Trond Vidar Hansen

Disulfooxy fatty acids from the American bird grasshopper Schistocerca americana, elicitors of plant volatiles

A previously unidentified class of compounds has been isolated from the regurgitant of the grasshopper species Schistocerca americana. These compounds (named here “caeliferins”) are composed of saturated and monounsaturated sulfated α-hydroxy fatty acids in which the ω-carbon is functionalized with either a sulfated hydroxyl or a carboxyl conjugated to glycine via an amide bond. The regurgitant contains a series of these compounds with fatty acid chains of 15–20 carbons and in varying proportions. Of these, the 16-carbon analogs are predominant and are also most active in inducing release of volatile organic compounds when applied to damaged leaves of corn seedlings. Caeliferins are nonlepidopteran elicitors identified in insect herbivores. This adds a category of insect herbivore-produced elicitors of plant responses, providing further evidence of the ability of plants to detect and respond to a broad range of insect herbivore-produced compounds.

1,5-Disubstituted 1,2,3-triazoles as cis-restricted analogues of combretastatin A-4: Synthesis, molecular modeling and evaluation as cytotoxic agents and inhibitors of tubulin

A series of cis-restricted 1,5-disubstituted 1,2,3-triazole analogues of combretastatin A-4 (1) have been prepared. The triazole 12f, 2-methoxy-5-(1-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazol-5-yl)aniline, displayed potent cytotoxic activity against several cancer cell lines with IC(50) values in the nanomolar range. The ability of triazoles to inhibit tubulin polymerization has been evaluated, and 12f inhibited tubulin polymerization with IC(50)=4.8microM. Molecular modeling experiments involving 12f and the colchicine binding site of alpha,beta-tubulin showed that the triazole moiety interacts with beta-tubulin via hydrogen bonding with several amino acids.

Asymmetric Iodolactonization Utilizing Chiral Squaramides

Asymmetric iodolactonization of γ- and δ-unsaturated carboxylic acids has been explored in the presence of six different chiral organocatalysts 5-8. The catalyst 6b was found to facilitate the cyclization of 5-arylhex-5-enoic acids 1 to the corresponding iodolactones 2 with up to 96% ee. By this protocol, unsaturated carboxylic acids are converted enantioselectively to synthetically useful δ-lactones in high yields using commercially available NIS. Apparently, both hydrogen bonding and aryl/aryl interactions are important for efficient stereodifferentiation.

1,2,3-triazole analogs of combretastatin A-4 as potential microtubule-binding agents.

A series of cis-restricted 1,4- and 1,5-disubstituted 1,2,3-triazole analogs of combretastatin A-4 (1) have been prepared. Cytotoxicity and tubulin inhibition studies showed that 2-methoxy-5-((5-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazol-1-yl)methyl)aniline (5e) and 2-methoxy-5-(1-(3,4,5-trimethoxybenzyl)-1H-1,2,3-triazol-5-yl)aniline (6e) were two of the most active compounds. Molecular modeling studies revealed that the N-2 and N-3 atoms in the triazole rings in 5e and 6e did not form hydrogen bonds with the amino acids in the anticipated pharmacophore.

Total synthesis of the lipid mediator PD1n-3 DPA: configurational assignments and anti-inflammatory and pro-resolving actions.

The polyunsaturated lipid mediator PD1n-3 DPA (5) was recently isolated from self-resolving inflammatory exudates of 5 and human macrophages. Herein, the first total synthesis of PD1n-3 DPA (5) is reported in 10 steps and 9% overall yield. These efforts, together with NMR data of its methyl ester 6, confirmed the structure of 5 to be (7Z,10R,11E,13E,15Z,17S,19Z)-10,17-dihydroxydocosa-7,11,13,15,19-pentaenoic acid. The proposed biosynthetic pathway, with the involvement of an epoxide intermediate, was supported by results from trapping experiments. In addition, LC-MS/MS data of the free acid 5, obtained from hydrolysis of the synthetic methyl ester 6, matched data for the endogenously produced biological material. The natural product PD1n-3 DPA (5) demonstrated potent anti-inflammatory properties together with pro-resolving actions stimulating human macrophage phagocytosis and efferocytosis. These results contribute new knowledge on the n-3 DPA structure–function of the growing numbers of specialized pro-resolving lipid mediators and pathways.

Synthesis, biological evaluation and molecular modeling of 1,2,3-triazole analogs of combretastatin A-1

The synthesis, cytotoxicity, inhibition of tubulin polymerization data and anti-angiogenetic effects of seven 1,5-disubstituted 1,2,3-triazole analogs and two 1,4-disubstituted 1,2,3-triazole analogs of combretastatin A-1 (1) are reported herein. The biological studies revealed that the 1,5-disubstituted 1,2,3-triazoles 3-methoxy-6-(1-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazol-5-yl)benzene-1,2-diol (6), 3-methoxy-6-(1-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazol-5-yl)benzene-1,2-diamine (8) and 5-(2,3-difluoro-4-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazole (9) were the three most active compounds regarding inhibition of both tubulin polymerization and angiogenesis. Molecular modeling studies revealed that combretastatins 1 and 2 and analogs 5-11 could be successfully docked into the colchicine binding site of α,β-tubulin.

Isatin 1,2,3-triazoles as potent inhibitors against caspase-3

Sixteen disubstituted 1,2,3-triazoles were prepared using the Huisgen cycloaddition reaction and evaluated as inhibitors against caspase-3. The two most potent inhibitors were found to be (S)-1-((1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1H-1,2,3-triazol-4-yl)methyl)-5-((2-(methoxymethyl)pyrrolidin-1-yl)sulfonyl)indoline-2,3-dione (7f) and (S)-1-((1-benzyl-1H-1,2,3-triazol-5-yl)methyl)-5-((2-(methoxymethyl)pyrrolidin-1-yl)sulfonyl)indoline-2,3-dione (8g) with IC(50)-values of 17 and 9 nM, respectively. Lineweaver-Burk plots revealed that these two triazoles show competitive inhibitory mechanism against caspase-3.

The Protectin PCTR1 Is Produced by Human M2 Macrophages and Enhances Resolution of Infectious Inflammation.

Inflammation and its natural resolution are host-protective responses triggered by infection or injury. The resolution phase of inflammation is regulated by enzymatically produced specialized pro-resolving mediators. We recently identified a new class of peptide-conjugated specialized pro-resolving mediators that carry potent tissue regenerative actions that belong to the protectin family and are coined protectin conjugates in tissue regeneration (PCTR). Herein, with the use of microbial-induced peritonitis in mice and liquid chromatography-tandem mass spectrometry-based lipid mediator metabololipidomics, we found that PCTR1 is temporally regulated during self-resolving infection. When administered at peak of inflammation, PCTR1 enhanced macrophage recruitment and phagocytosis of Escherichia coli, decreased polymorphonuclear leukocyte infiltration, and counter-regulated inflammation-initiating lipid mediators, including prostaglandins. In addition, biologically produced PCTR1 promoted human monocyte and macrophage migration in a dose-dependent manner (0.001 to 10.0 nmol/L). We prepared PCTR1 via organic synthesis and confirmed that synthetic PCTR1 increased macrophage and monocyte migration, enhanced macrophage efferocytosis, and accelerated tissue regeneration in planaria. With human macrophage subsets, PCTR1 levels were significantly higher in M2 macrophages than in M1 phenotype, along with members of the resolvin conjugates in tissue regeneration and maresin conjugate families. In contrast, M1 macrophages gave higher levels of cysteinyl leukotrienes. Together, these results demonstrate that PCTR1 is a potent monocyte/macrophage agonist, regulating key anti-inflammatory and pro-resolving processes during bacterial infection.

First total synthesis of (−)-aplyolide A

Abstract The first total synthesis of (−)-aplyolide A † , (16 S )-methyloxacyclohexadeca-(5 Z ,8 Z ,11 Z ,14 Z )-tetraen-2-one, 1 is reported. The synthesis is based on three consecutive couplings of terminal alkynes with propargylic halides and proves the absolute configuration of the stereogenic center of the natural product.

Synthesis and dual PPARα/δ agonist effects of 1,4-disubstituted 1,2,3-triazole analogues of GW 501516

Ten 1,4-disubstituted 1,2,3-triazoles 2a-2j were prepared and tested for their ability to increase oleic acid oxidation in human myotubes using a high-throughput multiwell assay. Compounds 2e (2-{4-[(1-(3-fluoro-4-(trifluoromethyl)phenyl)-1H-1,2,3-triazol-4-yl)methylthio]-2-methylphenoxy}acetic acid) and 2i (2-{4-[(1-(3-chloro-4-(trifluoromethoxy)phenyl)-1H-1,2,3-triazol-4-yl)methylthio]-2-methylphenoxy}acetic acid) exhibited potent agonist activities. Compounds 2e and 2i also exhibited powerful agonist effects for both PPARalpha and PPARdelta in a luciferase-based assay. Consequently, these triazoles can be categorized as dual PPAR agonists.