New Chiral Molecular Tweezers with a Bis-Tröger's Base Skeleton

Abstract

A convenient synthesis of 5alpha,8alpha,14alpha,17alpha-5,17:8,14-dimethano-5,8,14,17-tetraaza-5,6,7,8,13,14,17,18-octahydrodibenzo[e,e']benzo[1,2-a:3,4-a']dicyclooctene derivatives is described, and the compounds have been fully characterized by NMR; in some cases, the molecular structure has been determined by X-ray crystallography. These compounds represent the first examples of a new class of molecular tweezers.

Synthesis and spectroscopy of the Tröger’s base derived from 2-aminoacridine

“…The assignments in Table 2 are consistent both with other publications dealing with Tröger's bases, 8,10 or with acridines.…”

“…5 Then, some of the same workers extended the synthesis and biological studies to other, but always 3-amino-substituted, acridines. 6,7 Owing to our interest in Tröger's bases [8][9][10][11] and in aminoacridines, [12][13][14] we decided to study the reactivity of these last compounds towards formaldehyde in acid media. Only with 2-aminoacridine, 3, were we successful in obtaining the Tröger's base, 4.…”

A shorter synthesis of symmetrical 2,11-dimethyl-bis-Tröger`s bases. A new molecular tweezer

“…The anti stereoisomer 2b was identical to the previously described. [7] The syn stereoisomer 2a was unambiguously identified by 1 H and 13 C NMR at 500 MHz. As reported previously, [8] we can see in Tables 1 and 2 that in the syn isomer the protons of the external aromatic rings are more shielded and that the ∆δ between the exo and the endo protons of the methylene groups H-6(7) and H-13(18) are larger than in the anti arrangement.…”

“…[7] In the case of compound 2, an eight-step synthesis starting from p-toluidine, following Wilcox methodology for the synthesis of asymmetrically substituted Tröger's Bases, [8] affords only to the anti isomer in very low yield and with no trace of the most interesting syn isomer. [7] In the case of such symmetrical compounds, it is reasonable to imagine that in the absence of stabilizing π-stacking interactions between identical external phenyl rings, the anti stereoisomer is exclusively formed. These results and conclusions led us to disfavor this synthetic way for obtaining symmetrical dimethyl molecular tweezers.…”

Crystal structure of 1,1′-diformyl-4,4′-(6H,12H-5,11-methano-dibenzo[b,f][11,5]diazocine-2,8-diyl)dibenzene, C29H22N2O2

“…Since then, various of TB derivatives were synthesized and applied in the eld of molecular recognition [2], chiral ligands [3][4][5], DNA probes [6,7], stereo selective catalysis [8][9][10][11][12], drug development [13,14], CO 2 capture [15,16], bioorganic chemistry [17][18][19], electroluminescent materials [20,21] and supra molecular chemistry [22] in the last two decades. Their wide range of applications is based on their huge rigidity, V-shaped twisted con guration, N-central chirality and C 2 -symmetry.…”