Rearrangement of P‐N to P‐O bonds in mass spectra of N‐diisopropyloxyphosphoryl amino acids/alcohols

The cationized N-diisopropyloxyphosphoryl amino acids/alcohols were analyzed by electrospray ionization tandem mass spectrometry. A rearrangement reaction leading to the P-N to P-O bond migration was observed, and cationized phosphoric acid isopropyl ester (PAIE) was formed. The rearrangement did not depend on the chain length of the amino acids/alcohols. A possible rearrangement mechanism was proposed. It was shown that the phosphoryl group has a strong affinity to the hydroxyl group in the gas phase. Copyright © 2001 John Wiley & Sons, Ltd.