title: Role of the solvent on the stability of cycloserine under ESI-MS conditions.
abstract: The effects of methanol (M) and acetonitrile (A) on the stability of cycloserine (1) have been studied. InfraRed Multiphoton PhotoDissociation (IRMPD) spectroscopy of the ionic species from electrospray ionization tandem mass spectrometry (ESI-MS) of 1/M and 1/A solutions points to extensive dimerization of 1 to cis-3,6-bis(aminooxymethyl)-2,5-piperidinedione (2), while the same process is not observed in the ESI-MS of 1/M solutions. 1D and 2D nuclear magnetic resonance experiments confirmed these findings by showing that partial dimerization of 1 actually takes place at room temperature in acetonitrile even before ESI-MS analysis. Comparison of nuclear magnetic resonance and IRMPD spectroscopic data from the same 1/A solution suggests that dimerization of cycloserine is enhanced in the ESI source.
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università 'La Sapienza', P.le A. Moro 5, 00185, Roma, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Fraschetti
authors.forename: Antonello
authors.initials: A
authors.lastname: Filippi
authors.forename: Luisa
authors.initials: L
authors.lastname: Mannina
authors.forename: Anatoly P
authors.initials: AP
authors.lastname: Sobolev
authors.forename: Maurizio
authors.initials: M
authors.lastname: Speranza
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D003523:Cycloserine / Q000032:analysis / Q000737:chemistry*; D019281:Dimerization; D004355:Drug Stability; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000097:Acetonitriles; D012997:Solvents; D003523:Cycloserine; D000432:Methanol; C032159:acetonitrile
keywords: IRMPD spectroscopy; NMR spectroscopy; cycloserine; dimerization; solvent effects