Novel steroidal phosphoramidate conjugates of 3＇-azido-2＇,3＇-dideoxythymidine （AZT） and amino acid esters were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry. Th...Novel steroidal phosphoramidate conjugates of 3＇-azido-2＇,3＇-dideoxythymidine （AZT） and amino acid esters were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry. The MS fragmentation behaviors of the steroidal phosphoramidate conjugates have been investigated in conjunction with tandem mass spectrometry of ESI-MS/MS. There were three characteristic fragment ions in the positive ion ESI mass spectra, which were the Na adduct ions with loss of steroidal moiety, amino acid ester moiety from pseudo molecular ion （M＋Na）^＋, and the phosphoamino acid methyl ester Na adduct ion by α-cleavage of the phosphora- midate respectively. The main fragment ions in negative ion ESI mass spectra were the ion （M-HN3）^-, the ion （M - AZT- H）^-, and the ion （M-steroidal moiety-H）^- besides the pseudo molecular ion （M-H）^-. The fragmentation patterns did not depend on the attached amino acid ester moiety.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20542004）, the Specialized Research Fund for the Doctoral Program of Higher Education （No. 20050003104）, and the Beijing Commission of Education （No. XK 100030514）.
文摘Novel steroidal phosphoramidate conjugates of 3＇-azido-2＇,3＇-dideoxythymidine （AZT） and amino acid esters were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry. The MS fragmentation behaviors of the steroidal phosphoramidate conjugates have been investigated in conjunction with tandem mass spectrometry of ESI-MS/MS. There were three characteristic fragment ions in the positive ion ESI mass spectra, which were the Na adduct ions with loss of steroidal moiety, amino acid ester moiety from pseudo molecular ion （M＋Na）^＋, and the phosphoamino acid methyl ester Na adduct ion by α-cleavage of the phosphora- midate respectively. The main fragment ions in negative ion ESI mass spectra were the ion （M-HN3）^-, the ion （M - AZT- H）^-, and the ion （M-steroidal moiety-H）^- besides the pseudo molecular ion （M-H）^-. The fragmentation patterns did not depend on the attached amino acid ester moiety.
