scholarly journals Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

2018 ◽  
Vol 14 ◽  
pp. 318-324 ◽  
Author(s):  
Imane Nekkaa ◽  
Márta Palkó ◽  
István M Mándity ◽  
Ferenc Fülöp
Keyword(s):  
Efficient Method ◽  
Continuous Flow ◽  
Reaction Times ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Selection Of

The syntheses of various pyrimidinones as potentially bioactive products by means of the highly controlled continuous-flow retro-Diels–Alder reaction of condensed pyrimidinone derivatives are presented. Noteworthy, the use of this approach allowed us to rapidly screen a selection of conditions and quickly confirm the viability of preparing the desired pyrimidinones in short reaction times. Yields typically higher than those published earlier using conventional batch or microwave processes were achieved.

scholarly journals Diels–Alder reactions of myrcene using intensified continuous-flow reactors

2017 ◽  
Vol 13 ◽  
pp. 120-126 ◽  
Author(s):  
Christian H Hornung ◽  
Miguel Á Álvarez-Diéguez ◽  
Thomas M Kohl ◽  
John Tsanaktsidis
Keyword(s):  
Continuous Flow ◽  
Flow Reactor ◽  
Scale Up ◽  
Reaction Times ◽  
Alder Reaction ◽  
Diels Alder ◽  
Flow Reactors ◽  
Diels Alder Reaction ◽  
Naturally Occurring ◽  
Continuous Flow Reactors

This work describes the Diels–Alder reaction of the naturally occurring substituted butadiene, myrcene, with a range of different naturally occurring and synthetic dienophiles. The synthesis of the Diels–Alder adduct from myrcene and acrylic acid, containing surfactant properties, was scaled-up in a plate-type continuous-flow reactor with a volume of 105 mL to a throughput of 2.79 kg of the final product per day. This continuous-flow approach provides a facile alternative scale-up route to conventional batch processing, and it helps to intensify the synthesis protocol by applying higher reaction temperatures and shorter reaction times.

Synthesis of endo-fused 5-unsubstituted hexahydro-2H-pyrano[3,2- c]quinolines via sequential Sc(OTf)3-catalyzed cationic imino-Diels-Alder Reaction/N-debenzylation using N-benzylanilines, 3,4-dihydro-2H-pyran and paraformaldehyde under MW irradiation

2021 ◽  
Vol 18 ◽  
Author(s):  
Arturo René Mendoza Salgado ◽  
Carlos Eduardo Puerto Galvis ◽  
Vladimir V. Kouznetsov ◽  
Carlos Mario Meléndez
Keyword(s):  
Efficient Method ◽  
Cycloaddition Reaction ◽  
Acid Catalyst ◽  
Alder Reaction ◽  
Diels Alder ◽  
Synthetic Methods ◽  
Diels Alder Reaction ◽  
Catalytic Transfer ◽  
Lewis Acid Catalyst ◽  
Mw Irradiation

Background: Hexahydro-2H-pyrano[3,2-c]quinolines are known to have antibacterial, antifungal, and antitumor properties. Great efforts have been made to develop new synthetic methods that lead to the synthesis of valuable libraries. Extensive methodologies, low yields, excessive amounts of catalyst and expensive reactants are some of the limitations of current methodologies. Aim and Objective: Developing a useful and efficient method to construct diversely substituted hexahydro-2H-pyrano[3,2- c]quinolines into good to excellent yields through a cationic imino-Diels-Alder/N-debenzylation methodology. Method: The cationic imino-Diels-Alder/N-debenzylation methodology was used for the preparation of substituted hexahydro-2H-pyrano[3,2-c]quinolines. It involves the use of Sc(OTf)3 for activation of cationic imino-Diels-Alder cycloaddition reaction of N-benzylanilines, 3,4-dihydro-2H-pyran and paraformaldehyde in MeCN; and microwave irradiation to shorten reaction time to afford new 6-benzyl-hexahydro-2H-pyrano[3,2-c]quinolines whose catalytic transfer debenzylation reactions with HCO2NH4 in the presence of Pd/C (10%) and methanol give the new 5-unsubstituted pyrano[3,2- c]quinolines in excellent yields. Results: We found that optimal conditions for the preparation of hexahydro-2H-pyrano[3,2-c]quinolines were Sc(OTf)3 0,5 % and acetonitrile at 160 ° C for 15 min; and using paraformaldehyde obtained the 6-benzyl-hexahydro-2H-pyrano [3,2- c]quinolines with excellent yields, while the N-debenzylation process using ammonium formate in the presence of Pd/C and methanol resulted in the synthesis of hexahydro-2H-pyrano [3,2-c] quinolines with quantitative yields (95-98%). Conclusion: We describe an efficient method to synthesize hexahydro-2H-pyrano[3,2-c]quinolines via the cationic iminoDiels-Alder/N-debenzylation methodology using Sc(OTf)3 0,5 % as Lewis Acid catalyst. Excellent yields of the products, using of MW irradiation, short times of reactions and an efficient and highly diversified method are some of the main advantages of this new protocol.

scholarly journals Screening of metal ions and organocatalysts on solid support-coupled DNA oligonucleotides guides design of DNA-encoded reactions

2019 ◽  
Vol 10 (45) ◽  
pp. 10481-10492 ◽  
Author(s):  
Marco Potowski ◽  
Florian Losch ◽  
Elena Wünnemann ◽  
Janina K. Dahmen ◽  
Silvia Chines ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Dna Sequences ◽  
Solid Phase ◽  
Alder Reaction ◽  
Solid Support ◽  
Diels Alder ◽  
Dna Oligonucleotides ◽  
Compound Libraries ◽  
Diels Alder Reaction ◽  
Selection Of

DNA-encoded compound libraries are widely used in drug discovery. Screening of catalysts for compatibility with solid phase-coupled DNA sequences guided the selection of encoded reactions, exemplified by a Zn(II)-mediated aza-Diels–Alder reaction.

Highly efficient method for 125I-radiolabeling of biomolecules using inverse-electron-demand Diels–Alder reaction

2016 ◽  
Vol 24 (11) ◽  
pp. 2589-2594 ◽  
Author(s):  
Mi Hee Choi ◽  
Ha Eun Shim ◽  
Seong-Jae Yun ◽  
Hye Rim Kim ◽  
Sajid Mushtaq ◽  
...  
Keyword(s):  
Efficient Method ◽  
Alder Reaction ◽  
Diels Alder ◽  
Inverse Electron Demand ◽  
Highly Efficient ◽  
Diels Alder Reaction ◽  
Electron Demand

RNA–peptide conjugate synthesis by inverse-electron demand Diels–Alder reaction

2014 ◽  
Vol 12 (26) ◽  
pp. 4701-4707 ◽  
Author(s):  
Sandeep Ameta ◽  
Juliane Becker ◽  
Andres Jäschke
Keyword(s):  
Efficient Method ◽  
Alder Reaction ◽  
Diels Alder ◽  
Peptide Conjugates ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Electron Demand

We present an efficient method to synthesize RNA–peptide conjugates employing inverse Diels–Alder cycloaddition. Different dienophiles are enzymatically incorporated into RNA and then conjugated with a tetrazine peptide at 1 : 1 stoichiometry.

scholarly journals Continuous flow processing as a tool for the generation of terpene-derived monomer libraries

2019 ◽  
Vol 4 (2) ◽  
pp. 362-367 ◽  
Author(s):  
Renan Galaverna ◽  
Lucas P. Fernandes ◽  
Duncan L. Browne ◽  
Julio C. Pastre
Keyword(s):  
Continuous Flow ◽  
Alder Reaction ◽  
Diels Alder ◽  
Flow Conditions ◽  
Rapid Synthesis ◽  
Diels Alder Reaction

A Diels–Alder reaction employing terpenes for rapid synthesis of monomer libraries under flow conditions is presented.

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