Multistep Parallel Synthesis of Quinazoline‐2,4‐diones by a Fluorous Biphasic Concept without Perfluorinated Solvents

Abstract

Based on perfluoro‐tagged benzyl alcohol adsorbed via fluorous–fluorous interactions on fluorous reversed‐phase silica gel (FRPSG), we have performed a multistep synthesis leading finally to a small library of quinazoline‐2,4‐diones. The whole reaction sequence runs without isolation of intermediates and most importantly, without the need of perfluorinated solvents.

Assessment of the Reusability of Pd Complexes Supported on Fluorous Silica Gel as Catalysts for Suzuki Couplings

“…[20] (C 6 F 13 CH 2 CH 2 -)FSG was prepared from SG (particle size: 100-300 µm; pore size: 500 Å; specific surface: 70-90 m 2 g -1 ), obtained from Grace, and (C 6 F 13 CH 2 CH 2 )Si(OEt) 3 as described earlier. [21] Melting points were measured with an IA9000 apparatus from Electrothermal Engineering Ltd. and are uncorrected. NMR Spectra: chemical shifts δ are given in ppm relative to Si(CH 3 ) 4 (δ = 0 ppm) for 1 H NMR, CHCl 3 (δ = 77 ppm) for 13 C NMR and 85 % aq.…”

Repetitive Application of a Fluorous Chiral BINAP–Ru Complex in the Asymmetric Hydrogenation of Olefins

“…For this purpose, we utilised a mixture of [RuCl 2 (benzene)] 2 and BINAP 1 as an in situ prepared catalyst. Because we wanted to avoid the use of perfluorinated solvents, we suspended the FSG (prepared from silica gel with a 500 Å pore-size and bearing -CH 2 CH 2 C 6 F 13 tails) [19] in a mixture of methanol and BTF (1:1) containing the in situ formed catalyst as well as the substrate prior to the reaction. Upon completion of the re- action, the solvent was carefully removed.…”

“…[19] We originally intended to use this methodology to avoid the use of perfluorous solvents, which are expensive and not benign as far as environmental aspects are concerned. The supported catalyst can be used in organic solvents or water and the filtration of the crude reaction mixture allows its removal and potential reutilisation.…”

Noncovalent Attachment of Nucleotides by FluorousFluorous Interactions: Application to a Simple Purification Principle for Synthetic DNA Fragments

“…As a consequence, solid-phase extractions (SPEs) on fluorous reversed-phase silica gel (FRPSG) were developed as an alternative approach [4] [5]. Furthermore, FRPSG was used to support catalysts in organic solvents [6] [7] and in a catch-and-release approach for a multistep synthesis [8]. All the abovementioned examples were bound to perfluoro-alkyl tags in organic solvents.…”

“…The perfluoro-tagged silica gels used in this study, i.e., the FRPSGs 7a and 7b ( Fig. 1), were prepared by our standard procedures [8].…”