title: Chemical Conversion of Ryanodol to Ryanodine.
abstract: Ryanodine (1) is a plant-derived natural product with powerful pharmacological and insecticidal action, and is a potent modulator of intracellular calcium release channels. Compound 1 possesses a 1H-pyrrole-2-carboxylate ester at the C3-position of heptahydroxylated terpenoid ryanodol (2). Whereas 2 was readily obtained from 1 by basic hydrolysis, 1 has never been synthesized from 2, due to the extreme difficulty in selectively introducing the bulky pyrrole moiety at the severely hindered C3-hydroxyl group of heptaol 2. Here we report chemical conversion of 2 to 1 for the first time. The derivatization was realized through the use of a new protective group strategy and the application of on-site construction of the pyrrole-2-carboxylate ester from the glycine ester and 1,3-bis(dimethylamino)allylium tetrafluoroborate.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo.
authors.forename: Kengo
authors.initials: K
authors.lastname: Masuda
authors.forename: Masanori
authors.initials: M
authors.lastname: Nagatomo
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inoue
mesh_terms: D015394:Molecular Structure; D012433:Ryanodine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C000608459:ryanodol; D012433:Ryanodine