Position Of Phenyl Ring Research Articles

Enzymatic syntheses of dopamine glycosides

Glucoamylase from Rhizopus mold and β-glucosidase catalysed synthesis of dopamine- d-glucoside was optimized in terms of pH, buffer, enzyme, dopamine concentrations and incubation period in organic media. Under the optimum conditions, β-glucosidase showed regioselectivity by giving rise to 3-hydroxy-4- O-(β- d-glucopyranosyl)phenylethylamine 5b. Presence of hydroxyl group at 3rd and 4th position of phenyl ring showed only monoglycosylation/arylation products with d-glucose 2, d-galactose 3 and d-mannose 4 for both the enzymes. Synthesized glycosides also exhibited ACE inhibition and antioxidant activities.

Synthesis and Photophysical Studies of New Blue Phosphorescent Iridium Complexes of Fluorinated 2-phenyl-4-methoxypyridine

In this study, a new Ir(III) complex containing 2-(3′,5′-bistrifluoromethyl phenyl)-4-methoxypyridine have been synthesized and characterized for efficient blue organic light-emitting diodes (OLEDs). In order to tune photoluminescence (PL) spectra to a shorter wavelength, ppy ligand was fluorinated by –;CF3 and substituted by –OCH3 group. The methoxy group substituted on the 4-position of pyridyl ring as electron donating group strongly affected the lowest unoccupied molecular orbital (LUMO) and it raised the LUMO energy and increased the energy gap. The trifluoromethyl group substituted on the 3′,5′-position of phenyl ring as electron withdrawing group decreased the highest occupied molecular orbital (HOMO), and bulky CF3 groups occurs a steric hindrance of iridium complex helps decrease of self-quenching. As a result, Ir[(CF3)2OMeppy]2(acac) is more blue-shifted emission at 471 nm and strong luminescence efficiency.

Substituent effects of iridium (III) complexes with 2,4-diphenylquinoline for efficient red organic light-emitting diodes

We demonstrate efficient red electrophosphorescence using bis[2-(5-methoxyphenyl)-4-phenylquinolinato- N,C 2] iridium(III)(acetylacetonate) [Ir(dpq-5OCH 3) 2(acac)], bis[2-(5-methylphenyl)-4-phenylquinolinato- N,C 2] iridium(III)(acetylacetonate)[Ir(dpq-5CH 3) 2(acac)] and bis[2-(5-fluorophenyl)-4-phenylquinolinato- N,C 2] iridium(III) (acetylacetonate) [Ir(dpq-5F) 2(acac)] in compared with bis[2,4-diphenylquinolinato- N,C 2] iridium(III)(acetylacetonate) [Ir(dpq) 2(acac)]. The –CH 3, –OCH 3 and –F group substituted on the 5′-position of phenyl ring strongly affected the energy level of molecule. The organic light-emitting diodes (OLEDs) with Ir(dpq-5OCH 3) 2(acac), Ir(dpq-5CH 3) 2(acac), Ir(dpq-5F) 2(acac) and Ir(dpq) 2(acac) have a maximum luminous efficiency of 8.20 cd/A, 10.20 cd/A, 15.80 cd/A and 11.60 cd/A, respectively. Also, their electroluminescent emission appeared at 605, 617, 610 and 617 nm, respectively.

Design and Synthesis of Some 5-Substituted-2-(4-(azido or methylsulfonyl) phenyl)-1H-indole Derivatives as Selective Cyclooxygenase (COX-2) Inhibitors

A group of 5-substituted-2-(4-azido or (methylsulfonyl)phenyl)-1H-indoles were designed and synthesized as selective cyclooxygenase (COX-2) inhibitors. In vitro COX-1 and COX-2 isozyme inhibition studies were carried out to investigate the effect of different substituents (H, F, Cl, Me, OMe) at C-5 position and different pharmacophore groups (azido or methylsulfonyl) at para position of phenyl ring at C-2 position of the 1H-indole ring on COX-2 selectivity and potency. The structure-activity relationship study of these compounds indicated that the introduction of a methoxy substituent at C-5 position and 4-(methylsulfonyl) phenyl group at C-2 position of the 1H-indole ring (compound 4e) had the best COX-2 selectivity (S.I= 291.2). A molecular modeling study where 4e was docked in the binding site of COX-2 showed that the methylsulfonyl group at para position of phenyl ring is oriented in the vicinity of the COX-2 secondary pocket.

Photochemical degradation of six polybrominated diphenyl ether congeners under ultraviolet irradiation in hexane

The photodegradation of six individual PBDE congeners (BDE-28, 47, 99, 100, 153, 183) in hexane was investigated under UV light in the sunlight region, employing a mercury lamp filtered with Pyrex glass. All photodegradation reactions followed the pseudo-first-order kinetics, with the half-lives ranging from 0.26 h for BDE-183 to 6.46 h for BDE-100. The photochemical reaction rates of PBDEs decreased with decreasing number of bromine substituents in the molecule, also in some cases were influenced by the PBDE substitution pattern. Principal photoproducts detected were less brominated PBDEs, and no PBDE-solvent adducts were found. Consecutive reductive debromination was confirmed as the main mechanism for the photodegradation of PBDEs in hexane. In general, debromination firstly occurred on the more substituted rings, when the numbers of bromine atoms on the two phenyl rings were unequal. For less brominated PBDEs, the photoreactivity of bromines at various positions of phenyl rings decreased in the order: ortho > para; while for higher brominated PBDEs, the difference became not significant.

Synthesis and In Vitro Evaluation of Substituted Phenyl‐Piperazinyl‐Phenyl Oxazolidinones Against Gram‐positive Bacteria

With the incidence of linezolid-resistant Enterococcus faecalis, E. faecium and Staphylococcus aureus, modification of linezolid at the 5- and/or 3-positions led to the development of a series of 3-(methoxyl-phenyl)-piperazinyl-phenyl oxazolidinone analogues. These compounds were tested in vitro against six gram-positive standard organisms (S. aureus, S. epidermidis, S. pneumoniae, S. albus, Streptococcus enteridis and S. nonhemolyticus). 5-acetylaminomethyl oxazolidinones bearing fluorine at 3'-position of phenyl ring showed activities against several gram-positive bacteria (MIC: 3.13-6.25 mug/mL). The position of methoxyl group on the phenyl ring of piperazine group affected antibacterial spectrum. 3-(4'- (para-methoxyl-phenyl)-piperazinyl)-(3'-fluoro)-phenyl-5-acetylaminomethyl oxazolidinone was found active against 5 gram-positive organisms except S. nonhemolyticus, whereas 3-(4'-(ortho-methoxyl-phenyl)-piperazinyl)-(3'-fluoro)-phenyl-5-acetylaminomethyl oxazolidinone was found active only against 2 gram-positive organisms, namely S. albus, S. enteridis.

Computational notes on structural, electronic and QSAR properties of [C60]fulleropyrrolidine-1-carbodithioic acid 2; 3 and 4-substituted-benzyl esters

We have investigated theoretically by performing semi-empirical PM3 method three series of [C60]fulleropyrrolidine-1-carbodithioic acid 2; 3 and 4-substituted-benzyl esters. We have selected these molecules to be substituted in ortho, meta and para positions of phenyl ring with variable donating and acceptor substituents to show the effect of such structural change on the structural and electronic properties of the studied molecules. The optimized geometries, some of calculated energies, spatial distribution and positions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), and QSAR properties of structural variables are obtained.

Vibrational Spectra and Density functional calculation of Organic Nonlinear Optic Crystal p-Amino Acetanilide

The NIR-FT Raman, FT-IR spectral analysis of potential NLO material P-Amino Acetanilide is carried out by density functional computations. The optimized geometry shows that NH2 and NHCOCH3 groups substituted in para position of phenyl ring are non-planar which predicts maximum conjugation of molecule with donor and acceptor groups. Vibrational analysis reveals that simultaneous IR and Raman activation of the phenyl ring modes also provide evidence for the charge transfer interaction between the donors and the acceptor can make the molecule highly polarized and the intra molecular charge transfer interaction must be responsible for the NLO properties of PAA.

Study of the structural and electronic properties of the 1-phenyl-3,3-pentamethylenetriazenes

The structural and electronic properties of the 1-phenyl-3,3-pentamethylenetriazenes substituted at the para position of phenyl ring have been investigated theoretically by performing semi-empirical molecular orbital theory. The structures of molecules are optimized at the level of MNDO and PM3 of theory. The electronic properties and relative energies of the molecules are obtained.

A molecular recognition strategy towards tetra-chlorinated dibenzo- p-dioxins, TCDDs

Uniformly sized polymeric separation media were prepared using o- or p-xylene as porogenic template to investigate chromatographic selectivity towards tetra-chlorinated dibenzo- p-dioxins (TCDDs). TCDDs having chlorine atoms at ortho positions of phenyl rings were selectively retained on stationary phase prepared with o-xylene as porogenic template, while TCDDs having chlorine atoms at para positions of phenyl ring were found to be retained selectively on the stationary phase imprinted by the porogenic template, p-xylene. Slightly longer cross-linking agent afforded chromatographically selective retention for larger TCDD isomers. It was also found that positional relationship between substituted chlorine atoms was also important for chromatographic recognition.

A reassessment of the nomenclature of polychlorinated biphenyl (PCB) metabolites.

Polychlorinated biphenyls (PCBs) are a widespread class of persistent organic chemicals that accumulate in the environment and humans and are associated with a broad spectrum of health effects. PCB biotransformation has been shown to lead to two classes of PCB metabolites that are present as contaminant residues in the tissues of selected biota: hydroxylated (HO) and methyl sulfone (MeSO2) PCBs. Although these two types of metabolites are related structures, different rules for abbreviation of both classes have emerged. It is important that a standardized nomenclature for the notation of PCB metabolites be universally agreed upon. We suggest that the full chemical name of the PCB metabolite and a shorthand notation should be adopted using the International Union of Pure and Applied Chemistry's chemical name/original Ballschmiter and Zell number of the parent congener, followed by the assignment of the phenyl ring position number of the MeSO2- or HO-substituent. This nomenclature provides a clear, unequivocal set of rules in naming and abbreviating the PCB metabolite structure. Furthermore, this unified PCB metabolite nomenclature approach can be extended to the naming and abbreviation of potential metabolites of structurally analogous contaminants such as HO-polybrominated biphenyls and HO-polybrominated diphenyl ethers.

Synthesis of New Substituted 6‐Ureidopurines and 6‐Ureido‐9‐(2,3,5‐triacetyl ribofuranosyl)purines Having Cytokinin (Plant Growth Promoting) Activity.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cα-Methyl, Cα-phenylglycine peptides: A structural study

In order to obtain further information on the role played by phenyl ring position in the Cα-methylated α-amino acid side chain on peptide preferred conformation, the crystal-state structural preferences of Cα-methyl, Cα-phenylglycine peptides have been determined by X-ray diffraction. This study shows that either the fully extended conformation or the β-bend/310-helical structures are adopted by peptides characterized by this Cα-methylated, β-branched, aromatic α-amino acid.

Hydrogenation of Styrene Homologs Catalyzed by a Dihydridorhodium Complex.

(1,3-ジフェニルトリアゼニド)ジヒドリドビス(トリフェニルポスフィン)ロジウム(III)(ジヒドリドロジウム錯体)-ジメチルスルホキシド系によるスチレンの水素化反応を 30℃ で行い,反応を速度論を用いて検討した。その結果,反応速度はジヒドリドロジウム錯体濃度の 1 次と水素の分圧の1次,およびスチレン濃度の 0 次に比例することがわかった。また,スチレンのベンゼン環のパラ位に電子求引性の基を導入することにより水素化反応は速くなり,一方,電子供与性の基の導入では水素化反応は遅くなることがわかった。さらに,スチレ湘灘の水素化反応の結果と Hammett のσ+との間には直線関係が認められた。

Effect of phenyl ring position in the Cα-methylated α-amino acid side chain on peptide preferred conformation

The preferred conformations of Cα-methyl phenylglycine, Cα-methyl phenylalanine, and Cα-methyl homophenylalanine residues, as determined in model peptides (including homopeptides) by Fourier transform ir absorption, 1H-nmr, CD, and x-ray diffraction techniques, are compared with the aim of investigating the effect of phenyl ring position in the Cα-methylated amino acid side chain. This study shows that (a) β-turn and 310-helical structures are preferentially adopted by peptides rich in these Cα-methylated, aromatic α-amino acids and (b) turn and helix handedness is critically biased by the position of side-chain branching. © 1997 John Wiley & Sons, Inc. Biopoly 40: 523–527, 1996

Effect of phenyl ring position in the C‐methylated α‐amino acid side chain on peptide preferred conformation

The preferred conformations of Cα-methyl phenylglycine, Cα-methyl phenylalanine, and Cα-methyl homophenylalanine residues, as determined in model peptides (including homopeptides) by Fourier transform ir absorption, 1H-nmr, CD, and x-ray diffraction techniques, are compared with the aim of investigating the effect of phenyl ring position in the Cα-methylated amino acid side chain. This study shows that (a) β-turn and 310-helical structures are preferentially adopted by peptides rich in these Cα-methylated, aromatic α-amino acids and (b) turn and helix handedness is critically biased by the position of side-chain branching. © 1997 John Wiley & Sons, Inc. Biopoly 40: 523–527, 1996

Structure activity relationship of ar-turmerone analogues

For the analysis of structure activity relationship of ar-turmerone analogues, the compounds containing the various substituents on the phenyl ring and 1(or 2)-naphthyl group in the place of phenyl of ar-turmerone were prepared and tested their cytotoxicity against HL-60, K-562, and L1210 leukemia cellsin vitro. The substituents at para position are methoxy, phenoxy, methyl, trifluoromethyl, fluoro, and chloro. Atmeta position methoxy, methyl, trifluoromethyl, or chloro groups and atortho position methoxy or chloro group were introduced. Against HL-60 and K-562 cells, ED50 values of the analogues are ranged from 0.8 to 30.0 μg/ml. Against L1210 cell, these are located more than 20.0 μg/ml. However, 5-carboethoxy-2-methyl-6-(1-naphthyl)-2-octen-4-one (5n) possesses ED50 valuses 0.8, 2.1, 6.5 μg/ml against HL-60, K-562, L1210 cells, respectively. The electronic nature of the subsituents on phenyl ring of ar-turmerone dose not affect the biological activity. Therefore the flat structure of aromatic portion of ar-turmerone analogues is the more important factor for their activity rather than its electronic nature. The potentiation of the cytotoxicity with the enlargement of aromatic ring region also supports the importance of the plane structure of this area. The restriction of the single bond rotation between C-6 and aromatic ring through the introduction of substituents at theortho position of phenyl ring and the increment of size of alkyl group at C-6 position enhances the activity. Therefore the effective conformation should be the one having the orthogonal arrangement between the aromatic ring and the side chain.

Dynamic nuclear magnetic resonance and empirical force field studies of cannabidiol

Internal rotation of cannabidiol ( 1), its mono-( 2) and dimethyl ( 3) derivatives has been studied by 1H and 13C dynamic NMR spectroscopy. The free energy of activation for the rotation of C 3-C 2, bond that we have observed for cannabidiol of 14.7 kcal/mol at 22° in CDCl 3 is in contrast with values previously reported in the literature. Molecular mechanics simulation of the rotation of C 3-C 2, bond of a model structure ( 4) well reproduced the presently determined barrier height. Analysis of the calculated rotational transition state structure revealed severe nonbonded C 2H/O and C 8/O interactions as the source of barrier. Calculations of other model structures indicate general occurrence of restricted rotation about the pivot bond of phenylcyclohexanes appropriately substituted at β-carbon of cyclohexane ring and at ortho position of phenyl ring. The fully substituted 2,6-dimethyl-1-( o,o'-dimethylphenyl) cyclohexane ( 10) is predicted to show atropisomerism.

光学的活性フェニルプロパノールアミン誘導体に関する研究 (第7報)

Decomposition of α-aminopropiophenones, possessing a hydroxyl or methoxyl group in the para position of phenyl ring, with acetic acid afforded a mixture of arylacetylcarbinols (I) and aroylmethylcarbinols (II). This is due to the rearrangement of (I) during the reaction to a more stable (II). In a similar manner, benzoin and benzylmethylamine were obtained from α-benzylmethylaminodesoxybenzoin.