Anisotropic and hydrogen bonding effects in phenylglyoxamides and mandelamides: theoretical and NMR conformational evaluation.
Interesting anisotropic effects were observed for phenylglyoxamides and their respective mandelamides. Such effects were observed in experimental (1)H and (13)C NMR (in CDCl(3), CD(3)OD, and DMSO-d(6) solvents) and in some cases with good correlation to theoretical (1)H and (13)C NMR DFT-GIAO (B3LYP/6-311++G**//B3LYP/6-31G*) calculations. A systematic conformational analysis of these compounds was performed in a two-step methodology, using PM3 and DFT (B3LYP/6-31G*) calculations; with good accomplishment and computational time economy. It was observed that intramolecular hydrogen bonding plays a significant role in the conformation of such compounds. Finally, a geminal nonequivalence of an N-CH(2) moiety, in one of the alkyl side chain (R1 = R2), was found for the tertiary mandelamides studied.
Gonçalves
Biank T
BT
Departamento de Química Orgânica, Instituto de Química, Bloco A, 6 a Andar do CT, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, RJ, Brazil, 21949900.
Esteves
Pierre M
PM
Pinto
Angelo C
AC
Kaiser
Carlos R
CR
da Silva
Fernanda L
FL
Miguez
Eduardo
E
da Silva
Joaquim F M
JF
D016880:Anisotropy; D003198:Computer Simulation; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008333:Mandelic Acids / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D013453:Sulfonylurea Compounds / Q000737:chemistry*
D008333:Mandelic Acids; D013453:Sulfonylurea Compounds; C032160:glyoxamide; C010413:mandelamide; D006859:Hydrogen