摘要 |
Sterically hindered phosphoramidates such as N,N'-bis[di-(2,6-xylyl)phosphoryl]piperazine are prepared by the reaction of a sterically hindered diaryl chlorophosphate, such as di-(2,6-xylyl) chlorophosphate, with a basic nitrogen compound containing at least two basic N-H groups, preferably a heterocyclic compound such as piperazine, in the presence of an acid acceptor such as triethylamine. The reaction is conducted in methylene chloride or an aromatic hydrocarbon such as toluene as solvent. If an aromatic hydrocarbon is employed, there is also present at least one dipolar aprotic nitrogen compound, such as 4-dimethylaminopyridine, in an amount effective to increase the reaction rate.
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