title: New degradation product of spiradoline mesylate in aqueous solution: formation of an imidazolidine ring.
abstract: A new degradation product of spiradoline mesylate was recognized in aqueous solution stored at 80 degrees C for 10 days. The structure of the degradation product was elucidated with spectroscopic data and a synthetic method as (1RS,3RS,8RS,10RS)-2-methyl-2,7-diazatricyclo - [6.4.0.0(3,7)]dodecane-10-spiro-2'-tetrahydrofurane by several two-dimensional NMR spectra. The fused imidazolidine ring system was synthesized from (5RS,7RS,8RS)-N-methyl-8-(7-pyrrolidino-1-oxa spiro-[4.5] decane)amine reacted with mercuric acetate. Because the degradation was promoted by bubbling air or oxygen gas into the solution or by adding alpha,alpha'-azobisisobutylonitrile for radical initiation, and the reaction was suppressed by bubbling nitrogen gas or deaerating, the reaction mechanism of the degradation was considered to be oxidation caused by an oxygen radical.
authors.affiliation: Tsukuba Research Laboratories, Upjohn Pharmaceuticals Limited, Ibaraki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ogata
authors.forename: R
authors.initials: R
authors.lastname: Shimizu
authors.forename: H
authors.initials: H
authors.lastname: Abe
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005609:Free Radicals; D007093:Imidazoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry*; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005609:Free Radicals; D007093:Imidazoles; D011759:Pyrrolidines; D012996:Solutions; C051272:spiradoline; D010100:Oxygen