30604-81-0Relevant articles and documents
Rearrangement and cyclisation reactions on the 1-Arylpyrrol-2-iminyl-2-Aryliminopyrrol-1-yl radical energy surface
Borthwick, Scott,Foot, Jonathan,Ieva, Maria,McNab, Hamish,McNab, Lilian,Rozgowska, Emma J.,Wright, Andrew
supporting information, p. 161 - 175 (2021/02/02)
Independent generation of the iminyl (X = N) and pyrrol-1-yl (X = N) radicals by flash vacuum pyrolysis of the corresponding oxime ether and N-(dimethylamino) compound, respectively, provides two regioisomeric pyrrolo1,2-A]quinoxalines compounds. This shows that the radical species interconvert via the spirodienyl moeity at high temperatures. Corresponding generation of the pyrrol-1-yl (X = CH) radical gives the pyrrolo[1,2-A]quinoline as the only cyclised product. In this case, DFT calculations suggest that direct cyclisation of the pyrrol-1-yl takes place, rather than formation of the spirodienyl species and exclusive migration of the C-N bond.
Sulfoxylate Anion Radical-Induced Aryl Radical Generation and Intramolecular Arylation for the Synthesis of Biarylsultams
Gupta, Pankaj,Laha, Joydev K.
supporting information, (2022/03/16)
Aryl radical generation from the corresponding aryl halides using an electron donor and subsequent intramolecular cyclization with arenes could be an important advancement in contemporary biaryl synthesis. A green and practically useful synthetic protocol to access diverse six- and seven-membered biarylsultams especially with a free NH group including demonstration of a gram-scale synthesis is reported herein. The sulfoxylate anion radical (SO2-?), generated in situ from the reagents rongalite or sodium dithionite (Na2S2O4), was found to be the key single electron transfer agent forming aryl radicals from aryl halides, which upon intramolecular arylation gives biarylsultams with good to excellent yields. The approach features generation of aryl radicals that remained underexplored, use of a cheap and readily available industrial reagents, and transition metal-free, mild, and green reaction conditions.
Integrating Biomass into the Organonitrogen Chemical Supply Chain: Production of Pyrrole and d-Proline from Furfural
Di, Lu,Fung Kin Yuen, Vincent,Song, Song,Sun, Qiming,Yan, Ning,Zhou, Kang
supporting information, p. 19846 - 19850 (2020/09/02)
Production of renewable, high-value N-containing chemicals from lignocellulose will expand product diversity and increase the economic competitiveness of the biorefinery. Herein, we report a single-step conversion of furfural to pyrrole in 75 % yield as a key N-containing building block, achieved via tandem decarbonylation–amination reactions over tailor-designed Pd?S-1 and H-beta zeolite catalytic system. Pyrrole was further transformed into dl-proline in two steps following carboxylation with CO2 and hydrogenation over Rh/C catalyst. After treating with Escherichia coli, valuable d-proline was obtained in theoretically maximum yield (50 %) bearing 99 % ee. The report here establishes a route bridging commercial commodity feedstock from biomass with high-value organonitrogen chemicals through pyrrole as a hub molecule.
