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Pinacol Rearrangement of 3,4‐Dihydro‐3,4‐dihydroxyquinolin‐2(1 H )‐ones: An Alternative Pathway to Viridicatin Alkaloids and Their Analogs
Author(s) -
Rudolf Ondřej,
Rouchal Michal,
Lyčka Antonín,
Klásek Antonín
Publication year - 2013
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201300074
Subject(s) - chemistry , alkyl , aryl , medicinal chemistry , pinacol , stereochemistry , mass spectrometry , nuclear magnetic resonance spectroscopy , organic chemistry , catalysis , chromatography
3‐Alkyl/aryl‐3‐hydroxyquinoline‐2,4‐diones were reduced with NaBH 4 to give cis ‐3‐alkyl/aryl‐3,4‐dihydro‐3,4‐dihydroxyquinolin‐2(1 H )‐ones. These compounds were subjected to pinacol rearrangement by treatment with concentrated H 2 SO 4 , resulting in 4‐alkyl/aryl‐3‐hydroxyquinolin‐2(1 H )‐ones. When a benzyl (Bn) group was present in position 3 of the starting compound, its elimination occurred during the rearrangement, and the corresponding 3‐hydroxyquinolin‐2(1 H )‐one was formed. The reaction mechanisms are discussed for all transformations. All compounds were characterized by IR, 1 H‐ and 13 C‐NMR spectroscopy, as well as mass spectrometry.