69130-89-8Relevant academic research and scientific papers
N-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP) - An efficient, mild, stable oxidant for cleavage of carbon-nitrogen double bonds of oximes
Balasubramanian,Ramalingan,Kabilan
, p. 2979 - 2984 (2003)
Aldoximes and ketoximes are effectively deoximated to regenerate the carbonyl compound by an efficient, mild, stable oxidant N-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP).
Chlorination of 2-phenoxypropanoic acid with NCP in aqueous acetic acid: Using a novel ortho-para relationship and the para/meta ratio of substituent effects for mechanism elucidation
Segurado, Manuel A. P.,Reis, Joao Carlos R.,De Oliveira, Jaime D. Gomes,Kabilan, Senthamaraikannan,Shanthi, Manohar
, p. 5327 - 5336 (2008/02/07)
(Graph Presented) Rate constants were measured for the oxidative chlorodehydrogenation of (R,S)-2-phenoxypropanoic acid and nine ortho-, ten para- and five meta-substituted derivatives using (R,S)-1-chloro-3-methyl-2,6- diphenylpiperidin-4-one (NCP) as chlorinating agent. The kinetics was run in 50% (v/v) aqueous acetic acid acidified with perchloric acid under pseudo-first-order conditions with respect to NCP at temperature intervals of 5 K between 298 and 318 K, except at the highest temperature for the meta derivatives. The dependence of rate constants on temperature was analyzed in terms of the isokinetic relationship (IKR). For the 20 reactions studied at five different temperatures, tne isokinetic temperature was estimated to be 382 K, which suggests the preferential involvement of water molecules in the rate-determining step. The dependence of rate constants on meta and para substitution was analyzed using the tetralinear extension of the Hammett equation. The parameter λ for the para/meta ratio of polar substituent effects was estimated to be 0.926, and its electrostatic modeling suggests the formation of an activated complex bearing an electric charge near the oxygen atom belonging to the phenoxy group. A new approach is introduced for examining the effect of ortho substituents on reaction rates. Using IKR-determined values of activation enthalpies for a set of nine pairs of substrates with a given substituent, a linear correlation is found between activation enthalpies of ortho and para derivatives. The correlation is interpreted in terms of the selectivity of the reactant toward para- or ortho-monosubstituted substrates, the slope of which being related to the ortho effect. This slope is thought to be approximated by the ratio of polar substituent effects from ortho and para positions in benzene derivatives. Using the electrostatic theory of through-space interactions and a dipole length of 0.153 nm, this ratio was calculated at various positions of a charged reaction center along the benzene C1-C4 axis, being about 2.5 near the ring and decreasing steeply with increasing distance until reaching a minimum value of -0.565 at 1.3 nm beyond the aromatic ring. Activation enthalpies and entropies were estimated for substrates bearing the isoselective substituent in either ortho and para positions, being demonstrated that they are much different from the values for the parent substrate. The electrophilic attack on the phenolic oxygen atom by the protonated chlorinating agent is proposed as the rate-determining step, this step being followed by the fast rearrangement of the intermediate thus formed, leading to products containing chlorine in the aromatic ring.
13C NMR Chemical Shifts, in some N-chloro-2,6-diarylpiperidin-4-ones
Hasan, Misbah Ul,Arab, M.
, p. 987 - 989 (2007/10/02)
The 13C shifts in several N-chloro-2,6-diarylpiperidin-4-ones have been measured and compared with previously reported sifts in the corresponding 2,6-diarylpiperidones.The sifts of the α-carbons in these compounds move dowfield by 12-13 ppm, which can be attributed to the increased electronegativity of the nitrogen atoms.The changes in the chemical shifts of the β-carbons are minimal.Surprisingly, the absorptions of the carbonyl carbons move upfield by as much as 4.0 ppm.The magnitude of the shift in the resonance of the carbonyl carbon indicates the possibility of a transannular interaction between the nitrogen and the carbonyl group, which has not previously been observed in these systems.A preferred conformation for the aryl group in these compounds is also proposed.Key words 13C NMR N-chloro-2,6-diarylpiperidin-4-ones
Conformational Analysis of Some N-Chloro-2,6-diphenyl-piperidin-4-ones by Kinetic and Equilibrium Methods
Ganapathy, K.,Vijayan, B.
, p. 614 - 616 (2007/10/02)
Confromational analysis of some substituted N-chloro-2,6-diphenylpiperidin-4-ones (I-IX) has been carried out by kinetic and equilibrium methods.The buttressing effect of alkyl substituents on vicinal phenyl groups has been observed during the kinetic and
Synthesis and PMR Spectral Analysis of Some N-Chloropiperidin-4-ones and N-chloroazabicyclononan-9-ones
Ganapathy, K.,Vijayan, B.
, p. 572 - 574 (2007/10/02)
Various substituted N-chloropiperidin-4-ones and N-chloroazabicyclononan-9-ones have been prepared and they are found to be good oxidising agents.PMR spectra of the substituted N-chloropiperidin-4-ones reveal that they exist in chair conformation.T
