Synthesis of aminoalkylpyrazoles and-isoxazoles from cyclic β-(trifluoroacetyl) enamines
作者:V. G. Nenajdenko、S. V. Pronin、E. S. Balenkova
DOI:10.1007/s11172-007-0055-7
日期:2007.2
A method for the synthesis of cyclic β-(trifluoroacetyl) enamines was proposed. Reactions of the latter with hydrazine and hydroxylamine gave pyrazoles and isoxazoles, respectively, containing trifluoromethyl and ω-aminoalkyl fragments. Addition of hydrazine (hydroxylamine) to the above amino enones was regiospecific, the regiochemistry of the heterocyclization of trifluoromethyl ketones being different
A convenient and simple approach for the preparation of α-CF3 and α-C2F5 substituted pyrrolines, tetrahydropyridines, tetrahydroazepine is described. Claisen condensation of N-protected cyclic amides with esters of perfluorocarboxylic acids followed by deprotection and decarboxylation in acidic media leads to the desired products. Reduction of these imines permits to obtain 5-, 6-, and 7-membered cyclic
Highly β-Regioselective Friedel-Crafts Aminoalkylation of Pyrroles with Cyclic Perfluoroalkylated Imines
作者:Olga I. Shmatova、Nikolay E. Shevchenko、Elisabeth S. Balenkova、Gerd-Volker Röschenthaler、Valentine G. Nenajdenko
DOI:10.1002/ejoc.201201725
日期:2013.5
A Friedel–Crafts-type alkylation reaction was studied between various pyrroles and α-polyfluoroalkylated cyclicimines that were activated by Lewis acids. The reaction proceeded under mild conditions and provided a high yielding synthesis of α-CF3-substituted pyrrolidines and piperidines as well as seven-membered analogues that contained a pyrrole ring. The unpredictably high β-selectivity for the
Synthesis and the keto-enol equilibrium of 2-acyl lactams
作者:V. G. Nenajdenko、A. M. Gololobov、E. P. Zakurdaev、E. S. Balenkova
DOI:10.1023/b:rucb.0000012373.06094.ff
日期:2003.11
Condensation of N-substituted lactams with carboxylic acid esters was studied. A wide range of substituted 2-acyl lactams with different ring sizes were synthesized. The structure of 2-acyl lactams (primarily, the ring size) was found to influence the keto-enol tautomerism.
New method of preparation of C2F5Li and its reactions with cyclic imines and lactims: Synthesis of α-pentafluoroethyl proline
作者:Nikolay E. Shevchenko、Valentine G. Nenajdenko、Gerd-Volker Röschenthaler
DOI:10.1016/j.jfluchem.2008.01.013
日期:2008.5
Addition of pentafluoroethyllithium to cyclic imines leads to pentafluoroethyl substituted pyrrolidines, piperidines and azepanes while reaction of cyclic lactims gives rise to 2-pentafluoroethyl imines. Oxidative cleavage of 2-furyl-2-pentafluoroethyl pyrrolidine has been found to be an effective method for the preparation of a racemic α-pentafluoroethyl proline.