Synthesis and some properties of dyes containing the pyrano[2,3-d]-pyrimidine nucleus

Abstract

The condensation of 1.3-dialkylbarbituric acids with ethyl orthoacetate gives 7H-pyrano[2,3-d]pyrimidines. The structures of these dyes were confirmed by their reactions. The preparation and light absorptions of several nonionic trinuclear dyes containing the pyrano[2,3-d]pydmidine nucleus are discussed.

A one-step synthesis of tricyclic pyrimidines

“…[5][6][7][8] Many syntheses of such compounds involve metal-catalyzed or multi-step procedures or are restricted to N,N-dialkylated pyrimidines. 1,[6][7][8][9][10][11] Our group previously described the preparation of benzannulated pyrano [2,3-d]pyrimidines from readily available benzophenones and 5-phenylbarbituric acids in a metal-free one-step procedure. 12 Seeking for dyes capable of supramolecular interactions which may be formed from these compounds, we now present further studies on the scopes and limitations as well as the mechanism of this reaction to prepare substituted tricyclic pyrano [2,3-d]pyrimidines 1 and oxazolo [3,2-c]pyrimidines 2 which possess an ADA hydrogen bond pattern at the pyrimidine system.…”

“…They also gained widespread synthetic interest as dyes, 1 flavine model compounds [2][3][4] and due to their various pharmaceutical activities. [5][6][7][8] Many syntheses of such compounds involve metal-catalyzed or multi-step procedures or are restricted to N,N-dialkylated pyrimidines.…”