Cytidine derivatives

The IR spectra of chloroform solutions of 6-azacytidine and its derivatives show that these compounds, like the corresponding cytidine derivatives, exist in the amino form. ... 

Sessler JL, Jayawickramarajah J, Gouloumis A et al. (2006) Guanosine and fullerene derived deaggregation of a new phthalocyanine-linked cytidine derivative. Tetrahedron. 62 2123-2131. 

The presence of a 3 -keto function in 18a was confirmed by a carbonyl band at 1780 cm-1, in addition to those present at 1720 and 1675 cm-1 in the i.r. spectrum of the parent nucleoside 17a. Similarly, a new carbonyl band appeared at 1780 cm-1 in the spectrum25 of the 2 -keto-cytidine derivative 20a. 

Park and Strominger noticed the accumulation of a C3didine derivative in cultures of Staphylococcus aureus which had been inhibited by chloramphenicol, penicillin, or Crystal Violet. This cytidine derivative has been identified by Baddiley s group as cytidine ribitol pyrophosphate. Since these inhibitors affect the cell-wall synthesis, the data lend support to the belief that the cytidine compound is involved in the biosynthesis of a cell-wall constituent, and a likely candidate would be ribitol teichoic acid. 

However, under similar reaction conditions the N-benzoyl-cytidine derivative furnished a mixture of N-benzoyl-3 -0-DMTr-deoxycytidine and the corresponding N-unprotected nucleoside. However, this limitation was avoided using the corresponding levuUnic derivative because the protecting group was easily removed using hydrazine (Scheme 10.8). 

As far as the reactivity of the above-described Mannich bases is concerned, studies of prcxlucts 469 indicate a much better resistance to alkaline than to acid hydrolysis the nature of the nucleoside also plays a role, as the cytidine derivatives arc much more stable than the purine derivatives. Similar investigations have been madc into the deaminomethylation of Mannich bases of type 466. 

Hunziker described the synthesis of aromatic analogues of (54), uracil derivative (55) and cytidine derivative (56), and their incorporation into oligodeoxynucleotides. To avoid the cumbersome hydroxymethylation of 2 -deoxyuridine, uracil was hydroxymethylated with paraformaldehyde under basic conditions and the resulting alcohol was benzylated. The modified nuc-... 

Capecitabine is an orally active pyrimidine analog. Despite the similarity of its name to cytidine derivatives such as cytarabine and... 

The hydrogenation methods thus far described do not differentiate between uridine and cytidine derivatives. The discovery that 5,6-dihydrouridylic acid (20) (see p. 318) is a minor component of certain transfer ribonucleic acids has rekindled interest in the reduction of... 

S Additional information <3, 7> (<3> enzyme exists in different conformational states with different substrate kinetic properties [9] <3> presumably one common nucleoside acceptor site [15] <3> purine deoxynucleo-side activity inseparably associated with deoxycytidine kinase protein [16] <3> several isozymes cytosolic deoxycytidine kinase I and II, plus mitochondrial isozyme [10] <3> multisubstrate enzyme, that also phos-phorylates purine deoxyribonucleotides [9] <7> enzyme has two separate active sites for deoxycytidine and deoxyadenosine activity [22] <3> reacts with both enantiomers of -deoxycytidine, -deoxyguanidine, -deoxyadenosine, and a-D-deoxycytidine is also substrate [31] <3> reacts with both enantiomers of jS-deoxyadenosine, j3-arabinofuranosyl-adenine and jd-deoxyguanine ]34] <3> remarkably relaxed enantioselectivity with respect to cytidine derivatives in p configuration [36] <3> lack of enantioselectivity for D- and L-analogues of cytidine and adenosine [43]) [9, 10, 15, 16, 22, 31, 34, 43]... 

This represents the first well understood case of feedback inhibition, (using E. coli as the organism). It is specific to the final products of the sequence, i.e. to cytidine derivatives, and the entire CTP molecule contributes in binding to the transcarbamylase enzyme at an allosteric site (i.e. a different site from that of the substrate). Cytosine itself is not an inhibitor for the E. coli enzyme. Knowledge of this mode of inhibition has provided an added stimulus to... 

Regioselectively protected cytidine derivatives have been prepared from the peracetylated nucleoside using lipase and esterase reactions. There have been reports on the use of bacterial proteases for the selective acylation of sucrose to produce a variety of different acyl and acrylate esters. 8-Aminooctyl 5-5-coniferyl-5-thio-a-L-arabinofuranoside(27) attached to sepharose proved to be a selective affinity ligand for feruloyl esterase A. niger ... 

Uracil and cytosine derivatives of 4-thio-DL-erythrofuranose and adenine and guanine nucleoside analogues of 4-thio-D-ribofuranose, 4-thio-D-xylofuranose, and 5-thio-D-xylopyranose have been reported. Treatment of 2,2 -anhydro-cytosine with phosphorus pentasulphide gave the cyclic thiophosphate derivatives (49), which was used to prepare other 2 -thio-cytidine derivatives. The... 

Ac 4- -Acetyl-3, 5 -0-(tetraisopro-pyldisiloxane-1,3-diyl) cytidine C23H4iN307Si2 527.764 Protected cytidine deriv. useful in synthesis. Cryst. (EtOH). Mp 111-113". 

Fig. 210. Formation of orotic acid, uridine, and cytidine derivatives...

The synthesis of 2 -0-tetrahydropyranyladenosine (28) as an intermediate in oligoribonucleotide synthesis led to a mixture of two diastereoiso-mers, differing at C(20, but readily separable and with different properties e.g. [a] -8°, m.p. 171—172.5 °C [ ] -130°, m.p. 199—200 C). Similar results had previously been obseved for the 2 -0-tetrahydropyranyl ethers of uridine and AT(4)-benzoylcytidine. An analysis of the more laevorotatory isomer of (28) proves that it has the absolute stereochemistry (2T-S), and by analogy defines the absolute stereochemistries of the uridine and cytidine derivatives also as (2"-S). 

---