Nucleoside, XXVIII. Synthese und Eigenschaften von 2‐Thiolumazin‐nucleosiden

Southon, Ian W.; Pfleiderer, Wolfgang

doi:10.1002/cber.19781110713

Cited by 13 publications

(1 citation statement)

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“…Lumazine [2][3][4][5][6][7][8][9][10][11] and isopterin nucleosides 12 can be regarded as structural analogs of the pyrimidine nucleosides whereas the many pteridin-7-one N 8 -nucleosides [13][14][15][16][17][18][19][20][21][22][23] are structurally related to the purine nucleosides. The syntheses could be achieved either by a classical Hilbert-Johnson reaction 24 , the mercury salt method by Fox and Davoll 25 , the Hilbert-Johnson-Birkofer silyl procedure 26,27 or the silyl variant by Vorbrüggen 28 .…”

Section: Introductionmentioning

confidence: 99%

Syntheses and properties of pterin ribonucleosides

Pfadler¹,

Pfleiderer²

2008

Arkivoc

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Several pterin derivatives (1-8) have been ribosylated in form of their trimethylsilyl derivatives (9) with 1-bromo-(10) and 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (11) under the catalysis of HgO/HgBr 2 , BF 3 -etherate and trimethylsilyl triflate, respectively. Mixtures of the N-1-(19-25) and N-3-ribofuranosides (12-18) which are difficult to be separated were obtained. Debenzoylation by the Zemplen method led to the free pterin-nucleosides (28-30). A second approach starting from 2-methylthio-4(3H)pteridinones (31-33) gave again mixtures of the N-1-(35-37) and N-3-ribonucleosides (38-40). The 2-methylthio function in 35-37 can easily be substituted by various amines leading after subsequently debenzoylation to the N-2-substituted pterin-ribonucleosides (41-50). The structural assignments were based on comparisons of the UV spectra with the corresponding N-methyl substituted model substances. 1 H-NMR-spectra functioned as additional structural proof.

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Section: Introductionmentioning

confidence: 99%

Syntheses and properties of pterin ribonucleosides

Pfadler¹,

Pfleiderer²

2008

Arkivoc

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Synthesis Of Nucleosides

Vorbrüggen¹,

1999

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This chapter deals with the synthesis of nucleosides (e.g., the formation of N ‐glycosides of sugars such as D ‐ribose or 2‐deoxy‐D‐ribose with heterocyclic nitrogen bases). The methods of nucleoside synthesis have been treated in a number of reviews and monographs. It is now generally accepted that nucleosides were among the first organic compounds formed at the start of evolution in the early history of our planet earth. To support this point, guanine and adenine were heated with D ‐ribose in seawater, which contains the Lewis acid magnesium chloride as catalyst. One thus obtained the nucleosides guanosine and adenosine together with comparable yields of unnatural α‐nucleosides. The latter were gradually photoanomerized to the thermodynamically more stable compounds in overall yields of 5–6%. The furanose form of ribose reacts faster than the pyranose form. Corresponding syntheses of the pyrimidine nucleosides uridine and cytidine from uracil , cytosine and ribose are more problematic and remain an enigma. The recent conversion of glycolaldehyde‐ O ‐phosphate and formaldehyde to ribose‐2,4‐di‐ O ‐phosphate might give new insights into the prebiotic syntheses of uridine and cytidine. The evidence and hypotheses for these prebiotic conversions and the evolution of RNA, as well as the implications of an “RNA World,” have been reviewed. These RNA nucleosides are reduced in vivo as 5′‐ O ‐diphosphates by ribonucleotide reductases to the corresponding 2′‐deoxynucleosides—the building blocks of DNA such as 2′‐deoxyguanosine. The thermodynamically controlled synthesis of these four building blocks of RNA has implications for the design of efficient, high yielding, new methods for the synthesis of the naturally occurring nucleosides, nucleoside antibiotics, and modified nucleosides that may serve as antimetabolites to fight viral and parasitic diseases and cancer. The nucleoside rings in this chapter are depicted arbitrarily in the anti conformation, as occurs predominantly in the crystal and solution (based primarily on NOE‐ 1 H‐ and 13 C‐NMR measurements) forms of pyrimidine nucleosides. Only a few nucleosides, such as 6‐methyluridine, occur with the heterocyclic ring predominantly in the syn conformation. The synthesis of C ‐nucleosides has been reviewed previously and is not covered in this review.

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1988

Chemistry of Heterocyclic Compounds: A Series of Monographs

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Nucleoside, XXVIII. Synthese und Eigenschaften von 2‐Thiolumazin‐nucleosiden

Cited by 13 publications

References 41 publications

Syntheses and properties of pterin ribonucleosides

Syntheses and properties of pterin ribonucleosides

Synthesis Of Nucleosides

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