Lithiation of 2,4,5,7-Tetrabromo-1,8-bis(dimethylamino)naphthalene: Peculiarities of Directing Groups’ Effects and the Possibility of Polymetalation

Abstract

The bromine-lithium exchange sequence upon interaction of 2,4,5,7-tetrabromo-1,8-bis(dimethylamino)naphthalene with n-BuLi was studied. Experimental results were explained by means of quantum chemical calculations. It was demonstrated that the first exchange occurs in position 4 due to the significant decrease of a steric strain of the molecule. The second exchange takes place in either position 5 or 7 due to the even more negative charge distribution in the naphthalene core. As a result, the third exchange leads to the species containing lithium in positions 2,4,5 or 2,4,7. Using a large excess of n-BuLi in hexane, 2,4,5,7-tetralithio-1,8-bis(dimethylamino)naphthalene was successfully prepared. The latter was used for the synthesis of several tetrasubstituted derivatives of 1,8-bis(dimethylamino)naphthalene by quenching with different electrophiles.

Spontaneous Cyclization of peri-Diiminonaphthalenes Leading to the Formation of Benzo[de]isoquinolines and Stable Benzo[de]isoquinoliniums

“…We expanded the discovered reaction to the 1,8-bis(dimethylamino)naphthalene (DMAN) core using easily available dilithionaphthalene 7 . , Surprisingly, the reaction did not stop at the stage of the formation of 1 H -benzo[ de ]isoquinolines 9 but proceeded to carbocations 11a – c (Scheme and Figure ). We assume that the initially formed isoquinolines 9 undergo protonation with the formation of 10 followed by the elimination of ammonia to give 11 .…”

Organoboron Derivatives of 1,8-Bis(dimethylamino)naphthalene: Synthesis, Structure, Stability, and Reactivity

“…4-Bromo-1,8-bis­(dimethylamino)­naphthalene (300 mg, 1 mmol) and 20 mL of diethyl ether, freshly distilled over sodium, were placed in a flame-dried round-bottomed flask. The flask was filled with dry argon and closed with a septa cap.…”

“…4,5-dibromo-1,8-bis­(dimethylamino)­naphthalene (300 mg, 0.81 mmol) was placed in a flame-dried round-bottom flask. n -hexane (15 mL), freshly distilled over sodium, was added.…”

“…Using Olex2, 54 the structure was solved with the SHELXT 55 structure solution program using Intrinsic Phasing and refined with the SHELXL 56 refinement package using least squares minimization. Empirical absorption correction was applied in CrysAlisPro 57 program complex using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Crystallographic data for these samples have been deposed at Cambridge Crystallographic Data Centre: 52155747, 6b2155746, and 7b 2169551.…”

Synthesis, conformational stability and molecular structure of 4-aryl- and 4,5-diaryl-1,8-bis(dimethylamino)naphthalenes

“…Moreover, the φ3 torsions observed for 3 are almost two times higher than that of the proton sponge. 69 In the series of 4,5-disubstituted DMAN derivatives, only DMAN-4,5-dicarbaldehyde (φ3 = 26.1°) 70 and 4,5-dibromo-DMAN 6 (φ3 = 26.1°) 71 surpass compound 3a (φ3 = 24.2°) in terms of twisting. The peri-NMe 2 groups of 3 are flattened (see the corresponding sum of the bond angles at nitrogen atoms, ∑∠C-N-C).…”