New approaches to the synthesis of canthin-4-one alkaloids and synthetic analogues
作者:Tim Tremmel、Franz Bracher
DOI:10.1016/j.tet.2015.05.002
日期:2015.7
Two novel approaches to the canthin-4-one ring system have been worked out. Claisen-type condensation of 1-acetyl-β-carboline with N-acyl benzotriazoles gives, via intermediate 1,3-diketones, 6-alkylcanthin-4-ones in one single operation, but this protocol is restricted to small alkyl substituents. An alternative approach, via 1-ethynyl-β-carboline and 1-isoxazolyl-β-carbolines, followed by reductive
已经研究出两种新颖的canthin-4-one环系统方法。1-乙酰基-β-咔啉与N-酰基苯并三唑的克莱森型缩合在一个单一的操作中通过中间体1,3-二酮生成6-烷基can实-4-酮,但该规程仅限于小的烷基取代基。通过1-乙炔基-β-咔啉和1-异恶唑基-β-咔啉然后还原性异恶唑裂解和环化的另一种方法更具通用性。5,6-二取代的canthin-4-ones可通过C-5处的碘化和随后的Pd催化的交叉偶联来获得。