Vibrational and electronic circular dichroism studies on the axially chiral pyridine-N-oxide: trans-2,6-di-ortho-tolyl-3,4,5-trimethylpyridine-N-oxide
作者： Florina Teodorescu , Simona Nica , Cornelia Uncuta , Emeric Bartha , Petru Ivan Filip
DOI: 10.1016/J.TETASY.2015.08.006
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摘要: Abstract The absolute configuration of the resolved axially chiral pyridine- N -oxide derivative, (±)- trans -2,6-di- ortho -tolyl-3,4,5-trimethylpyridine- -oxide, has been determined by VCD and ECD analyses supported TD-DFT calculations carried out at different levels theory. DFT confirmed that in spite two biaryl axes, compound is conformationally less flexible major conformer stabilized weak hydrogen bonds formed between methyl group tolyl moieties nitroxide oxygen. experimental spectra this previously studied (±)-2,6-di-sec-butyl-4-methylpyridine-N-oxide with stereogenic centers were compared frequency range 1200–1300 cm −1 . A (+,−,+)/(−,+,−) pattern bands was observed both cases. By replacing sec -butyl ones, peaks shifted toward higher frequencies intensities increased.
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