99557-38-7Relevant academic research and scientific papers
Synthesis and Mechanistic Insights of the Formation of 3-Hydroxyquinolin-2-ones including Viridicatin from 2-Chloro- N,3-diaryloxirane-2-carboxamides under Acid-Catalyzed Rearrangements
Mamedov, Vakhid A.,Mamedova, Vera L.,Qu, Zheng-Wang,Zhu, Hui,Galimullina, Venera R.,Korshin, Dmitry E.,Khikmatova, Gul'Naz Z.,Litvinov, Igor A.,Latypov, Shamil K.,Sinyashin, Oleg G.,Grimme, Stefan
, p. 13514 - 13534 (2021/09/28)
N-Benzyl-2-chloro-N,3-diaryloxirane-2-carboxamides, easily obtained from aromatic aldehydes and anilides of dichloroacetic acid under Darzens condensation conditions, proved to be excellent starting compounds for the synthesis of 3-hydroxyindolin-2-ones, cyclohepto[b]pyrrole-2,3-diones, and 1-azaspiro[4.5]deca-3,6,9-triene-2-ones via the C(sp2)-C(sp2) bond formation in the first case and C(sp2)-C(sp3) bond formation in the second and third cases. Under optimized reaction conditions, 3-hydroxyindolin-2-ones are obtained in a one-pot process, which involves the treatment of N-benzyl-2-chloro-N,3-diaryloxirane-2-carboxamides with CF3CO2H or AcOH/H2SO4. In the case of intramolecular cyclization, the detailed reaction channels depend strongly on the substituents present in the anilide component and in the aromatic ring of the aldehyde component of N-benzyl-2-chloro-N,3-diaryloxirane-2-carboxamides, as well as the temperature and duration of the reaction. A combined experimental and DFT mechanistic study of the formation of 1-benzyl-3-hydroxy-4-arylquinolin-2(1H)-ones showed that there are three competing reaction channels: (a) ring-closure via the ipso site, (b) ring-closure via the 1,2-Cl shift, and (c) ring-closure via the ortho site. Such mechanistic insights enabled an effective one-pot gram-scale synthesis of viridicatin from benzaldehyde and 2,2-dichloro-N-(4-methoxybenzyl)-N-phenylacetamide.
Regioselective Ring Expansion of Isatins with in Situ Generated α-Aryldiazomethanes: Direct Access to Viridicatin Alkaloids
Tangella, Yellaiah,Manasa, Kesari Lakshmi,Krishna, Namballa Hari,Sridhar,Kamal, Ahmed,Nagendra Babu, Bathini
supporting information, p. 3639 - 3642 (2018/06/26)
A novel efficient one-pot regioselective ring-expansion reaction of isatins with in situ generated α-aryl/heteroaryldiazomethanes for the construction of viridicatin alkaloids has been described under metal-free conditions. The utility of this protocol is further demonstrated in the synthesis of naturally occurring viridicatin, viridicatol, and substituted 3-O-methyl viridicatin and their scale up.
