- Visible-Light Photocatalytic Functionalization of Isocyanides for the Synthesis of Secondary Amides and Ketene Aminals
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A new visible light-induced photocatalytic protocol enabling the formation of secondary amides from electron-poor organic bromides and isocyanides was developed. In addition, the in situ interception of ketenimine intermediates with nitrogen nucleophiles such as amines, hydrazines, and TMSN3 afforded, in a one-pot two-step procedure, valuable scaffolds such as ketene aminals, pyrazolones, and tetrazoles. Mechanistic evidence confirmed a radical pathway where isocyanides acted as radical geminal acceptors generating key imidoyl radical species.
- Cannalire, Rolando,Amato, Jussara,Summa, Vincenzo,Novellino, Ettore,Tron, Gian Cesare,Giustiniano, Mariateresa
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p. 14077 - 14086
(2020/11/20)
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- TMSCL as a rate-accelerating additive in acylations of amines with 5-(α-AMINO-α′-Hydroxy)methylene meldrum acids
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Aspects are presented of the acylation of amines, alcohols, and thiols with 5-(α-amino-α′-hydroxy)methylene Meldrum acids. We placed special emphasis on the acylation reaction of secondary amines with 5-(α-amino-α′-hydroxy)methylene Meldrum acids, which, because of their basicity, caused problems concerning salt formation with a Meldrum acid derivative. We found that secondary amines, which react at the slowest rate and give a poor yield with 5-(α-amino-α′-hydroxy)methylene Meldrum's acid, react quickly and with high yields with the same reagent in the presence 1 to 3 equivalents of TMSCl. Acylation with this derivative of Meldrum acid was optimized for such factors as reaction temperature, solvent polarity, and acidity of the environment. We have prepared a wide range of nonsymmetrical malononic acid diamids, esters, and thioesters of malonamic acid. Taylor & Francis Group, LLC.
- Janikowska, Karolina,Makowiec, Slawomir
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experimental part
p. 975 - 988
(2012/02/03)
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- Reactions of Acetoacetic Ester Blocked Cyclohexyl Isocyanate
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Acetoacetic ester has been widely reported to be a blocking agent for isocyanates.However, we find that only a trace of isocyanate is formed by thermolysis of acetoacetic ester blocked cyclohexyl isocyanate, 1, at 150 deg C and atmospheric pressure.The major portion is unchanged even after 8 h, with some conversion to acetylmalonic ester, 2, and acetyl-N,N'-dicyclohexylmalonamide, 3.Alcoholysis does not yield the "normal" urethane as blocked isocyanates do but rather esters of 1 with some diesters of 2 and smaller amounts of 3.Significant amounts of N-cyclohexylacetamide, N-cyclohexylmalonamate ester, and some N,N'-dicyclohexylmalonamide are also obtained.Aminolysis leads to N-substituted acetamides and N-cyclohexylmalonamate but no substituted ureas, the "normal" products for aminolysis of blocked isocyanates.In the presence of acid catalysts, alcoholysis leads to N-cyclohexylmalonamates with acetate esters as the other product.
- Wicks, Zeno W.,Wu, Kuang-Jong
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p. 2446 - 2448
(2007/10/02)
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