Efficient construction of pyrazolo[1,5-a]pyrimidine scaffold and its exploration as a new heterocyclic fluorescent platform.
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/H(2)SO(4) 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.
Wu
Yan-Chao
YC
Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, No.2 Zhongguancun North 1st Street, Beijing, China. ycwu@iccas.ac.cn
Li
Hui-Jing
HJ
Liu
Li
L
Wang
Dong
D
Yang
Hua-Zheng
HZ
Chen
Yong-Jun
YJ
D001667:Binding, Competitive; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000737:chemistry*; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
D005456:Fluorescent Dyes; D011720:Pyrazoles; D011743:Pyrimidines