78539-87-4Relevant academic research and scientific papers
Two-Step One-Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2-Diketones by Addition-Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles
Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
, p. 494 - 505 (2018/02/09)
An efficient one-pot two-step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2-diketones has been developed. The reaction proceeds through a palladium-catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper-catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2-diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron-rich and electron-poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one-pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.
Synthesis of Thieno and pyrroles
Kumar, G.,Rajagopalan, K.,Swaminathan, S.,Balasubramanian, K. K.
, p. 271 - 274 (2007/10/02)
A simple and useful synthesis of thienopyrrole (1) and thienopyrrole (2) is reported. 2-Acetylthiophene (8) on bromination using iron/bromine affords 2-bromoacetylthiophene (9) which on treatment with sodium azide in aqueous ethanol at 0 deg C furnishes 2-azidoacetylthiophene (10). 10 on reduction with sodium borohydride in 95percent ethanol at room temperature furnishes 1-(2-thienyl)-2-azidoethanol (11) which on dehydration with methanesulphonyl chloride and dry pyridine in dry dimethylformamide affords 2-(ω-azidovinyl)-thiophene (12).Thermolysis of 12 in re-fluxing xylene furnishes the thienopyrrole (2).By a similar sequence of reactions thienopyrrole (1) is prepared starting from 3-acetylthiophene.
