Catalytic hydration of cyanamides with phosphinous acid-based ruthenium(<scp>ii</scp>) and osmium(<scp>ii</scp>) complexes: scope and mechanistic insights
phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40–70 °C), in the absence of any additive, employing low metal loadings (1 mol%) and water as the sole solvent. In almost all the cases, the osmiumcomplex 2 featured a superior reactivity in comparison to that of its ruthenium counterpart 1. In addition
通过使用水合相应的氰胺R 1 R 2 NC N成功地完成了多种脲R 1 R 2 NC(O)NH 2的合成(R 1和R 2 =烷基,芳基或H; 26个实例)的三价膦酸基配合物[的MC1 2(η 6 - p -cymene)(PME 2 OH)](M =茹(1),锇(2))作为催化剂。反应在温和的条件下(40-70°C)干净进行,没有任何添加剂,使用低金属负载量(1 mol%)和水作为唯一溶剂。在几乎所有情况下,complex配合物2的反应活性都比钌配合物1高。另外,对于两种催化剂,氰酰胺底物水合所观察到的反应速率明显快于涉及传统脂族和芳族腈的反应速率。计算研究使我们能够合理化所有这些趋势。因此,计算表明存在直接与碳原子相连的氮原子当与金属中心配位时,N键通过感应效应使腈碳电子减少,从而促进次膦酸配体的OH基团对该碳的分子内亲核攻击。另一方面,Os对Ru的较高反应性似乎与初始金属环上较低的环应
A one-pot preparation of cyanamide from dithiocarbamate using molecular iodine
作者:Jayashree Nath、Bhisma K. Patel、Latonglila Jamir、Upasana Bora Sinha、K. V. V. V. Satyanarayana
DOI:10.1039/b914283p
日期:——
method for the synthesis of cyanamides from dithiocarbamate salts via a double desulfurization strategy using molecular iodine is disclosed. Dithiocarbamates, by the action of iodine yield isothiocyanates in situ, which on treatment with aqueous NH3 give thioureas. The thioureas so generated undergo further oxidative desulfurization with I2 giving corresponding cyanamides in good yields. Environmental
An efficient synthesis of cyanamide from amine promoted by a hypervalent iodine(III) reagent
作者:Harisadhan Ghosh、Ramesh Yella、Abdur Rezzak Ali、Santosh K. Sahoo、Bhisma K. Patel
DOI:10.1016/j.tetlet.2009.03.017
日期:2009.5
In a one-pot strategy we have achieved an efficient method for the synthesis of organic cyanamides starting from dithiocarbamic acid salts/amines. In this strategy the in situ generated alkyl or aryl isothiocyanates, obtained by the desulfurization of dithiocarbamic acid salts with diacetoxyiodobenzene (DIB) react with aqueous ammonia forming alkyl or aryl thiourea which on subsequent oxidative desulfurization
The synthesis of cyanamides and tetrazoles from isothiocyanates through tandem reaction using cobalt catalyst has been demonstrated. In the case of tetrazole preparation, the reaction involved addition/desulfurization/nucleophilic addition/electrocyclization, whereas aromatic cyanamides were constructed from isothiocyanates through addition/desulfurization. Cheap cobalt sulfate was used for the synthesis
Bromineless Bromine as an Efficient Desulfurizing Agent for the Preparation of Cyanamides and 2-Aminothiazoles from Dithiocarbamate Salts
作者:Ramesh Yella、Veerababurao Kavala、Bhisma K. Patel
DOI:10.1080/00397911003642658
日期:2011.2.28
desulfurizing agent in the preparation of organic cyanamides and substituted thiazoles starting from dithiocarbamicacidsalts. In this approach, alkyl/aryl isothiocyantes were first obtained by the desulfurization of dithiocarbamicacidsalts with EDPBT. The in situ–generated isothiocyanates reacts with an aqueous ammonia, forming alkyl or aryl thioureas, which on subsequent oxidative desulfurization