19255-80-2Relevant academic research and scientific papers
Synthesis and evaluation of a conformationally constrained pyridazinone PNA-monomer for recognition of thymine in triple-helix structures
Olsen, Anne Goldbech,Dahl, Otto,Nielsen, Peter E.
, p. 1551 - 1554 (2004)
A novel conformationally constrained pyridazinone Eag-base PNA-monomer 2 capable of binding thymine in a triplex motif was designed and synthesised. A bis-PNA with the Eag-base incorporated in the Hoogsteen strand was hybridised with a complementary DNA. Thermal stability studies revealed an increase in Tm (4.3°C per mod.) compared to a no-base unit, but showed no improvement over a previously described unconstrained analogue (E, 1). Surprisingly, no significant difference was found in the thermodynamic parameters (ΔH°, ΔS° and ΔG°) for PNA-DNA triplex formation involving 2 or the unconstrained analogue 1.
Reactions of diazo esters with electron-deficient alkenes in the presence of Lewis acids
Novikov,Platonov,Dokichev,Tomilov,Nefedov
experimental part, p. 984 - 990 (2011/02/27)
1,3-Dipolar cycloaddition reaction of diazo esters to electron-deficient dipolarophiles to yield the corresponding 1- or 2-pyrazolines was found to be significantly accelerated with Lewis acids (Yb(OTf)3, Sc(OTf) 3, GaCl3, EtAlCl2). The use of GaCl3 as the catalyst leads to the acceleration not only of the 1,3-dipolar cycloaddition reaction, but also subsequent insertion of the CHCO2Me electrophilic fragment of methyl diazoacetate into the N-H bond of 2-pyrazolines formed. Such Lewis acids as SnCl4, BF3, TiCl4, and In(OTf)3 are not efficient in the described processes, since they rapidly decompose starting diazo compounds.
