| 摘要 |
PURPOSE:To readily obtain the titled compound by a method suitable for mass- production, by reacting a 3-alkoxycarbonyl-2H-cyclohepta[b]furan-2-one with a secondary amine while heating and heating the resultant product in a mineral acid. CONSTITUTION:A 3-alkoxycarbonyl-2H-cyclohepta[b]furan-2-one expressed by formula I (R1 is H or lower alkyl; R2 is lower alkyl) is reacted with acetone and a secondary amine, particularly diethylamine, while heating and refluxing to give a 2-methylazulene-3-carboxylate expressed by formula II, which is then heated in a mineral acid, e.g. hydrochloric acid, sulfuric acid, phosphoric acid, etc., particularly phosphoric acid while heating at about 90-95 deg.C temperature to carry out dealkoxycarbonylation and industrially and advantageously afford the aimed compound, expressed by formula III and useful as a compound, containing azulene ring and extensively used for medicines, cosmetics, etc., in a simple process by a well-known method.
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