Synthesis and evaluation of a conformationally constrained pyridazinone PNA-monomer for recognition of thymine in triple-helix structures
摘要:
A novel conformationally constrained pyridazinone E-ag-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 T-m (4.3degreesC 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 (DeltaHdegrees, DeltaSdegrees and DeltaGdegrees) for PNA-DNA triplex formation involving 2 or the unconstrained analogue 1. (C) 2004 Elsevier Ltd. All rights reserved.
Lewis acid catalyzed reactions of donor–acceptor cyclopropanes with 1- and 2-pyrazolines: formation of substituted 2-pyrazolines and 1,2-diazabicyclo[3.3.0]octanes
作者:Yury V. Tomilov、Roman A. Novikov、Oleg M. Nefedov
DOI:10.1016/j.tet.2010.09.092
日期:2010.11
The reaction of 2-substituted cyclopropane-1,1-dicarboxylates with 1- and 2-pyrazolines is efficiently catalyzed by scandium or ytterbium triflates to give N-substituted 2-pyrazolines or 1,2-diazabicyclo[3.3.0]octanes. The reactions of 2-pyrazolines give diazabicyclooctanes as the major products. In contrast, the reactions starting from 1-pyrazolines predominantly give N-substituted 2-pyrazolines,
Reactions of diazo esters with electron-deficient alkenes in the presence of Lewis acids
作者:R. A. Novikov、D. N. Platonov、V. A. Dokichev、Yu. V. Tomilov、O. M. Nefedov
DOI:10.1007/s11172-010-0194-0
日期:2010.5
Abstract1,3-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 Lewisacids (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
Reactions of 4-phenyl-1,2,4-triazoline-3,5-dione with 2-pyrazolines
作者:R. A. Novikov、V. A. Korolev、Yu. V. Tomilov
DOI:10.1007/s11172-011-0252-2
日期:2011.8
4-triazoline-3,5-dione (PTAD) acts as an efficient Michael acceptor in reactions with 1-unsubstituted 2-pyrazolines, giving substituted (3,5-dioxo-4-phenyl-1,2,4-triazol-idin-1-yl)-1-pyrazolines in quantitative yields. Through elimination of molecular nitrogen, the latter are easily transformed into the corresponding cyclopropanes. A reaction of methyl 5-methyl-2-pyrazoline-5-carboxylate with a twofold excess
Catalytic hydrogenation of methyl esters of some 1h-pyrazoline-3-carboxylic acids
作者:V. A. Gorpinchenko、D. V. Petrovcx、S. S. Lozhkin、E. G. Galkin、V. A. Dokichev
DOI:10.1007/s10593-010-0408-2
日期:2009.10
Hydrogenation over Raney nickel of the methyl ester of 1H-pyrazoline-3-carboxylic acid and also of its 4-phenyl and 5-methoxycarbonyl-substituted analogs, leads respectively to 3-aminopyrrolidin-2-one, its 4-phenyl- and 5-methoxycarbonyl derivatives, predominantly to the trans isomer. Under the same conditions 1-amino-4-methoxycarbonylpyrrolidin-2-one was obtained from 3,4-di(methoxycarbonyl)-1H-pyrazoline