Reaction of 3-Cl/OMe-Substituted 5-Nitrobenzisothiazoles with Hydrazine: Structural and Computational Evidence for Rearrangement Pathways Implicating Intramolecular Formation of Pivotal Meisenheimer Complexes
作者:Zheng Sonia Lin、Xing Tong、Brian Patrick、Pierre Kennepohl、David S. Grierson
DOI:10.1021/acs.joc.1c00118
日期:2021.5.7
compound 3 could be prepared through reaction of 3-hydrazino-5-nitrobenzisothiazole 5 with the methyl ester of 4-chloropyridine-3-carboxylic acid, followed by N-methylation of the pyridine nitrogen. However, the reaction of 3-methoxyl-5-nitrobenzisothiazole with hydrazine resulted in formation of ring-opened hydrazonate product 18. In the corresponding reaction with 3-chloro-5-nitrobenzisothiazole
在新颖的基于diheteroarylamide-抗HIV剂的投影结构-活性关系的研究2(1C8),一个目的是评估结合在中央酰胺基序的影响2成五元吡唑啉酮环,如在发现3。据设想,化合物3可以通过3-肼基-5- nitrobenzisothiazole的反应来制备5用4-氯吡啶-3-羧酸甲基酯,随后吡啶氮的N-甲基化。然而,3-甲氧基-5-硝基苯并噻唑与肼的反应导致开环的酸酯产物18的形成。。在与3-氯-5-硝基苯并噻唑的相应反应中,形成了不同的重排产物19,其中两个2,1-苯并噻唑单元通过硫桥连接。据推测,在苯并异噻唑环上存在5-硝基取代基的Meisenheimer配合物形成是这些深层重排产物形成的关键特征。通过密度泛函理论计算获得了对拟议的关键迈森海默配合物的形成及其随后向观察到的产物的支持,在该产物中,苯并异噻唑硫原子被驱逐或维持在异构体2,1-苯并噻唑体系中。