Nitrosation of dialkylhydroxylamines, and computational and NMR investigations of the interconversion of conformational isomers of <i>N</i>
-nitroso-dimethylhydroxylamine
作者:Juan Crugeiras、Howard Maskill、William MacFarlane、Iain D. Menneer、Ana Rios、Miguel A. Rios
DOI:10.1002/poc.1723
日期:2011.2
9 × 109 dm3 mol−1 s−1). In contrast, there is only a very slight increase in kobs with increasing [H3O+] for nitrosation of N,O‐dimethylhydroxylamine (4) in dilute aqueous solution at 25 °C to give N‐nitroso‐dimethylhydroxylamine, 5. This also fits a two‐channel mechanism (Scheme 3). Again, one involves the nitrosation of the free base by NO+ (k2 = 8 × 109 dm3 mol−1 s−1, 25 °C) but the other channel now involves
研究了酸度对25°C下1:1(v / v)H 2 O / MeOH中N-苄基,O-甲基羟胺(3)亚硝化速率的影响。随着[H 3 O + ]的增加,随着限制试剂的减少,HNO 2损失的拟一级反应速率常数(k obs)。这与两个平行的反应通道兼容(方案2)。一种涉及游离羟胺与HNO 2(k 1 = 1.4×10 2 dm 3 mol-1 s -1,25 ℃),另一个涉及游离羟胺与NO +的反应(k 2 = 5.9×10 9 dm 3 mol -1 s -1)。相比之下,在25°C的稀水溶液中,N,O-二甲基羟胺(4)的亚硝化作用[H 3 O + ]增加时,k obs仅有很小的增加,从而得到N-亚硝基二甲基羟胺5。这也符合两通道机制(方案3)。同样,一个通道涉及NO +对游离碱的亚硝化(k 2 = 8×10 9 dm 3 mol -1 s -1,25 °C),但另一个通道现在涉及氯化物的催化作用(k