Derivatives of 6-unsubstituted 2H-pyran-2-one have been synthesized by several different methods. The 4-chloro-2H-pyran-2-one (9) is the most important, since it serves as starting material for the synthesis of different 4-substituted 2H-pyran-2-ones (Scheme 2). Also described are simple transformations of cumalic-acid derivatives producing 5-(2,2-dichlorovinyl)-2H-pyran-2-one (23), 2-0~0-2H-pyran-2-carbonitrile (26), and 4,5-bis(tritluoromethyl)-2H-pyran-2-one (32) (Scheme 3 and 4 ) .
A New Azepine-Ring SynthesisA new one-step synthesis of an azepine ring is described. The 2H-pyran-2-one ring of methyl cumalate (8) or cumalaldehyde (2) upon reaction with an I-aminoacryl derivative, e.g. 1 or 6, is opened with subsequent decarboxylation to give a 1-aminobutadiene derivative that undergoes an electrocyclic ring closure to the azepine ring (Schemes 1 and 2).1. Einleitung. -Die Azepine, obwohl lange bekannt [l], haben erst in den 60er Jahren einen grossen Aufschwung verzeichnet, nachdem entdeckt wurde, dass unter ihnen wertvolle Pharmazeutika, vor allem Tranquilizer, Antidepressiva und andere psychotrope Pharmaka aus der Benzodiazepin bzw. Dibenzazepin-Klasse, zu finden sind.Entsprechend der wachsenden Bedeutung dieser Substanzklasse ist die Zahl der Methoden zur Azepin-Synthese in einem solchen Ausmass angewachsen, dass hier nur auf einige neuere Monographien verwiesen wird [2]. Im vorliegenden Beitrag wird eine neue Azepin-Synthese prasentiert, die in einer Eintopf-Reaktion einen 2H-Pyran-2-onRing in einen Azepin-Ring umwandelt.
The regioselectivity of nucleophilic substitution of the nitro groups in 3,5-dinitrophthalic anhydrides and 3,5-dinitrophthalimides (Scheme) with a variety of nucleophiles (Nu-) was studied. In all cases, the 3-nitro group was selectively substituted. With excess of the same nucleophilic reagent or with other nucleophiles, the 5-nitro group could subsequently be replaced.
The synthesis of the title compound 1 may provide a way of obtaining new calcium antagonists. Compound 1, RNO2 combines, for the first time, all the structural features that have proven to be especially advantageous.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.