|The Effect of Microwave Irradiation Towards Carbodiimide-Mediated Esterifications on Solid Phase|
Alexander Stadler and Oliver Kappe
A number of publications have reported the coupling of carboxylic acids to Merrifield resin via the cesium salt method and the esterification of Wang resin using carbodiimide either via the isourea method or the symmetrical anhydride method. Reaction times using conventional conditions have been reported to be rather long so we have investigated the effects of microwave irradiation towards both of these reactions using benzoic acid derivatives.
|Rapid Scaffold Decoration of Dihydropyrimidine Derivatives by Microwave-Assisted Solution Phase Synthesis|
Doris Dallinger, Alenka Lengar, Bogdan Khanetskyy, Bimbisar Desai and C. Oliver Kappe
In recent work we have reported the generation of a diverse library of DHPMs, employing an automated, sequential microwave-assisted solution phase strategy. We now present the high-speed microwave scaffold decoration around the DHPM heterocyclic core exploiting the diversity on at least six positions.
|Microwave-Assisted Organic Synthesis in Near-Critical Water at 300°C. A Proof-of-Concept Study|
Jennifer M. Kremsner and C. Oliver Kappe
Microwave-assisted organic synthesis in near-critical water (NCW) in the 270-300 °C temperature range has been investigated in a dedicated multimode microwave reactor utilizing heavy-walled quartz reaction vessels.
Several different known transformations such as the hydrolysis of esters or amides, the hydration of alkynes, Diels-Alder cycloadditions, pinacol rearrangements, and the Fischer indole synthesis were successfully performed in microwave-generated NCW without the addition of an acid
|Microwave-Promoted Hetero-Diels-Alder Reactions of 2(1H)-Pyrazinones in Ionic Liquid Doped Solvents and on Solid Support|
Nadya Kaval, Erik Van der Eycken and C. Oliver Kappe
The readily available and broadly functionalized 2-azadiene system of the 2(1H)-pyrazinones easily undergo inter- and intramolecular Diels-Alder reactions with a wide range of dienophiles providing convenient routes to specifically substituted heterocycles. The reactions in this series are known to be rather sluggish, requiring long reaction times, high temperatures and even sometimes high pressures. Since speed is generally recognized as an important factor in high-throughput synthesis, we have
|High-Speed Microwave Chemistry in Solution Phase. Applications Toward Transition Metal-Catalyzed C-P Couplings, the Kindler Reaction and Other Organic Chemistry Transformations|
Alexander Stadler, Oleksandr I. Zbruyev and C. Oliver Kappe
Speeding-up of organic reactions using microwave dielectric heating has attracted increasing importance in recent years. This poster presents applications towards a number of various synthetic protocols including a microwave-enhanced protocol for a one-pot three-component coupling reaction.
|Traceless Solid Phase Synthesis of Bicyclic Dihydropyrimidone Libraries Using Microwave-Assisted Cyclization Cleavage |
Rolando Pérez, Doris Dallinger and C. Oliver Kappe
This poster presents a variation of the Biginelli condensation using methyl 4-chloroacetoacetate as the building block both in solution and in solid phase. This modification allows the rapid entry into a variety of bicyclic heterocyclic ring scaffolds.
|The "Victory" Reaction: A Three Component Synthesis of Pyrido[2,3-d]pyrimidines|
Núria Mont, Jordi Teixidó, José I. Borrell, and C. Oliver Kappe
Here, we report our preliminary results that pyridopyrimidines 6 can be obtained in a single step as a result of a one-pot three component reaction using controlled microwave-assisted synthesis (Emrys Synthesizer).
|Microwave-Assisted Scavenging of Electrophiles Utilizing Polymer-Supported Sequestration Reagents|
Doris Dallinger and C. Oliver Kappe
Recent work has reported the automated generation of a diverse library of multifunctional dihydropyrimidines (DHPMs) utilizing a microwave-mediated solution phase Biginelli three component condensation. Since most of the pharmacologically attractive DHPM derivatives are N3-acylated analogs, we became interested in developing a rapid method for accessing libraries containing this structure motif in high-throughput format.
|Tunable Carbon-Carbon and Carbon-Sulfur Cross-Coupling of Boronic Acids with 3,4-Dihydropyrimidine-2-thiones |
Hana Prokopcova, Alenka Lengar and C. Oliver Kappe
Here we present a direct microwave-assisted Pd(0)-catalyzed/Cu(I)-mediated carbon-carbon cross-coupling of 3,4-dihydropyrimidine-2-thiones and 3,4-dihydropyrimidine-5-carboxylic acid thiol ester with boronic acids under Liebeskind-Srogl conditions.