The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Seong Gyoung Gang - One of the best experts on this subject based on the ideXlab platform.
-
a facile synthesis of benzo c phenanthridine alkaloids oxynitidine and oxysanguinarine using lithiated toluamide Benzonitrile cycloaddition
Tetrahedron Letters, 2004Co-Authors: Thanh Nguyen Le, Seong Gyoung GangAbstract:Abstract Benzo[c]phenanthridine alkaloids oxynitidine and oxysanguinarine were synthesized from easily available starting Benzonitrile 5 and toluamide 6 using toluamide–Benzonitrile cycloaddition reaction in six steps. This method is so highly efficient that it could be a more useful way for preparing fully aromatized benzo[c]phenanthridine compounds.
-
a versatile total synthesis of benzo c phenanthridine and protoberberine alkaloids using lithiated toluamide Benzonitrile cycloaddition
Journal of Organic Chemistry, 2004Co-Authors: Thanh Nguyen Le, Seong Gyoung GangAbstract:A new versatile synthesis of benzo[c]phenanthridine and protoberberine alkaloids using lithiated toluamide−Benzonitrile cycloaddition was carried out. The coupling reaction between Benzonitrile 6 with o-toluamides (8a−c) afforded 3-arylisoquinolines (9a−c) that were transformed to the protoberberines (11a−c) or benzo[c]phenanthridines (14a−c). These compounds were synthesized by ring closure of the two-carbon chain on either position 2 or 4 of the 3-arylisoquinolinone (9a−c). Several kinds of substituted benzo[c]phenanthridine alkaloids such as oxysanguinarine, oxyavicine, and oxynitidine as well as protoberberines such as 8-oxocoptisine, 8-oxopseudoberberine, and 8-oxopseudocoptisine were synthesized.
Thanh Nguyen Le - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of oxychelerythrine using lithiated toluamide Benzonitrile cycloaddition
Chemical & Pharmaceutical Bulletin, 2005Co-Authors: Thanh Nguyen LeAbstract:Oxychelerythrine, benzo[c]phenanthridine alkaloid, was synthesized from easily available starting toluamide 5 and Benzonitrile 6 using toluamide-Benzonitrile cycloaddition reaction in 6 steps.
-
a facile synthesis of benzo c phenanthridine alkaloids oxynitidine and oxysanguinarine using lithiated toluamide Benzonitrile cycloaddition
Tetrahedron Letters, 2004Co-Authors: Thanh Nguyen Le, Seong Gyoung GangAbstract:Abstract Benzo[c]phenanthridine alkaloids oxynitidine and oxysanguinarine were synthesized from easily available starting Benzonitrile 5 and toluamide 6 using toluamide–Benzonitrile cycloaddition reaction in six steps. This method is so highly efficient that it could be a more useful way for preparing fully aromatized benzo[c]phenanthridine compounds.
-
a versatile total synthesis of benzo c phenanthridine and protoberberine alkaloids using lithiated toluamide Benzonitrile cycloaddition
Journal of Organic Chemistry, 2004Co-Authors: Thanh Nguyen Le, Seong Gyoung GangAbstract:A new versatile synthesis of benzo[c]phenanthridine and protoberberine alkaloids using lithiated toluamide−Benzonitrile cycloaddition was carried out. The coupling reaction between Benzonitrile 6 with o-toluamides (8a−c) afforded 3-arylisoquinolines (9a−c) that were transformed to the protoberberines (11a−c) or benzo[c]phenanthridines (14a−c). These compounds were synthesized by ring closure of the two-carbon chain on either position 2 or 4 of the 3-arylisoquinolinone (9a−c). Several kinds of substituted benzo[c]phenanthridine alkaloids such as oxysanguinarine, oxyavicine, and oxynitidine as well as protoberberines such as 8-oxocoptisine, 8-oxopseudoberberine, and 8-oxopseudocoptisine were synthesized.
Hermann M. Bolt - One of the best experts on this subject based on the ideXlab platform.
-
Chromosomal genotoxicity of nitrobenzene and Benzonitrile
Archives of Toxicology, 2004Co-Authors: Daniela Bonacker, Konrad J. Böhm, Eberhard Unger, Gisela H. Degen, Ricarda Thier, Thomas Stoiber, Hermann M. BoltAbstract:In order to investigate the chromosomal genotoxicity of nitrobenzene and Benzonitrile, we studied the induction of micronuclei (MN) by these test compounds in V79 cells, as well as effects on the formation and stability of microtubules and on motor protein functions. No cytotoxicity was seen in V79 cell cultures in terms of Neutral red uptake after 18 h treatment with up to 1 mM nitrobenzene or 1 mM Benzonitrile. Subsequently, a concentration range up to 100 micro M was used in the experiments on induction of MN. Both test compounds exhibit a weak, but definitely positive test result compared to the solvent (DMSO) control. Minimal effect concentrations of nitrobenzene and Benzonitrile appeared as low as 0.01 micro M, and no-effect-concentrations were between 0.001 and 0.005 micro M. Clearly enhanced MN rates were found at 0.1 micro M and higher. Both, nitrobenzene and Benzonitrile, induced mostly kinetochor (CREST)-positive micronuclei, thus characterising the chromosomal effects as aneugenic. In cell-free assays, a slight effect on tubulin assembly was observed at 1 mM nitrobenzene without addition of DMSO. Higher concentrations (5 mM) led to secondary effects. In presence of 1% DMSO, nitrobenzene exerted no detectable effect on tubulin assembly up to the solubility limit in water of about 15 mM. For Benzonitrile in presence of DMSO, a clear dose-response of inhibition of tubulin assembly at 37 degrees C was seen above the no-effect-concentration of 2 mM, with an IC(50) of 13 mM and protein denaturation starting above a level of about 20 mM. The nature of the effects of nitrobenzene and Benzonitrile on the association of tubulin to form microtubules was confirmed by electron microscopy. Treatment by either 5 mM nitrobenzene or 13 mM Benzonitrile plus 1% DMSO left the microtubular structure intact whereas 5 mM nitrobenzene, in absence of DMSO, led to irregular cluster formations. The experiments demonstrate that both nitrobenzene and Benzonitrile, in millimolar concentration ranges, may lead to interference with tubulin assembly in a cell-free system. The functionality of the tubulin-kinesin motor protein system was assessed using the microtubule gliding assay. Nitrobenzene affected the gliding velocity in a concentration-dependent manner, starting at about 7.5 micro M and reaching complete inhibition of motility at 30 micro M, whereas Benzonitrile up to 200 micro M did not affect the kinesin-driven gliding velocity. The micronucleus assay data demonstrate a chromosomal endpoint of genotoxicity of nitrobenzene and Benzonitrile. Aneugenic effects of both compounds occur at remarkably low concentrations, with lowest-effect-concentrations being 0.1 micro M. This points to the relevance of interactions with the cellular spindle apparatus.
-
Chromosomal genotoxicity of nitrobenzene and Benzonitrile
Archives of Toxicology, 2003Co-Authors: Daniela Bonacker, Konrad J. Böhm, Eberhard Unger, Gisela H. Degen, Ricarda Thier, Thomas Stoiber, Hermann M. BoltAbstract:In order to investigate the chromosomal genotoxicity of nitrobenzene and Benzonitrile, we studied the induction of micronuclei (MN) by these test compounds in V79 cells, as well as effects on the formation and stability of microtubules and on motor protein functions. No cytotoxicity was seen in V79 cell cultures in terms of Neutral red uptake after 18 h treatment with up to 1 mM nitrobenzene or 1 mM Benzonitrile. Subsequently, a concentration range up to 100 µM was used in the experiments on induction of MN. Both test compounds exhibit a weak, but definitely positive test result compared to the solvent (DMSO) control. Minimal effect concentrations of nitrobenzene and Benzonitrile appeared as low as 0.01 µM, and no-effect-concentrations were between 0.001 and 0.005 µM. Clearly enhanced MN rates were found at 0.1 µM and higher. Both, nitrobenzene and Benzonitrile, induced mostly kinetochor (CREST)-positive micronuclei, thus characterising the chromosomal effects as aneugenic. In cell-free assays, a slight effect on tubulin assembly was observed at 1 mM nitrobenzene without addition of DMSO. Higher concentrations (5 mM) led to secondary effects. In presence of 1% DMSO, nitrobenzene exerted no detectable effect on tubulin assembly up to the solubility limit in water of about 15 mM. For Benzonitrile in presence of DMSO, a clear dose–response of inhibition of tubulin assembly at 37°C was seen above the no-effect-concentration of 2 mM, with an IC50 of 13 mM and protein denaturation starting above a level of about 20 mM. The nature of the effects of nitrobenzene and Benzonitrile on the association of tubulin to form microtubules was confirmed by electron microscopy. Treatment by either 5 mM nitrobenzene or 13 mM Benzonitrile plus 1% DMSO left the microtubular structure intact whereas 5 mM nitrobenzene, in absence of DMSO, led to irregular cluster formations. The experiments demonstrate that both nitrobenzene and Benzonitrile, in millimolar concentration ranges, may lead to interference with tubulin assembly in a cell-free system. The functionality of the tubulin–kinesin motor protein system was assessed using the microtubule gliding assay. Nitrobenzene affected the gliding velocity in a concentration-dependent manner, starting at about 7.5 µM and reaching complete inhibition of motility at 30 µM, whereas Benzonitrile up to 200 µM did not affect the kinesin-driven gliding velocity. The micronucleus assay data demonstrate a chromosomal endpoint of genotoxicity of nitrobenzene and Benzonitrile. Aneugenic effects of both compounds occur at remarkably low concentrations, with lowest-effect-concentrations being 0.1 µM. This points to the relevance of interactions with the cellular spindle apparatus.
Gerard Meijer - One of the best experts on this subject based on the ideXlab platform.
-
alternating gradient focusing of the Benzonitrile argon van der waals complex
Journal of Chemical Physics, 2012Co-Authors: Stephan Putzke, Jochen Kupper, Frank Filsinger, Gerard MeijerAbstract:We report on the focusing and guiding of the van der Waals complex formed between Benzonitrile molecules (C6H5CN) and argon atoms in a cold molecular beam using an ac electric quadrupole guide. The distribution of quantum states in the guided beam is non-thermal, because the transmission efficiency depends on the state-dependent effective dipole moment in the applied electric fields. At a specific ac frequency, however, the excitation spectrum can be described by a thermal distribution at a rotational temperature of 0.8 K. From the observed transmission characteristics and a combination of trajectory and Stark-energy calculations we conclude that the permanent electric dipole moment of Benzonitrile remains unchanged upon the attachment of the argon atom to within ±5%. By exploiting the different dipole-moment-to-mass (µ/m) ratios of the complex and the Benzonitrile monomer, transmission can be selectively suppressed for or, in the limit of 0 K rotational temperature, restricted to the complex.
Sergey I Druzhinin - One of the best experts on this subject based on the ideXlab platform.
-
two state intramolecular charge transfer ict with 3 5 dimethyl 4 dimethylamino Benzonitrile mmd and its meta isomer mmmd ground state amino twist not essential for ict
Journal of Physical Chemistry A, 2015Co-Authors: Sergey I Druzhinin, Victor A Galievsky, Attila Demeter, S A Kovalenko, Tamara Senyushkina, Srinivas Reddy Dubbaka, Paul Knochel, Peter MayerAbstract:From X-ray structure analysis, amino twist angles of 90.0° for 2,4-dimethyl-3-(dimethylamino)Benzonitrile (mMMD), 82.7° for 4-(di-tert-butylamino)Benzonitrile (DTABN), and 88.7° for 6-cyanobenzoquinuclidine (CBQ) are determined, all considerably larger than the 57.4° of 3,5-dimethyl-4-(dimethylamino)Benzonitrile (MMD). This large twist leads to lengthening of the amino–phenyl bond, 143.5 pm (mMMD), 144.1 pm (DTABN), 144.6 pm (CBQ), and 141.4 pm (MMD), as compared with 136.5 pm for the planar 4-(dimethylamino)Benzonitrile (DMABN). As a consequence, the electronic coupling between the amino and phenyl subgroups in mMMD, DTABN, CBQ, and MMD is much weaker than in DMABN, as seen from the strongly reduced molar absorption coefficients. The fluorescence spectrum of MMD in n-hexane at 25 °C consists of two emissions, from a locally excited (LE) and an intramolecular charge transfer (ICT) state, with a fluorescence quantum yield ratio Φ′(ICT)/Φ(LE) of 12.8. In MeCN, a single ICT emission is found. With mMMD in n-...
