observed in these polar cycloaddition reactions. In all the cases studied the regioselectivity expected by theoretical calculations corresponds with the ones obtained experimentally.
Experimental and theoretical studies on polar Diels-Alder reactions of 1-nitronaphathalene developed in ionic liquids
Mancini, Pedro M. E.,Rosa, Claudia D. Della,Ormachea, Carla M.,Kneeteman, Maria N.,Domingo, Luis R.
, p. 13825 - 13834 (2013/08/23)
The reactions between 1-nitronaphthalene 1 and two nucleophilic dienes, Danishefskys diene 2 and 1-trimethylsilyloxy-1,3-butadiene 3, to yield phenanthrenols 7 and 8 developed in protic and aprotic ionic liquids (ILs) with an imidazolium cation base permit to conclude that the reactions occur in better experimental conditions than in molecular solvents. The yields obtained with protic ILs are better than those observed with aprotic ILs. In this sense, the higher yields obtained with aprotic ILs, (working at 60°C, 48 h) are comparable with the lower yields observed in protic ILs (60°C, 24 h). DFT calculations for the reaction of 1-nitronaphthalene 1 with diene 3, in the absence and in the presence of tetrafluoroborate of 1-metilimidazolium [HMIM][BF4] as protic ILs, indicate that this reaction is a domino process that comprises two consecutive processes: i) a polar Diels-Alder (P-DA) reaction between 1 and 3, and ii) an elimination of nitroso acid 5 to yield dihydrophenanthrene 11. Thermodynamic calculations indicate that while the first reaction is the rate-determining step of this domino process, the nitroso acid elimination is the driving force responsible for the formation of dihydrophenanthrene 11. Implicit and explicit solvent effects indicate that while the hydrogen bond formation between HMIM and one oxygen atom of the nitro groups favour the two reactions, implicit solvent effects modelled by PCM decelerate the P-DA reaction by a large solvation of reagents. Finally, DFT analysis of reagents offers an explanation of the catalytic role of protic ILs in these P-DA reactions.
Regiospecific oxidation of polycyclic aromatic phenols to quinones by hypervalent iodine reagents
Wu, Anhui,Duan, Yazhen,Xu, Daiwang,Penning, Trevor M.,Harvey, Ronald G.
experimental part, p. 2111 - 2118 (2010/04/26)
The hypervalent iodine reagents o-iodoxybenzoic acid (IBX) and bis(trifluoro-acetoxy)iodobenzene (BTI) are shown to be general reagents for regio-controlled oxidation of polycyclic aromatic phenols (PAPs) to specific isomers (ortho, para, or remote) of polycyclic aromatic quinones (PAQs). The oxidations of a series of PAPs with IBX take place under mild conditions to furnish the corresponding ortho-PAQs. In contrast, oxidations of the same series of PAPs with BTI exhibit variable regiospecificity, affording para-PAQs where structurally feasible and ortho-PAQs or remote PAQ isomers in other cases. The structures of the specific PAQ isomers formed are predictable on the basis of the inherent regioselectivities of the hypervalent iodine reagents in combination with the structural requirements of the phenol precursors. IBX and BTI are recommended as the preferred reagents for regio-controlled oxidation of PAPs to PAQs.
Genome-to-function characterization of novel fungal P450 monooxygenases oxidizing polycyclic aromatic hydrocarbons (PAHs)
Syed, Khajamohiddin,Doddapaneni, Harshavardhan,Subramanian, Venkataramanan,Lam, Ying Wai,Yadav, Jagjit S.
scheme or table, p. 492 - 497 (2011/10/18)
Fungi, particularly the white rot basidiomycetes, have an extraordinary capability to degrade and/or mineralize (to CO2) the recalcitrant fused-ring high molecular weight (≥4 aromatic-rings) polycyclic aromatic hydrocarbons (HMW PAHs). Despite over 30years of research demonstrating involvement of P450 monooxygenation reactions in fungal metabolism of HMW PAHs, specific P450 monooxygenases responsible for oxidation of these compounds are not yet known. Here we report the first comprehensive identification and functional characterization of P450 monooxygenases capable of oxidizing different ring-size PAHs in the model white rot fungus Phanerochaete chrysosporium using a successful genome-to-function strategy. In a genome-wide P450 microarray screen, we identified six PAH-responsive P450 genes (Pc-pah1-Pc-pah6) inducible by PAHs of varying ring size, namely naphthalene, phenanthrene, pyrene, and benzo(a)pyrene (BaP). Using a co-expression strategy, cDNAs of the six Pc-Pah P450s were cloned and expressed in Pichia pastoris in conjunction with the homologous P450 oxidoreductase (Pc-POR). Each of the six recombinant P450 monooxygenases showed PAH-oxidizing activity albeit with varying substrate specificity towards PAHs (3-5 rings). All six P450s oxidized pyrene (4-ring) into two monohydroxylated products. Pc-Pah1 and Pc-Pah3 oxidized BaP (5-ring) to 3-hydroxyBaP whereas Pc-Pah4 and Pc-Pah6 oxidized phenanthrene (3-ring) to 3-, 4-, and 9-phenanthrol. These PAH-oxidizing P450s (493-547 aa) are structurally diverse and novel considering their low overall homology (12-23%) to mammalian counterparts. To our knowledge, this is the first report on specific fungal P450 monooxygenases with catalytic activity toward environmentally persistent and highly toxic HMW PAHs.
Isomerization of 7-oxabenzonorbornadienes into naphthols catalyzed by [RuCl2(CO)3]2
Ballantine, Melissa,Menard, Michelle L.,Tam, William
supporting information; experimental part, p. 7570 - 7573 (2009/12/28)
(Chemical Equation Presented) Ruthenium-catalyzed isomerization of 7-oxanorbornadienes into naphthols was investigated. Among the various ruthenium catalysts tested, [RuCl2(CO)3]2 gave the highest yields in the isomerizati
