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A convenient method for synthesizing -(1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonyl)methane derivatives, 3 and 4, by the well known Knoevenagel reaction, in one step, is described. The two chromophores are stilbene-type chromophores containing the same D--A structures and end-capped with aromatic group as their donors. Measured with femtosecond multipass Ti:sapphire amplifier as irradiation source (pumped by the laser at 800 nm), the two chromophores show efficient two-photon induced orange red fluorescence emission. The experimental results indicate that the numbers of branches of the two chromophores affect their one-photon properties and two-photon up-conversion emission behaviors, and with the increasing numbers of branches, their wavelengths of

Fused pyrimidine derivatives R 0515 A Convenient Route to Synthesize 1,2,4-Triazolo[1,5-a]pyrimidine Derivatives and Their One and Two-Photon Absorption Spectral Properties. -Stilbene-type chromophores, i.e. title compounds (III) and (IV), are obtained by the Knoevenagel reaction in one step. They show efficient two-photon induced orange red fluorescence emission. -(WANG*, H.; XU, W.; DAI, Y.; ZHANG, B.; WU, Q.; WANG, D.; ZHANG, M.; TIAN, M.; WU, H.; J. Heterocycl. Chem. 44 (2007) 5, 993-997; Dep. Chem., Central Chin. Normal Univ., Wuhan 430079, Peop. Rep. China; Eng.) -H. Toeppel 04-175

The title compound, C10H9N3, is essently planar, except for the methyl H atoms. The asymmetric unit consists of two molecules. In the crystal structure, weak intramolecular C—H...N hydrogen-bonding interactions occur, linking the molecules into chains propagating along the a axis.