The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Thierry Chiavassa - One of the best experts on this subject based on the ideXlab platform.
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Carbamic Acid and carbamate formation in NH3:CO2 ices-UV irradiation versus thermal processes
Astronomy and Astrophysics - A&A, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] can be formed from both thermal reactions and energetic photons in an NH3:CO2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH3: CO2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1: 1 ratio from NH3 and CO2 above 80 K. They can be also formed in a 28: 1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in nh _ sf 3 co _ sf 2 ices uv irradiation versus thermal processes
Astronomy and Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in NH$_{\sf 3}$:CO$_{\sf 2}$ ices – UV irradiation versus thermal processes
Astronomy & Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
Jean-baptiste Bossa - One of the best experts on this subject based on the ideXlab platform.
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Carbamic Acid and carbamate formation in NH3:CO2 ices-UV irradiation versus thermal processes
Astronomy and Astrophysics - A&A, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] can be formed from both thermal reactions and energetic photons in an NH3:CO2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH3: CO2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1: 1 ratio from NH3 and CO2 above 80 K. They can be also formed in a 28: 1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in nh _ sf 3 co _ sf 2 ices uv irradiation versus thermal processes
Astronomy and Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in NH$_{\sf 3}$:CO$_{\sf 2}$ ices – UV irradiation versus thermal processes
Astronomy & Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
Mohammad Amjad Kamal - One of the best experts on this subject based on the ideXlab platform.
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Computational study of human tyrosine hydroxylase mutants to uphold [4-(propan-2-yl) phenyl]Carbamic Acid as a potential inhibitor
CNS & neurological disorders drug targets, 2014Co-Authors: Muhammad Sulaman Nawaz, Zahida Parveen, Liyong Wang, Sajid Rashid, Muhammad Qaiser Fatmi, Mohammad Amjad KamalAbstract:Neurodegenerative diseases that afflict nervous system are characterized by progressive nervous system dysfunction and associated with the one-set of many diseases like Segawa’s syndrome (recessive form), autosomal recessive L-dopa-responsive dystonia, L-dopa non-responsive dystonia or progressive early-onset encephalopathy and recessive L-dopa-responsive parkinsonism. It has been reported that a number of mutations in coding regions, splice sites and promoter regions of tyrosine hydroxylase (TH) are associated with many such diseases. TH is responsible for catalyzing the conversion of L-tyrosine to L-3,4-dihydroxyphenylalanine. This reaction is considered as rate-limiting step in the biosynthesis of catecholamines, dopamine, norepinephrine and epinephrine, which has made TH an important target for drug development. In our previous study using comparative molecular docking approach, it was concluded that [4- (Propan-2-yl) Phenyl]Carbamic Acid (PPCA) may serve as a potential inhibitor. By further extending, our focus is to determine the binding affinities of PPCA and mutated TH. 3D structures of mutated TH were predicted and subjected to molecular docking studies. PPCA was found to bind in the deep narrow groove lined with polar and aromatic amino Acids in 14 out of 17 mutants under study (R202H, L205P, H215Y, G216S, T245P, F278P, T283M, R297W, R306H, C328F, A345V, L356M, T368M, Q381K, P461L, T463M and D467G). Our results corroborate efficient binding of PPCA with normal and mutated TH, indicating that PPCA might be a strong therapeutic candidate for the management of Parkinson’s disease and other related disorders. It may be a valuable target for evaluation in preclinical models.
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Molecular docking study of catecholamines and [4-(propan-2-yl) phenyl]Carbamic Acid with tyrosine hydroxylase.
CNS & neurological disorders drug targets, 2012Co-Authors: Zahida Parveen, Muhammad Sulaman Nawaz, Shazi Shakil, Nigel H. Greig, Mohammad Amjad KamalAbstract:Parkinson’s disease is a major age-related neurodegenerative disorder. As the classical disease-related motor symptoms are associated with the loss of dopamine-generating cells within the substantia nigra, tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of catecholamines has become an important target in the development of Parkinson’s disease drug candidates, with the focus to augment TH levels or its activity. By contrast, TH inhibitors are of relevance in the treatment of conditions associated with catecholamine over-production, as occurs in pheochromocytomas. To aid characterizing new drug candidates, a molecular docking study of catecholamines and a novel hypothetical compound [4-(propan-2-yl) phenyl]Carbamic Acid (PPCA) with TH is described. Docking was performed using Autodock4.2 and results were analyzed using Chimera1.5.2. All the studied ligands were found to bind within a deep narrow groove lined with polar aromatic and Acidic residues within TH. Our results corroborated a ‘hexa interacting amino Acids unit’ located in this deep narrow groove crucial to the interaction of PPCA and the studied catecholamines with TH, whereby the ‘His361-His336 dyad’ was found to be even more crucial to these binding interactions. PPCA displayed a binding interaction with human TH that was comparable to the original TH substrate, L-tyrosine. Hence PPCA may warrant in vitro and in vivo characterization with TH to assess its potential as a candidate therapeutic.
Patrick Depreux - One of the best experts on this subject based on the ideXlab platform.
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Novel and Efficient One-Pot Synthesis of (Aminophenyl)Carbamic Acid Esters
Synthetic Communications, 2011Co-Authors: Antonio Garofalo, Laurence Goossens, Perrine Six, Nicolas Lebegue, Patrick DepreuxAbstract:Abstract A novel and efficient protocol is developed for the synthesis of various (aminophenyl)Carbamic Acid esters from the reduction and condensation of nitrophenyl isocyanate derivatives. The reaction takes place in various hydroxy derivatives such as alcohols or phenols under a hydrogen atmosphere using Raney nickel as catalyst. Products are obtained by a convenient one–pot synthesis with excellent yields and short reaction times.
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[4-(6,7-Disubstituted quinazolin-4-ylamino)phenyl] Carbamic Acid esters: a novel series of dual EGFR/VEGFR-2 tyrosine kinase inhibitors
Med. Chem. Commun., 2011Co-Authors: Antonio Garofalo, Laurence Goossens, Perrine Six, Amélie Lemoine, Séverine Ravez, Mike Howsam, Amaury Farce, Patrick DepreuxAbstract:Investigating a series of anilinoquinazoline derivatives substituted by Carbamic Acid esters, we have established the importance of the carbamate functional group and the substitution on the arylamino ring by a donor/acceptor group such as halide or methyl. All the newly-synthesized compounds described were evaluated for both their in vitroEGFR and VEGFR-2 kinase inhibition and antiproliferative activities against various cancer cells. These novel compounds were effective tyrosine kinase inhibitors (TKIs) for these two enzymes with in vitro IC50 values in the submicromolar range, but showed a moderated inhibitory activity on cancer cells. Modification of the ether linkage at the 6- or 7- position of the quinazoline core with a basic or aliphatic side chain (70–80) was investigated and it was demonstrated that introduction of aminoalkyl substituents such as morpholinoethoxy is a key modification that increases antiproliferative activity.
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4 6 7 disubstituted quinazolin 4 ylamino phenyl Carbamic Acid esters a novel series of dual egfr vegfr 2 tyrosine kinase inhibitors
MedChemComm, 2011Co-Authors: Antonio Garofalo, Laurence Goossens, Perrine Six, Amélie Lemoine, Séverine Ravez, Mike Howsam, Amaury Farce, Patrick DepreuxAbstract:Investigating a series of anilinoquinazoline derivatives substituted by Carbamic Acid esters, we have established the importance of the carbamate functional group and the substitution on the arylamino ring by a donor/acceptor group such as halide or methyl. All the newly-synthesized compounds described were evaluated for both their in vitroEGFR and VEGFR-2 kinase inhibition and antiproliferative activities against various cancer cells. These novel compounds were effective tyrosine kinase inhibitors (TKIs) for these two enzymes with in vitro IC50 values in the submicromolar range, but showed a moderated inhibitory activity on cancer cells. Modification of the ether linkage at the 6- or 7- position of the quinazoline core with a basic or aliphatic side chain (70–80) was investigated and it was demonstrated that introduction of aminoalkyl substituents such as morpholinoethoxy is a key modification that increases antiproliferative activity.
Fabien Borget - One of the best experts on this subject based on the ideXlab platform.
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Carbamic Acid and carbamate formation in NH3:CO2 ices-UV irradiation versus thermal processes
Astronomy and Astrophysics - A&A, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [NH2COOH] and ammonium carbamate [NH2COO-][NH4+] can be formed from both thermal reactions and energetic photons in an NH3:CO2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH3: CO2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1: 1 ratio from NH3 and CO2 above 80 K. They can be also formed in a 28: 1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in nh _ sf 3 co _ sf 2 ices uv irradiation versus thermal processes
Astronomy and Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.
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Carbamic Acid and carbamate formation in NH$_{\sf 3}$:CO$_{\sf 2}$ ices – UV irradiation versus thermal processes
Astronomy & Astrophysics, 2008Co-Authors: Jean-baptiste Bossa, Patrice Theulé, Fabrice Duvernay, Fabien Borget, Thierry ChiavassaAbstract:Context. We study Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] formation in interstellar ice analogs. Aims. We demonstrate how Carbamic Acid [ NH 2 COOH] and ammonium carbamate [ NH 2 COO - ] [ NH 4 + ] can be formed from both thermal reactions and energetic photons in an NH 3 :CO 2 ice mixture. Methods. Infrared and mass spectroscopy are used to monitor NH 3 :CO 2 ice mixture evolution during both warming and VUV photon irradiation. Results. Carbamic Acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH 3 and CO 2 above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into Carbamic Acid formation in interstellar ices. Conclusions. We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, Carbamic Acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.