Synthesis and Optoelectronic Properties of Hexahydroxylated 10‐O‐R‐Substituted Anthracenes via a New Modification of the Friedel–Crafts Reaction Using O‐Protected ortho‐Acetal Diarylmethanols

Abstract

A new modification of the Friedel-Crafts type intramolecular cyclization involving O-protected ortho-acetal diarylmethanols as a new type of reactant, was carried out for the first time in a medium containing a large amount of water at room temperature and enabled synthesis of a series of electron-rich, hexahydroxylated 10-O-R-substituted anthracenes, where R is an alkyl (Me, nBu, n-C(16)H(33)) or arylalkyl group (CH(2)Ph, CH(2)-2-Napht, CH(2)C(6)H(4)CH(2)OAr) and also evaluation of their electronic and optoelectronic properties in solution, crystal, and solid thin film. In this transformation, a central 10-O-R-substituted benzene ring was formed, fused to rings originating from two independent aromatic aldehydes. The reaction proceeded via two identified mechanisms involving acetal and/or free aldehyde groups. The acid sensitive acetal and dibenzyl alkoxy functions have never been used together in the intramolecular Friedel-Crafts type cyclization. The new compounds revealed deep blue fluorescence and quantum yields in solution around 0.3. The electrical properties investigated for thin films obtained by vacuum deposition on glass were 10-O-R-substituent dependent and showed much faster transient current decay in the case of the 10-O-CH(2)Ph derivative than for the material with a 10-O-Me substituent (the lifetime of charge carriers was 25 times shorter in this case). The AFM images of thin films, Stokes shifts, and X-ray analysis of π-stacking interactions in crystals of the new materials have been also obtained.

Organosulfur Materials with High Photo- and Photo-Oxidation Stability: 10-Anthryl Sulfoxides and Sulfones and Their Photophysical Properties Dependent on the Sulfur Oxidation State

“…The study complements the literature investigations on symmetrically SO n bridged, unsubstituted analogs. The (S) substrates were synthesized via the thio-Friedel-Crafts-Bradsher (thio-F-C-B) cyclization [33] as an extension of the oxo-variant of this reaction [39][40][41][42][43][44][45][46][47], while (SO) and (SO 2 ) were obtained by a successive oxidizing of the sulfide bridge. The thio-F-C-B reaction is also a tool to introduce a significant substitution on the mono-RSacene (anthracene) core, which also remains in the (SO) and (SO 2 ) products after oxidation.…”

Recent advances in the syntheses of anthracene derivatives

“…In 2012, Balczewski and co-workers reported a new methodology to synthesize 10-OR-substituted anthracenes 82 via an acid-catalyzed cyclization of O -protected ortho -acetal diarylmethanols 81a and 81b as a new type of reactants ( Scheme 19 ) [ 52 ]. To carry out the cyclization step, this new methodology employed a diluted aqueous methanolic solution of HCl at room temperature.…”

“…The scope of the reaction consisted of five examples ( 82a – e ) that were obtained in moderate yields (30–68%). According to the authors, the reaction conditions were the mildest ever used in this type of intramolecular cyclization until 2012 [ 52 ].…”

“…The scope of the reaction consisted of five examples (82a-e) that were obtained in moderate yields (30-68%). According to the authors, the reaction conditions were the mildest ever used in this type of intramolecular cyclization until 2012 [52]. Mohanakrishnan's group has contributed with numerous methodologies for the synthesis of anthracene derivatives, mainly methodologies involving Lewis acid-mediated intramolecular cyclizations.…”

Regioselective Annulation of Unsymmetrical 1,2‐Phenylenebis(diaryl/diheteroarylmethanol): A Facile Synthesis of Anthracene, Tetracene, and Naphtho[b]thiophene Analogues

“…An easy route to anthracenes was achieved by In(OTf) 3 ‐catalyzed cyclodehydration reaction of 2‐benzbenzaldehydes 19. The Brønsted acid catalyzed synthesis of substituted anthracenes was realized by Bodzioch et al20 In 2007, Liu and co‐workers reported the synthesis of 9‐arylanthracenes and heteroacenes through triflic acid mediated annulation reaction of symmetrical diacetates 21. We recently reported22 the regiospecific synthesis of annulated arenes and heteroarenes by ZnBr 2 ‐mediated domino reaction of unsymmetrical dipivalates.…”