Nitrosative adenine deamination: facile pyrimidine ring-opening in the dediazoniation of adeninediazonium ion.
نویسندگان
چکیده
[reaction: see text]. Dediazoniation of adeninediazonium ion, 1, forms the heteroaromatic cation, 2. Ab initio studies at the CCSD(fc)/6-31G**//MP2(full)/6-31G** level now reveal that the cyclic cation 2 is kinetically and thermodynamically unstable with respect to the pyrimidine ring-opened cation, 3. The results suggest that 4-cyano-5-isocyano-imidazole, 4, and 4,5-dicyanoimidazole, 5, might be formed to some extent in nitrosative deaminations of adenine.
منابع مشابه
Cytosine catalysis of nitrosative guanine deamination and interstrand cross-link formation.
Effects are discussed of the anisotropic DNA environment on nitrosative guanine deamination based on results of an ab initio study of the aggregate 3 formed by guaninediazonium ion 1 and cytosine 2. Within 3, the protonation of 2 by 1 is fast and exothermic and forms 6, an aggregate between betaine 4 (2-diazonium-9H-purin-6-olate) and cytosinium ion 5. Electronic structure analysis of 4 shows t...
متن کاملA Synthetic Approach for Evaluation of Cytosinediazonium Susceptibility
Reaction of a nucleobase with nitrosonium ion leads to its diazotization. Due to the instability,the nucleobase-diazonium assumingly falls in dediazotization and successive ring openingreactions. The resulting intermediate of the ring opening reaction is able to covalently cross-linkthe opposite strands of DNA. To examine this assumption for cytosine, some 4-amino-5-cyanopyrimidines were synthe...
متن کاملNitrosative cytosine deamination. An exploration of the chemistry emanating from deamination with pyrimidine ring-opening.
A discussion of nitrosative deamination of cytosine 1 is presented that argues for the formation of 6 by diazotization of 1 to cytosinediazonium ion 2 and its electrostatic complex 3, dediazoniation to 4 <--> 5, and amide-bond cleavage to 6. The reaction channels available to 6 include hydrolytic deglycation to 3-isocyanatoacrylonitrile 7, water addition to carbamic acid 9 with the possibility ...
متن کامل5-Cyanoamino-4-imidazolecarboxamide and nitrosative guanine deamination: experimental evidence for pyrimidine ring-opening during deamination.
5-Cyanoamino-4-imidazolecarboxamide 4a (R = CH2-O-CH2-CH2-OH) has been synthesized, purified, and fully characterized by MS, MS/MS, HRMS, IR spectroscopy, and by 1H and 13C NMR spectroscopy. It is shown that cyclization of 4a yields the guanine 6a and the isoguanine 12a. Our findings provide experimental evidence in support of our hypothesis that the formation of oxanine and xanthine in nitrosa...
متن کاملChemical carcinogens in non-enzymatic cytosine deamination: 3-isocyanatoacrylonitrile
Uracil has long been known as the main product of nitrosative cytosine deamination in aqueous solution. Recent mechanistic studies of cytosinediazonium ion suggest that the cation formed by its dediazoniation can ring-open to N-protonated (Z,s-cis)-3-isocyanatoacrylonitrile 7. Stereochemical preferences are discussed of the 3-isocyanatoacrylonitriles (Z,s-cis)-10, (E,s-cis)-11, (Z,s-trans)-12, ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Organic letters
دوره 5 22 شماره
صفحات -
تاریخ انتشار 2003