25790-41-4Relevant articles and documents
Unwinding DNA and RNA with Synthetic Complexes: On the Way to Artificial Helicases
Gasiorek, Martin,Schneider, Hans-J?rg
, p. 18328 - 18332 (2015)
Synthetic helicases can be designed on the basis of ligands that bind more strongly to single-stranded nucleic acids than to double-stranded nucleic acids. This can be achieved with ligands containing phenyl groups, which intercalate into single strands, but due to their small size not into double strands. Moreover, two phenyl rings are combined with a distance that allows bis-intercalation with only single strands and not double strands. In this respect, such ligands also mimic single-strand binding (SSB) proteins. Exploration with more than 23 ligands, mostly newly synthesised, shows that the distance between the phenyl rings and between those and the linker influence the DNA unwinding efficiency, which can reach a melting point decrease of almost ΔTm=50°C at much lower concentrations than that with any other known artificial helicases. Conformational pre-organisation of the ligand plays a decisive role in optimal efficiency. Substituents at the phenyl rings have a large effect, and increase, for example, in the order of Hm=48°C), whereas the AT strand remains untouched, and with poly(rA)-poly(rU) as an RNA model one observes unfolding at 29°C with a concentration of only 30 μM. Sit back, relax! Unwinding of nucleic acid double helices into single strands by helicases plays an important role in many processes. Synthetic helicases can be designed with ligands containing phenyl groups that intercalate only into single strands (see figure). The best ligand lowered the melting points of double strands by 48°C at a ligand concentration of only 40 μM, and could discriminate between AT and GC homopolymers.
Synthesis and solid-state characterization of self-assembled macrocyclic molecular rotors of bis(dithiocarbamate) ligands with diorganotin(IV)
Torres-Huerta, Aaron,Rodriguez-Molina, Braulio,Hoepfl, Herbert,Garcia-Garibay, Miguel A.
, p. 354 - 362 (2014/02/14)
Two bis(dithiocarbamate) (bdtc) metallamacrocyclic compounds, 1 and 2, and the deuterated analogues 1-d8 and 1-d20 were readily prepared through self-assembly processes involving the corresponding secondary bis(diamines), with two equivalents each of CS2 and dimethyltin(IV) dichloride. Solid-state characterization using FTIR, PXRD, and TGA indicated that the solid phases of both macrocycles were amorphous solids. For compound 1, a crystalline phase could only be obtained in the form of a dichloromethane solvate; however, the corresponding crystal lattice was unstable and collapsed rapidly under ambient conditions. The bdtc ligands containing para-disubstituted phenylene (compound 1) and bicyclo[2.2.2]octane groups (compound 2) showed rotational motion within the macrocyclic assemblies in the solid state. For compound 1, the internal rotation of the phenylene groups was examined first by 13C NMR CPMAS spectroscopy using the 1-d20 derivative in which the hydrogen atoms of the pendant phenyl groups had been substituted with deuterium atoms and also by 2H NMR spin echo experiments using the 1-d8 derivative in which the rotating phenylene groups have been deuterated. Line shape analysis using a log-Gaussian distribution model indicated that the central phenylene rings experience fast 2-fold flip reorientations over the sp2-sp3 carbon atom axes, overcoming an activation energy of Ea = 10 kcal/mol with a preexponential factor A = 3.9 × 1014 s-1. For compound 2, the 13C CPMAS experiments suggested that the bicyclo[2.2.2]octane moieties also undergo fast internal dynamics, which is in agreement with the higher symmetry of these fragments when compared to the phenylene spacers.
Ketoester methacrylate resin, secondary amine clean-up in the presence of primary amines
Yu,Alesso,Pears,Worthington,Luke,Bradley
, p. 1947 - 1952 (2007/10/03)
A ketoester resin was developed as the basis for a selective scavenger for primary amines in the presence of secondary amines. The utility of the scavenger was demonstrated with a range of reductive amination chemistries with both mono- and diamines. The resin's specificity is based on the removal of the primary amines via their enamines.
