نتایج جستجو برای: aromatic compounds

تعداد نتایج: 258549  

Journal: :organic chemistry research 2016
mehdi nabati mehrdad mahkam

one main group of organic chemistry is related to the aromatic compounds. in the present work, we replaced the ch group of benzene by silicon and nitrogen analogues. then, density functional theory (dft) calculations were carried out for six-membered heterocyclic si-n aromatic rings. full geometry optimizations were performed in gas-phase, and at b3lyp level using 6-311++g(d,p) and cbsb7 basis ...

Journal: :Journal of the American Chemical Society 2001
H Dang M A Garcia-Garibay

Many efforts have been directed toward the synthesis of polynuclear aromatic hydrocarbons (PAH) that have peri-fused fiveand six-membered-ring carbon fragments corresponding to portions of the fullerene surface.1 These include polycyclic aromatic systems with potentially interesting fullerene-like photophysical properties such as acenaphthalene (I), pyracylene (II), aceanthrylene (III), and sev...

Journal: :Organic letters 2005
Don M Cho Sean R Parkin Mark D Watson

[structure: see text] We report the synthesis and characterization of partially fluorinated condensed tetracyclic aromatic compounds. Typical edge-to-face/herringbone packing of nonfluorinated analogues is replaced here by columnar stacks with disk planes orthogonal to the columnar axes. Enhanced pi-overlap results with overlaid electron-poor and -rich regions.

Journal: :Chemistry & biodiversity 2004
Joseph R Votano Marc Parham Lowell H Hall Lemont B Kier L Mark Hall

Several QSPR models were developed for predicting intrinsic aqueous solubility, S(o). A data set of 5,964 neutral compounds was sub-divided into two classes, aromatic and non-aromatic compounds. Three models were created with different methods on both data sets: two regression models (multiple linear regression and partial least squares) and an artificial neural network model. These models were...

Journal: :Journal of general microbiology 1949
S DAGLEY M E FEWSTER F C HAPPOLD

Evans (1947) observed that cultures of Vibrio 01 developing at the expense of phenol gave an intense violet Rothera reaction during the later stages of growth. The Rothera test is a nitroprusside reaction used clinically to detect the presence of "acetone bodies" (acetone and acetoacetic acid) in urine. Although Evans did not succeed in identifying the substance responsible for the positive Rot...

Journal: :Journal of bacteriology 1987
D K Chatterjee A W Bourquin

Cultures of Caulobacter crescentus were found to grow on a variety of aromatic compounds. Degradation of benzoate, p-hydroxybenzoate, and phenol was found to occur via beta-ketoadipate. The induction of degradative enzymes such as benzoate 1,2-dioxygenase, the ring cleavage enzyme catechol 1,2-dioxygenase, and cis, cis-muconate lactonizing enzyme appeared similar to the control mechanism presen...

2015
Christine Achten Jan T. Andersson

The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an atte...

Journal: :Environmental Health Perspectives 1990
M J Wornat A G Braun A Hawiger J P Longwell A F Sarofim

The polycyclic aromatic compounds (PAC) produced from the pyrolysis of a bituminous coal at temperatures of 1125 to 1425 degrees K prove to be mutagenic to S. typhimurium, both in the presence and in the absence of postmitochondrial supernatant (PMS) prepared from Aroclor 1254-induced rat liver. Mutagenicity of the PAC samples measured in the absence of PMS exhibits little dependence on pyrolys...

1999
Kirk T. Semple Ronald B. Cain Stefan Schmidt

The microbial degradation of aromatic pollutants has been well characterized over a period of more than 30 years. The microbes of most interest have been bacteria and fungi. Only relatively recently has the question of how algae figure in the catabolism of these compounds attracted a degree of interest. The aim of this review is to highlight the biodegradative capabilities of microalgae on arom...

Journal: :Journal of bacteriology 1971
B F Johnson R Y Stanier

The range of aromatic compounds that support the growth of Alcaligenes eutrophus has been determined, and the pathways used for the dissimilation of these substrates have been explored, largely by enzymatic analyses. The beta-ketoadipate pathway operates in the dissimilation of benzoate and p-hydroxybenzoate; the genetisate pathway, in the dissimilation of m-hydroxybenzoate; and the meta cleava...

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