Research output: Contribution to journal › Article › peer-review
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. / Pozharskii, Alexander F.; Ozeryanskii, Valery A.; Mikshiev, Vladimir Y.; Antonov, Alexander S.; Chernyshev, Anatoly V.; Metelitsa, Anatoly V.; Borodkin, Gennady S.; Fedik, Nikita S.; Dyablo, Olga V.
In: Journal of Organic Chemistry, Vol. 81, No. 13, 01.07.2016, p. 5574-5587.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - 10-Dimethylamino Derivatives of Benzo[h]quinoline and Benzo[h]quinazolines
T2 - Fluorescent Proton Sponge Analogues with Opposed peri-NMe2/-N= Groups. How to Distinguish between Proton Sponges and Pseudo-Proton Sponges
AU - Pozharskii, Alexander F.
AU - Ozeryanskii, Valery A.
AU - Mikshiev, Vladimir Y.
AU - Antonov, Alexander S.
AU - Chernyshev, Anatoly V.
AU - Metelitsa, Anatoly V.
AU - Borodkin, Gennady S.
AU - Fedik, Nikita S.
AU - Dyablo, Olga V.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84977531593&partnerID=8YFLogxK
U2 - 10.1021/acs.joc.6b00917
DO - 10.1021/acs.joc.6b00917
M3 - Article
AN - SCOPUS:84977531593
VL - 81
SP - 5574
EP - 5587
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 13
ER -
ID: 41270642