title: Domino reactions of amidines with methyl 2-chloro-2-cyclopropylideneacetate as an efficient access to cyclobutene-annelated pyrimidinones.
abstract: [reaction: see text] An efficient one-step synthesis of 2,4-diazabicyclo[4.2.0]octa-1(6),2-dien-5-ones 3 from methyl 2-chloro-2-cyclopropylideneacetate (1) and amidines 2a-c as well as N,N-dimethylguanidine (2d) is described. Similar to the benzocyclobutenes, the cyclobutene-annelated pyrimidones 3 undergo thermal ring opening and the resulting o-quinodimethane analogues readily cycloadd dienophiles to yield tetrahydroquinazolone derivatives.
authors.affiliation: Institut für Organische Chemie der Georg-August Universität Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany.
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Nötzel
authors.forename: Karsten
authors.initials: K
authors.lastname: Rauch
authors.forename: Thomas
authors.initials: T
authors.lastname: Labahn
authors.forename: Armin
authors.initials: A
authors.lastname: de Meijere
mesh_terms: D000475:Alkenes / Q000737:chemistry; D000578:Amidines / Q000737:chemistry; D003503:Cyclobutanes / Q000737:chemistry; D003521:Cyclopropanes / Q000737:chemistry; D011744:Pyrimidinones / Q000138:chemical synthesis*
chemical_list: D000475:Alkenes; D000578:Amidines; D003503:Cyclobutanes; D003521:Cyclopropanes; D011744:Pyrimidinones; C030797:cyclopropane