Heterocyclische ?-Enaminoester. 57. Studien zur N-Glycosidierung heterokondensierter Uracile

Wamhoff, Heinrich; Wambach, W.; Herrmann, Stefan; Jansen, Martin; Brühne, Birke

doi:10.1002/prac.19943360206

Cited by 9 publications

(2 citation statements)

References 62 publications

(6 reference statements)

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“…Organic azides are valuable compounds because they possess remarkable biological activity in pharmaceutical chemistry and are important precursors for the construction of N-containing structural motifs . Accordingly, numerous efforts have been devoted to the synthesis of these compounds, resulting in various synthetic strategies, − particularly the insertion of the azido group via substitution or addition. − Among these methods, the azidation of alkynes is very attractive for the preparation of functionalized organic azides. Bi and co-workers synthesized vinyl azides through Ag-catalyzed hydroazidation of alkynes (Scheme A), , Levy and co-workers and Friderang and co-workers independently prepared β-iodo vinyl azide via the iodoazidation of alkynes with iodine azide. , Recently, Yanada and co-workers realized the synthesis of α,α-diazido ketones via a three component iodoazidation of alkynes with N -iodosuccinimide (NIS) and trimethylsilyl azide (TMSN 3 ) (Scheme B(i)) .…”

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confidence: 99%

Copper-Catalyzed Azidative Multifunctionalization of Alkynes

et al. 2017

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A facile and efficient copper-catalyzed azidative multifunctionalization of alkynes has been developed by using N-fluorobenzenesulfonimide (NFSI) as both nitrogen source and aryl source and trimethylsilyl azide (TMSN) as azido source. This transformation proceeds under mild conditions, providing a series of α-azido-α-aryl imine in good yields by a single operation starting from a wide range of alkynes. The prepared α-azido-α-aryl imines could be easily converted into 1,5-piperizine-fused 1,2,3-triazoles and azido enamines.

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Copper-Catalyzed Azidative Multifunctionalization of Alkynes

et al. 2017

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“…The triazenyl anions that are formed in the presence of an internal electrophile undergo ring closure to give triazoles (Dimroth reaction). 10 Malonic, cyanoacetic, and related esters can be used as substrates. Furthermore, in b-keto sulfones or bnitrile sulfones the internal electrophile can be a carbonyl or cyano group.…”

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confidence: 99%

(Arylsulfonyl)acetones and -acetonitriles: New Activated Methylenic Building Blocks for Synthesis of 1,2,3-Triazoles

Pokhodylo¹,

Matiychuk²,

Обушак³

2009

Synthesis

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b-Keto sulfones and b-nitrile sulfones were used as building blocks for 1,2,3-triazole synthesis in the Dimroth cyclization. It was shown, that sulfone reagents undergo base-catalyzed cyclization under mild conditions (at room temperature) to give 1,2,3-triazoles in moderate to excellent yields. This fact has confirmed the high nucleophilicity of sulfonylmethylenic compounds and allows new synthetic applications.

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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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Heterocyclische ?-Enaminoester. 57. Studien zur N-Glycosidierung heterokondensierter Uracile

Cited by 9 publications

References 62 publications

Copper-Catalyzed Azidative Multifunctionalization of Alkynes

Copper-Catalyzed Azidative Multifunctionalization of Alkynes

(Arylsulfonyl)acetones and -acetonitriles: New Activated Methylenic Building Blocks for Synthesis of 1,2,3-Triazoles

Synthesis Of Nucleosides

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