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Regioselective Acylation of 2,3,4,6‐Tetrahydro‐1,6‐dithia[3‐ a ]azaphenalene toward Donor–Acceptor‐Type Benzophenones
Author(s) -
Wu Yuewei,
Zhao Jinlian,
Yan Chaoxian,
Li Dongxu,
Shao Xiangfeng
Publication year - 2018
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201700624
Subject(s) - chemistry , regioselectivity , acceptor , acylation , reactivity (psychology) , structural isomer , photochemistry , medicinal chemistry , aryl , porphyrin , stereochemistry , organic chemistry , catalysis , medicine , alternative medicine , alkyl , pathology , physics , condensed matter physics
2,3,4,6‐Tetrahydro‐1,6‐dithia[3‐ a ]azaphenalene (THDTAP) is a heteropolycycle possessing two reactive sites for acylation. The regioselective acylation of THDTAP was achieved at the para and meta positions with respect to the nitrogen atom under conditions of AlCl 3 (1.3 equiv, 25 °C) and AlCl 3 (4 equiv, 40 °C), respectively. A series of para ‐ and meta ‐benzophenones having a donor–acceptor‐type structure were then synthesized, in which the THDTAP and benzoyl moieties serve as donor and acceptor, respectively. Under typical McMurry reaction conditions, para ‐ and meta ‐benzophenones show different reactivity, and the electronic nature of the aryl group also plays a pivotal role. Theoretical, electrochemical, and photophysical studies indicate that the electronic structures of para ‐ and meta ‐benzophenones are distinct because the electronic communication between donor and acceptor subunits are different for the two regioisomers. The para ‐benzophenones show off/on fluorescence upon acidification/neutralization and hence might be useful as chemosensors.