Single step green process for the preparation of substituted cinnamic esters with trans-selectivity
申请人:Sinha Kumar Arun
公开号:US20080045742A1
公开(公告)日:2008-02-21
The invention provides a green process for direct oxidation of a large number of substituted or unsubstituted cinnamaldehydes or cinnamyl alcohols into the corresponding alkyl or aryl cinnamates in one step. The process of the present invention is a convenient and efficient green process for the preparation of various aryl or alkyl cinnamates under conventional, microwave and ultrasound directly from cinnamaldehydes or cinnamyl alcohols in the presence of an oxidizing agent, catalyst and an alcohol, with or without an organic solvent. These esters are immensely important compounds in flavor, perfumery and pharmaceutical industries. There are several prior arts available for the preparation of cinnamic esters, but all of them suffer from deficiencies such as use of expensive reagents and catalysts, harsh reaction conditions, use of toxic chemicals and others. In contrast, the present methodology is extremely simple and involves reaction of the substrate with an oxidizing agent mixed with a homogeneous or heterogeneous catalyst and an alcohol with or without organic solvent by stirring at room temperature or refluxing or under microwave or ultrasound irradiation to get the requisite products.
本发明提供了一种绿色工艺,用于将大量取代的或未取代的肉桂醛或肉桂醇直接氧化成相应的烷基或芳基肉桂酸酯的一步法。本发明的过程是一种方便有效的绿色工艺,可以在常规、微波和超声波条件下,在氧化剂、催化剂和醇的存在下,直接从肉桂醛或肉桂醇制得各种芳基或烷基肉桂酸酯,可使用或不使用有机溶剂。这些酯类化合物在香料、香精和医药行业中具有极其重要的作用。尽管存在一些用于制备肉桂酸酯的现有技术,但它们都存在诸如使用昂贵的试剂和催化剂、反应条件苛刻、使用有毒化学品等缺陷。相比之下,本方法极为简单,涉及将底物与氧化剂混合均相或非均相催化剂和醇,在有机溶剂存在下或不存在的条件下,通过在室温下搅拌或回流或微波或超声波照射下反应,以得到所需产品。