Synthesis and structural studies of symmetric and unsymmetric adamantylmethyleneazines

Abstract

The synthesis and spectroscopic properties ( 1 H, 13C and 15 N NMR, in solution and in the solid state) of six new 1-adamantylmethylene azines are reported. The crystal and molecular structures of 1-adamantylcarbaldehyde azine and 1-adamantyl methyl ketone azine, which exist in the solid state in the E,E-configuration, were determined by x-ray analysis. The geometric characteristics of the azine central bridge and the preferred configuration with regard to it (E,E, E,Z or Z,Z) were investigated by means of the crystallographic data retrieved from the Cambridge Structural Database and ab initio quantum chemical calculations.

Why Does Pivalaldehyde (Trimethylacetaldehyde) Unexpectedly Seem More Basic Than 1‐Adamantanecarbaldehyde in the Gas Phase? FT‐ICR and High‐Level Ab Initio Studies

“…Synthesis of 1‐adamantanecarbaldehyde (2) : Compound 2 was synthesized by the Bouveault reaction3 starting from dry 1‐bromoadamantane (1.07 g, 5.0 mmol), anhydrous N , N ′‐dimethylformamide (5.2 mmol), and a 25 % lithium dispersion in mineral oil or lithium wire (10.5 mmol, both containing 1 % sodium; with a lesser amount of Na, for instance 0.05 %, the reaction did not work) in anhydrous THF (50 mL) under argon and external cooling with ultrasonic radiation from a VIRSONIC 300 CELL Disrupter Model #175893 (20 kHz). The reaction was completed at room temperature in 5 min when the lithium dispersion was utilized or in 50 min with lithium wire (the reaction was followed by thin‐layer chromatography).…”

The structure of azines derived from C‐formyl‐1H‐imidazoles in solution and in the solid state: tautomerism, configurational and conformational studies

“…The study of two doubly 15 N‐labeled azines, adamantylmethyleneazine and benzalazine provided a wealth of information concerning 1 H‐ 15 N and 13 C‐ 15 N spin–spin coupling constants(SSCC) and even the 1 J NN coupling (−11.5 Hz) through iterative analysis of the spectra. Unfortunately, as we will see later, the tautomerism of 2L prevents the observation of several couplings with 15 N.…”

“…Recently, we have devoted several papers to the NMR and theoretical study of some azines like benzalazine, acetophenoneazine and cinnamaldazine; these were preceded by a theoretical study of the simplest azine, formaldazine, followed by a paper on α,β‐unsaturated azines . Unfortunately, the azine term is used both for aromatic six‐membered rings (e.g.…”

The structures of two aldazines: [1,1′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)dinaphthalen‐2‐ol] (Lumogen) and 2,2′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)diphenol (salicylaldazine) in the solid state and in solution

“…We have been interested in the structure and configuration of azines of aldehydes (aldazines) and ketones (ketazines), i.e. compounds presenting the >CN–NC< motive . After, we reported the mesogenic properties of some mixtures of azines .…”