The Claisen rearrangements
of 1,4-bis(prop-2'-enyloxy)anthraquinone (4) and 1,4-bis(2'-chloroprop-
2'-enyloxy)anthraquinone (3) in o-dichlorobenzene
have been examined. The former gives a low yield of
1,4-dihydroxy-2,3-bis(prop-2'-enyl)anthraquinone (22), and
1,4-dihydroxy-2-(prop-2'-eny1)- anthraquinone (5) as the major product. Also
formed is 1-hydroxy-4-propanoyl-2-(prop-2'-enyl)- anthraquinone (6) which
arises from an unprecedented rearrangement of one allyloxy group.
1,4-Bis(2?-chloroprop-2'-enyloxy)anthraquinone (3) gives mainly
2-(2'-chloroprop-2'-enyl)-4-(2'- chloroprop-2'-enyloxy)-1-hydroxyanthraquinone
(11) and a variety of minor products which are dependent on the time of
reaction. Treatment of compound (11) with ethanolic potassium hydroxide, followed
by a further Claisen rearrangement, gives a high yield of the synthetically
useful 4-(2'-chloro-prop-2'-enyl)-5-hydroxy-2-methyl-6,11-dihydroanthra[1,2-b]furan-6,11-dione (19).
克莱森重排
1,4-双(丙-2'-烯酰氧基)蒽醌(4)和 1,4-双(2'-氯丙-2'-烯酰氧基)蒽醌(3)
2'-烯酰氧基)蒽醌 (3) 在邻二氯苯中的克莱森重排进行了研究。
进行了研究。前者得到的
1,4-二羟基-2,3-双(丙-2'-烯基)蒽醌 (22),以及
1,4-二羟基-2-(丙-2'-烯基)-蒽醌(5)为主要产物。同时形成的还有
1-羟基-4-丙酰基-2-(丙-2'-烯基)-蒽醌 (6)。
它是由一个烯丙氧基发生前所未有的重排反应生成的。
1,4-双(2?
2-(2'-氯丙-2'-烯基)-4-(2'-氯丙-2'-烯氧基)-1-羟基蒽醌
(11) 和多种次要产物,这些产物取决于反应时间。
反应时间而定。用乙醇氢氧化钾处理化合物 (11)
再进行一次克莱森重排,可得到高产率的合成有用的 4-(2'-氯)-1-羟基蒽醌 (11)。
useful 4-(2'-chloro-prop-2'-enyl)-5-hydroxy-2-methyl-6,11-dihydroanthra[1,2-b]furan-6,11-dione (19).