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Herein we successfully developed a domino [3 + 2] cycloaddition of isatin-based (trifluoromethyl)imine ylides with benzylidenechromanones for the construction of a series of biologically important and structurally diverse bispiro-[oxindole-pyrrolidine-chromanone]s incorporating a CF3 motif under the organocatalyst DABCO catalysis. The reaction offers a straightforward and atom-economical procedure for the preparation of the desired products featuring four contiguous stereocenters including two vicinally spiro quaternary stereocenters in moderate to good yields with high diastereoselectivity via an exo-transition state (up to 91 % yield and >20:1 diastereomeric ratio). Of note, this is the first example of the introduction of CF3 units into spirocyclic chromanone compounds, which might be valuable in medicinal chemistry.

Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3 via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties and a polycyclic pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 85% yield) with good diastereoselectivity (up to >20:1). Valuable features of this method were application of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles and the design of new hybrid architectures for biological screenings through the adequate fusion of these sub-units of isoxazole and 3,3′-pyrrolidinyl-dispirooxindole, generating drug-like molecules.

Described herein is a facile and efficient methodology for diversity-oriented one-pot multicomponent synthesis of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5via knoevenagel condensation/Michael/cyclization and then aminomethylation reaction. A wide variety of products with varying degrees of substitution around it, were obtained smoothly with high efficiency (up to overall yield 73% and >20:1 diastereoselectivity). In particular, their biological activities against these three cell lines K562, A549 and PC-3 have been evaluated. These results suggested that most of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5 showed equipotent or more potent than the positive control of Cisplatin (up to 3.4 times).

Inspired by the chemistry and biology of isoflavones and pyrazolones, herein we report the first example of synthesis of 3-pyrazolyl isoflavones by two steps, starting from commercially available chromanones and pyrazolones. The [1,5]-proton transfer was used as a key strategy. All the 3-pyrazolyl isoflavones 3, which are hard to synthesize by traditional methods, are smoothly obtained in up to 86% total yield. Interestingly, the product forms a stable 7-membered ring through intramolecular hydrogen bond between carbonyl group on chromone core and hydroxyl group on pyrazolone core, preventing further ketone-enol tautomerization. In particular, the products are featured with an intriguing combination of two privileged motifs including isoflavone and pyrazolone substructures, which might be valuable in medicinal chemistry.

A facile and efficient methodology was developed for the synthesis of isoxazole-fused spiropyrrolidine oxindoles 3–5 via a 1,3-dipolar cycloaddition reaction of 3-methyl-4-nitro-5-alkenyl-isoxazoles with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline or sarcosine). Products bearing adjacent quaternary-tertiary centers were smoothly obtained in high yields (up to 90% yield) with good diastereoselectivity (up to 20:1). Furthermore, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays using the commercially available standard drug Cisplatin as a positive control. These results suggested that most of isoxazole-fused spiropyrrolidine oxindoles 3–5 showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and that isoxazole-fused spiropyrrolidine oxindoles may be potential leads for further biological screening.

A new methodology was developed for the synthesis of hexahydro-1 H -pyrido[2,3- b ]indol-2-one scaffolds via a sequential Michael addition/amidation/reductive cyclization process. A wide variety of products bearing a hexahydro-1 H -pyrido[2,3- b ]indol-2-one core with varying degrees of substitution around it, which is a key structural skeleton found in a large number of biologically active natural products and pharmaceutical compounds, were obtained smoothly with high efficiency (up to overall yield of 67%). Furthermore, their biological activities have been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drug Cisplatin as a positive control. These results suggested there is a trend that lipophilic groups improve the potency, and also suggested a carbonyl moiety located in the hexahydro-1 H -pyrido[2,3- b ]indol-2-one scaffolds is beneficial for the activity. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and that hexahydro-1 H -pyrido[2,3- b ]indol-2-one scaffolds may be potential leads for further antitumor activity screenings.

A facile and efficient methodology was developed for the synthesis of multifunctional polycyclic spiropyrrolidine oxindoles bearing mesityl oxide unit via a three-component 1,3-dipolar cycloaddition reaction of dienones 2 with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline). Products bearing adjacent four chiral carbon centers were smoothly obtained in high yields (up to 98% yield) with diastereoselectivities up to >20:1. Furthermore, the key structural characteristic of the products of such a reaction is the natural product ingredient turmerone motif fused at the 3-position of the spirooxindole core, with varying degrees of substitution around it. In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drugs Cisplatin as a positive control. These results suggested there is a trend that lipophilicity groups improve the potency, and also suggested an mesityl oxide moiety located in the polycyclic spiropyrrolidine oxindoles is beneficial for the activity. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and indicated that polycyclic spiropyrrolidine oxindole analogs bearing mesityl oxide unit may be potential leads for further antitumor activity screenings.

The first Lewis base-catalysed allylic sulfuration of Morita–Baylis–Hillman (MBH) adducts derived from ketones (isatins) has been developed, which affords C3-quaternary oxindole derivatives bearing thio-group at 3-position in good to excellent yield (up to 98% yield) under mild reaction conditions. Significantly, the potential utility of the protocol also has been demonstrated by gram-scale synthesis of 3-alkylthio-2-oxindole (3ae), a low catalyst loading (0.3 mol %) and facile conversion of resulting product (3ad) into functionalized pyrrolidinone (5ad).

A series of 1,3-alternate conformation thiacalix[4]arenes containing different isomeric aminopyridyl pendent arms have been synthesized. It was found that their self-assembly behaviors and complexation properties strongly depended on the structures of aminopyridyl pendent arms. The crystal structures demonstrate that tetra(meta-aminopyridyl)-thiacalix[4]arene motif is capable of forming intramolecular hydrogen bondings between the sp2 nitrogen donors in the meta position of the aminopyridyl groups and the facing amide N–H of the adjacent aminopyridyl groups, and self-assembles via C–H⋯O weak hydrogen bondings and C–H⋯π interaction to generate a double stranded rectilineal networks. By contrast, in the case of tetra(para-aminopyridyl)-thiacalix[4]arene, the presence of para-aminopyridyl units enables the formation of N–H⋯N strong hydrogen bondings between the individual molecules leading to the solid-state structure with water-bridged double strands. Their complexation properties had been also studied by measurement of the stability constants for their complexation in a range of metal cations and investigation of their binding models via 1H NMR titration and ESI-MS experiments. It was found that the three ligands exhibited high and selective extractability toward Ag+, and their stoichiometry of ligand to Ag+ was 1:1, while the meta-aminopyridyl derivative showed the best extraction capacity and possessed the most efficient binding sites.

The ethanolic extract of the seeds of Uvaria tonkinensis (Annonaceae), collected on Hainan Island, have led to the isolation of a new polyoxygenated cyclohexane derivative tonkinenin A [ 1 ]. The structure of 1 was deduced from spectroscopic characteristics and the absolute stereochemistry assigned by the O -methylmandelate ester method.