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. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.