Liquid Chromatography−Electrospray Ionization Mass Spectrometric Detection of an Ethenodeoxyguanosine Adduct and Its Hemiaminal Precursors in DNA Reacted with α-Acetoxy-N-nitrosopiperidine and cis-4-Oxo-2-pentenal
摘要:
N-Nitrosopiperidine, a carcinogenic cyclic nitrosamine that occurs in the diet and may be formed endogenously, is believed to be metabolically activated by alpha-hydroxylation. The DNA reactive compounds that could be formed in this process have been studied using alpha-acetoxy-N-nitrosopiperidine as a model, Previous studies have shown that 4-oxo-2-pentenal is one product of the hydrolysis of alpha-acetoxyNPIP and that it reacts with deoxyguanosine to produce 7-(2-oxopropyl)-5,9-dihydro-9-oxo-3-beta-D-(7-(2-oxopropyl)-1,N-2-ethenodG). Several other products were formed in that reaction, and these have now been identified as diastereomers of 7-(2-oxopropyl)-5-hydroxy-5,6,7,9-tetrahydro-9-oxo-3-beta-D-deoxyribofuranosylimidazo[1,2-a]purine, the hemiaminal precursors to 7-(2-oxopropyl)-1,N-2-ethenodG. Their structures were characterized by electrospray ionization mass spectrometry (ESI-MS), and by reduction with NaBH4 followed by hydrolysis to 7-(2-hydroxypropyl)-5,6,7,9-tetrahydro-9-oxoimidazo[1,2-a]purine, which was characterized by H-1-NMR, MS, and UV. The presence of 7-(2-oxopropy)-1,N-2-ethenodG and its hemiaminal precursors in DNA reacted with either alpha-acetoxy-N-nitrosopiperidine or cis-4-oxo-2-pentenal was confirmed by LC-ESI-MS and LC-ESI-MS/MS. The results of this study demonstrate that ethenodG adducts and their precursors are present in DNA reacted with alpha-acetoxy-N-nitrosopiperidine, which suggests a possible basis for the unique carcinogenic properties of this nitrosamine.
First Exclusive Regioselective Fragmentation of Primary Ozonides Controlled by Remote Carbonyl Groups and a New Method for Determining the Regiochemistry of Carbonyl Oxide Formation
作者:Hsien-Jen Wu、Chu-Chung Lin
DOI:10.1021/jo952284p
日期:1996.1.1
The first exclusive regioselective fragmentation of primaryozonides controlled by remote carbonyl groups on ozonolysis of norbornene derivatives and reaction of final ozonides with triethylamine as a new probe for determining the regiochemistry of carbonyl oxide formation from primaryozonide fragmentation are reported. Ozonolysis of the endo adducts 3a-d and the deuterated compounds 8a and 8b in
Synthesis of Diacetal Trioxa-cage Compounds via Reaction of Bicyclo[2.2.1]heptenes and Bicyclo[2.2.2]octenes with Dimethyldioxirane
作者:Hui-Chang Lin、Hsien-Jen Wu
DOI:10.1016/s0040-4020(99)00997-7
日期:2000.1
A new entry for the synthesis of diacetal trioxa-cage compounds via oxirane-induced sequential cyclization reaction of 2,3-bis-endo-diacylbicyclo[2.2.1]-5-heptenes and 2,3-bis-endo-diacylbicyclo[2.2.2]-5-octenes is reported. In the case of bicyclo[2.2.2]octenes, sequential cyclization reaction induced by iodine as electrophile failed. We have also demonstrated that dimethyldioxirane can selectively
Titanium Silicalite 1 (TS-1) Catalyzed Oxidative Transformations of Furan Derivatives with Hydrogen Peroxide
作者:Joos Wahlen、Bart Moens、Dirk E. De Vos、Paul L. Alsters、Pierre A. Jacobs
DOI:10.1002/adsc.200303185
日期:2004.2
The oxidation of furan derivatives with titaniumsilicalite 1 (TS-1) and hydrogen peroxide is described. Oxidation products are identified and possible reaction pathways are discussed. It is shown that the oxidation of these compounds occurs via epoxidation of one of the furan double bonds. The initially formed epoxides immediately undergo rearrangement, furans yielding unsaturated 1,4-dicarbonyl compounds
作者:Brian M. Adger、Collette Barrett、Joseph Brennan、M. Anthony McKervey、R. W. Murray
DOI:10.1039/c39910001553
日期:——
Dimethyldioxirane reacts rapidly at room temperature in acetone with a variety of furans, furnishing in high yield products of oxidative ring opening and, with 2-furanmethanol, 2H-pyran-3(6H)-one via subsequent ring closure.
tetraacetal tetraoxa cages11 and 12. Various reaction conditions have been used to optimize the overall yield for the synthesis of methyl group substituted pentaoxa[5]peristylane 7d. Ozonolysis of 6d in CDCl(3) at -78 degrees C without reduction was performed to study the ozonolysis chemistry of the triacylnorbornenes 6a-d. The synthesis of the parent (unsubstituted) compound 25 of pentaoxa[5]peristylane