Efficient direct 2,2,2-trifluoroethylation of indoles via C–H functionalization

Metal free direct trifluoroethylation of unprotected indoles at position 3 via C–H functionalization is presented: straightforward synthesis and DFT studies.

Rapid, laser-induced conversion of 20-hydroxyecdysone - a follow-up study on the products obtained

We have recently reported the set-up of an experimental system for the laser-induced photochemical modification of bioactive substances, where two ecdysteroids, 20-hydroxyecdysone (20E) and its diacetonide derivative served as probes. As a direct continuation of our previous work, three new compounds together with five other ecdysteroid derivatives, have been identified from the novel, laser-induced photo-transformation reaction of 20E. The structures and NMR signal assignment were established by comprehensive one- and two-dimensional NMR spectroscopy supported by mass spectroscopy. Possible ways for the formation of each species is also discussed. Similar to their parental compound, the products obtained are potentially bioactive and worthy for further investigations; due to the low yields, however, a different approach for their higher scale production is suggested.

Efficient copper-catalyzed trifluoromethylation of aromatic and heteroaromatic iodides: the beneficial anchoring effect of borates

Efficient copper-catalyzed trifluoromethylation of aromatic iodides was achieved with TMSCF3 in the presence of trimethylborate. The Lewis acid was used to anchor the in situ generated trifluoromethyl anion and suppress its rapid decomposition. Broad applicability of the new trifluoromethylating reaction was demonstrated in the functionalization of different aromatic and heteroaromatic iodides.

TGFβ activated kinase 1 (TAK1) at the crossroad of B cell receptor and Toll-like receptor 9 signaling pathways in human B cells

B cell development and activation are regulated by combined signals mediated by the B cell receptor (BCR), receptors for the B-cell activating factor of the tumor necrosis factor family (BAFF-R) and the innate receptor, Toll-like receptor 9 (TLR9). However, the underlying mechanisms by which these signals cooperate in human B cells remain unclear. Our aim was to elucidate the key signaling molecules at the crossroads of BCR, BAFF-R and TLR9 mediated pathways and to follow the functional consequences of costimulation.Therefore we stimulated purified human B cells by combinations of anti-Ig, B-cell activating factor of the tumor necrosis factor family (BAFF) and the TLR9 agonist, CpG oligodeoxynucleotide. Phosphorylation status of various signaling molecules, B cell proliferation, cytokine secretion, plasma blast generation and the frequency of IgG producing cells were investigated. We have found that BCR induced signals cooperate with BAFF-R- and TLR9-mediated signals at different levels of cell activation. BCR and BAFF- as well as TLR9 and BAFF-mediated signals cooperate at NFκB activation, while BCR and TLR9 synergistically costimulate mitogen activated protein kinases (MAPKs), ERK, JNK and p38. We show here for the first time that the MAP3K7 (TGF beta activated kinase, TAK1) is responsible for the synergistic costimulation of B cells by BCR and TLR9, resulting in an enhanced cell proliferation, plasma blast generation, cytokine and antibody production. Specific inhibitor of TAK1 as well as knocking down TAK1 by siRNA abrogates the synergistic signals. We conclude that TAK1 is a key regulator of receptor crosstalk between BCR and TLR9, thus plays a critical role in B cell development and activation.

Recognition of new citrulline-containing peptide epitopes by autoantibodies produced in vivo and in vitro by B cells of rheumatoid arthritis patients

Anti-citrullinated peptide/protein antibodies (ACPAs) are highly sensitive and specific markers of rheumatoid arthritis (RA). Identification of peptide epitopes that may detect different subgroups of RA patients might have diagnostic and prognostic significance. We have investigated citrulline- and arginine-containing peptide pairs derived from filaggrin, collagen or vimentin, and compared this citrulline-peptide panel with the serological assays conventionally used to detect ACPAs. Furthermore, we studied if the same citrulline-peptides identify antibody-secreting cells in in vitro cultures of RA B cells. Recognition of citrulline- and arginine-containing filaggrin, vimentin and collagen peptide epitopes were tested by Multipin ELISA system, by indirect ELISA and by a peptide-specific microarray. B cells were purified from blood by negative selection; antibody-producing cells were enumerated by ELISPOT assay. The panel composed of citrulline-peptide epitopes of filaggrin, collagen and vimentin was recognized by RA sera with a sensitivity and specificity comparable with the currently used tests. Moreover, the combined citrulline-peptide panel including the new short epitope peptide of filaggrin, fil311-315, also identified nearly one-third of RA cases that were negative for antibodies against cyclic citrullinated peptides, mutated citrullinated vimentin or for rheumatoid factor. The results with the peptide-specific microarray have shown that although most ACPAs recognizing the four citrulline peptides are IgG, some of them specifically recognizing citrulline-containing filaggrin peptides (fil311-315 and fil306-326) are IgM, and so may be produced either by newly formed activated B cells or by unswitched B memory cells. Furthermore, the citrulline-peptides of filaggrin and vimentin detect ACPA-producing cells, and so could also be applied to study the B cells of RA patients.

[Systemic lupus erythematosus and pregnancy]

Systemic Lupus Erythematosus (SLE) is a disease primarily targeting fertile women. The odds of spontaneous miscarriage, preeclampsia, intrauterine growth restriction is higher in pregnant women with SLE as well as there are increased risks of preterm delivery and perinatal fetal death. The occurrence of spontaneous abortion is closely related to the presence of antiphospholipid antibodies. The disease on its own is not a contraindication of pregnancy but at least a six-month remission is suggested prior conception. The physiological changes in the course of pregnancy might have close resemblance to the symptoms of lupus, therefore these changes should be differentiated from symptoms caused by lupus. For mothers suffering from SLE, regular visits not only to their obstetricians but also to a rheumatologist are also recommended in order to allow at proper time recognition of potential complications and their appropriate treatment. Thorough check of the maternal disease is of high importance not only during but also prior to and following pregnancy. An overview is given of the opportunities of recent diagnosis and opportunities of therapeutic approaches including biological as well as stem cell treatments. The antithrombotics treatment increases the chance of survival and healthy child birth in the case of pregnant women suffering from antiphospholipid syndrome. Although occurring rarely, neonatal SLE has significantly higher morbidity and mortality compared to healthy births. Recent studies show positive results in the case of prophylactic treatment of neonatal lupus. Prenatal care is recommended to be conducted at an institute where the obstetrician is experienced in the possible complications of lupus and where consultation with a rheumatologist, and the treatment of neonates with low birth weight are ensured.

Selective NR1/2B N-methyl-D-aspartate receptor antagonists among indole-2-carboxamides and benzimidazole-2-carboxamides

(4-Benzylpiperidine-1-yl)-(6-hydroxy-1H-indole-2-yl)-methanone (6a) derived from (E)-1-(4-benzylpiperidin-1-yl)-3-(4-hydroxy-phenyl)-propenone (5) was identified as a potent NR2B subunit-selective antagonist of the NMDA receptor. To establish the structure-activity relationship (SAR) and to attempt the improvement of the ADME properties of the lead, a series of compounds were prepared and tested. Several derivatives showed low nanomolar activity both in the binding and in the functional assay. In a formalin-induced hyperalgesia model in mice, 6a and (4-benzylpiperidine-1-yl)-[5(6)-hydroxy-1H-benzimidazol-2-yl]-methanone (60a) were as active as besonprodil (2) after oral administration. A CoMSIA model was developed based on binding data of a series of indole- and benzimidazole-2-carboxamides.

New benzoyl urea derivatives as novel NR2B selective NMDA receptor antagonists

A novel series of benzoyl urea derivatives was prepared and identified as NR2B selective NMDA receptor antagonists. The influence of the substitution of the piperidine ring on the biological activity of the compounds was studied. Compound 9 was active in the formalin test in mice.

Carbon protonation of 2,4,6-triaminopyrimidines: synthesis, NMR studies, and theoretical calculations

Several C5-substituted 2,4,6-triaminopyrimidine derivatives and their HBF4 salts were synthesized to study the carbon protonation of the pyrimidine ring. NMR investigations in DMSO-d6 prove experimentally that, in addition to the usual protonation at N1, the compounds can be protonated at C5 as well. We present several new stable cationic sigma-complexes in the pyrimidine series, where C5 protonation predominates over N1 protonation. Quantum chemical calculations using the B3LYP/cc-pVDZ method were utilized in the gas phase and also in DMSO solvent with the polarized continuum model (PCM) method to rationalize the observed protonation behavior. Results of the calculations accord with the experimental observations and prove that combined steric and electronic effects are responsible for the observed C5 protonation and for sigma-complex stability. We demonstrate that C5 protonation is a general feature of the 2,4,6-triaminopyrimidine system.

Effective enantiodifferentiation of spirochalcogenuranes by the dirhodium method: Towards the determination of absolute configurations?

The properties of chiral spirochalcogenuranes acting as ligands in adducts with a chiral dirhodium tetracarboxylate complex is explored, and the individual adduct species are characterized by low-temperature NMR spectroscopy. Chiral recognition and the determination of enantiomeric composition of the chiral spirochalcogenuranes is easy by evaluating NMR signal dispersions both at low and at room- or slightly elevated temperatures. The uniformity in the signs of 1H dispersion effects and taking reference to the spiroselenurane with known absolute configuration [(S)-(-)-2] indicates that a convenient rule for the determination of absolute configuration in the spirochalcogenurane system can be established on the basis of 1H chemical shift dispersions.

Adducts of Rh2[MTPA]4 with some phosphine chalcogenides: nature of binding and ligand exchange

Adducts of four phosphine chalcogenides with the chiral dirhodium complex ([Rh-Rh]) were investigated by variable-temperature 1H and 31P NMR spectroscopy in order to compare their properties as axial ligands. Whereas the selenide (1) and the sulfide (2) are strong ligands with electrostatic attraction and, in addition, a significant orbital (HOMO-LUMO) interaction, the phosphine oxide compounds (P=O) bind primarily via electrostatic attraction and are relatively weak donors. Moreover, the overall bond strength in these adducts depends on steric congestion around the P=O group.

Synthesis of 4-cyano and 4-nitrophenyl 1,6-dithio-D-manno-, L-ido- and D-glucoseptanosides possessing antithrombotic activity

1,6-Anhydro-3,4-O-isopropylidene-1-thio-D-mannitol was converted into its sulfoxide which after hydrolysis, acetylation and subsequent Pummerer rearrangement gave the penta-O-acetyl-1-thio-D-mannoseptanose anomers in excellent yield. This anomeric mixture was used as donor for the glycosylation of 4-nitro- and 4-cyanobenzenethiol in the presence of boron trifluoride etherate and trimethylsilyl triflate, respectively, to yield the corresponding thioseptanosides in high yield. The same strategy was applied for the synthesis of the corresponding L-idothioseptanosides using 1,6-anhydro-3,4-O-isopropylidene-1-thio-L-iditol as starting material. The penta-O-acetyl-D-glucothioseptanose donors could not be synthesised the same way, as the Pummerer reaction of the corresponding tetra-O-acetyl-1,6-thioanhydro-1-thio-D-glucitol sulfoxides led to an inseparable mixture of the corresponding L-gulo- and D-glucothioseptanose anomers. Therefore, D-glucose diethyl dithioacetal was converted via its 2,3,4,5-tetra-O-acetyl-6-S-acetyl derivative into an anomeric mixture of its 6-thio-septanose and -furanose peracetates which could be separated by column chromatography. Condensation of the 6-thio-glucoseptanose peracetates with 4-cyano- and 4-nitrobenezenethiol in the presence of boron trifluoride etherate afforded anomeric mixtures of the corresponding thioseptanosides. The D-manno-, L-ido- and D-glucothioseptanosides obtained after Zemplén deacetylation of these mixtures were tested for their oral antithrombotic activity.

3-Methylbutanoyl and 3-methylbut-2-enoyl disaccharides from green coffee beans (Coffea arabica)

Three 3-methylbutanoyl and 3-methylbut-2-enoyl disaccharides isolated from green coffee beans (Coffea arabica) were identified as 3-methylbutanoyl-1-O-beta-D-glucopyranosyl-beta-D-apiofuranoside, 3-methylbutanoyl-6-O-alpha-D-glucopyranosyl-beta-D-fructofuranoside, and 3-methylbut-2-enoyl-1-O-beta-D-glucopyranosyl-beta-D-apiofuranoside. The structures were established by one- and two-dimensional 1H and 13C NMR spectra as well as by ESI MS/MS spectra.