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Proton and Hydride Transfer in the Skraup Reaction
Author(s) -
Yamabe Shinichi,
Yamazaki Shoko
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600459
Subject(s) - acrolein , aniline , chemistry , hydride , quinoline , oxidizing agent , proton , photochemistry , medicinal chemistry , nitrobenzene , acetanilide , catalysis , glycerol , organic chemistry , hydrogen , physics , quantum mechanics
The Skraup reaction affording quinoline was investigated computationally by the use of a model consisting of aniline, glycerol (HO‐CH 2 ‐CH(OH)‐CH 2 OH) and H 3 O + (H 2 O) 7 . First, two reaction channels up to the 1,2‐dihydroquinoline were considered. One is the traditional one involving acrolein. The other is for the direct linkage of aniline and glycerol. The channel without acrolein was calculated to be more likely. Second, the oxidation process of 1,2‐dihydroquinoline to quinoline was examined with and without the oxidizing agent, nitrobenzene. With it, the hydride‐shift path was obtained and it is likely energetically. Without it, while the process is feasible in accord with a microwave‐irradiation study, the large activation energy was required in the acid catalyzed either (1,2‐dihydroquinoline + glycerol) or (1,2‐dihydroquinoline + acrolein) reaction. The proton transfer was found to be primary driving force of the Skraup reaction.