The solution conformations of lidocaine analogues.
IR and 1H NMR studies in CDCl3 and CCl4 of a series of tertiary aminoxylidides with the amino group in the 2 to 6 position of the acyl chain are described. Lidocaine, diethylaminoaceto-2',6'-xylidide, forms an intramolecular five-membered ring hydrogen-bonded monomer at all concentrations in both solvents. beta-Diethyl-amino-propiono-2',6'-xylidide forms an intramolecular six-membered ring hydrogen-bonded monomer in CDCl3 and CCl4 but a trans intermolecularly associated species is the major form present at high concentrations in CCl4. The longer-chain homologues are mixtures of nonassociated trans and cis monomers at low concentrations but associated trans forms predominate at high concentrations. Evidence for the presence of a hydrogen-bonded seven-membered ring intramolecular monomer in CDCl3 for gamma-diethylaminobutyro-2',6'-xylidide is presented. The relationship between the molecular conformation and the partition coefficient is discussed.
Chemistry Department, College of the Holy Cross, Worcester, Massachusetts 01610.
P D
PD
McMaster
V J
VJ
Noris
C E
CE
Stankard
E W
EW
Byrnes
P R
PR
Guzzo
D002251:Carbon Tetrachloride; D002725:Chloroform; D008012:Lidocaine / Q000031:analogs & derivatives / Q000737:chemistry*; D008968:Molecular Conformation; D012996:Solutions
D012996:Solutions; D002725:Chloroform; D008012:Lidocaine; D002251:Carbon Tetrachloride