Pyridyloxy carboxylate derivative, preparation method therefor, herbicidal composition and use thereof

A pyridyloxy carboxylate derivative represented by formula I,

• wherein, A, B each independently represent halogen;
• or alkyl or cycloalkyl with or without halogen;
• C represents hydrogen, halogen, alkyl or haloalkyl;
• Q represents halogen, cyano, cyanoalkyl, hydroxyalkyl, amino, nitro, formyl;
• alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl, alkylaminoalkyl or alkoxyalkyl with or without halogen;
• or unsubstituted or substituted aryl, heteroaryl, arylalkyl or heteroarylalkyl;
• M represents -alkyl-R, -haloalkyl-R or
• R represents
• R3 each independently represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl;
• or unsubstituted or substituted heterocyclyl, aryl, heteroaryl, heterocyclylalkyl, arylalkyl or heteroarylalkyl;
• R4, R5, and R6 each independently represent hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, alkoxy, alkoxycarbonyl;
• or unsubstituted or substituted heterocyclyl, aryl, heteroaryl, heterocyclylalkyl, arylalkyl or heteroarylalkyl;
• X represents nitro or NR1R2, wherein R1 represents H;
• alkyl, alkenyl or alkynyl optionally substituted by 1-2 R11;
• —COR12, nitro, OR13, SO2R14, NR15R16, N═CR17R18, alkylcarbamoyl, dialkylcarbamoyl, trialkylsilyl or dialkylphosphono;
• R2 represents H;
• alkyl optionally substituted by 1-2 R11;
• or —COR12;
• or NR1R2 represents N═CR21NR22R23, N═CR24OR25;
• or a 5- or 6-membered saturated or unsaturated ring with or without oxygen atom, sulfur atom, or other nitrogen atom, which is unsubstituted or substituted by 1-2 groups independently selected from the group consisting of halogen, alkyl, alkoxy, haloalkoxy, alkylthio, haloalkylthio, amino, alkylamino, dialkylamino and alkoxycarbonyl;
• wherein R11 independently represents halogen, hydroxy, alkoxy, haloalkoxy, alkylthio, haloalkylthio, amino, alkylamino, dialkylamino, alkoxycarbonyl;
• or unsubstituted or substituted aryl or heteroaryl;
• R12 represents H, alkyl, haloalkyl, alkoxy, phenyl, phenoxy or benzyloxy;
• R13 represents H, alkyl, haloalkyl, phenyl, benzyl or CHR31C(O)OR32;
• R31 represents H, alkyl or alkoxy;
• R32 represents H, alkyl or benzyl;
• R14 represents alkyl or haloalkyl;
• R15 represents H, alkyl, formyl, alkylacyl, haloalkylacyl, alkoxycarbonyl, phenylcarbonyl, phenoxycarbonyl or benzyloxycarbonyl;
• R16 represents H or alkyl;
• R17 represents H, alkyl;
• or phenyl that is unsubstituted or substituted by 1-3 groups selected from the group consisting of halogen, alkyl and alkoxy;
• R18 represents H or alkyl;
• or N═CR17R18represents
• R21, R24 each independently represent H or alkyl;
• R22, R23 each independently represent H or alkyl;
• or NR22R23 represents a 5- or 6-membered saturated or unsaturated ring with or without oxygen atom, sulfur atom, or other nitrogen atom;
• R25 represents alkyl.