Interaction of acetonitrile with trifluoromethanesulfonic acid: unexpected formation of a wide variety of structures
作者:George E. Salnikov、Alexander M. Genaev、Vladimir G. Vasiliev、Vyacheslav G. Shubin
DOI:10.1039/c2ob06841a
日期:——
Interaction of acetonitrile with trifluoromethanesulfonic acid has been studied by multinuclear NMR and ESI-MS. It has been found that the interaction results in formation of a great variety of different cations and neutral compounds which is controlled by the ratio of CH3CN to TfOH. In the presence of an excess of the acid (molar ratio 1 : 8–14) diprotonated N-acetylacetamidine 1 is formed as the major product, which eventually transforms into protonated acetamidine 3 and acetic acid 4. At molar ratio of (1 : 1–2) diprotonated 2,4-dimethyl-6-methylidene-3H-1,3,5-triazine 12, tautomer of the diprotonated trimethyl-s-triazine 11, becomes the main product at an early stage of the reaction and diprotonated 1-(dimethyl-1,3,5-triazin-2-yl)prop-1-en-2-ol 15 at a later stage. In the case of a large excess of acetonitrile (4–20 : 1) trication 17 is formed as a result of the interaction between 11 and 12 along with some oligomers [(CH3CN)3]n (n = 4–12).
丙腈与三氟甲磺酸的相互作用已通过多核NMR和ESI-MS进行了研究。研究发现,这种相互作用导致形成多种不同的阳离子和中性化合物,这些化合物的形成受到CH3CN与TfOH比例的控制。在酸的过量存在下(摩尔比1:8–14),双质子化的N-乙酰乙腈1作为主要产物形成,最终转化为质子化的乙腈3和醋酸4。在摩尔比为(1:1–2)时,双质子化的2,4-二甲基-6-甲烯-3H-1,3,5-三嗪12,作为双质子化的三甲基-s-三嗪11的互变异构体,在反应早期成为主要产物,反应后期则为双质子化的1-(二甲基-1,3,5-三嗪-2-基)丙-1-烯-2-醇15。在丙腈过量存在的情况下(4–20:1),阳离子17的形成是由于11和12之间的相互作用,并伴随形成一些寡聚物[(CH3CN)3]n(n = 4–12)。