NMR spectroscopic study of some novel N,N-disubstituted phosphonoacetamides

LILIANA R. ORELLI; NADIA GRUBER

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 921 p. 215 - 218

0022-2860

The complete 1H and 13C NMR assignments of a series of tertiary phosphonoacetamides (1) with different N-substitution patterns are reported. N,N-dialkyl derivatives show two sets of signals due to hindered rotation of the (O)C-N bond, which originate E/Z diastereoisomers for unsymmetrically N,N-disubstituted derivatives. Complete assignment of the 1H NMR resonances of both rotamers was made on the basis of the magnitude of the diamagnetic shifts and confirmed in the corresponding NOESY spectra. Differential assignment of the 13C NMR signals was performed by HSQC experiments. N-alkyl-N-phenyl phosphonoacetamides show a unique set of signals corresponding to the E isomers as disclosed by NOESY experiments.