A theoretical quantum study of the electronic properties of mentoxy dichloro phosphorous (C10H19OPCl2)

Indexación: Scopus.A theoretical quantum study of the organophosphorus compound with formula C10H19OPCl2 (MEPCL2) was carried out. The results of the calculations show excellent agreement between experimental and computed frequencies evaluated at the B3LYP/6-311++G(d,p) level of theory. A study of the electronic properties, such as excitation energies and wavelengths were performed employing the time-dependent DFT (TD-DFT) method. Global a chemical reactivity of MEPCL2 was analyzed through global reactivity descriptors, while its local reactivity was analyzed by mean maps of the electrostatic potential. Also, the orbital energies values suggest that a charge transfer is occurring within the molecule. © 2018 American Physical Society.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072018000103887&lng=en&nrm=iso&tlng=e

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

Inhibition of 6-hydroxydopamine-induced oxidative damage by 4,5-dihydro-3H-2-benzazepine N-oxides

A number of new analogs of 3,3-dimethyl-4,5-dihydro-3H-2-benzazepine 2-oxide, structurally related to the nitrone spin trap α-phenyl-N-tert-butylnitrone (PBN), were synthesized and evaluated for their activity in vitro as protectants against oxidative stress induced in rat brain mitochondria by 6-hydroxydopamine (6-OHDA), a neurotoxin producing experimental model of Parkinson's disease (PD). As assessed by a fluorimetric assay, all 2-benzazepine-based nitrones were shown to decrease hydroxyl radicals ({radical dot}OH) generated during 6-OHDA autoxidation. The inhibition effects on the {radical dot}OH formation shown by the 5-gem-dimethyl derivatives, 2-4 times higher than those of the corresponding 5-methyl derivatives, were attributed to the flattening effect of the 5-gem-dimethyl group on the azepine ring, which should enhance nitrone reactivity and/or increase stability of the radical adducts. In contrast, owing to steric hindrance, a methyl group to C-1 diminishes the {radical dot}OH-scavenging activity of the nitrone group. All the assayed compounds were more potent than PBN as inhibitors of 6-OHDA-induced lipid peroxidation (LPO) and protein carbonylation (PCO), taken as an indicator of mitochondrial protein oxidative damage. The most promising antioxidant (compound 11), bearing 5-gem-dimethyl and spiro C-3 cyclohexyl groups, highlighted in this study as the best features, inhibited LPO and PCO with IC50 values of 20 and 48 μM, respectively, showing a potency improvement over PBN of two order magnitude. Both LPO and PCO inhibition potency data were found primarily related to the {radical dot}OH-scavenging activities, whereas lipophilicity plays a role in improving the LPO (but not PCO) inhibition, as a statistically valuable two-parameter equation proved. © 2008 Elsevier Inc. All rights reserved

Physicochemical properties and antimicrobial activity of new spirocyclic thieno[2,3-d]pyrimidin-4(3H)-one derivatives

(figure presented) A number of 6'-methylidene-2,3-dihydro-1H-spiro[pyridine-4,5'-thieno[2,3-d]pyrimidin]-4'(3'H)-one derivatives, obtained as major products of a domino reaction between 5,6,7,8-tetrahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidines and electron-deficient alkynes, were characterized for their acid-base properties and lipophilicity and evaluated for the antimicrobial activity against a number of clinical isolates of bacterial and fungal strains. The cytotoxicity against four tumor cell lines was also screened for some compounds. The dissociation constants (pKa) and partition coefficients (log P) in 1-octanol–water system were determined using a potentiometric technique. The negative difference between the observed and calculated log P values could be explained in the light of the conformational rigidity. Most of the studied compounds showed a moderate and selective activity against Gram-positive bacteria strains (S. agalactiae, E. faecalis, S. epidermidis), whereas did not exhibit any effect against Gram-negative bacteria and fungi at the maximum test concentration (500 μM). Implications of the physicochemical properties in modulating the antimicrobial activity and cytotoxicity of the examined spirocyclic thieno[2,3-d]pyrimidin-4(3H)-one derivatives are also discussed. © 2017 Springer Science+Business Media New York

Ester derivatives of annulated tetrahydroazocines: A new class of selective acetylcholinesterase inhibitors

A series of ester derivatives of annulated tetrahydroazocines, namely 2,3,6,11-tetrahydro-1H-azocino[4,5-b]indoles (5-10), 2,3,6,7-tetrahydro-1H-azocino[5,4-b]indoles (11-14), and 4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocines (15-18), synthesized through an efficient 6 → 8 membered ring expansion procedure, were investigated for their acetylcholinesterase (AChE) inhibitory activities. Most of the compounds acted as AChE inhibitors in vitro, with IC50 values ranging from 5 to 40 μM. The most potent compounds 11 and 15, both as racemic mixtures, proved selective toward AChE, exhibiting selectivity ratios versus butyrylcholinesterase (BuChE) of ca. 15 and more than 20, respectively. Structure-activity studies highlighted, among other factors, lipophilicity as a property modulating the AChE inhibition potency, as shown by a reasonable parabolic correlation between pIC50 and experimental 1-octanol/water partition coefficient (log P), which described the prevailing behavior of the examined compounds (r2 = 0.665). Molecular docking simulations using the X-ray crystal structure of AChE from Torpedo californica suggested possible binding modes of the tetrahydroazocine ester derivatives 11 and 15. © 2006

Recyclization of benzofuropyridines by the action of activated alkynes in the synthesis of spiro[benzofuropyridines], representatives of a new class of acetylcholinesterase inhibitors

A study was carried out on the domino transformations of tetrahydrobenzofuro[2,3-c]pyridines and tetrahydrobenzofuro[3,2-c]pyridines by the action of activated alkynes in methanol and acetonitrile. This reaction is a new method for the synthesis of spiro[benzofuropyridines] showing acetylcholinesterase inhibition activity. © 2013 Springer Science+Business Media New York

Ester derivatives of annulated tetrahydroazocines: a new class of selective acetylcholinesterase inhibitors

A series of ester derivatives of annulated tetrahydroazocines, namely 2,3,6,11-tetrahydro-1H-azocino[4,5-b]indoles (5-10), 2,3,6,7-tetrahydro-1H-azocino[5,4-b]indoles (11-14), and 4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocines (15-18), synthesized through an efficient 6-->8 membered ring expansion procedure, were investigated for their acetylcholinesterase (AChE) inhibitory activities. Most of the compounds acted as AChE inhibitors in vitro, with IC(50) values ranging from 5 to 40 microM. The most potent compounds 11 and 15, both as racemic mixtures, proved selective toward AChE, exhibiting selectivity ratios versus butyrylcholinesterase (BuChE) of ca. 15 and more than 20, respectively. Structure-activity studies highlighted, among other factors, lipophilicity as a property modulating the AChE inhibition potency, as shown by a reasonable parabolic correlation between pIC(50) and experimental 1-octanol/water partition coefficient (logP), which described the prevailing behavior of the examined compounds (r(2)=0.665). Molecular docking simulations using the X-ray crystal structure of AChE from Torpedo californica suggested possible binding modes of the tetrahydroazocine ester derivatives 11 and 15

Physicochemical properties and antimicrobial activity of new spirocyclic thieno[2,3-d]pyrimidin-4(3H)-one derivatives

(figure presented) A number of 6'-methylidene-2,3-dihydro-1H-spiro[pyridine-4,5'-thieno[2,3-d]pyrimidin]-4'(3'H)-one derivatives, obtained as major products of a domino reaction between 5,6,7,8-tetrahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidines and electron-deficient alkynes, were characterized for their acid-base properties and lipophilicity and evaluated for the antimicrobial activity against a number of clinical isolates of bacterial and fungal strains. The cytotoxicity against four tumor cell lines was also screened for some compounds. The dissociation constants (pKa) and partition coefficients (log P) in 1-octanol–water system were determined using a potentiometric technique. The negative difference between the observed and calculated log P values could be explained in the light of the conformational rigidity. Most of the studied compounds showed a moderate and selective activity against Gram-positive bacteria strains (S. agalactiae, E. faecalis, S. epidermidis), whereas did not exhibit any effect against Gram-negative bacteria and fungi at the maximum test concentration (500 μM). Implications of the physicochemical properties in modulating the antimicrobial activity and cytotoxicity of the examined spirocyclic thieno[2,3-d]pyrimidin-4(3H)-one derivatives are also discussed. © 2017 Springer Science+Business Media New York

A New Class of 1-Aryl-5,6-dihydropyrrolo[2,1-a]isoquinoline Derivatives as Reversers of P-Glycoprotein-Mediated Multidrug Resistance in Tumor Cells

A number of aza-heterocyclic compounds, which share the 5,6-dihydropyrrolo[2,1-a]isoquinoline (DHPIQ) scaffold with members of the lamellarin alkaloid family, were synthesized and evaluated for their ability to reverse in vitro multidrug resistance in cancer cells through inhibition of P-glycoprotein (P-gp) and/or multidrug-resistance-associated protein 1. Most of the investigated DHPIQ compounds proved to be selective P-gp modulators, and the most potent modulator, 8,9-diethoxy-1-(3,4-diethoxyphenyl)-3-(furan-2-yl)-5,6-dihydropyrrolo[2,1-a]isoquinoline-2-carbaldehyde, attained sub-micromolar inhibitory potency (IC50: 0.19 μm). Schiff bases prepared by the condensation of some 1-aryl-DHPIQ aldehydes with p-aminophenol also proved to be of some interest, and one of them, 4-((1-(4-fluorophenyl)-5,6-dihydro-8,9-dimethoxypyrrolo[2,1-a]isoquinolin-2-yl)methyleneamino)phenol, had an IC50 value of 1.01 μm. In drug combination assays in multidrug-resistant cells, some DHPIQ compounds, at nontoxic concentrations, significantly increased the cytotoxicity of doxorubicin in a concentration-dependent manner. Studies of structure–activity relationships and investigation of the chemical stability of Schiff bases provided physicochemical information useful for molecular optimization of lamellarin-like cytotoxic drugs active toward chemoresistant tumors as well as nontoxic reversers of P-gp-mediated multidrug resistance in tumor cells. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei