Journal of Fluorescence

, Volume 18, Issue 2, pp 357–363 | Cite as

Efficient Construction of Pyrazolo[1,5-a]pyrimidine Scaffold and its Exploration as a New Heterocyclic Fluorescent Platform

Original Paper


An efficient, fast and facile pyrazolo[1,5-a]pyrimidine synthetic protocol has been established by the condensation of aminopyrazoles with 1,3-dicarbonyl components in AcOH/H2SO4 system. The pyrazolo[1,5-a]pyrimidine sulfides were selectively oxidized to the sulfones via a temperature-controlled stepwise oxidative fashion. The correlation between the substitution patterns of these pyrazolo[1,5-a]pyrimidines and their fluorescent spectroscopic properties were further examined, which provided the fundamentals for their potential applications in the development of new fluorescent probes. Red-shifts were easily achieved by the incorporation of unsaturated groups at the 5- and 7-positions, which suggested an approach for synthesizing long wavelength pyrazolo[1,5-a]pyrimidine dyes. The fluorescent spectroscopic properties were found to be sensitive to the hydroxy-containing and carbonyl-containing media such as alcohol and acetone, which helps to confirm the promising perspectives of further investigations in this area.


Fluorophore Heterocycle Pyrazolo[1,5-a]pyrimidine Fluorescence 



We thank the National Key Project for Basic Research and the National Natural Science Foundation of China for financial support.


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Center for Molecular Science, Institute of ChemistryChinese Academy of SciencesBeijingChina
  2. 2.Institute of Element-Organic ChemistryNankai UniversityTianjinChina

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