Solution-phase parallel synthesis of an N-alkylated dihydropteridinone library from fluorous amino acids

Polymer-Supported Synthesis of Various Pteridinones and Pyrimidodiazepinones

In this report, we employed the solid-phase synthetic approach to prepare variously substituted dihydropteridinones, tetrahydropyrrolopteridinones, and pyrimidodiazepinones, using a versatile building block-4,6-dichloro-5-nitropyrimidine. All these compounds are pharmacologically significant scaffolds of the great importance of medicinal chemists. The fast and efficient synthetic methodology is highly desirable for defining their structure-activity relationship (SAR) and optimizing pharmacokinetic properties. Our research efforts utilize simple synthetic methods to generate a library of analogues for future SAR studies. The efficiency of our approach was exemplified in various pteridinones as well as pyrimidodiazepinones.

Fluorous synthesis of sclerotigenin-type benzodiazepine-quinazolinones

A new synthetic protocol for sclerotigenin-type benzodiazepine-quinazolinone library scaffold is introduced. A fluorous benzyl protecting group is used for synthesis of 4-benzodiazepine-2,5-dione intermediate and also as a phase tag for fluorous solid-phase extraction (F-SPE).

Automation of fluorous solid-phase extraction for parallel synthesis

An automatic fluorous solid-phase extraction (F-SPE) technique is developed by using FluoroFlash SPE cartridges on the RapidTrace workstation. A 10-module workstation has the capability to complete a maximum of 100 SPEs each round in 1-2 h. Another important feature of the RapidTrace system is that it has the capability to load slurry samples onto the F-SPE cartridges. The F-SPE cartridge charged with 2 g of fluorous silica gel is used to purify up to 200 mg of crude sample. Sample loading, elution solvent, cartridge reuse, and SPE reproducibility are evaluated. The automatic SPE system is used for purification of a small urea library generated from amine-scavenging reactions using fluorous dichlorotriazine, a 96-membered amide library generated using 2-chloro-4,6-bis[(perfluorohexyl)propyloxy]-1,3,5-triazine as the coupling agent, and another 96-membered library generated from fluorous Mitsunobu reactions. Approximately 90% of the products have > 90% purity after F-SPE.

Microwave-Enhanced High-Speed Fluorous Synthesis

Increasing reaction speed and simplifying product purification are two major ways to improve the efficiency of organic synthesis. A new technology for high-speed solution-phase synthesis has been developed by combination of microwave heating and fluorous purification. This review describes different techniques for microwave-enhanced fluorous synthesis and their applications in Pd-catalyzed cross-coupling reactions, free-radical reactions, multicomponent reactions, and compound library synthesis.

Advances in Microwave-Assisted Combinatorial Chemistry Without Polymer-Supported Reagents

Combinatorial methodologies have dramatically changed the chemical research and discovery process, offering an unlimited source of new molecule entities to be screened for activity. The application of microwave irradiation in Combinatorial Chemistry and high-throughput synthesis has become increasingly popular. By taking advantage of this energy source, compound libraries for lead generation can be assembled in a fraction of time required by conventional thermal heating. This review focuses on the advances in developing synthetic methodologies in microwave without polymer-supported reagents suitable for combinatorial chemistry, including the advances in microwave-assisted fluorous synthesis technology.

Plate-to-plate fluorous solid-phase extraction for solution-phase parallel synthesis

A commercially available Argonaut VacMaster-96 plate-to-plate solid-phase extraction (SPE) station equipped with 24 FluoroFlash cartridges is employed for parallel purification of fluorous reaction mixtures. Each cartridge charged with 3 g of fluorous silica gel has the capability to produce up to 100 mg of purified small molecules. The 24-well receiving plate has a standard footprint that can be directly concentrated in a Genevac vacuum centrifuge. Important issues such as sample loading, product cross-contamination, cartridge reuse, and reproducibility are investigated. The SPE system has been demonstrated in the purification of three small libraries that were produced involving amine scavenging reactions with fluorous isatoic anhydride, amide coupling reactions with 2-chloro-4,6-bis[(perfluorohexyl)propyloxy]-1,3,5-triazine (fluorous CDMT), and amide coupling reactions with a newly developed fluorous Mukaiyama condensation reagent.