Nucleosides. VIII. Synthesis of 5-Nitrocytidine and Related Nucleosides<sup>1</sup>

Fox, Jack J.; Praag, Dina Van

doi:10.1021/jo01061a058

Cited by 32 publications

(20 citation statements)

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“…The cytidine 7, which has the interfering hydroxyls blocked with a benzylidine and a trityl group, has a pKHA of 14. This increase in acidity of 1.9 pK units is comparable to the 1.4 pK unit increase found by Fox et al (35,37) for the nitro-substituted compound. It is significant that 7 does not possess a 2'-hydroxyl group and, hence, the increased acidity cannot be attributed to the presence of such a group.…”

Section: Ribonucleoside Aciditysupporting

confidence: 82%

“…For personal use only. used a 5-nitro substituent to increase the acid strength of 1-methylcytosine and cytidine so that their acidities could be directly compared in aqueous solution (35,36). They found the pK to be 10.55 for the 1-methyl compound and 9.12 for the cytidine, a 1.4 pK unit acid-strengthening effect of ribosyl over methyl.…”

Section: Ribonucleoside Aciditymentioning

confidence: 99%

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Amino group acidity in nucleotide bases

Stewart¹,

Harris²

1977

Can. J. Chem.

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Ross STEWART and MADELEINE G. HARRIS. Can. J. Chem. 55,3807 (1977). The acidities (standard state, water) of the amino groups in 17 N-alkylated derivatives of adenine, guanine, cytosine, and isocytosine have been determined in aqueous DMSO containing base. Adenine methylated at the 9-position is a weaker acid than its 7-methylated isomer by 2.0 pK units and this difference is explained in terms of the known stabilities of the parent tautomers. A similar situation exists with 1-and 3-methylcytosine (ApK = 3.3). The position of alkylation of the isocytosine and guanine systems has a small or negligible effect on acidity, again consistent with known tautomeric effects. A modified ribosyl group attached to the 1-position of cytosine has an acid-strengthening effect of 1.9 units, relative to methyl. Of the amino groups involved in nucleotide base-pairing, that in the methyl derivative of guanine has the highest acidity, pKHA = 14.6; those in the cytosine and adenine derivatives have identical acidities, 16.7. An acidity function for purines and pyrimidines is reported for aqueous DMSO containing 0.011 M tetramethylammonium hydroxide (H-P).

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Section: Ribonucleoside Aciditysupporting

confidence: 82%

Section: Ribonucleoside Aciditymentioning

confidence: 99%

Amino group acidity in nucleotide bases

Stewart¹,

Harris²

1977

Can. J. Chem.

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“…Most likely nucleoside 10 was formed by conversion occurring during UV-measurement. 13 According to the pH-dependent equilibrium of the cyclic compound and the open chain nucleoside, we were not able to isolate the 2 0 -deoxyribonucleoside 9. Contrary to cyclonucleoside 8, cyclonucleoside 6 is stable under those conditions and cannot be converted to the open chain nucleoside 4 (Fig.…”

Section: Synthesis Of Nucleoside and Phosphoramiditementioning

confidence: 95%

“…iC¼2 0 -deoxy-5-methylisocytidine. 13 C NMR. DEPT-135 and 1 He 13 C gateddecoupled spectra were used for the assignment of the 13 C signals (Table 2).…”

Section: General Methods and Materialsmentioning

confidence: 99%