Kinetics and mechanism of the anilinolysis of<i>S</i>-aryl<i>N</i>-arylthiocarbamates in acetonitrile
作者:Dae Dong Sung、Hee Man Jang、Dae Il Jung、Ikchoon Lee
DOI:10.1002/poc.1418
日期:2008.11
values that are consistent for a stepwise mechanism with rate-limiting formation of the zwitterionic tetrahedral intermediate. Signs of cross-interaction constants, ρXY (>0), ρXZ (>0) and ρYZ (<0), are all consistent with a stepwise mechanism. It is concluded that the change of the amine from benzylamines to anilines causes a shift of the aminolysis mechanism from a concerted to a stepwise process. Copyright
A Pd/C‐catalyzed domino synthesis of symmetrical and unsymmetrical ureas fromaryl iodides, sodium azide, amines and CHCl3 in water has been developed. This reaction proceeds with sequential carbonylation, Curtius rearrangement and nucleophilic addition. CHCl3 serves as a convenient and safe alternation of CO gas in the presence of KOH. A series of urea derivatives were obtained in moderate to good
[EN] PROCESS FOR PREPARING CARBAMATES<br/>[FR] PROCEDE DE PREPARATION DE CARBAMATES
申请人:COUNCIL SCIENT IND RES
公开号:WO2005063698A1
公开(公告)日:2005-07-14
A process for the preparation of carbamates from organic urea and organic carbonate in presence of a solid base catalyst is disclosed. The process works at the milder reaction conditions and utilizes inexpensive catalysts that can be recycled several times.
A process for the preparation of carbamates from organic urea and organic carbonate in presence of a solid base catalyst is disclosed. The process works at the milder reaction conditions and utilizes inexpensive catalysts that can be recycled several times.
Photocatalyzed synthesis of unsymmetrical ureas via the oxidative decarboxylation of oxamic acids with PANI-g-C3N4-TiO2 composite under visible light
作者:Liang Wang、Hao Wang、Yaoyao Wang、Minggui Shen、Shubai Li
DOI:10.1016/j.tetlet.2020.151962
日期:2020.6
The synthesis of unsymmetrical ureas via the photocatalyzed oxidative decarboxylation of oxamic acids has been developed. The carbamoyl radicals were generated from oxamic acids in the presence of a hypervalent iodine reagent and the PANI(Polyaniline)-g-C3N4-TiO2 composite under visible light irradiation. The radicals were converted in situ into the corresponding isocyanates, which were then trapped
已经开发了通过光催化的草酰胺酸氧化脱羧合成不对称脲的方法。在高价碘试剂和PANI(聚苯胺)-gC 3 N 4 -TiO 2复合材料的存在下,由草酰胺酸在可见光照射下生成氨基甲酰基自由基。自由基被原位转化进入相应的异氰酸酯,然后被胺捕获,以中等至良好的产率得到相应的产物。该方案避免了直接使用对环境不利的异氰酸酯,并且可以耐受一系列底物。而且,光催化剂可以通过简单的过滤而容易地回收,并且可以在仅轻微降低催化活性的情况下重复使用几次。