2',4',6'-Trimethoxyacetophenone

Bioaccumulation, maternal transfer and effects of dietary 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) exposure on medaka fish (Oryzias latipes) offspring.[Pubmed:28987991]

Aquat Toxicol. 2017 Nov;192:241-250.

A previous study conducted in our laboratory with growing medaka (Oryzias latipes) showed the capacity of BDE-47 (10-1000ng/g) to bioaccumulate during a 40-day oral exposure. However, the results did not provide evidence for effects during or after the exposure period. In this study, breeding medakas were fed a diet for 40days that contained 1000ng of BDE-47/g. At predefined time points, females (time points 10, 20, 30 and 40), males (time points 30 and 40) and pools of laid eggs (time points 10, 20, 30 and 40) were sampled and collected for: 1) the BDE-47 quantitative analysis in adults in the <24-h-old post-fertilization (hpf) embryos, and in the <24-h-old post-hatch (hph) eleutheroembryos; 2) the evaluation of fecundity, fertility and hatching. Additional pools of embryos collected at time point 40 were evaluated for: 1) the active swimming behavior of the 48hph offspring in the eleutheroembryonic stage; 2) the BDE-47 quantification in the 240hph resultant larvae. BDE-47 accumulated in parents rapidly, and concentrations remained constant at higher levels in males (values within the 50-60ng/g wet weight -w.w.- range) compared with females (70ng/g w.w. range). The BDE-47 concentrations detected in embryos and eleutheroembryos ranged from 200 to 500ng/g w.w. for time points 10-40. Reproductive capacity, hatching and ensuing swim bladder inflation were not affected by parental BDE-47 dietary exposure, nor was the active swimming behavior in eleutheroembryos. The BDE-47 concentration in the 240hph larvae lowered to levels close to those detected in parents. Despite the efficient BDE-47 maternal transfer, these results offered no evidence for BDE-47 effects on fish reproduction or in the early life stages of offspring.

Orange Fluorescent Ru(III) Complexes Based on 4'-Aryl Substituted 2,2':6',2''-Terpyridine for OLEDs Application.[Pubmed:28956219]

J Fluoresc. 2018 Jan;28(1):173-182.

A series of ruthenium (III) complexes of the formulae [Ru(4-Mephtpy)2]Cl3(1) [Ru(L 1 )], [Ru(3,4,5-tmphtpy)2]Cl3(2) [Ru(L 2 )], and [Ru(4-thptpy)2]Cl3(3) [Ru(L 3 )], (where L = terpy = 2.2':6'2'' terpyridine ligands) are synthesized. The complexes were characterized by elemental analyses, spectroscopic and electrochemical data. The density functional theory (DFT) outlines the geometric optimisation and electronic charge transition of these complexes. Photophysical studies describe that the luminescence of Ru(III) complexes is due to electronic transition between the energy levels of singly unoccupied molecular orbitals (SUMO) and singly occupied molecular orbitals (SOMO). It also exhibits the potential charge transfer to pi-pi* and n-pi* states due to MLCT and ILCT processes of the complexes. The observed bands centered at 591 and 620 nm demonstrate that these emissions originated from the transition of SUMO to SOMO energy levels, that is, from the radiative decay from the doublet exciton. Due to the heavy metal effect of Ru(III) ions the photophysical behaviour depends on the MLCT process. In conclusion, that the all three Ru(L 1 -L 3 ) complexes are fallen orange emission.

Copper-Catalyzed Cascade Cyclization of 1,7-Enynes toward Trifluoromethyl-Substituted 1'H-Spiro[azirine-2,4'-quinolin]-2'(3'H)-ones.[Pubmed:28933859]

Org Lett. 2017 Oct 6;19(19):5186-5189.

A novel method for the synthesis of trifluoromethyl-containing 1'H-spiro[azirine-2,4'-quinolin]-2'(3'H)-ones by a CF3-radical-triggered tandem reaction of benzene-linked 1,7-enynes is described. This protocol utilizes 1-trifluoromethyl-1,2-benziodoxole as the trifluoromethylating reagent and TMSN3 as the aminating reagent. By this method, various potentially bioactive trifluoromethylated 1'H-spiro[azirine-2,4'-quinolin]-2'(3'H)-ones were facilely synthesized via a radical cascade process.

4'-C-Methoxy-2'-deoxy-2'-fluoro Modified Ribonucleotides Improve Metabolic Stability and Elicit Efficient RNAi-Mediated Gene Silencing.[Pubmed:28937776]

J Am Chem Soc. 2017 Oct 18;139(41):14542-14555.

We designed novel 4'-modified 2'-deoxy-2'-fluorouridine (2'-F U) analogues with the aim to improve nuclease resistance and potency of therapeutic siRNAs by introducing 4'-C-methoxy (4'-OMe) as the alpha (C4'alpha) or beta (C4'beta) epimers. The C4'alpha epimer was synthesized by a stereoselective route in six steps; however, both alpha and beta epimers could be obtained by a nonstereoselective approach starting from 2'-F U. (1)H NMR analysis and computational investigation of the alpha-epimer revealed that the 4'-OMe imparts a conformational bias toward the North-East sugar pucker, due to intramolecular hydrogen bonding and hyperconjugation effects. The alpha-epimer generally conceded similar thermal stability as unmodified nucleotides, whereas the beta-epimer led to significant destabilization. Both 4'-OMe epimers conferred increased nuclease resistance, which can be explained by the close proximity between 4'-OMe substituent and the vicinal 5'- and 3'-phosphate group, as seen in the X-ray crystal structure of modified RNA. siRNAs containing several C4'alpha-epimer monomers in the sense or antisense strands triggered RNAi-mediated gene silencing with efficiencies comparable to that of 2'-F U.