- Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation
-
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.
- Jiang, Bo,Chen, Yating,Xing, Yi,Lian, Luning,Shen, Yaoxin,Zhang, Baogang,Zhang, Han,Sun, Guangdong,Li, Junyi,Wang, Xinzi,Zhang, Dayi
-
-
- Modular Synthesis of Organoboron Helically Chiral Compounds: Cutouts from Extended Helices
-
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.
- Full, Julian,Panchal, Santosh P.,G?tz, Julian,Krause, Ana-Maria,Nowak-Król, Agnieszka
-
supporting information
p. 4350 - 4357
(2021/01/29)
-
- Could London Dispersion Force Control Regioselective (2 + 2) Cyclodimerizations of Benzynes? YES: Application to the Synthesis of Helical Biphenylenes
-
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.
- 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)
-
- Modular Design of Fluorescent Dibenzo- and Naphtho-Fluoranthenes: Structural Rearrangements and Electronic Properties
-
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.
- 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.
-
p. 8036 - 8053
(2018/05/31)
-
- Synthesis and Evaluation of Sterically Demanding Ruthenium Dithiolate Catalysts for Stereoretentive Olefin Metathesis
-
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.
- Montgomery, T. Patrick,Grandner, Jessica M.,Houk,Grubbs, Robert H.
-
p. 3940 - 3953
(2017/10/31)
-
- Synthesis of phenanthrenol derivatives through polar Diels-Alder reactions employing nitronaphthalenes and (E)-1-(trimethylsilyloxy)-1,3-butadiene. Theoretical calculations
-
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.
- 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)
-
- Experimental and theoretical studies on polar Diels-Alder reactions of 1-nitronaphathalene developed in ionic liquids
-
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.
- Mancini, Pedro M. E.,Rosa, Claudia D. Della,Ormachea, Carla M.,Kneeteman, Maria N.,Domingo, Luis R.
-
p. 13825 - 13834
(2013/08/23)
-
- Genome-to-function characterization of novel fungal P450 monooxygenases oxidizing polycyclic aromatic hydrocarbons (PAHs)
-
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.
- Syed, Khajamohiddin,Doddapaneni, Harshavardhan,Subramanian, Venkataramanan,Lam, Ying Wai,Yadav, Jagjit S.
-
scheme or table
p. 492 - 497
(2011/10/18)
-
- Regiospecific oxidation of polycyclic aromatic phenols to quinones by hypervalent iodine reagents
-
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.
- Wu, Anhui,Duan, Yazhen,Xu, Daiwang,Penning, Trevor M.,Harvey, Ronald G.
-
experimental part
p. 2111 - 2118
(2010/04/26)
-
- Isomerization of 7-oxabenzonorbornadienes into naphthols catalyzed by [RuCl2(CO)3]2
-
(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
- Ballantine, Melissa,Menard, Michelle L.,Tam, William
-
supporting information; experimental part
p. 7570 - 7573
(2009/12/28)
-
- From armchair to zigzag peripheries in nanographenes
-
Synthetic concepts toward the synthesis of large, not-fully benzenoid polycyclic aromatic hydrocarbons (PAHs), decorated with phase-forming and solubilizing n-dodecyl chains, are presented based on the intramolecular cyclodehydrogenation reaction of suitable oligophenylene precursors. The formal addition of successive C2 units into the armchair bays of the parent hexa-per/-hexabenzocoronene extends the aromatic system and leads to PAHs with a partial zigzag periphery. This variation of the nature of the periphery, symmetry, size, and shape has a distinct impact upon the electronic properties and the organization into columnar superstructures. Both computational and experimental UV/vis spectra, which are in good agreement, emphasize the dependence of the characteristic bands α, p, and β upon the overall size and symmetry of the PAHs. While the number and the substitution patterns of attached n-dodecyl chains do not influence the electronic properties, the thermal behavior and supramolecular organization are strongly influenced, which has been elucidated with differential scanning calorimetry (DSC) and 2D wide-angle X-ray diffractometry (2D-WAXS) on mechanically aligned samples. This study provides valuable insight into the future design of semiconducting materials based on extended PAHs.
- Kastler, Marcel,Schmidt, Jochen,Pisula, Wojciech,Sebastiani, Daniel,Muellen, Klaus
-
p. 9526 - 9534
(2007/10/03)
-
- The directed ortho metalation - Palladium catalyzed cross coupling connection. A general regiospecific route to 9-phenanthrols and phenanthrenes. Exploratory further metalation
-
A new general and regiospecific synthesis of 9-phenanthrols (1 + 2 → 3 → 4, Scheme 1, Table 1) proceeding by a Directed ortho Metalation (DoM), Suzuki-Miyaura crocs coupling, and a new LDA-mediated Directed remote Metalation sequence is described. The facile Pd-catalyzed hydrogenolysis of the phenanthrols 4 into the corresponding phenanthrenes 5 via their triflates 18 translates the original DoM regioselectivity also into a general synthesis of phenanthrenes (Table 2). Further DoM (19 → 20, 21; 24 → 25), cross coupling (20c → 23), as well as oxidation - ring contraction (4b, 4f → 28a, 28b) chemistry of phenanthrene derivatives is reported.
- Fu, Jian-Min,Snieckus, Victor
-
p. 905 - 919
(2007/10/03)
-
- Selective palladium-catalyzed cocyclotrimerization of arynes with dimethyl acetylenedicarboxylate: A versatile method for the synthesis of polycyclic aromatic hydrocarbons
-
Benzyne (1a) and the substituted derivatives 4,5-difluorobenzyne (1b) and 3-methoxybenzyne (2) undergo chemoselective palladium-catalyzed [2 + 2 + 2]-cocyclotrimerization with dimethyl acetylenedicarboxylate (DMAD) to afford the corresponding phenanthrenes s and/or naphthalenes. The major products are phenanthrenes if Pd(PPh3)4 is used as the catalyst, naphthalenes if Pd2(dba)3 is used. When the method is applied to polycyclic arynes 3-6, which are generated from the corresponding o-trimethylsilylaryl triflates, the same reactivity pattern is observed: the reaction can be selectively directed either toward the cocyclization of one molecule of aryne and two molecules of alkyne or to the reaction of two molecules of aryne with one molecule of alkyne, by appropriate choice of the palladium catalyst. The synthesis of polycyclic aromatic compounds 33-39 using this methodology is reported.
- Pena,Perez,Guitian,Castedo
-
p. 6944 - 6950
(2007/10/03)
-
- Photographic products and processes
-
This invention relates to diffusion transfer photographic processes adapted to be performed in the presence of ambient light and to diffusion transfer products useful in such processes wherein unexpectedly enhanced opacification in the red and near infrared region of the visible spectrum is achieved by employing phenanthrol/carboxynaphthol phthaleins as the light-absorbing, pH-sensitive optical filter agent for the longer wavelength region of the visible spectrum.
- -
-
-
- Aromatic Nucleophilic Substitution. 21. Electronic Structures of 1,3-Dinitro-4-phenanthryl Methyl Ether and the 4,4-Disubstituted 1,3-Dinitrophenanthrene Meisenheimer Complex
-
The electronic structures of 1,3-dinitro-4-phenanthryl methyl ether (2) and its 4,4-dimethoxy-1,3-dinitrophenanthrene Meisenheimer complex (3), formed from 2 and NaOCH3, were studied by UV-visible and NMR spectra and compared with the results calculated by a semiempirical Pariser-Parr-Pople method.The electronic transitions in the ether 2 and complex 3 were assigned to *? ?.Calculated transition energies and oscillator strengths agree well with the observed values.Calculations showed that in the S0 state of complex 3 90.3percent of one negative charge donated by -OCH3 is distributed on the 1- and 3-NO2 groups and that in the S1 S0 transition of the complex the ? formal charge is further spread over the 1- and 3-NO2 groups.A kinetic measurement in CH3OH at 25 deg C gave a little smaller equilibrium constant for formation of 3 than that for the similar naphthalene anionic ? complex.
- Sekiguchi, Shizen,Hirai, Motohiko,Ota, Etsuro,Hiratsuka, Hiroshi,Mori, Yuji,Tanaka, Shigeyuki
-
p. 5105 - 5108
(2007/10/02)
-
- Stereochemical and Mechanistic Aspects of Sulphoxide, Epoxide, Arene Oxide, and Phenol Formation by Photochemical Oxygen Atom Transfer from Aza-aromatic N-Oxides
-
Stereoselectivity and relative yields are determined for the sulphoxide formation resulting from the u.v. irradiation of a range of aza-aromatic N-oxides in the presence of cyclic thioethers.A comparison is made with the results of oxidation by oxaziridines and by mono-oxygenase enzymes present in the fungus Aspergillus niger.The photochemical oxidation results are consistent with a transition state involving an oxaziridine intermediate where partial bonding of the oxygen atom to the ring nitrogen atom is maintained during the oxygen transfer process.Photolysis of aza-aromatic N-oxides in the presence of cis- and trans-olefins yields epoxides. cis-4-Methylpent-2-ene yielded both cis and trans-epoxides in almost equal proportions indicating that the oxygen atom addition to a carbon-carbon bond in this system is non-concerted.The photochemically induced oxygenation of perdeuteriated aromatic substrates provides no evidence for direct insertion of an oxygen atom into an aromatic carbon-hydrogen bond.Addition of an oxygen atom to form an epoxide (arene oxide) intermediate in this system is evidenced by the NIH shift in a wide range of aromatic substrates, and by the detection of arene oxide intermediates (and their isomeric phenols) from naphthalene and phenanthrene.
- Akhtar, M. Naseem,Boyd, Derek R.,Neill, John D.,Jerina, Donald M.
-
p. 1693 - 1699
(2007/10/02)
-