描述了新型氢过氧阿马酸1b-d的合成及其作为非水介质中广泛的氮,硫和磷杂原子的可再生化学选择性亲电子氧化剂的潜力。1b,c与仲胺10f,g的反应产生羟基磺酰胺2b,c和硝酮11f或自由基11g,这取决于底物和化学计量,而叔胺10a-d给出氧化胺11a-d。化合物1c,d将各种硫醚12a-g平滑地氧化为亚砜13a-g,其通过色谱法以接近定量的产率分离。通过用酸化的H 2 O 2处理2c,从1c再生出1c。1c与1,4-噻吨12f反应的动力学研究表明,该反应遵循二级动力学,底物上的第一级和氧化剂中的第一级,其第二级速率常数比与过氧化氢和叔丁基氢过氧化物的相应反应的速率大几个数量级,而无需任何酸或重金属催化剂。膦14a,b也被1c容易地以定量收率氧化成各自的膦氧化物15a,b。反应可以在环境温度或更低的温度下进行,并且似乎是通过非自由基机理进行的。反应对空间和电子因素均敏感。b容易获得定量产量。
描述了新型氢过氧阿马酸1b-d的合成及其作为非水介质中广泛的氮,硫和磷杂原子的可再生化学选择性亲电子氧化剂的潜力。1b,c与仲胺10f,g的反应产生羟基磺酰胺2b,c和硝酮11f或自由基11g,这取决于底物和化学计量,而叔胺10a-d给出氧化胺11a-d。化合物1c,d将各种硫醚12a-g平滑地氧化为亚砜13a-g,其通过色谱法以接近定量的产率分离。通过用酸化的H 2 O 2处理2c,从1c再生出1c。1c与1,4-噻吨12f反应的动力学研究表明,该反应遵循二级动力学,底物上的第一级和氧化剂中的第一级,其第二级速率常数比与过氧化氢和叔丁基氢过氧化物的相应反应的速率大几个数量级,而无需任何酸或重金属催化剂。膦14a,b也被1c容易地以定量收率氧化成各自的膦氧化物15a,b。反应可以在环境温度或更低的温度下进行,并且似乎是通过非自由基机理进行的。反应对空间和电子因素均敏感。b容易获得定量产量。
Synthesis of 2-Nitrothiophenes <i>via</i>
Tandem Henry Reaction and Nucleophilic Substitution on Sulfur from β-Thiocyanatopropenals
作者:Lin Rong、Yingxia Shen、Guoxi Xiong、Yuefa Gong
DOI:10.1002/jhet.3446
日期:2019.2
A new synthetic route of 2‐nitrothiophenes was described through a tetra‐n‐butylammonium fluoride‐promoted or diisopropylethylamine‐promoted tandem Henry reaction and nucleophilicsubstitution of nitromethane with 3‐thiocyanatopropenals, which were conveniently prepared by the replacement reaction of 3‐chloropropenals with potassium thiocyanate under a mild acidic condition.
The synthesis of new N-aroylisothiazole-2-imines (4g-n) as well as the corresponding acceptor-substituted 2-amino-isothiazolium salts (6f-n) by cyclocondensation of thiocyanatovinylaldehyde hydrazones (3) is reported. The structure of these N-imines was proved by spectroscopic methods. The alternative cyclization route to 1,2,3-thiadiazines (8) is not observed. The hydrazones (3a-e) could not be cyclized to N-imines, only sulfides (5a-c) were obtained. The reaction of 2-thiocyanatomethylen-cycloheptan-2-one (9) with benzhydrazides gave the same ring closure to the salts (10a,b). The structure of the N-imine 11b has been confirmed unequivocally by X-ray structure analysis.