74954-95-3Relevant academic research and scientific papers
Evaluation of Nitrosamide Formation in the Cytochrome P450-Mediated Metabolism of Tobacco-Specific Nitrosamines
Carlson, Erik S.,Upadhyaya, Pramod,Hecht, Stephen S.
, p. 2194 - 2205 (2016/12/26)
N′-Nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are carcinogenic tobacco-specific nitrosamines believed to play a vital role in the initiation of tobacco-related cancers. For their carcinogenicities to be exhibited, both NNN and NNK must be metabolically activated by cytochrome P450s, specifically P450 2A6 and P450 2A13, respectively. Prior research has focused on α-hydroxylation, which leads to the formation of several DNA adducts that have been identified and quantified in vivo. However, some studies indicate that P450s can retain substrates within their active sites and perform processive oxidation. For nitrosamines, this would oxidize the highly unstable α-hydroxynitrosamines to potentially more stable nitrosamides, which could also alkylate DNA. Thus, we hypothesized that both NNN and NNK are processively oxidized in vitro to nitrosamides by P450 2A6 and P450 2A13, respectively. To test this hypothesis, we synthesized the NNN- and NNK-derived nitrosamides, determined their half-lives at pH 7.4 and 37 °C, and monitored for nitrosamide formation in an in vitro P450 system with product analysis by LC/NSI+-HRMS/MS. Half-lives of the nitrosamides were determined by HPLC-UV and ranged from 7-35 min, which is more than 40 times longer than the corresponding α-hydroxynitrosamines. Incubation of NNN in the P450 2A6 system resulted in the formation of the nitrosamide N′-nitrosonorcotinine (NNC) at low levels. Similarly, the nitrosamide 4-(methylnitrosamino)-1-(3-pyridyl)-1,4-butanedione (CH2-oxo-NNK) was detected in low amounts in the incubation of NNK with the P450 2A13 system. The other possible NNK-derived nitrosamide, 4-(nitrosoformamido)-1-(3-pyridyl)-1-butanone (CH3-oxo-NNK), was not observed in the P450 2A13 reactions. CH2-oxo-NNK readily formed O6meGua in reactions with dGuo and calf thymus DNA. These results demonstrate that NNC and CH2-oxo-NNK are novel metabolites of NNN and NNK, respectively. Though low-forming, their increased stability may allow for mutagenic DNA damage in vivo. More broadly, this study provides the first account of a cytochrome P450-mediated conversion of nitrosamines to nitrosamides, which warrants further studies to determine how general this phenomenon is in nitrosamine metabolism.
Silica-supported phosphorus pentoxide: A reusable catalyst for S,S-acetalization of carbonyl groups under ambient conditions
Shaterian, Hamid Reza,Azizi, Kobra,Fahimi, Nafiseh
experimental part, p. 85 - 91 (2012/01/06)
Phosphorus pentoxide supported on silica gel (P2O 5/SiO2) efficiently acts as a highly active and reusable catalyst for cyclic and non-cyclic S,S-acetalization of a variety of carbonyl compounds under mild, solvent-free an
Molybdenum pentachloride (MoCl5) or molybdenum dichloride dioxide (MoO2Cl2): advanced catalysts for thioacetalization of heterocyclic, aromatic and aliphatic compounds
Goswami, Shyamaprosad,Maity, Annada C.
, p. 3092 - 3096 (2008/09/20)
A new, convenient and mild method for thioacetalization of heterocyclic, aromatic and aliphatic compounds catalyzed by MoCl5 or MoO2Cl2 is described. This novel method is important for the synthesis of the difficult to prepare heterocyclic thioacetals such as the pterin thioacetals and it offers significant advantages such as high conversion, short reaction times and simplicity in operation.
Synthesis and Biological Activity of trans-(+/-)-N-Methyl-2-(3-pirydyl)-2-tetrahydrothiopyrancarbothioamide 1-Oxide (RP 49356) and Analogues: A New Class of Potassium Channel Opener
Brown, Thomas J.,Chapman, Robert F.,Cook, David C.,Hart, Terance W.,McLay, Iain M.,et al.
, p. 3613 - 3624 (2007/10/02)
The synthesis and biological activity of trans-(+/-)-N-methyl-2-(3-pyridyl)-2-tetrahydrothiopyrancarbothioamide 1-oxide (8a, RP 49356) and analoques is reported.These compounds constitute a new structural class of K+-channel opener.The effects of changes in the pyridyl group, thioamide, and thiane ring on in vitro K+-channel opening activity are discussed.A 3-pyridyl or 3-quinolyl group, a small N-alkyl thioamide function, and a thiane oxide ring, in which the sulfoxide is in a trans relationship to thioamide, are preferred for activity.Selected compounds were tested intravenously in the normotensive anaesthetized rat for hypotensive effects, and the activities reflect their in vitro K+-channel opening activity.This led to further evaluation of compound 8a and the selection of the (-)-enantiomer 8b (RP 52891) for development as an antihypertensive and antianginal agent.
The Synthesis and Pyrolysis of 2-Substituted 1,3-Dithiane 1,1-Dioxide
Kabzinska, Krystyna,Kawecki, Robert
, p. 117 - 121 (2007/10/02)
The 2-substituted derivatives of tetrahydrothiophene were obtained by pyrolysis of monosulfones of 1,3-dithiane, the latter being synthesized in a three-step procedure.
