A new versatile linker for the solid-phase synthesis of secondary amines

A novel linker for the solid-phase synthesis of secondary amines based on an intramolecular cyclization was developed. The linker allows for a stepwise built-up of the secondary amines on the support. The feasibility was demonstrated in the parallel synthesis of a small set of different secondary amines.     

A new method for cleavage of silicon-carbon linkers on glass plate supports with applications to solid-phase syntheses on silica resins

We describe herein a novel and facile method for the cleavage of a silicon-based linker on solid-phase supports such as glass plates or silica resin. The linker was efficiently cleaved by oxidation of the silicon-carbon bond (Tamao-Kumada oxidation) to release the functionalized molecule.     

A novel solid-phase microextraction method based on polymer monolith frit combining with high-performance liquid chromatography for determination of aldehydes in biological samples

In this work, a polypropylene frit with porous network structure (20 μm pole size) was first utilized as the mould of polymer monolithic material, poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) monolith was synthesized within channels and macropores of the frit. A simple and sensitive solid-phase microextraction method based on polymer monolith frit coupled with high-performance liquid chromatography (HPLC) was established and applied to analysis of hexanal and heptanal in biological samples (human urine and serum). In the method, small molecule metabolites (aldehydes) in biological samples derivatized with 2,4-dinitrophenylhydrazine (DNPH), and the formed hydrazones were extracted simultaneously on the monolithic frit and thereafter ultrasound-assisted desorbed with acetonitrile as elution solvent. The experimental parameters with regard to polymerization, derivatization and extraction were investigated. Under the optimal conditions, the linearity was in the range of 0.02–5.0 μmol L⁻¹ (r = 0.9994) for both hexanal and heptanal and the limits of detection (S/N = 3) were 0.81 nmol L⁻¹ for hexanal and 0.76 nmol L⁻¹ for heptanal. The relative standard deviations (RSDs, n = 5) were less than 6.5% for the same monolithic frit and less than 8.9% for the different monolithic frits. Satisfactory recoveries ranging from 70.71% to 88.73% were obtained for the urine samples. The method possesses many advantages including simple setup, fast analysis, low cost, sufficient sensitivity, good biological compatibility and less organic solvent consumption. The proposed method is a useful assistant tool in the clinical early diagnosis of lung disease by monitoring aldehyde biomarker candidates in complex biological samples.