| Summary: | Bibliography: pages 154-161. === The effect of protonation and Lewis acid-base interaction on the ¹H n.m.r. chemical shifts of the ester and amide bonds in selected phosphoramidates (RO)₂P(O)NR'₂ was investigated. The results are interpreted in terms of the interaction of the phosphoryl oxygen atom with Lewis acids and oxygen/nitrogen diprotonation in trifluoromethanesulphonic acid. Intramolecular nucleophilic displacement of the halide ion from secondary β-chloroethyl-substituted phosphoramidates X₂P(O)NHCH₂CH₂Cl, diamidates (RO) (MeNH)P(O)NHCH₂CH₂Cl and β-chloroethyl phosphates Y(MeO)P(O)OCH₂CH₂Cl, was studied under conditions of electrophilic (Ag+) and basic (NaH) catalysis. 1,3-Substitution by the nitrogen atom of the phosphdramidates, yielding ethylenimine derivatives was found to be the preferred reaction-pathway; the alternative 1,5-reaction involving the amide nittogen or phosphoryl oxygen atoms was not observed. No intramolecular nucleophilic displacement occurred in the β-chloroethyl phosphate esters.
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