199477-91-3Relevant articles and documents
Visible Light-Driven Efficient Synthesis of Amides from Alcohols using Cu?N?TiO2 Heterogeneous Photocatalyst
Singha, Krishnadipti,Ghosh, Subhash Chandra,Panda, Asit Baran
supporting information, p. 657 - 662 (2021/02/02)
Amides were synthesized from alcohols and amines in high yields using an in situ generated active ester of N-hydroxyimide with our developed Cu?N?TiO2 catalyst at room temperature using oxygen as a sole oxidant under visible light. The catalyst can be easily prepared, robust, and recycled four times without a considerable change in catalytic activity. This developed protocol applies to a wide substrate scope and has good functional group tolerance. The application of this amidation reaction has been successfully demonstrated for the synthesis of moclobemide, an antidepressant drug, and an analog of the itopride drug on a gram scale.
Rhodium-Catalyzed Copper-Assisted Intermolecular Domino C?H Annulation of 1,3-Diynes with Picolinamides: Access to Pentacyclic π-Extended Systems
Martínez, ángel Manu,Alonso, Inés,Rodríguez, Nuria,Gómez Arrayás, Ramón,Carretero, Juan C.
supporting information, p. 5733 - 5742 (2019/04/03)
A new mode of reactivity of 1,3-diynes in rhodium-catalyzed oxidative annulation reactions has enabled the rapid assembly of extended π systems from readily available picolinamide derivatives. The process involves a double C?H bond activation and the iterative annulation of two 1,3-diyne units, with each alkyne moiety engaged in an orchestrated insertion sequence with high regiocontrol, leading to the formation of five new C?C bonds and the construction of four fused rings in a single operation. Either isoquinoline-1-carboxamides or fused polycyclic systems can be accessed by a switch in the regioselectivity of the second diyne insertion depending on the reaction conditions. DFT theoretical calculations have elucidated that the cooperative participation of both rhodium and copper in substrate activation, favored in the presence of excess of the copper(II) salt, is key to such a reversal of regioselectivity and subsequent multiple cyclization leading to fused polycyclic products. The role of copper was found to be essential in assisting both multiple insertion and rhodium-walking sequences, with the implication of intermediates with a Rh?Cu bond (2.60 ?).
Direct Amidation of Carboxylic Acids through an Active α-Acyl Enol Ester Intermediate
Xu, Xianjun,Feng, Huangdi,Huang, Liliang,Liu, Xiaohui
, p. 7962 - 7969 (2018/06/18)
The development of a highly efficient and simple protocol for the direct amidation of carboxylic acids is described employing ynoates as novel coupling reagents. The transformation proceeds in good to excellent yields via in situ α-acyl enol ester intermediates formation under mild reaction conditions. This useful method has been demonstrated for a range of substrates to provide a succinct access to structurally diverse amides, including key intermediates of glibenclamide, tiapride hydrochloride, and nateglinide, and can be conducted on a mole scale.
