Tautomerization in Naphthalenediimines:  A Keto-Enamine Schiff Base Macrocycle

Abstract

[reaction: see text] A new [3 + 3] Schiff base macrocycle incorporating naphthalene groups has been prepared. By examination of its properties, X-ray crystallography of model compounds, and calculations, it has been determined that the macrocycle exists predominantly as the keto-enamine tautomer. This unexpected tautomerization presents an unusual hexaketo interior in the macrocycle.

Palladium-Catalyzed Amination in the Synthesis of Macrocycles Comprising Two Naphthalene And Two Polyamine Moieties

“…A two-neck flask equipped with a condenser and magnetic stirrer, flushed with dry argon, was charged with 2,7-dibromonaphthalene 2 (629 mg, 2.2 mmol), Pd(dba) 2 (11.5 mg, 0.02 mmol, 2 mol%) and Xantphos (15 mg, 0.025 mmol, 2.5 mol%) in the case of dioxa-and trioxadiamines 1a,b, or Pd(dba) 2 (23 mg, 0.04 mmol, 4 mol%) and BINAP (28 mg, 0.045 mmol, 4.5 mol%) in the case of tetraamine 1c, 20 ml (in the case of dioxa-and trioxadiamines 1a,b) or 10 ml (in the case of tetraamine 1c) dioxane were added, the mixture was stirred for 2-3 min, then corresponding polyamine 1a-c (1 mmol) and t BuONa (288 mg, 3 mmol) were added, and the reaction mixture was refluxed for 5-8 h. After cooling it down to ambient temperature the reaction mixture was diluted with CH 2 Cl 2 , the residue was filtered off, the organic solvents were evaporated in vacuo, and the residue was chromatographed on silica gel using a sequence of eluents: CH 2 Typical procedure for the synthesis of cyclodimers 7 from compounds 4.…”

“…were added, and the reaction mixture was refluxed for 6-10 h. After cooling it down to ambient temperature the reaction mixture was diluted with CH 2 Cl 2 , the residue was filtered off, the organic solvents were evaporated in vacuo, and the residue was chromatographed on silica gel using a sequence of eluents: CH 2 …”

“…Then 2,7-dibromonaphthalene (386 mg, 1.35 mmol), Pd(dba) 2 (62 mg, 0.11 mmol, 8 mol%), BINAP (76 mg, 0.12 mmol, 9 mol%), 20 ml abs. dioxane and t BuONa (390 mg, 4 mmol) were added, and the reaction mixture was refluxed for 6-15 h. After cooling it down to ambient temperature the reaction mixture was diluted with CH 2 Cl 2 , the residue was filtered off, the organic solvents were evaporated in vacuo, and the residue was chromatographed on silica gel using a sequence of eluents: CH 2 Spectral data are given above. Macrocycle 6b was obtained as the side product.…”

“…[1] This rigid lipophilic fragment possessing interesting photophysical properties draws considerable interest and dozen of works appeared dealing with the synthesis and investigation of the macrocycles of different geometry based on naphthalene, as well with the azacrown ethers derivatives containing naphthalene as exocyclic substituents. In these polyazacycles nitrogen atoms are present in such fragments as Schiff bases, [2] diamides, [3] diimides, [4] lactames. [5] Naphthalene system can be condensed with tetraazamacrocycles, [6] macrocycles may contain phosphorus atoms [7] or only carbon atoms, [8] it can be incorporated into calixarene [9] and catenane [10] structures, combined in various manners with porphyrins.…”

Pd-Сatalyzed Amination for the Synthesis of Macropolycycles Comprising Cyclen, Cyclam and Naphthalene Moieties

“…[11] Spherands with 2,2'-dioxy-1,1'-binaphthalenes and 2,7-disubstituted 1,8-dihydroxynaphtahlene moieties constitute another class of macrocycles, [10,12] the latter compound was tested in the coordination studies with Mg(II), Fe(II), Co(II), Ni(II) and Zn(II) cations. Various nitrogen-containing macrocycles with naphthalene moieties were reported, among them are cyclic Schiff bases, [13] diamides and diimides, [14,15] lactams; [16] naphthalene fragments were also condensed with tetraazamacrocycles. [17] Naphthalene fragments were combined with calixarenes, [18] catenanes, [19] and porphyrins.…”