title: One-pot synthesis of γ -spiroiminolactones and γ -dispiroiminolactones usingN,N'-disubstituted parabanic acid and thioparabanic acid derivatives.
abstract: A direct entry and simple process for the synthesis of [Formula: see text]-spiroiminolactones present in a large number of natural products has been developed. In the first step, the synthesis of parabanic acid derivatives was commenced from the reaction of [Formula: see text]-disubstituted urea and thiourea with oxalyl chloride, then a three-component reaction was carried out with isocyanides, acetylenic esters, and [Formula: see text]-disubstituted parabanic acid derivatives. The method allows the construction of a variety of [Formula: see text]-spiroiminolactone structures in good to high yields starting from readily available precursors. It was found that in the case of [Formula: see text]-diphenyl thioparabanic acid, additional products of [Formula: see text]-dispiroiminolactones have been formed due to the higher electrophilicity of [Formula: see text]-dicarbonyl groups. The structures were fully established using spectroscopic analysis NMR, IR, and Mass spectrometry. The crystal structure of [Formula: see text]-dispiroiminolactone was confirmed from single-crystal X-ray diffraction study.
authors.affiliation: Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, 47416-95447, Iran. s.asghari@umz.ac.ir.|Nano and Biotechnology Research Group, University of Mazandaran, Babolsar, Iran. s.asghari@umz.ac.ir.
authors.forename: Sakineh
authors.initials: S
authors.lastname: Asghari
authors.affiliation: Department of biology, Garmsar Branch, Islamic Azad University, Garmsar, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Qandalee
authors.affiliation: Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, 47416-95447, Iran.
authors.forename: Amir Ali
authors.initials: AA
authors.lastname: Sarmadi
mesh_terms: D060326:Chemistry Techniques, Synthetic; D006827:Hydantoins / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006827:Hydantoins; D007783:Lactones; D013141:Spiro Compounds; C005411:parabanic acid
keywords: -Dispiroiminolactones; -spiroiminolactones; Dialkyl acetylenedicarboxylates; Isocyanide; Parabanic acid derivatives; Zwitterionic intermediate