Synthese neuer Pyridin-C-nukleoside der 2 ,3 -Didesoxyribose durch „inverse“ [4+2]-Cycloaddition Synthesis of Novel Pyridine-C-nucleosides of 2,3-Dideoxyribose by „Inverse“ [4+2]-Cycloaddition

1997 ◽  
Vol 52 (7) ◽  
pp. 851-858 ◽  
Author(s):  
Gunther Seitz ◽  
Johanna Siegl
Keyword(s):  
Cycloaddition Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
The Novel ◽  
Protecting Group ◽  
Enol Ethers ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Cyclic Ketene Acetals

The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine „aglycon“ of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an „inverse“ [4+2]-cycloaddition reaction. The Diels-Alder adducts spontaneously eliminate N2 and after follow-up reactions the O-TBDPS protected pyridine-C-nucleosides 13, 15, 17,19, 21 and 23 are formed. Removal of the protecting group by treatment with CF3CO2H /H2O leads to the corresponding 2’,3’-dideoxy-β-D-ribofuranosyl- pyridines.

The catalytic asymmetric synthesis of tetrahydropyridazines via inverse electron-demand aza-Diels–Alder reaction of enol ethers with azoalkenes

2015 ◽  
Vol 51 (84) ◽  
pp. 15374-15377 ◽  
Author(s):  
Liang Wei ◽  
Chun-Jiang Wang
Keyword(s):  
Asymmetric Synthesis ◽  
Good Yield ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enol Ethers ◽  
Inverse Electron Demand ◽  
Catalytic Asymmetric Synthesis ◽  
Diels Alder Reaction ◽  
Catalytic Asymmetric ◽  
Electron Demand

A highly efficient catalytic asymmetric IEDDA reaction of azoalkenes with enol ethers is reported. This methodology provides a facile entry to biologically important tetrahydropyridazines in good yield with good to excellent ee.

scholarly journals Recent Advances in Bioorthogonal Click Chemistry for Efficient Synthesis of Radiotracers and Radiopharmaceuticals

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3567 ◽  
Author(s):  
Mushtaq ◽  
Yun ◽  
Jeon
Keyword(s):  
Cycloaddition Reaction ◽  
Reaction Rates ◽  
Alder Reaction ◽  
Diels Alder ◽  
Pharmacokinetic Studies ◽  
Preclinical Research ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Specific Reactions

In recent years, several catalyst-free site-specific reactions have been investigated for the efficient conjugation of biomolecules, nanomaterials, and living cells. Representative functional group pairs for these reactions include the following: (1) azide and cyclooctyne for strain-promoted cycloaddition reaction, (2) tetrazine and trans-alkene for inverse-electron-demand-Diels–Alder reaction, and (3) electrophilic heterocycles and cysteine for rapid condensation/addition reaction. Due to their excellent specificities and high reaction rates, these conjugation methods have been utilized for the labeling of radioisotopes (e.g., radiohalogens, radiometals) to various target molecules. The radiolabeled products prepared by these methods have been applied to preclinical research, such as in vivo molecular imaging, pharmacokinetic studies, and radiation therapy of cancer cells. In this review, we explain the basics of these chemical reactions and introduce their recent applications in the field of radiopharmacy and chemical biology. In addition, we discuss the significance, current challenges, and prospects of using bioorthogonal conjugation reactions.

Synthese neuer Pyridin-, Pyrindin- bzw. Isochinolin-substituierter α- und β-C-Nukleoside der 2-Desoxy-D-ribose / Synthesis of Novel Pyridine-, Pyrindine- and Isoquinoline-Substituted α- and β-C-Nucleosides of 2-Deoxy-D-ribose

1999 ◽  
Vol 54 (4) ◽  
pp. 549-558 ◽  
Author(s):  
Gunther Seitz ◽  
Jens Lachmann
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
The Novel ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Electron Demand

The novel imido esters of 2-deoxy-α- and -β-D-ribose 8 and 9 have been synthesized and successfully transformed to the protected 1,2,4-triazine-C -nucleosides 11 and 12 using an inverse type Diels-Alder reaction with the 1,2,4,5-tetrazine 10. The electron deficient diazadiene system of both C -nucleosides 11 and 12 proved to be highly reactive in a consecutive [4 + 2] cycloaddition with inverse electron demand towards several electron rich dienophiles yielding after successful deprotection the novel pyridine-, pyrindine- and isoquinoline-C-nucleosides 15, 18 and 21 of 2 -deoxy-α-D-ribose and 23, 25 and 27 of 2-deoxy-β-D-ribose.

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