| 摘要 |
<p>Prepn. of alkyl halopyridyloxyalkanoates of formula (I) comprises reacting an alkali metal halopyridinate of formula (II) with an alkyl haloalkanoate of formula ZYCHCO2R (III) in presence of DMF or DMSO. In the formulae, X is H, Cl or F; Y is H or CH3; R is 1-4C alkyl; M is Na or K and Z is Cl or Br. Reaction is pref. at 25-130 degrees C, esp. 75-110 degrees C. Pref. 2-4 mole % alkali metal carbonate (esp. Na2CO3) is present, based on amt. of (II). Good yields are obtd. and presence of Na2CO3 (etc.) reduces by-prod. formation. In an example, Na 3,5,6-trichloro-2-pyridinate and methyl chloroacetate were reacted in DMF together with Na2CO3 to give methyl 3,5,6-trichloro-2-pyridyloxyacetate.</p> |
