| Abstract: | The 1-aza-2-azoniaallene salt 8 prepared from 3-acetyl coumarin via the hydrazone 6 and the (chloroalkyl)azo derivative 7 reacts with nitriles to afford the 3-(3-chromenyl)-1,2,4-triazolium salts 11a–d . With diisopropylcarbodiimide the triazolium salt 13 and with norborene a tricyclic pyrazolium salt 14 are obtained. Concurrent to these cycloadditions the by-product 12 is formed by intramolecular cyclization of the cumulene 8 . Similarly, the intramolecular cyclization product 18 is isolated as the sole product when the 1-aza-2-azoniaallene salt 17a (prepared from the ethyl carbazone of camphor by chlorination and treatment of the product 16a with SbCl5) was treated with nitriles, carbodiimides or alkenes. In contrast, 1,2,4-triazolium salts 20a–c , 23c , respectively pyrazolium salts 20d–f , and 1,3,4-thiadiazolium salts 23a,b are obtained by reaction of the 1-aza-2-azoniaallene salt 17b with nitriles, respectively alkenes, alkynes, diisopropylcarbodiimide, and isothiocyanates. The constitutions of two of these products ( 20e, 23a ) were secured by X-ray structural analysis. |
