2-Amino-6-(3,4-ethylenedioxythiophen-2-yl)-4-(2-thienyl)-pyrimidine: Synthesis and properties

Abstract

In 1988 poly(ethylenedioxythiophene) (PEDOT, BAYETRON P) was synthesized for the first time [5, 6] from ethylenedioxythiophene (EDOT) [7, 8]. The doped polymer showed a high conductivity (about 300 S/cm); its oxidized films were almost transparent and thermally stable. Molecular conductors containing fragments of electron-rich [9–12] and electron-deficient aromatic carboand heterocycles [13–15] in addition to EDOT fragments were prepared. Synthesis of such compounds attracts undoubted interest for the design of light-emitting devices [16]. In the present communication we describe the synthesis of a new heterocyclic compound containing an electron-deficient pyrimidine ring linked to two electron-donating fragments, thiophene and ethylenedioxythiophene rings. The synthetic procedure was based on a convenient approach including initial preparation of 2-acetyl-3,4-ethylenedioxythiophene (II) [8] which was brought into condensation with thiophene-2-carbaldehyde in alkaline medium to obtain previously unknown chalcone III. Cyclization of the latter in the presence of guanidine sulfate in alkaline medium according to the procedure described in [17] gave dihydropyrimidine IV, which was oxidized in situ to target product V.