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Design, synthesis and herbicidal evaluation of novel 4‐(1 H ‐pyrazol‐1‐yl)pyrimidine derivatives
Author(s) -
Ma HongJu,
Zhang JianHua,
Xia XiangDong,
Kang Jing,
Li JianHong
Publication year - 2015
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3918
Subject(s) - trifluoromethyl , pyrimidine , chemistry , alkoxy group , stereochemistry , amine gas treating , medicinal chemistry , organic chemistry , alkyl
BACKGROUND A series of novel pyrazolylpyrimidine derivatives were designed, synthesised and characterised by IR , 1 H NMR , 13 C NMR , mass spectroscopy and elemental analysis. The herbicidal activities of 30 pyrazolylpyrimidine derivatives were assessed. RESULTS Nine compounds caused good herbicidal activity for Pennisetum alopecuroides L . Among them, N ‐ethyl‐6‐[5‐methyl‐3‐(trifluoromethyl)‐1 H ‐pyrazol‐1‐yl]‐pyrimidin‐4‐amine exhibited the strongest inhibitory activity against the root growth of P. alopecuroides , with an IC 50 of 1.90 mg L −1 . 2‐Methyl‐4‐[5‐methyl‐3‐(trifluoromethyl)‐1 H ‐pyrazol‐1‐yl]‐6‐(prop‐2‐yn‐1‐yloxy)pyrimidine produced the highest inhibition of chlorophyll level in seedlings of P. alopecuroides (IC 50 = 3.14 mg L −1 ). CONCLUSION The structure–activity relationship indicated that the alkynyloxy group at the 6‐position on the pyrimidine ring played a very important role for bleaching activities. When the alkynyloxy group was replaced by alkoxy, amino, alkylthio and alkylsulfonyl groups, the bleaching activities of the compounds were diminished. However, the compounds substituted by an amino at the 6‐position of the pyrimidine ring exhibited excellent inhibition activities against weed root growth. © 2014 Society of Chemical Industry