Model compounds and polymers with quinoxaline units

Abstract

synopsis Tetra-and hepbnuclear N-heterocycles, their dimers and their polymers have been prepared by condensation of o-phenylenediamine or 3,3'-diaminobenzidine with 2,3dihydroxyquinoxaline, 2,3,2,3'-tetrahydroxyd,6'-bisquinoxaline, or 2,3,7&tetrahydroxy-1,4,6,4tetraazaanthracene in polyphosphoric acid, or with the 0-phenyl derivatives of the latter three compounds in phenol. The condensation products are highly colored compounds with characteristic absorption spectra. The polymers show good thermal stability. 2834 JADAMUS, D E SCHRYVER, DE WINTER, MARVELThe tetraphenoxy compound XI1 from diaminobenzidine has been converted to 2,2'-bisfluoflavine (XVII) by heating with o-phenylenediamine. The same product has been obtained by heating 3,3'-diaminobenzidine H H X W with 2,3-diphenoxyquinoxaline (VII) and by heating tetrahydroxybisquinoxaline (XII) with o-phenylenediamine in polyphosphoric acid. These reactions might be expected to give somewhat different products, but, apparently, they tautomerize to the same final product since all had ultraviolet absorption at 410,433, and 459 mp. 5,8,8,9,14,15,17, 18-0ctaaza-8,8, 15,17-tetrahydroheptacene (XVIII) was prepared from tetraphenoxytetraazaanthracene (XVI) and o-phenylenediamine, from tetraaminobenzene and 2,3-diphenoxyquinoxaline (VII) and from tetrahydroxytetraazaanthracene (XIV) and o-phenylenediamine by treatment with polyphosphoric acid. Again isomers were not obtained.

Hinged Molecular Capsules: Synthesis and Conformational Control via Temperature, pH, or Solvent Composition

“…Trimethylene-bridged cavitand “cap” 6a and linker 8 were prepared according to literature procedures. , Direct bridging of resorcinarene 3 using ethylene or propylene ditosylate yielded <3% of either “cap” 6b or 6c , respectively. Brominated resorcinarene 4 provided better yields (∼25%) of the trialkylidene-bridged 5b or 5c (not shown) .…”