Rhodium(III)-catalyzed synthesis of cinnolinium salts from azobenzenes and alkynes: application to the synthesis of indoles and cinnolines was written by Muralirajan, Krishnamoorthy;Cheng, Chien-Hong. And the article was included in Chemistry – A European Journal in 2013.Electric Literature of C6H10O2 This article mentions the following:
A rhodium-catalyzed C-H activation/annulation of azobenzenes with alkynes to give various substituted cinnolinium salts in good to excellent yields is reported. The reaction is compatible with a wide substrate scope and highly atom- and step-economic. The proposed mechanism is strongly supported by the isolation of a five-membered rhodacycle. This protocol has been successfully applied to the synthesis of indole, indoloindole, and cinnoline derivatives In the experiment, the researchers used many compounds, for example, 1,4-Dimethoxy-2-butyne (cas: 16356-02-8Electric Literature of C6H10O2).
1,4-Dimethoxy-2-butyne (cas: 16356-02-8) belongs to ethers. Relative to alcohols, ethers are generally less dense, are less soluble in water, and have lower boiling points. They are relatively unreactive. Ethers can form hydrogen bonds with other molecules (alcohols, amines, etc.) that have O―H or N―H bonds. The ability to form hydrogen bonds with other compounds makes ethers particularly good solvents for a wide variety of organic compounds and a surprisingly large number of inorganic compounds.Electric Literature of C6H10O2
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem