A Facile, Eco-friendly, Proton Donor-Acceptor Catalyzed, One-Pot, Three-Component Synthesis of Tetrahydrobenzo[b]pyrans
作者:A. Indrasena、Sd. Riyaz、A. Naidu、P.K. Dubey
DOI:10.14233/ajchem.2014.15657
日期:——
Piperidinium acetate catalyzed, three-component cyclocondensation between aryl aldehydes (1), malononitrile (2) and cyclic-1,3-diketo compounds (3) in the eco-friendly and universal solvent water at room temperature for 0.5 h, resulted in the formation of tetrahydro[b]pyran derivatives (4). The formation of 4 could also be established in a step-wise fashion by isolating independently each of the intermediates benzylidine malononitrile 5 and benzylidine cyclohexane-1,3-dione 6 and treating them subsequently with 3 and 2, respectively to obtain benzopyrans 4. Mechanistic studies on the formation of 4 from 1, 2 and 3 are reported. Further, the synthesis of 4 could also be achieved in two variable but identical end-product giving tandem syntheses by treating 1 with 2 and then with 3 giving 4 or by treating 1 with 3 and then with 2 giving 4. All the products were suitably characterized using NMR, IR and Mass spectroscopy.
在环境友好且通用的溶剂水中,以室温进行0.5小时,采用哌啶铵乙酸盐催化,苯基醛(1)、氟代酸(2)和环状1,3-二酮化合物(3)之间的三组分环缩合反应,形成四氢[b]吡喃衍生物(4)。4的形成也可以通过逐步法来实现,分别独立分离每个中间体苄亚基氟代酸(5)和苄亚基环己烷-1,3-二酮(6),然后分别与3和2处理以获得苯并吡喃(4)。报告了关于从1、2和3形成4的机理研究。此外,通过将1与2反应后再与3处理或将1与3反应后再与2处理,都可以获得4,从而实现两种可变但相同的最终产物的串联合成。所有产品均通过NMR、IR和质谱进行了适当表征。