2-(substituted phenyl)-6-amino-5-alkoxy, thioalkoxy and aminoalkyl-4-pyrimidinecarboxylates and their use as herbicides

A compound of the formula I

• wherein
• Q represents a C1-C4 alkoxy, C1-C4 haloalkoxy, C1-C4 thioalkoxy, C1-C4 halothioalkoxy or —NR3R4;
• R1 and R2 independently represent H, C1-C6 alkyl, C3-C6 alkenyl, C3-C6 alkynyl, hydroxy, C1-C6 alkoxy, amino, C1-C6 acyl, C1-C6 carboalkoxy, C1-C6 alkylcarbamyl, C1-C6 alkylsulfonyl, C1-C6 trialkylsilyl or C1-C6 dialkyl phosphonyl or R1 and R2 taken together with N represent a 5- or 6-membered saturated ring;
• Ar represents a phenyl group substituted with one to four substitutents selected from halogen, nitro, cyano, formyl, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, C2-C4 alkoxyalkyl, C2-C6 alkylcarbonyl, C1-C6 alkythio, C1-C6 alkylsulfinyl, C1-C6 alkylsulfonyl, C2-C4 alkenyloxy, C2-C4 alkynloxy, C2-C4 alkenylthio, C2-C4 alkynylthio, C1-C6 haloalkyl, C2-C6 haloalkenyl, C2-C6 haloalkynyl, C1-C6 haloalkoxy, C2-C4 haloalkoxyalkyl, C2-C6 haloalkylcarbonyl, C1-C6 haloalkythio, C1-C6 haloalkylsulfinyl, C1-C6 haloalkylsulfonyl, C3-C6 trialkylsilyl, C2-C4 haloalkenyloxy, C2-C4 haloalkynyloxy, C2-C4 haloalkenylthio, C2-C4 haloalkynylthio, —OCH2CH2—, —OCH2CH2CH2—, —OCH2O—, —OCH2CH2O—, —C(O)OR4, —C(O)NR3R4, —CR3NOR4, —NR3R4, —NR3OR4, —NR3SO2R4, —NR3C(O)R4, —NR3C(O)OR4, —NR3C(O)NR3R4 or —NCR3NR3R4;
• R3 represents H, C1-C4 alkyl or C1-C4 haloalkyl;
• and
• R4 represents C1-C4 alkyl or C1-C4 haloalkyl;
• and agriculturally acceptable derivatives of the carboxylic acid group.