The reaction rates in the Dimroth rearrangements of the marine sponge base 1, 9-dimethyl-8-oxoadenin (1) and related compounds such as 1, 9-dimethyladenine (6a) and 8-bromo-1, 9-dimethyladenine (6b) were measured in H2O at various pH's and ionic strength 1.0 at 40°C. In all cases, attack of hydroxide ion on the protonated species of the substrate at the 2-position was faster than that on the neutral species by a factor of 100-1400. In the reaction of the protonated species, the relative ease of undergoing Dimroth rearrangement was in the order of 6b>6a>1. The same order of reactivity was found to hold for the neutral species.
在40°C、pH值不同、离子强度为1.0的
H2O中,测量了海洋海绵基质1, 9-二甲基-8-氧代
腺嘌呤(1)和1, 9-二甲基
腺嘌呤(6a)以及8-
溴-1, 9-二甲基
腺嘌呤(6b)等相关化合物的迪姆罗斯重排反应速率。在所有情况下,氢氧根离子对2位基质质子化物种的侵袭速度比中性物种快100-1400倍。在质子化物种的反应中,发生迪姆罗斯重排的相对难易程度依次为6b>6a>1。中性物种的反应顺序也与此相同。