Stereochemical and electronic interaction studies of some N-methoxy-N-methyl-2-[(4′-substituted)phenylsulfinyl]propanamides

Synthesis, X-ray crystal structure and theoretical calculations of antileishmanial neolignan analogues

“…In addition, the conformational analysis were carried out to confirm the minimum energy structure to molecules 12 and 20, by carrying out a series of partial optimizations constraining the concerned dihedral angle step by step within the appropriate range, with a step size of 5°, these calculations were carried out using the B3LYP/6-31G* basis set, the dihedral angles analyzed were C1-C7-C8-O and C4'-O-C8-C7 for molecule 12 and C1-C7-C8-S and C4'-S-C8-C7 for molecule 20. Previous studies about conformational preferences in solid state (crystal) and in solution has been published [55][56][57] for a large number of compounds analogues of the compounds 12 and 20, studied in the present paper. The geometrical structures of the radicals studied were optimized independently from the neutral molecules prior to the calculations of energies, treated as open shell systems DFT/UB3LYP.…”

Complete assignment of 1H and 13C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

“…This reaction allowed us to synthesize some acyl derivative of β-lactams in good yields, which were not possible through traditional methods employing other carboxylic acid derivatives. [6,7] Therefore, in order to extend the conformational studies to α-sulfinyl-amides, infrared, theoretical and X-ray diffraction studies of the N-methoxy-N-methyl-2-[(4 -substituted)phenylsulfinyl]-propanamide [8] (Weinreb sulfinyl-amides) were undertaken recently.…”

“…[8] This proportion was estimated from the methine (H-5) and methyl (H-3) hydrogen signals in the 1 H NMR spectrum of 5 in CDCl 3 . The estimated averaged diastereomeric ratio of diast 1 relative to diast 2 , for the whole series, is of ca 7 : 3.…”

“…The relative configurations of both diastereomers (diast 1 and diast 2 ) were obtained from single crystal X-ray diffraction analysis as previously described. [8,12] Elemental analyses were carried out on a Perkin-Elmer 2400 CHN standard analyzer (Table 1). …”

Stereochemical and electronic interaction studies of 4′-substituted 2-(phenylselanyl)-2-(ethylsulfinyl)-acetophenones

“…Previous conformational analysis performed on some β-carbonyl-sulfoxides XC(O)CH2S(O)R using (IR, 13 C NMR, UV and UPS) spectroscopic techniques, X-ray diffraction (XRD) and theoretical calculations have shown that the gauche conformer is the most stable for α-sulfinyl-ketones [1][2][3], α-sulfinyl-thioesters [4] and sulfinyl-esters [5], while the cis conformer is predominant for the α-sulfinylacetophenones and α-sulfinylamides [6][7][8][9][10]. The stabilisation of the gauche conformers for these compounds has been ascribed to the π*CO/σC-S and, to a minor extent, the πCO/σ*C-S orbital interactions, while the larger stabilisation of the cis conformers has been attributed to the πPh/π*CO and nN/π*CO conjugations, which originate the strong electrostatic [S δ+ =O δ-…”