Various 3,3′-methylenebis azulenes were prepared in high yields upon treatment of 1-substituted azulenes with a solution of 0.1–0.2 wt% paraformaldehyde in glacial acetic acid at 25°C for 1 h. Thus, 1-methyl-, 1-isopropyl-, 1,5-diisopropylazulene, guaiazulene, and methyl 2-hydroxy-1-azulenecarboxylate readily provided the corresponding 3,3′-methylenebisazulenes, respectively. Acetic acid which had been refluxed with 5 wt% KMnO4 for 2 h and then distilled according to a purification method was found to contain 0.1–0.2 wt% formaldehyde and exert the same 3,3′-methylenebisazulene formation. 3,3′-Dideuteriomethyl-enebis(guaiazulene) was obtained by employing the similar distillate from acetic acid-d4.
在25°C下,用0.1-0.2 wt%的
冰醋酸中的多
聚甲醛溶液处理1-取代的
苊烯1小时,可以制备出各种3,3′-亚甲基双
苊烯,且产量高。因此,1-甲基、1-异丙基、1,5-
二异丙基苊烯、
愈创木苊烯和2-羟基-1-
苊烯甲酸甲酯很容易分别提供相应的3,3′-亚甲基双
苊烯。
醋酸与5 wt%的KMnO4回流2小时,然后根据纯化方法进行蒸馏,发现其中含有0.1-0.2 wt%的
甲醛,并产生相同的3,3′-亚甲基双
苊烯。通过采用
乙酸-d4的类似馏分,可以得到3,3′-二
氘代甲基-双(
愈创木苊烯)。