Thymine, nucleosides

A photochemical process consisting in the esterification, with pyru-voyl chloride,45 of the alcohol to be oxidized, followed by photochemical reaction of the ester obtained, has been applied to some thymine nucleosides.43 Derivatives (33a and 33b) of 3 -ketothymidine were prepared43 by this method. 

The syntheses of the thymine nucleosides of 2,4-dideoxy-p-D-eryt/zro-hexo-pyranose starting from l,2 5,6-di-(9-isopropylidene-a-D-glucofuranose (12 steps) or from tri-O-acetyl-D-glucal (11 steps) have been reported.250... 

Cytosine, guanine, adenine, and thymine nucleosides are shown here ... 

Fig. 9. Synthesis of 3 -C-Cyano-3 -deoxythymidine from thymine nucleosides...

Uridine phosphorylase, but not thymidine phosphorylase, is inhibited powerfully by the thymine nucleosides, deoiQ xylosylthymine and deoi -glycosylthymine ( ) ... 

Detailed n.m.r. studies have been reported on some bicyclic uridine analogues reported last year by Chattopadhyaya s group, formed by intramolecular addition of free radicals to allyl ethers (see Vol. 25, p. 258).i66 The same group have described the preparation of the thymine nucleoside 134 by means of intramolecular free radical trapping by an allyl group tethered by a temporary silicon connection (Scheme 15). Similar sequences were used to make analogous compounds with the three-carbon branch at C-2 in a down position (D-ribo-), and at C-3 in the up orientation, but an attempt to make the compound with the C-2 up stereochemistry led to a tricyclic product after oxidation in which the intermediate bicyclic radical had attacked C-6 of the thymine ring. 167... 

In a synthesis of 3 -C-carbomethoxymethyl-3 -deoxythymidine, and related nucleosides, the cyclization of bromide (113), induced by BusSnH-AIBN, was the key step. 134 Thymine nucleosides (114, X=OH, H) have been made by a-selective attack of ethynylmagnesium bromide on 3 -keto-derivatives.135 A variety of C-3 branched uracil nucleosides (115) have been prepared by a sequence involving conjugate additions of cuprates to an... 

Boron-containing analogs of the biochemical precursors of nucleic acids, including purines, pyrimidines, thymines, nucleosides, and nucleotides, have been synthesized and several were evaluated in cellular and animal studies. Figure 10.8 shows several representative molecules of this class (35-42) containing carborane cages linked via various spacers to either the base or the carbohydrate... 

The thymine nucleoside 106 has been prepared by coupling of silylated thymine with the glycosyl bromide (Vol.18, p.84-85), made by a photobromination procedure. 

Miller, P. S, Fang, K. N., Konda, N. S., and Ts o, P. O. P (1971) Syntheses and properties of adenine and thymine nucleoside alkyl phosphotriesters, the neutral analogs of dinucleoside monophosphates. J. Am. Chem. Soc. 93,6657-6665. Laster, B H., Schinazi, R. F., Fairchild, R. G, Popenoe, E. A, and Sylvester, B (1985) Neutron Capture Therapy, Proc. 2nd Int Sym. (pub. 1986), 46-54. Kobayashi, T and Konda, K. (1984) Boron-10 dosage in cell nucleus for neutron capture therapy—Boron selective dose ratio Proceeding of the First International Symposium on Neutron Capture Therapy, October 12-14,1983, BNL Report No. 51730, pp. 120-127. 

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