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Reaction of Enaminones with Aminopyrazoles: Synthesis, Structures and Bioactivities of 7‐Aryl‐3‐cyano‐2‐substituted Pyrazolo[1,5‐ a ] pyrimidines
Author(s) -
Wen LiRong,
Wang ShuWen,
Li Ming,
Yang HuaZheng
Publication year - 2005
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200591231
Subject(s) - chemistry , acetic acid , aryl , elemental analysis , bioassay , condensation , pyrazole , medicinal chemistry , condensation reaction , proton nmr , combinatorial chemistry , organic chemistry , stereochemistry , catalysis , alkyl , genetics , physics , biology , thermodynamics
The condensation reactions of 5‐amino‐4‐cyano‐3‐substituted‐1 H ‐pyrazole 2 or 3 with enaminones 1 in the presence of glacial acetic acid gave twelve new 7‐aryl‐3‐cyano‐2‐substituted pyrazolo[1,5‐ a ]pyrimidines 4 and 5 at room temperature. Their structures were characterized by elemental analysis, IR and 1 H NMR. The structure of 4a was further confirmed by X‐ray crystallography analysis. A plausible reaction mechanism for the formation of the title compounds was also proposed. The bioassay tests showed that compounds 4a , 4c , 4e , 4f , 5a and 5d possessed moderate herbicidal activity.