100784-27-8Relevant articles and documents
Evaluation of Synthesis of Methyl 3-Chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate Using Green Metrics
Gilbile, Rohidas,Bhavani, Ram,Vyas, Ritu
, p. 1477 - 1481 (2017/05/29)
A modified synthesis of methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate (halosulphuron) is described. The merits of the synthesis are (i) one pot chlorination of methyl 1-methyl-1 H-pyrazole-4-carboxylate (1) in presence of sulphuryl chloride resulting in methyl 3,5-dichloro-1-methyl-1 H-pyrazole-4-carboxylate (2) (ii) conversion of 3-chloro-5-mercapto-1-methyl-1 H-pyrazole-4-carboxylate (3) to 3-chloro-1-methyl-5-sulfamoyl pyrazole-4-carboxylate (4) under mild reaction conditions utilizing tetrabutyl ammonium chloride, N-chlorosuccinimide and ammonium carbonate (iii) condensation of sulphonamide (4) with carbamate (6) by microwave irradiation. Efforts were made to calculate, atom economy, reaction mass efficiency and E-factor for all the reaction steps involved in the synthesis of halosulfuron. The E-factor values in step 2 and step 4 reaction is lower, indicating that these reactions are greener (generation of less waste) when compared to the remaining steps in the synthesis.
Transformation kinetics and mechanism of the sulfonylurea herbicides pyrazosulfuron ethyl and halosulfuron methyl in aqueous solutions
Zheng, Wei,Yates, Scott R.,Papiernik, Sharon K.
experimental part, p. 7367 - 7372 (2010/05/18)
Pyrazosulfuron ethyl (PE) and halosulfuron methyl (HM) are two new highly active sulfonylurea herbicides that have been widely used for weed control in a variety of vegetables and other crops. These two herbicides have similar molecular structures, differing only in the substitutions on the pyrazole ring. Chemical hydrolysis is a primary process affecting the environmental fate of sulfonylurea pesticides. The hydrolytic transformation kinetics of PE and HM were investigated as a function of pH and temperature. For both herbicides, the hydrolysis rate was pH-dependent and increased with increasing temperature. The hydrolysis of both sulfonylureas was much faster in acidic or basic media than under neutral conditions. Identification of hydrolytic products by liquid chromatography-mass spectrometry (LC-MS) suggested that both PE and HM were subject to cleavage and contraction of the sulfonylurea bridge. The hydrolysis rate of HM was significantly higher than that of PE in alkaline solutions, despite their structural similarity. A chlorine substitution on HM's pyrazole ring makes HM more susceptible to bridge contraction than PE under basic conditions. The hydrolysis of HM and PE was relatively unaffected by the presence of cyclic oligosaccharides (cyclodextrins), indicating that natural OH-containing organic compounds occurring in aquatic environments may have little impact on the transformation of these sulfonylurea herbicides.
Pyrazolesulfonylurea useful for controlling the growth of undesired vegetation
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, (2008/06/13)
There are disclosed a compound formula (I): STR1 wherein R1 represents a chlorine atom or a bromine atom; R2 represents methyl or ethyl; and X represents methyl or methoxy; a herbicidal composition containing the same as an active ingredient; and a method of use of the compound represented by formula (I) for controlling the growth of weeds without harm to crop plants in the same location.
