The one-pot method for the synthesis of 4,8-dialkoxy-6-aryl-1,3-dimethylcyclohepta [c]furanium perchlorates has been developed. The method is based on the cyclocondensation of 3,4-diacetylhexane-2,5-diones with aromatic aldehydes and trialkyl orthoformates under the action of a 16% perchloric acid solution in acetic anhydride. Under similar conditions, with hydrogen sulfide, cyclohepta[c]thiophenium perchlorates have been obtained, while cyclohepta[c]pyrrolium perchlorates have been prepared with arylamines, ammonium acetate, or aliphatic amine acetates. A heteroanalog of azulene, 4,8-diethoxy-1,3-dimethyl-2-azaazulene, has been obtained for the first time. Hydrolysis of aza- and thiaazulenium salts gives the corresponding cyclohepta[c]pyrrol-4-ones and cyclohepta [c]thiophen-4-ones.

中文翻译：

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3,4-二乙酰己烷-2,5-二酮——通过环缩合反应合成取代的芴杂类似物的有效合成子

已经开发了用于合成 4,8-二烷氧基-6-芳基-1,3-二甲基环庚 [c] 呋喃高氯酸盐的一锅法。该方法基于 3,4-二乙酰己烷-2,5-二酮与芳香醛和原甲酸三烷基酯在 16% 高氯酸乙酸酐溶液作用下的环缩合反应。在类似的条件下，用硫化氢制备了环庚[c]噻吩高氯酸盐，而环庚[c]吡咯高氯酸盐用芳胺、乙酸铵或脂肪胺乙酸盐制备。首次获得了 azulene 的杂类似物 4,8-diethoxy-1,3-二甲基-2-azaazulene。氮杂-和噻唑鎓盐的水解产生相应的环庚[c]吡咯-4-酮和环庚[c]噻吩-4-酮。