| Ureas(contain cyclic urea) and carbamates compounds, their molecules contain peptide bond(-CONH-), therefore, most of them show strong biological activity. Especially cyclic urea compounds containing heterocyclic ring skeleton, common in bioactive molecules,medical value is very high. As two important kinds of fine chemicals, they are widely used in many areas such as pesticide, medicine, organic synthesis, etc. While be used as herbicides,pesticides, plant growth regulators, and fungicides in agriculture, in medicine they can be used for drug intermediates, antiviral drugs, antitumor drugs, nerve regulators, HIV protease inhibitors, etc. So they have attracted peoples’ wide range of research interests in recent years.There were many methods of ureas and carbamates compounds synthesis in the past,such as phosgene and its derivatives method, hydrazoates rearrangement method and transition metal catalysis method, etc. But each of them had lots of drawbacks in different degree: The phosgene and its derivatives method generated a large number of chlorine-free waste in the process of reaction, which had strong causticity to equipment and did environmental pollution, in addition, the synthesis step was complex and it had difficulty in product separation and purification, the phosgene was also highly toxic gas. In the hydrazoates rearrangement method, the raw material hydrazoates themselves were strong explosive, so it was dangerous to do experimental operation and not suitable for industrial production. The catalysts used in the transition metal catalysis method often tended to be expensive transition metal complexes, moreover, some necessary cocatalysts need to be added when using and the reaction conditions was more demanding. Therefore, with the increasingly serious environmental pollution and people’s gradually enhancing environmental protection consciousness, developing a kind of catalytic system concerning green environmentalprotection, high atom economy and safety operation is the inevitable requirement of green chemistry.The Se/CO catalytic system employing in this paper uses CO as carbonylation reagent directly, which possesses the properties of green environmental protection and high atom economy. This system occupies a very significant field of carbon monoxide chemistry, and it is seen as a vital way of efficient use of C1 resource. As catalyst, non-metallic selenium has the virtues of cheap, easy getting, high catalytic activity and convenient post-processing, and it takes only a few minutes to precipitate selenium powder which can be recycling used. In carbonylation reaction the whole Se/CO catalytic system takes advantages of high atomic economy, green environmental protection, convenient disposal and short synthetic route, etc,and it is now one of the important areas of green chemistry and chemical research.This paper first successfully apply Se/CO catalytic system to selenium-catalyzed oxidative carbonylation synthesis of 1, 4-butanediamine to 1, 3-diazepan-2-one,2-aminothiazole and aromatic nitro compounds to substituted unsymmetrical heterocyclic2-thiazole ureas through “one pot” conditions, 3-aminopyridine and some series alcohols to the corresponding pyridine-3-amino carbamates in one step.This paper expands the scope of application of Se/CO catalytic system, successfully completes the synthesis of a variety of important ureas and carbamates, and also opens up a new way which has the advantages such as short route, convenient disposal, high atomic economy, low cost and environmental benignancy for the synthesis of these compounds at the same time. |
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