Cytosine-5-carboxylic acid

In benzene solution mutarotation is catalysed by a range of bifunctional proton-transfer catalysts, including carboxylic acids and the nucleoside cytosine. Ab initio calculations on formic acid catalysis of the mutarotation of 2-hydroxytetrahydropyran indicate strong coupling of the double proton transfer to endocyclic C-O bond cleavage. ... 

Aristeromycin 5 -aldehyde has been prepared, and was shown to be a potent inhibitor of SAH hydrolase this study indicated that the fluoromethylene compounds (Vol. 26, p. 247), which are also inhibitors, do not act as precursors of the aldehyde. 2-Halo-derivatives 39 (X=F, Cl) of neplanocin A have been prepared, as have the equivalent structures lacking the CH2OH group and the analogue 40. Neplanocin analogues with the primary alcohol oxidized to the carboxylic acid level have also been made by oxidation, and aristeromycin and its cytosine analogue (carbodine) have been incorporated into a hammerhead ribozyme domain. ... 

Our group published the first organometallic derivatives of PNA monomers [138]. Ferrocene carboxylic acid 3 and benzoic acid chromium tricarbonyl 50 were coupled to the amino group of PNA monomers with different nucleobases (Thymine (T) a and Z-protected Cytosine (Z-C) b) using HBTU as the coupling agent to give compounds 51 and 52, respectively (Scheme 5.27). The activation barrier AG for the rotation about the tertiary amide bond has been determined for the ferrocenylated T-PNA monomer 51a to be 75 0.5 kj moD. For the same compound 51a, a T-T self-association constant = 2.5 0.2 has been... 

Hydroxymethylcytosine (967) was isolated only in 1952 from the T-even bacteriophages of Escherichia coli, in which it occurs instead of cytosine in the 2-deoxyribonucleic acid (65MI21304). Of several syntheses described, the most convenient is probably that beginning with ethyl 4-amino-2-methylthiopyrimidine-5-carboxylate which is reduced by LAH to 4-amino-2-methylthiopyrimidin-5-ylmethanol followed by hydrolysis to 5-hydroxymethyl-cytosine (967) (B-68MI21302, B-68MI21306). 

The intramolecular photodimerization and [2 + 2]-photocycloaddition in DNA involves thymine or cytosine as the chromophore. This chemistry has been intensively investigated with regards to DNA damage and repair [131]. Despite the fact that the area is of continuous interest [132], the synthetic applications are limited and are not covered here in detail. However, some preparative aspects of 4-pyrimidinone photocycloaddition chemistry will be addressed. Aitken et al. have prepared a plethora of constrained cyclobutane P-amino acids by intra- or intermolecular [2 + 2]-photocycloaddition to uracil and its derivatives [133, 134]. In a chiral adaptation of this method, the uracil-derived enone 140 was employed to prepare the diastereomeric cyclobutanes 141 in very good yield (Scheme 6.49). The compounds are easily separated and were - despite the relatively low auxiliary-induced diastereoselectivity - well suited to prepare the as-2-aminocyclobutanecarboxylic acids 142 in enantiomerically pure form. Enantioselective access to the corresponding trans-products was feasible by epimerization in a-position to the carboxyl group [135],... 

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