Herbicidal benzyl- or phenoxy-substd. D-phenoxy-propionic acids prodn. - by reacting phenol cpds. with L-2-chloro-propionic acid in presence of alkali hydroxide

摘要

In a new process for the prodn. of D-phenoxy-propionic acids or their alkali salts of formula (I), where W is H or an alkali cation M; and Z is O, X is Cl, Br or CF3 and Y is H or Cl; or Z is CH2, X is Cl and Y is H or Cl, a phenol of formula (II) is reacted in a water-immiscible solvent with an excess of L-2-chloropropionic acid (III) with controlled heating and distn. of water formed or added during the reaction, with simultaneous addn. of the calculated amt. of a slight excess of aq. alkali hydroxide. Controlled addn. of alkali hydroxide during the reaction minimises the hydrolysis of (III) to lactic acid and thus increases the yield of (I). (I) are known hormone herbicides.