10-Dimethylamino Derivatives of Benzo[h]quinoline and Benzo[h]quinazolines: Fluorescent Proton Sponge Analogues with Opposed peri-NMe2/-N= Groups. How to Distinguish between Proton Sponges and Pseudo-Proton Sponges

Alexander F. Pozharskii, Valery A. Ozeryanskii, Vladimir Y. Mikshiev, Alexander S. Antonov, Anatoly V. Chernyshev, Anatoly V. Metelitsa, Gennady S. Borodkin, Nikita S. Fedik, Olga V. Dyablo

Результат исследований: Научные публикации в периодических изданияхстатьярецензирование

16 Цитирования (Scopus)

Аннотация

For the first time, 10-dimethylamino derivatives of benzo[h]quinoline 6 and benzo[h]quinazoline 7a-e as mixed analogues of archetypal 1,8-bis(dimethylamino)naphthalene ("proton sponge") 1 and quino[7,8-h]quinoline 2a have been examined. Similar to 1 and 2, compounds 6 and 7 display rather high basicity, forming chelated monocations. At the same time, unexpected specifics of the protonated NMe2/ - N= systems consist of a strong shift of the NH proton to the 10-NMe2 group, contrary to the "aniline-pyridine" basicity rule. In case of 4H+, a rapid migration (in the NMR time scale) of the NH proton between two nitrogen atoms along the N-H···N hydrogen bond was registered at room temperature and frozen below -30 °C with the proton fixed on the NMe2 group. Two different approaches for classification of strong neutral nitrogen organic bases as proton sponges (kinetically inert compounds) or pseudo-proton sponges (kinetically active) are discussed. On this basis, benzoquinoline 6 was identified as staying closer to pseudo-proton sponges while 7a-e to proton sponges due to the presence in their molecules of bulky substituents in the pyrimidine ring. Other remarkable peculiarities of 6 and 7 are their yellow color and luminescence in the visible region distinguishing them from colorless 1 and 2a.

Язык оригиналаанглийский
Страницы (с-по)5574-5587
Число страниц14
ЖурналJournal of Organic Chemistry
Том81
Номер выпуска13
DOI
СостояниеОпубликовано - 1 июл 2016

Предметные области Scopus

  • Органическая химия

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