4-amino-6-(1,3-benzodioxole)picolinates and their use as herbicides

A compound defined by Formula I:

• wherein
• R2 is halogen, C1-C4 alkyl, C1-C4 haloalkyl, C2-C4 alkenyl, C2-C4 haloalkenyl, C2-C4 alkynyl, C1-C4 alkoxy, C1-C4 haloalkoxy, C1-C4 alkylthio, C1-C4 haloalkylthio, amino, C1-C4 alkylamino, C2-C4 haloalkylamino, formyl, C1-C3 alkylcarbonyl, C1-C3 haloalkylcarbonyl, cyano, or a group of the formula —CR5═CR6—SiR7R8R9, wherein R5 is hydrogen, F, or Cl;
• R6 is hydrogen, F, Cl, C1-C4 alkyl, or C1-C4 haloalkyl;
• and R7, R8, and R9 are independently C1-C10 alkyl, C3-C6 cycloalkyl, phenyl, substituted phenyl, C1-C10 alkoxy, or OH;
• and
• R3 and R4 are independently hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C3-C6 alkenyl, C3-C6 haloalkenyl, C3-C6 alkynyl, formyl, C1-C3 alkylcarbonyl, C1-C3 haloalkylcarbonyl, C1-C6 alkoxycarbonyl, C1-C6 alkylcarbamyl, C1-C6 alkylsulfonyl, C1-C6 trialkylsilyl, C1-C6 dialkylphosphonyl, or R3 and R4 taken together with N is a 5- or 6-membered saturated ring, or R3 and R4 taken together represent ═CR3′(R4′), wherein R3′ and R4′ are independently hydrogen, C1-C6 alkyl, C3-C6 alkenyl, C3-C6 alkynyl, C1-C6 alkoxy or C1-C6 alkylamino, or, R3′ and R4′ taken together with ═C represent a 5- or 6-membered saturated ring;
• or an agriculturally acceptable salt, ester, or N-oxide thereof.