6407-34-7Relevant articles and documents
Reviving electrocatalytic reductive amination: A sustainable route from biogenic levulinic acid to 1,5-dimethyl-2-pyrrolidone
Holzh?user, F. Joschka,Kurig, Nils,Mürtz, Sonja D.,Palkovits, Regina
, p. 8428 - 8433 (2021/11/17)
The electrocatalytic reductive amination offers a green pathway to N-containing platform and fine chemicals by using water as a hydrogen source and benign reaction conditions. However, systematic studies about suitable reaction conditions and application to biogenic substrates are rare. Here, we present the electrochemical transformation of levulinic acid to 1,5-dimethyl-2-pyrrolidone. Data from Smirnov et al. for the amination of conventional ketones were validated and extended by systematically investigating the impact of electrode material, substrate concentration, current density, solvent, electrolyte, and pH value. High substrate concentrations in an aqueous electrolyte with a high pH value enable imine formation and copper is identified as the most selective cathode material at current densities lower than 40 mA cm-2. The application of optimized reaction conditions to levulinic acid, followed by a short heating procedure for dehydrative ring closure, led to 1,5-dimethyl-2-pyrrolidone in 78% yield. The systematic approach of this work presents the first example of an electrochemical levulinic acid amination and provides a methodology for the benign synthesis of other N-containing species. This journal is
Characterization of three novel enzymes with imine reductase activity
Gand,Müller,Wardenga,H?hne
, p. 126 - 132 (2015/02/19)
Imine reductases (IRED) are promising catalysts for the synthesis of optically pure secondary cyclic amines. Three novel IREDs from Paenibacillus elgii B69, Streptomyces ipomoeae 91-03 and Pseudomonas putida KT2440 were identified by amino acid or structural similarity search, cloned and recombinantly expressed in E. coli and their substrate scope was investigated. Besides the acceptance of cyclic amines, also acyclic amines could be identified as substrates for all IREDs. For the IRED from P. putida, a crystal structure (PDB-code 3L6D) is available in the database, but the function of the protein was not investigated so far. This enzyme showed the highest apparent E-value of approximately Eapp = 52 for (R)-methylpyrrolidine of the IREDs investigated in this study. Thus, an excellent enantiomeric purity of >99% and 97% conversion was reached in a biocatalytic reaction using resting cells after 24 h. Interestingly, a histidine residue could be confirmed as a catalytic residue by mutagenesis, but the residue is placed one turn aside compared to the formally known position of the catalytic Asp187 of Streptomyces kanamyceticus IRED.
Thermolysis of 5-Alkylidene-1,4-dihydro-5H-tetrazoles
Quast, Helmut,Bieber, Lothar,Regnat, Dieter
, p. 1739 - 1747 (2007/10/02)
In benzene solution at 100 deg C, the isopropylidenedihydrotetrazole 1a decomposes mainly (80percent) into molecular nitrogen and the aziridinimines (E)- and (Z)-2a which are thermally unstable and afford methyl isocyanide and the imine 3a.In addition, the novel spirocyclic tetrahydropyrimidine 7a is formed (18percent yield) in a cycloaddition of 1a and the hypothetical intermediate 1,3-diazabutadiene 19a generated from 1a through a hydrogen shift and loss of molecular nitrogen.The thermolysis of the neopentylidenedihydrotetrazole 1b at 100 deg C is more complex.Only small amounts of the aziridinimines (E)- and (Z)-2b and their decomposition products 3b and methyl isocyanide are observed.A major product is the spirocyclic tetrahydropyrimidine 7b which exhibits moderate thermal stability.Slow thermolysis of 7b affords the tetrahydropyrimidinimine 8b and methyl azide.The latter reacts with 1b in a cycloaddition furnishing the spiro compound 5b which partially decomposes into the amino-1,2,3-triazole 16, thus regenerating methyl azide.This catalyzed isomerization 1b -> 16 which is initiated through the thermal cycloreversion of 7b involves a total of 19percent of 1b.The structures of the products are elucidated by means of mass spectra and high-field NMR spectra.The mechanism of formation of the 1,3-diazabutadienes 19 from 1 is discussed.