Synthesis and Herbicidal Activity of α-Amino Phosphonate Derivatives Containing Thiazole and Pyrazole Moieties

Abstract

A series of novel α-amino phosphonate derivatives containing the thiazole and pyrazole moieties 3 were synthesized by the Mannich-type reaction of substituted pyrazole-aldehyde 1, 2-amino-5-ethoxycarbonyl-4-methyl-thiazole 2, and dialkyl phosphites or triphenyl phosphite in the presence of a Lewis acid such as magnesium perchlorate as the catalyst under solvent-free conditions. Their structures were clearly confirmed by spectroscopy data (IR, ¹H NMR, ³¹P NMR, MS) and elemental analysis. The results of a preliminary bioassay (in vitro) indicated that some of the title compounds 3 possessed moderate herbicidal activities against dicotyledonous plants (Brassica campestris L) or monocotyledonous plants (Echinochloa crus-galli) at the concerntration of 100 mg/L.

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Keywords:

• α-Amino phosphonate
• herbicidal activity
• pyrazole
• thiazole

Acknowledgments

The authors are grateful to the Natural Science Foundation of China (Grant No. 20872046) and the Natural Science Foundation of Hubei Province (Grant No. 2008CDB086) for financial support.