Unique Oxidation Reaction of Amides with Pyridine-N-oxide Catalyzed by Ruthenium Porphyrin: Direct Oxidative Conversion of N-Acyl-L-proline to N-Acyl-
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- 作者：Rina Ito ; Naoki Umezawa ; and Tsunehiko Higuchi
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：January 26, 2005
- 年：2005
- 卷：127
- 期：3
- 页码：834 - 835
- 全文大小：58K
- 年卷期：v.127,no.3(January 26, 2005)
- ISSN：1520-5126
文摘
Oxidations of alkanes, alkenes, and aromatic rings with pyridine N-oxides are efficiently catalyzed by ruthenium porphyrins under mild conditions. We show here that the oxidation of N-acyl cyclic amines with RuIVtetraarylporphyrin dichloride-2,6-substituted pyridine N-oxides directly gives N-acyl amino acids in modest to good yield via oxidative C-N bond cleavage. N-Acylpyrrolidines and N-acylpiperidines were converted to N-acyl-
-aminobutyric acids and N-acyl-
-aminovaleric acids, respectively. This type of reaction is a novel one in which the C-N bond is cleaved selectively at the less substituted carbon. Notably, the proline residue in proline-containing peptides was selectively converted to glutamate. A large intramolecular kinetic isotope effect (kH/kD = 9.8) was observed in the oxidation of N-benzoyl[2,2,-d2]pyrrolidine, indicating that the reaction should involve an 
-hydrogen atom abstraction process as the rate-determining step. N-Acylcarbaldehyde, the putative intermediate ring-opened form of -hydroxylated N-acyl cyclic amine, was readily oxidized with the oxidizing system to afford the corresponding N-acylamino acid in good yield. Further, lactams (1-methyl-2-pyrrolidone and 1-methyl- 2-piperidone) were also oxidized to give the corresponding imides (1-methylsuccinimide and 1-methylpiperidine-2,6-dione).
-aminobutyric acids and N-acyl--aminovaleric acids, respectively. This type of reaction is a novel one in which the C-N bond is cleaved selectively at the less substituted carbon. Notably, the proline residue in proline-containing peptides was selectively converted to glutamate. A large intramolecular kinetic isotope effect (kH/kD = 9.8) was observed in the oxidation of N-benzoyl[2,2,-d2]pyrrolidine, indicating that the reaction should involve an -hydrogen atom abstraction process as the rate-determining step. N-Acylcarbaldehyde, the putative intermediate ring-opened form of -hydroxylated N-acyl cyclic amine, was readily oxidized with the oxidizing system to afford the corresponding N-acylamino acid in good yield. Further, lactams (1-methyl-2-pyrrolidone and 1-methyl- 2-piperidone) were also oxidized to give the corresponding imides (1-methylsuccinimide and 1-methylpiperidine-2,6-dione).