Effect of nitro groups and alkyl chain length on the negative ion tandem mass spectra of alkyl 3-hydroxy-5-(4'-nitrophenoxy) and alkyl 3-hydroxy-5-(2', 4'-dinitrophenoxy) benzoates

H Kangas; Franz n R; J Tois; J Taskinen; R Kostiainen

doi:10.1002/(SICI)1097-0231(19990830)13:16<1680::AID-RCM698>3.0.CO;2-R

Effect of nitro groups and alkyl chain length on the negative ion tandem mass spectra of alkyl 3-hydroxy-5-(4'-nitrophenoxy) and alkyl 3-hydroxy-5-(2', 4'-dinitrophenoxy) benzoates

Rapid Commun Mass Spectrom. 1999 Aug;13(16):1680-4. doi: 10.1002/(SICI)1097-0231(19990830)13:16<1680::AID-RCM698>3.0.CO;2-R.

Authors

H Kangas¹, Franz n R, J Tois, J Taskinen, R Kostiainen

Affiliation

¹ Department of Pharmacy, Division of Pharmaceutical Chemistry, P.O. Box 56, FIN-00014 University of Helsinki, Finland.

Abstract

Tandem mass spectrometric behaviour was studied for a small combinatorial library of alkyl 3-hydroxy-5-(4'-nitrophenoxy) benzoates (A1-A5) and alkyl 3-hydroxy-5-(2', 4'-dinitrophenoxy) benzoates (B1-B5). The spectra were recorded by negative ion electrospray low-energy collision induced dissociation (CID) tandem mass spectrometry. The product ion spectra of [M - H](-) of the benzoates A1-A5 are similar, as are those of benzoates B1-B5. However, the spectra of the B series compounds differ significantly from those of the A series owing to the second electron-withdrawing nitro substituent in the B compounds. In addition, the length of the alkyl chain has an effect on the fragmentation. However, both series of compounds exhibit an abundant nitrophenoxy ion formed by the loss of 3-hydroxybenzoate. This is at m/z 138 in A1-A5 and at m/z 183 in B1-B5. A precursor ion scan of the nitrophenoxy ion provides a rapid method to identify the synthesised compounds in this type of combinatorial mixture. Copyright 1999 John Wiley & Sons, Ltd.