33693-57-1Relevant articles and documents
NMR Spectroscopy and Theoretical Calculations in the Conformational Analysis of 1-Methylpyrrolidin-2-one 3-Halo-derivatives
De Melo, Ulisses Zonta,Silva, Ra G. M.,Yamazaki, Diego A. S.,Pontes, Rodrigo M.,Gauze, Gisele F.,Rosa, Fernanda A.,Rittner, Roberto,Basso, Ernani A.
, p. 2111 - 2121 (2015/08/19)
This study reports the results of ab initio and density functional theory (DFT) electronic structure calculations as well as 3JHH experimental and calculated coupling constant data obtained in the investigation of the conformational equilibrium of 3-halo-derivatives of 1-methylpyrrolidin-2-one. The five-membered ring assumes an envelope conformation owing to the plane of formation of the O=C-N-R bond, with C4 forming the "envelope lid". When the conformation changes, the "lid" alternates between positions above and below the amide plane. The α-carbonyl halogen assumes two positions: a pseudo-axial and a pseudo-equatorial. In the gaseous phase, the calculations indicate that the pseudo-axial conformer is more stable and preferable going down the halogen family. Natural bond orbital analysis showed that electronic delocalization is significant only for the iodo derivative. In the other derivatives, the electrostatic repulsion between oxygen and the halogen determines the conformational equilibrium. When the solvated molecule was taken into account, the pseudo-equatorial conformer population increased with the relative permittivity of the solvent. This variation was strong in the fluoro derivative, and the preference was inverted. In the chlorine derivative, the two populations became closer in methanol and acetonitrile. In the bromine and iodine derivatives, the percentage of pseudo-equatorial conformer increased only slightly owing to the dipole moment of the conformation: the pseudo-equatorial conformation has a greater dipole moment and thus is stable in media with high relative permittivity.
Rapid and catalyst-free α-halogenation of ketones using N-halosuccinamides in DMSO
Sreedhar,Reddy, P. Surendra,Madhavi
, p. 4149 - 4156 (2008/03/13)
α-Halogenation of various carbonyl compounds such as β-keto-esters, cyclic ketones, and lactams with N-halosuccinamides (NBS, NCS, NIS) in the presence of DMSO proceeded very smoothly to give the corresponding α-monohalogenated products in good to excellent yields with high selectivity under catalyst-free conditions. Copyright Taylor & Francis Group, LLC.
HAIR PROCESSING AGENT AND METHOD FOR PERMANENT WAVING HAIR
-
Page/Page column 117, (2008/06/13)
Provided are hair processing agents capable of permanent waving hair even at a neutral to weakly acidic pH range that causes less irritation to the skin, and hair processing agents in which an unpleasant odor is masked. Hair processing agents contain at least one compound represented by the formula (2). Hair processing agents contain a compound of the formula (2) and at least one compound (ii) selected from thioglycolic acid, thiolactic acid, cysteine, acetylcysteine, cysteamine, acylcysteamine, salts thereof and ester derivatives thereof. Hair processing agents contain a compound of the formula (2), a surfactant and water, and are emulsified. Hair processing agents contain a compound of the formula (2) and a specific perfume. wherein X is a structure selected from -O-, -S-, -NH- and -NR1-; R1 is an alkyl group of 1 to 6 carbon atoms; Y is an oxygen atom or a sulfur atom; in the formula (1), Z is a divalent organic residue having at least one mercapto group; in the formula (2), R is a divalent organic residue optionally having a mercapto group; and R2 is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms.
