Addition of Diphenyldiazomethane to Unsubstituted and Chloro-Substituted 1,4-Benzoquinones. Effects of Chloro Substituents on the Addition Modes
作者:Takumi Oshima、Toshikazu Nagai
DOI:10.1246/bcsj.61.2507
日期:1988.7
Unsubstituted 1,4-benzoquinone (1a) reacted with diphenyldiazomethane (DDM) at the C=C double bonds to give dihydroxy-3H-indazole (2a) and its benzhydryl ether (3a) together with benzodipyrazole derivative (4a). Similarly, reactions of 2-chloro- and 2,3-dichloro-1,4-benzoquinones (1b and 1c) with DDM yielded the corresponding dihydroxy-3H-indazoles (2b, 2b′, and 2c) and their benzhydryl ethers (3b, 3b′, and 3c) along with 5–13% benzophenone (6). On the other hand, reaction of 2,6-dichloro-1,4-benzoquinone (1e) with DDM gave bicyclic 5e and tricyclic diones (7e), together with benzophenone dimethyl acetal (9) in the presence of added methanol. In the same conditions, 2,3,5-trichloro-1,4-benzoquinone (1f) provided bicyclic dione (5f) and 9. Formation of 6 and 9 was interpreted as arising from the hydrolysis and methanolysis of the 1:1 betaine intermediates given by the addition of DDM to the quinonoid C=O double bonds. The C=O addition increased with increasing chlorine substituents.
未取代的 1,4-苯醌(1a)与二苯基二氮甲烷(DDM)在 C=C 双键处发生反应,生成二羟基-3H-吲唑(2a)及其苯甲醚(3a)和苯并二吡唑衍生物(4a)。同样,2-氯和 2,3-二氯-1,4-苯醌(1b 和 1c)与二甲基二咪唑反应生成相应的二羟基-3H-吲唑(2b、2b′ 和 2c)及其苯甲醚(3b、3b′ 和 3c)以及 5-13%的二苯甲酮(6)。另一方面,在加入甲醇的情况下,2,6-二氯-1,4-苯醌(1e)与 DDM 反应生成双环 5e 和三环二酮(7e)以及二苯甲酮二甲缩醛(9)。在相同条件下,2,3,5-三氯-1,4-苯醌(1f)可生成双环二酮(5f)和 9。6 和 9 的形成可解释为 1:1 甜菜碱中间体的水解和甲醇分解产生的。随着氯取代基的增加,C=O 的添加量也在增加。