1682-66-2Relevant academic research and scientific papers
Sigmatropic isomerizations in azaallyl systems: XXII. 1,3-proton transfer in (N-alkyltrifluoroacetimidoyl)phosphonates
Onys'ko,Kim,Kiseleva,Pustovit,Sinitsa
, p. 1197 - 1203 (2005)
The reaction of N-alkyltrifluoroacetimidoyl chlorides with trialkyl phosphites leads to corresponding imidoylphosphonates CF 3C[P(O)(OAlk)2]=NCH2R. These compounds undergo irreversible 1,3-H shift catalyzed by nitrogenous bases to give phosphorylated imines CF3CH[P(O)(OAlk)2]N=CHR. The tendency for prototropism increases with increasing electronegativity of substituents R: CF3 > CH2OMe > H > Me. N-Cyclopentyl analogs of the obtained compounds show no tendency for prototropism. Imidoylphosphonates exist mainly as Z isomers [Z/E (6-10) : 1].
Convenient one-pot synthesis of N-substituted 3-trifluoroacetyl pyrroles
Zanatta, Nilo,Wouters, Ana D.,Fantinel, Leonardo,Da Silva, Fabio M.,Barichello, Rosemário,Da Silva, Pedro E. A.,Ramos, Daniela F.,Bonacorso, Helio G.,Martins, Marcos A. P.
experimental part, p. 755 - 758 (2009/07/18)
A new one-pot strategy for the synthesis of a series of new N-substituted 3-trifluoroacetyl pyrroles is presented. These compounds were obtained by the reaction of 3-trifluoroacetyl-4,5-dihydrofuran with primary amines, which generated 1,1,1-trifluoro-3-(2-hydroxyethyl)-4-alkylaminobut-3-en-2-one intermediates. In most cases these intermediates were not stable enough to be isolated. Thus, in the same reaction vessel they were directly submitted to oxidation with PCC (Corey's reagent) to furnish 1,1,1-trifluoro-3-(2-ethanal)-4- alkylaminobut-3-en-2-ones, which under reflux underwent intramolecular cyclization to give the desired N-substituted 3-trifluoroacetyl pyrroles, in moderate yields. All of these pyrroles were tested against pan-susceptible Mycobacterium tuberculosis H37Rv and clinical isolates INH- and RMP-resistant strain and some of these compounds showed significant in vitro antimicrobial activity. Georg Thieme Verlag Stuttgart.
Predominant 18O exchange accompanying base hydrolysis of a tertiary toluamide: N-ethyl-N-(trifluoroethyl)toluamide. Assessment of the factors that influence partitioning of anionic tetrahedral intermediates
?lebocka-Tilk,Bennet,Hogg, Heather J.,Brown
, p. 1288 - 1294 (2007/10/02)
The hydrolysis of N-ethyl-N-(trifluoroethyl)toluamide (III) in basic media at 100 °C (μ = 1.0 (KCl)) is reported. 18O exchange in III recovered from the hydrolytic medium is observed; kex/khyd = 33.4 ± 1.6 and is independent of [OH-]. The low basicity of the amine in III (PKa(H2+N(Et)CH2CF3) = 6.3) leads to 2300-3500-fold more exchange in III relative to N,N-dimethyltoluamide (I) or N-toluoylpyrrolidine (II). These findings indicate that amine leaving ability controls whether a tertiary amide will exhibit 18O exchange and that restriction of conformational mobility in the manner required by the Deslongchamps' stereoelectronic theory is of little importance in the exchange process. Solvent deuterium kinetic isotope data for III indicate that (keX)H/D = 0.90 ± 0.08 and (Ahyd)H/D = 1.05 ± 0.04. These respective solvent kinetic isotope effects (SKIE) refer essentially to isolated kinetic processes k1 (the attack of OH- to form T0-) and k2 (the breakdown of the anionic intermediate to product). The small observed SKIE on exchange and hydrolysis is analyzed in terms of the fractionation factors for species involved in the transition states leading to the anionic tetrahedral intermediate T0- and away from it, respectively. The mechanism consistent for the SKIE on khyd is suggested to involve rate-limiting breakdown of one or both of two anionic forms having a protonaled N, an anionic zwitterion Tzw- or a neutral zwitterion with an encounter complex associated OH-. On the basis of SKIE, 18O exchange, and hydrolysis data for a series of tertiary toluamides having an amine portion varying in basicity by ～ 14 pK units, a unified mechanism for base-promoted hydrolysis is presented.
Conformations and Vibrational Dynamics of Six Monoalkyltrifluoroacetamides. Low-Resolution Microwave and Gas-Phase NMR Spectroscopic Studies
True, Nancy S.,Ross, Brian D.
, p. 3216 - 3220 (2007/10/02)
Low resolution microwave spectra of six N-alkyltrifluoroacetamides (F3C(O)NHR; r = CH3, C2H5, i-C3H7, n-C3H7, i-C4H9, t-C4H9) display band series consistent with a single species having the R group oriented syn to the carbonyl moiety. 5JH-F coupling constats observed in gas- and liquid-phase NMR spectra of N-methyltrifluoroacetamide confirm this assignment.For each molecule the observed rotational constats, anomalously broad microwave bandwidths, and absence of resolvable fine structure are consistent with predicted effects of rapid intramolecular vibrational redistribution (IVR).Sufficient state density for IVR in these molecules occurs at low internal energies.
