Five-to-Six Membered Ring-Rearrangements in the Reaction of 5-Perfluoroalkyl-1,2,4-oxadiazoles with Hydrazine and Methylhydrazine
作者:Silvestre Buscemi、Andrea Pace、Antonio Palumbo Piccionello、Ivana Pibiri、Nicolò Vivona、Gianluca Giorgi、Andrea Mazzanti、Domenico Spinelli
DOI:10.1021/jo061251e
日期:2006.10.1
The hydrazinolysis reaction of 5-perfluoroalkyl-1,2,4-oxadiazoles with hydrazine or methylhydrazine as bidentate nucleophiles has been investigated. The reaction occurred through the addition of the bidentate nucleophile to the C(5)−N(4) double bond of the 1,2,4-oxadiazole followed by ring-opening and ring-closure (ANRORC) involving the second nucleophilic site of the reagent. This ring-closure step
已经研究了5-全氟烷基-1,2,4-恶二唑与肼或甲基肼作为二齿亲核试剂的肼解反应。通过将双齿亲核试剂添加到1,2,4-恶二唑的C(5)-N(4)双键中,然后进行涉及第二个亲核位点的开环和闭环(ANRORC)来进行反应试剂。此闭环步骤可能涉及1,2,4-恶二唑的原始C(3)(产生5至5元环重排)或与之相连的另一个亲电子中心(利用5至5六元环重排)。替代性的初始亲核攻击可能涉及在C(3)处连接的另一个亲电子中心,即羰基,导致the原子的形成,该hydr经过Boulton-Katritzky重排(BKR)。选择的反应路径取决于所用亲核试剂和C(3)上取代基的性质。与以前的假设不同,当使用甲基肼时,观察到的区域化学总是显示受较少的NH影响的首选初始攻击C(5)上亲核试剂的2个末端。而且,新的光谱学证据允许将正确的结构分配给由5-全氟烷基-3-苯基-1,2,4-恶二唑与甲基肼反应形成的产物。