•A series of novel sulfonamide derivatives were synthesized.•The antiproliferative activities against four cancer cell lines were determined.•These compounds exert antitumor effect via tubulin depolymerization.•BA-3b was very potent against both drug-sensitive and MDR cancer cell lines.A series of benzenesulfonamide derivatives were synthesized and evaluated for their anti-proliferative activity and interaction with tubulin. These new derivatives showed significant activities against cellular proliferative and tubulin polymerization. Compound BA-3b proved to be the most potent compound with IC50 value ranging from 0.007 to 0.036 μM against seven cancer cell lines, and three drug-resistant cancer cell lines, which indicated a promising anti-cancer agent. The target tubulin was also verified by dynamic tubulin polymerization assay and tubulin intensity assay.

•The total synthesis of parkacine has not been reported before.•The intramolecular cycloaddition was highly stereoselective.•A mechanism for the epimerization of phenyl substituted chiral carbon was proposed.Intramolecular 1,3-dipolar cycloaddition of chiral hept-6-yne-azomethine ylide was attempted to construct the C/D ring system of a lycorine-type alkaloid parkacine (3). However, the cycloaddition reactions gave C/D ring-closure product with opposite configurations at 7- and 7a-carbons, comparing with the natural product. The unexpected epimerization of phenyl substituted chiral carbon may occur through imine–enamine tautomerism before the intramolecular cycloaddition.

Thiabendazole, already approved by FDA for oral use as an anti-fungal and anti-helminthic drug since 1967, has recently been repurposed as a vascular disrupting agent. By optimization of the structure of the lead compound, we successfully identified compound TBZ-19 and the new derivative is over 100-fold more potent than the lead compound against the growth of four different cell lines (A549, HCT-116, HepG2 and HUVECs). The most potent two candidates TBZ-07 and TBZ-19, exhibiting moderate inhibitory cell proliferation activity, were also verified as anti-angiogenesis and vascular disrupting agents. Therefore, TBZ-07 and TBZ-19 would be promising candidates with vasculature targeting activity and merit further development.

(−)-Dinemasones B and C were isolated from a culture of the endophytic fungus Dinemasporium strigosum and had shown attractive antimicrobial activities in vitro. Described herein is the concise synthesis of their analogue, ent-4-deoxy-2,3-di-epi-dinemasone BC, from glucal derivatives, including C-glycoside and 3-deoxy-glucal, and the strategies proceeded in 7 steps in 13% overall yield and in 9 steps in 17% overall yield respectively.

An efficient, stereoselective, and base-controlled procedure for the preparation of polyhydroxy bicyclic diazenes and polyhydroxy bicyclic hydrazones is described, starting from sugar-derived methyl 6-deoxy-6-iodo-hexosides. The one-pot synthesis involves a three-step reaction, including ring-opening, condensation with tosylhydrazine, and intramolecular cycloaddition with terminal alkene, which affords important synthetic precursors of bicyclic diazenes and hydrazones.

N-Galactosyl aziridines were synthesized via BF3·OEt2 promoted addition of carbenes generated from diazocarbonyl compounds with O-pivaloylated β-D-galactosylimines in good yields and high diastereoselectivity. The ring-opening reactions with p-toluenethiol of the aziridines provided enantiometrically pure β-S-substituted phenylalanine derivatives in a highly regioselective manner.

A series of 1-sulfonyl indolines was synthesized and evaluated for antiproliferative activity. The most potent compounds 9a and 9e showed significant cytotoxicity (IC50 in the range of 0.055–0.105 and 0.039–0.112 μM, respectively) against four human cancer cell lines HCT116, PC3, HepG2 and SK-OV-3. The structure–activity relationship of this series of sulfonamides, including the influence of azaheterocycle rings, substituent at the different positions of indoline, and the cyclopropane moiety, was described.

A metal-free and 4-methyl aniline mediated method for the oxidative C–C bond cleavage has been developed. The reaction proceeds in air using molecular oxygen as the oxidant, affording one-carbon shortened esters in moderate to good yields within a short time. Moreover, it provides a model reaction for the highly enantioselective synthesis of (D)-serine esters by combining with a L-proline catalyzed Mannich reaction.

(−)-Dinemasone B was isolated by Krohn and co-workers from a culture of the endophytic fungus Dinemasporium strigosum and has shown promising antimicrobial activity. Described herein is the first total synthesis of (−)-dinemasone B, (+)-4a-epi-dinemasone B, (−)-7-epi-dinemasone B, and (+)-4a,7-di-epi-dinemasone B. Their absolute configurations were also determined. The developed synthesis features a stereoselective reduction of C-glycosidic ketone, lactonization, and E-olefination of aldehyde starting from d-glucose.

A metal-free method for the direct regioselective fluorination of anilides has been developed. In the presence of bis(tert-butylcarbonyloxy)iodobenzene (PhI(OPiv)2) and hydrogen fluoride-pyridine, the para-fluorination products of anilides were obtained in moderate to good yields. Because of its operational safety and the use of readily available reagents, this new procedure provides facile access to a variety of para-fluorinated anilides.

A series of conformationally constrained kanamycin A derivatives with a 2′-hydroxyl group in ring I and a 5-hydroxyl group in ring II tethered by carbon chains were designed and synthesized. Pivotal 5,2′-hydroxyl groups were exposed, and the kanamycin A intermediate was synthesized from 5, 2′, 4″, 6″-di-O-benzylidene-protected tetraazidokanamycin A. Cyclic kanamycin A derivatives with intramolecular 8-, 9-, 10-, and 11-membered ethers were then prepared by cesium carbonate mediated Williamson ether synthesis or a ring-closing metathesis reaction. The kanamycin A derivatives were assayed against both susceptible and resistant bacterial strains. Although no derivative showed better antibacterial activities than kanamycin A, the antibacterial activities of these cyclic kanamycin A derivatives indeed varied with the length of the bridge. Moreover, different variations of activities were observed between the susceptible and resistant bacterial strains. More tightly constrained derivative 2 with a one-carbon bridge showed better activity than the others against susceptible strains, but it was much less effective for resistant bacterial strains than derivative 3 with a two-carbon bridge and derivative 6 with an unsaturated four-carbon bridge.

A novel method for the organocatalytic syn diacetoxylation of alkenes has been developed using aryl iodides as efficient catalysts. A broad range of substrates, including electron-rich as well as electron-deficient alkenes, are smoothly transformed by the new procedure, furnishing the desired products in good to excellent yields with high diastereoselectivity (up to >19:1 dr).

An efficient synthesis method for fusing triazole ring onto the naphthalimide core was described. The anti-cancer activities of the generated triazolonaphthalimide derivatives were evaluated with five cancer cell lines. The compounds generally displayed higher potency than amonafide. 4d,4e carrying two amino side chains showed the strongest cytotoxicities. N-oxide 5, a prodrug of 4a, was designed and synthesized. The agent was expected to be activated under the hypoxic condition in tumor tissue. Compared with 4a, 5 manifested much lower cytotoxicity both in cancer cell lines and human normal cells in the in vitro assays. However, N-oxide 5 performed potent anti-cancer activity in vivo using S-180 sarcoma bearing mice. All the results suggested that 5 was a promising anti-cancer agent.Highlights► A series of novel triazolonaphthalimide derivatives were synthesized via a new method. ► Cytotoxicity evaluation with five cancer cell lines was conducted and a preliminary SAR was summarized. ► Much higher cytotoxic effects were observed compared with the lead compound amonafide. ► N-oxide 5 as tumor-activated prodrug was further tested with an in vivo tumor model (S-180 cancer cell formed xenograft).

A convenient, metal-free intramolecular aminofluorination of alkenes has been developed. Employing readily available PhI(OPiv)2 and hydrogen fluoride–pyridine in the presence of BF3·OEt2, tosyl-protected pent-4-en-1-amines were converted to 3-F-piperidines in one step in good yields as well as high stereoselectivity.

2-Deoxyglycosides were synthesized in high α-selectivity by the direct addition of alcohols to d-glucal and d-galactal catalyzed by TMSI and PPh3. The acid labile isopropylidene group is tolerated under this condition.

Various C-pyrrolyl glycosides were obtained through tandem condensation of aminosugars (d-glucosamine and d-galactosamine) and 1,3-dicarbonyl compounds under green conditions in moderate to good yields. The reactions were carried out in the presence of 10 mol % InCl3 in water at 50 °C. A reaction mechanism through carbocation intermediates was proposed.

A series of 4,5-substituted chiral γ-lactams were synthesized through a highly diastereoselective addition—rearrangement approach from 2,3-unsaturated sugar lactones. The single-crystal X-ray structure of one product indicated that the sugar ring was attacked from the axial side. Partial reduction of the nitro group produced N-hydroxy-γ-lactams, which were further reduced with TiCl3 to yield the 4,5-substituted chiral γ-lactams. The absolute configuration of C5 of the γ-lactam was determined by NOESY spectra.

Selective syn and anti diacetoxylations of alkenes have been achieved using a PhI(OAc)2/BF3·OEt2 system in the presence and absence of water, respectively. A broad range of substrates including electron-deficient alkenes (such as α,β-unsaturated esters) could be elaborated efficiently at room temperature with this methodology, furnishing the desired products in good to excellent yields and diastereoselectivity. In particular, a multigram-scale diastereoselective diacetoxylation of methyl cinnamate (5.00 g) was also accomplished in a few hours, maintaining the same efficiency as small-scale reaction. This novel methodology provides an alternative approach for the preparation of various 1,2-diols.

γ-Aminobutyric acid analogs based on sugar scaffolds were prepared in six to nine steps starting from d-glucal and d-galactal. The key step in the synthesis is the Vilsmeier–Haack reaction that affords the corresponding 2-C-formyl glycal on treatment with DMF and POCl3. Oxidation of the aldehyde and reduction of the 4-azido group provided the corresponding GABA analog. Acylamide and tetrazole analogs were also prepared as the bioisosteres of the carboxylic acid.

The highly diastereoselective InCl3-catalyzed aza-Friedel–Crafts reaction of substituted indoles with aldimines generated from Kunz’s amine was studied. The reaction afforded the desired product in good to high yields with up to >19:1 diastereoselective ratios. The O-pivaloylated β-d-galactosyl moiety could not be cleaved under the traditional acidic conditions. It was removed successfully after unmasking of the O-pivaloyl groups using MeOH/NaOMe and treatment with HOAc/H2O subsequently, to yield the 3-indolyl aryl methanamine derivatives in high optical purity.

N-Galactosyl aziridines were synthesized via BF3·OEt2 promoted addition of carbenes generated from diazocarbonyl compounds with O-pivaloylated β-D-galactosylimines in good yields and high diastereoselectivity. The ring-opening reactions with p-toluenethiol of the aziridines provided enantiometrically pure β-S-substituted phenylalanine derivatives in a highly regioselective manner.

A metal-free and 4-methyl aniline mediated method for the oxidative C–C bond cleavage has been developed. The reaction proceeds in air using molecular oxygen as the oxidant, affording one-carbon shortened esters in moderate to good yields within a short time. Moreover, it provides a model reaction for the highly enantioselective synthesis of (D)-serine esters by combining with a L-proline catalyzed Mannich reaction.

A convenient, metal-free intramolecular aminofluorination of alkenes has been developed. Employing readily available PhI(OPiv)2 and hydrogen fluoride–pyridine in the presence of BF3·OEt2, tosyl-protected pent-4-en-1-amines were converted to 3-F-piperidines in one step in good yields as well as high stereoselectivity.