Persistence of foliar applied and pre-storage seed-treated insecticides in rice and its processed products.

A field study was conducted to investigate the persistence of foliar-applied thiamethoxam 25% WG at a rate of 25 g ai ha-1 and chlorantraniliprole 18.5% SC at 30 g ai ha-1 in various parts of rice plants, including whole grain rice, brown rice, bran, husk, straw, and cooked rice. Liquid Chromatography-Mass spectrometry/Mass spectrometry was used for sample analysis. Chlorantraniliprole residues were found to persist in whole grains, bran, husk, and straw at the time of harvest, while thiamethoxam residue was not detected in harvested grains, processed products, or straw. The study concluded that foliar-applied chlorantraniliprole and thiamethoxam did not pose any dietary risk in cooked rice. In a pre-storage seed treatment study, thiamethoxam 30% FS at 3 mL kg-1 was evaluated against Angoumois grain moth infestation during storage. The seeds remained unharmed for nine months and exhibited significantly less moth damage (2.0%) even after twelve months of storage. Thiamethoxam residues persisted for more than one year in whole rice grain, brown rice, bran, and husk with seed treatment, with higher residue levels observed in bran and husk. Parboiling and cooking led to the degradation of thiamethoxam residues.

2,2,4-Trimethyl-5-(4-tolyl-sulfon-yl)-2,3,4,5-tetra-hydro-1H-1,5-benzo-diazepine.

In the title compound, C(19)H(24)N(2)O(2)S, the benzodiazepine ring adopts a distorted boat conformation. The S atom shows a distorted tetra-hedral geometry, with the O-S-O [119.16 (14)°] and N-S-C [107.48 (10)°] angles deviating significantly from ideal values. The crystal packing is controlled by C-H⋯O, N-H⋯O and C-H⋯π inter-actions.

3,3-Dimethyl-cis-2,6-di-p-tolyl-piperidin-4-one.

In the title mol-ecule, C(21)H(25)NO, the piperidine ring adopts a chair conformation. The benzene rings and one of the methyl groups attached to the piperidine ring have equatorial orientations. The dihedral angle between the two benzene rings is 72.53 (9)°. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds. Weak C-H⋯π inter-actions involving the benzene rings are also present in the crystal structure.

1-Formyl-r-2,c-6-bis-(4-methoxy-phen-yl)-t-3,t-5-dimethyl-piperidin-4-one.

In the title compound, C(22)H(25)NO(4), the piperidine ring adopts a distorted boat conformation. The methyl groups at the 3 and 5 positions of the piperidine ring are in axial and equatorial orientations, respectively. Both H and O atoms in the aldehyde group are disordered over two positions with occupancies of 0.534 (5) and 0.466 (5). In the crystal, the mol-ecules are linked into a three-dimensional network by C-H⋯O hydrogen bonds.

r-2,c-6-Bis(4-chloro-phen-yl)-c-3,t-3-dimethyl-piperidin-4-one.

In the title mol-ecule, C(19)H(19)Cl(2)NO, the piperidine ring adopts a chair conformation and the dihedral angle between the two benzene rings is 77.23 (7)°. In the crystal structure, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds, and a weak C-H⋯π inter-action is also observed.