Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• amine oxidation is increased. Electrochemical synthesis of pyridoindazolium salts The results of the voltammetry testing allowed to assume that pyridoindazolium salts can also be obtained using an anodic synthesis. Electric current as a reagent is inherently safe and easily scalable; electrosynthesis is

• . Our experiments with the acid additives (see above) showed that protonation of the pyridyl group suppresses the pyridoindazolium salt formation. Voltammetry testing also showed that 2,6-lutidine addition facilitates oxidation of the amine (Figure 2); the peak potential was of 100 mV shifted toward

• replacement of NaOTs for more basic CF3CO2Na), addition of lutidine did not help. To solve the problem, the mediatory oxidation of A3 was also tried. Three possible mediators were tested: TEMPO, bis(4-tert-butylphenyl)nitroxide and tris(4-bromphenyl)amine. The voltammetry testing was performed in DMF using

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• complex. Solubility of the t-Bu-containing ligand and its Schiff base complexes is increased, facilitating scaling-up the reaction procedure and isolation of the functionalized amino acid. Keywords: asymmetric synthesis; chiral auxiliaries; cysteine derivatives; Ni–Schiff base complexes; voltammetry

• testing; Introduction Asymmetric synthesis of functionalized amino acids is a subject of intense research because these compounds are of great demand for pharmaceutical industry, health care, and food production [1][2][3]. Various approaches to enantiomerically enriched amino acids have been developed

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• base complexes of (S)-N-(N-benzylprolyl)aminobenzophenone and ʟ-amino acids (i.e., (R)-cysteine derivatives) [48]. Conclusion Electroreductive opening of a cyclopropane ring in α,α-cyclopropanated amino acids in the form of Ni(II)–Schiff base complexes was studied. Preliminary voltammetry testing