A facile synthesis of benzo[h]quinolines has been developed via improved Combes reaction. A combination of silica gel, p-toluenesulfonic acid and phosphorus pentoxide was utilized to promote the condensation of 1-naphthylamines with 1,3-diketones under solvent free conditions. In this case, silica gel was used as reaction media, p-toluenesulfonic acid and phosphorus pentoxide were acted as catalyst and dehydrating agent, respectively.

A new one-pot, three component reaction involving the use of Julia reagent, aldehyde, and sodium azide was developed for the efficient synthesis of N-unsubstituted 1,2,3-triazoles. This reaction could be carried out under mild reaction conditions without any precaution, and broad scope of substrates, both respect to Julia reagents and aldehydes, could be applied in this reaction system in generation of a small library of title compounds.Keywords: 1,2,3,-triazoles; Julia reagent; multicomponent reaction; one pot; sodium azide

An inexpensive silica sulfuric acid (SSA) mediated acylation of amines with 1,3-diketones via CC bond cleavage was realized under solvent and transient metal free conditions. In this chemistry, both catalytic aerobic oxidative and hydrolyzed CC bond cleavage were coexisted. Furthermore, the activation of molecular oxygen by non-transient metal catalyst (SSA) was disclosed.

•Novel tridentate zwitterionic click N-benzyl IDA stationary phase was prepared by Click chemistry.•Click chemistry is a good strategy for the preparation of stationary phase.•Click N-benzyl IDA displayed good HILIC characteristics.•Click N-benzyl IDA could be applied to separate highly polar compounds efficiently.Iminodiacetic acid (IDA) is dicarboxylic acid amine, which may produce stronger interaction with polar or charged compounds than bidentate α,β-amino acid. In this article, a novel type of tridentate zwitterionic HILIC stationary phase was prepared by covalently bonding N-benzyl IDA on silica gel via copper(I) catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition (CuAAC). The structure of this stationary phase and all related intermediates was confirmed by NMR, FT-IR, MS spectrum and elemental analysis. The new stationary phase showed good HILIC characteristics and high column efficiency (the theoretical plate number is up to 44000 plates m−1 in the case of guanosine) in the application of separation of polar compounds, including organic acids, organic bases, as well as highly polar and hydrophilic compounds, such as cephalosporins and carbapenems. Most of them displayed good peak shape and selectivity.

A silica based amino stationary phase was prepared by immobilization of propargylamine on azide-silica via click chemistry. This readily prepared click amino stationary phase demonstrated good selectivity in separation of common inorganic anions under ion chromatography (IC) mode, and the triazole ring in combination with free amino group was observed to play a major role for separation of the anions examined. On the other hand, the stationary phase also showed good hydrophilic interaction liquid chromatography (HILIC) properties in the separation of polar compounds including nucleosides, organic acids and bases. The retention mechanism was found to match well the typical HILIC retention.

A novel type of zwitterionic HILIC stationary phase was prepared by covalently bonding the l-azido lysine on silica gel via click chemistry. The key intermediate azido lysine was synthesized by transformation the amino group in l-Boc-lysine to corresponding azido group and subsequent removal of the N-protected group (Boc). Finally, the azido lysine was covalently bonded to silica beads by click chemistry to get click lysine. Its structure was confirmed by FT-IR and elemental analysis. The new stationary phase showed good HILIC characteristics, when it was applied to separate polar and hydrophilic compounds, such as organic acids, cephalosporins and carbapenems. Compared with the commercial stationary phases, such as Atlantics HILIC and ZIC-HILIC, click lysine displayed better or similar chromatographic behaviors.Highlights► A zwitterionic HILIC stationary phase was developed by covalently bonded azido lysine on silica beads by click chemistry. ► This new stationary phase showed good HILIC chromatographic properties. ► Hydrophilic compounds such as cephalosporins and carbapenems could be well separated by using click lysine stationary phase. ► This stationary phase displayed good stability and reproducibility.

With the increasing requirement for analysis and separation of samples related to genomics, proteomics, metabolomics, pharmacology and agrochemistry, diverse stationary phases for liquid chromatography have been prepared by Cu(I)-catalyzed 1, 3-dipolar azide-alkyne cycloaddition reaction (CuAAC). It has been proved that CuAAC is a powerful tool for preparing covalently bonded stationary phases. In this tutorial review, we highlighted the preparation of separation materials by immobilization of functional groups on silica beads, polymer beads and agarose via CuAAC and their applications in liquid chromatography and related purposes, such as separation of polar compounds, enrichment of valuable bio-samples, orthogonal two-dimensional HPLC and chiral separation. Meanwhile, agarose-based separation materials for affinity chromatography are reviewed.

Ion chromatography (IC) is one of the most powerful analysis technologies for the determination of charged compounds. A novel click lysine stationary phase was prepared viaCu(I) catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC) and applied to the analysis of inorganic ions. The chromatographic evaluation demonstrated good performance (e.g. the plate number of thiocyanate is ∼50000 plates m−1) and effective separation ability for the common inorganic anions with aqueous Na2SO4 eluent. The separation mechanism was observed to be mainly dominated by ion exchange interaction. The retention of these analytes is highly dependent on the pH value of eluent. Compared with the lysine stationary phase prepared via the conventional manner, the click lysine exchanger demonstrated shorter retention time and better ion separation characteristics under the same chromatographic conditions, which is a great advantage for rapid separation and analysis of inorganic ions.

A novel glycosyl amino acid hydrophilic interaction chromatography (HILIC) stationary phase was prepared via click chemistry. The key intermediate N3-glycosyl d-phenylglycine was prepared by a three steps procedure, including selective condensation of amino glucose with N-succinimidyl ester of Boc-d-phenylglycine, deprotection and transformation of amino group to azido group. The structure of all the intermediates and functionalized silica beads were confirmed by 1H NMR, IR, elemental analysis and 13C CP-MAS. The chromatography test showed that this new type of separation material possessed good HILIC properties and glycopeptide enrichment characteristics. Nucleosides and bases could be separated in a simple eluent composition (only acetonitrile in combined with water), and with the same condition, these model compounds could not be separated on the commercial HILIC column (Atlantis). Click glycosyl amino acid thus prepared also showed longer retention and better separation ability in the separation of polar organic acids.

A novel chitooligosaccharide stationary phase for hydrophilic interaction liquid chromatography (HILIC) was developed via click chemistry and showed great HILIC characteristics on separation of polar compounds and enrichment of glycopeptides.

2D-HPLC is an important technique for the separation of complex samples. Developing new types of stationary phases is of great interest to construct 2D-LC systems with high orthogonality. In this study, a novel stationary phase-Click dipeptide (l-phenylglycine dipeptide) was prepared by immobilization of α-azido l-phenylglycine dipeptide on alkyne-silica via click chemistry. In the preparation of this new material, an efficient, inexpensive and shelf-stable diazo transfer reagent (imidazole-1-sulfonyl azide hydrochloride) was utilized to transfer the amino group of l-phenylglycine to corresponding azido group under mild conditions. The Click dipeptide thus prepared was confirmed by FT-IR, solid state CP/MAS 13C NMR and elemental analysis. The Click dipeptide packing showed high orthogonality with C18, which reached 63.5%. An off-line 2D-RP/RPLC system was developed to analyze a traditional Chinese medicine (TCM)-Rheum Palmatum L. The results showed high orthogonality between Click dipeptide and C18 as well as great separating power in the practical separation of complex samples.

A novel chitooligosaccharide stationary phase for hydrophilic interaction liquid chromatography (HILIC) was developed via click chemistry and showed great HILIC characteristics on separation of polar compounds and enrichment of glycopeptides.

With the increasing requirement for analysis and separation of samples related to genomics, proteomics, metabolomics, pharmacology and agrochemistry, diverse stationary phases for liquid chromatography have been prepared by Cu(I)-catalyzed 1, 3-dipolar azide-alkyne cycloaddition reaction (CuAAC). It has been proved that CuAAC is a powerful tool for preparing covalently bonded stationary phases. In this tutorial review, we highlighted the preparation of separation materials by immobilization of functional groups on silica beads, polymer beads and agarose via CuAAC and their applications in liquid chromatography and related purposes, such as separation of polar compounds, enrichment of valuable bio-samples, orthogonal two-dimensional HPLC and chiral separation. Meanwhile, agarose-based separation materials for affinity chromatography are reviewed.