182230-62-2

Upstream product

• 126875-83-0 N-acetoxy-4-methylaniline 
• 6220-62-8 2'-deoxyguanosine-3'-monophosphate 
• 623-10-9 N-(4-methylphenyl)hydroxylamine 

Relevant academic research and scientific papers

Synthesis, characterization, and conformational analysis of DNA adducts from methylated anilines present in tobacco smoke

The ability of a series of aromatic amines present in tobacco smoke (2-, 3-, and 4-methylaniline, 2,3- and 2,4-dimethylaniline) to bind to DNA has been investigated by reacting N-(acyloxy)arylamines with dG, dG nucleotides, and DNA. The predominant products from reactions with dG and the nucleotides were characterized as N-(deoxyguanosin-8-yl)arylamines by spectroscopic and HPLC methods. HPLC and spectroscopic analyses of the modified DNA indicated the same adducts. Analyses of the 1H and 13C NMR spectra suggested that the adducts containing a methyl substituent ortho to the arylamine nitrogen had a higher percentage of syn conformers. This observation was supported by theoretical simulation studies that indicated substantial percentages of low energy syn conformers, increasing with the substitution pattern in the order para meta ortho ortho,para ortho,meta. The results demonstrate that, although single-ring arylamines are considered weak carcinogens, their electrophilic N-acetoxy derivatives, which are plausible metabolic intermediates, react with DNA to yield covalent adducts structurally identical to those derived from carcinogenic polyarylamines, such as 2- aminofluorene and 4-aminobiphenyl. Furthermore, the conformational perturbation induced in DNA by the formation of the monoarylamine-DNA adducts, especially those with an ortho substituent, may contribute to the biological activities of these compounds.

Synthesis and quantification of DNA adducts of 4,4'-methylenedianiline

4,4'-Methylenedianiline (MDA) is used as a hardener in the manufacture of plastics and polyurethanes. MDA has been classified as a carcinogen in animals and is a suspected human carcinogen. Assuming that MDA would yield similar DNA adducts to other arylamines, we synthesized the following C-8 guanine adducts: N'-acetyl-N-(deoxyguanosin-8-yl)-MDA, N-(deoxyguanosin-8- yl)-MDA, N-(deoxyguanosin-8-yl)-4MA, and their corresponding 3'-monophosphate derivatives. We developed methods to identify these adducts of MDA in liver DNA using 32P-postlabeling, HPLC, and GC-MS techniques. Liver DNA was obtained from rats treated with radiolabeled MDA (1.11 and 116.5 μmol/kg body weight). The total radioactivity bound to the DNA corresponded to 0.06 and 2.7 adducts per 107 nucleotides [covalent binding index (CBI = (μmol of adduct per mol of nucleotide)/(mmol of compound per kg body weight)) of 1.05 and 2.3]. This DNA-binding potency is in the range of weakly genotoxic compounds. The liver DNA was analyzed for the presence of the synthesized adducts by the following methods: (I) HPLC analysis of nucleotides and purines after enzymatic and acid hydrolysis, and (II) 32P-postlabeling after enzymatic hydrolysis. The major adducts found in vivo did not correspond to the synthesized standards. Further work was carried out to determine the structure of the unidentified adducts. It was possible to release MDA and MDA-d4 from DNA of rats dosed with MDA and/or MDA-d4 and from the synthesized adducts using strong base hydrolysis. Liver of two female Wistar rats given 500 μmol/kg MDA · 2HCl was hydrolyzed in 0.1 M NaOH overnight at 110 °C. GC-MS analysis of the heptafluorobutyric anhydride derivatized dichloromethane extracts detected 428 ± 40 fmol of MDA/mg of DNA. In the control animals no MDA was found. The experiment was repeated with livers from animals dosed 500 μmol/kg MDA-d4 · 2DCl. In these rats 488 ± 19 final MDA-d4 was found to be bound at liver DNA. Taking into account a 68% yield of the method, the CBI found in these cases was 0.82 and 1.0, respectively.