Compounds and compositions for nematode treatment

A compound of formula (IIa) having the following structure:

• wherein
• R4 is selected from the group consisting of:
• phenyl;
• phenyl substituted only at the para position with a halogen, CF3, NO2, S(C1-C3 alkyl), dimethylamine, C1-C3 alkyl, sulfonyl, C1-C3 alkoxy, morpholinyl, or tetrazolyl;
• phenyl substituted only at the meta position with a halogen;
• phenyl substituted only at the para and meta positions with substituents independently selected from halogen and C1-C3 alkoxy;
• phenyl substituted only at the para and ortho positions with a halogen other than chlorine;
• C1-C3 alkyl substituted pyrazolyl;
• 2,3-dihydrobenzofuranyl;
• pyridinyl;
• thiophenyl;
• and
• benzodioxolyl;
• R5 is H;
• and
• R6 is H.