title: Disulfide exchange in hydrogen-bonded cyclic assemblies: stereochemical self-selection by double dynamic chemistry.
abstract: Stereoselective cyclization of cystine-based bifunctional 2-ureido-4[1H]-pyrimidinone derivatives in CDCl(3) solutions was demonstrated by (1)H NMR spectroscopy. Thiolate-catalyzed disulfide exchange in solution led to the equilibration of different diastereomers of 1. At low concentrations, where formation of cyclic assemblies is the dominant mode of association, the molecules act as their own template. At these concentrations the meso diastereomer is formed preferentially, indicating a higher stability of its cyclic assemblies under the applied conditions, in comparison to the other diastereomers.
authors: Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands.
authors: A Tessa
authors: AT
authors: ten Cate
authors: Patricia Y W
authors: PY
authors: Dankers
authors: Rint P
authors: RP
authors: Sijbesma
authors: E W
authors: EW
authors: Meijer
mesh_terms: D002384:Catalysis; D003500:Cyclization; D003553:Cystine / Q000737:chemistry; D003903:Deuterium / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D011744:Pyrimidinones / Q000737:chemistry; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013997:Time Factors
chemical_list: C109276:2-ureido-4-pyrimidone; D004220:Disulfides; D011744:Pyrimidinones; D013438:Sulfhydryl Compounds; D003553:Cystine; D006859:Hydrogen; D003903:Deuterium