No abstract

The fate of alloxydim-sodium (ADS), sodium salt of 2-(l-allyloxyaminobutylidene)-5, 5-dimethyl-4-methoxycarbonylcyclohexane-l, 3-dione, in soybean plants was studied using 14C-compound labeled at C-7 position. The 14C-ADS was applied on the first trifoliate at the first trifoliate stage of the plant. Total recovery of the radioactivity decreased rapidly to 50. 7% of the initial radioactivity 14 days and then slowly to 35. 7% 63 days after treatment. The radioactivity penetrated slowly into the leaves and reached the maximum 27. 7% of the applied one 28 days after treatment. The majority of the radioactivity was found in the treated leaves and only 3. 8% of the applied radioactivity was translocated to the other parts of the plant. ADS degraded mainly to a deallyloxylated compound (CM-I) in the leaves. The amount of CM-I reached 45. 6% of applied radioactivity 4 days and decreased to 12. 4% 63 days after treatment. As minor metabolites, two oxazoles (CM-II and CM-III) and a demethoxycarbonylated compound (CM-VII) were found within a week to an extent of 0. 5% of the applied radioactivity, respectively. When the water soluble 14C-compounds were treated with pectinase or cellulase, parent compound, CM-I, II and III were found in small amounts. Acid or alkaline hydrolyses of polar metabolites gave several unknowns. * All values are the average of duplicates.

Alloxydim-sodium (ADS), sodium salt of 2-(1-allyloxyaminobutylidene)-5, 5-dimethyl-4-(methoxycarbonyl)cyclohexane-l, 3-dione, 14C-labeled at butylidene-1 and ring-1, 5, respectively, was degraded with a half-life of about 5 days in Oiso soil at 25oC in the dark. The following were identified as degradation compounds by thin-layer cochromatography and mass spectrometry; deallyloxylated compound (I), two isomers of oxo-tetrahydrobenzoxazoles (II and III), deallyloxyaminated compound (VI), demethoxycarbonylated compound (VII) and ring-opened dicarboxylic acid (XX). These compounds further decomposed to 14C02 for the extent of 20% of applied radioactivity at 28 days. Moreover, the evolution of 14C02 was much faster in the case of XX incubation. In the sterilized soil, ADS degraded slowly and the oxazoles accumulated up to 43% at 28 days. The half-life of ADS under outdoor winter conditions was about 2 days and major degradation compound was I. The amount of soil-bound materials of ADS reached the maximum around 2 months after treatment, but thereafter decreased gradually.

The behavior of the herbicide Sethoxydim, (+)-2-(1-ethoxyiminobutyl)-5-[2-(ethylthio)propyl]-3-hydroxycyclohex-2-enone, in sugar beets (Beta vulgaris) was investigated by leaf treatment of the [4-14C]-labeled compound. The 14C in treated leaves gradually decreased to 37% 7 days after application. Much of it was translocated to untreated leaves and a little to the root. The amount reached a maximum of 15.9% (9.7 ppm as the parent compound) and 4.2% (13.4ppm), respectively, on day 3 after treatment, and then decreased to 0.02 ppm or less at the final sampling on day 90. Sethoxydim was rapidly converted to its sulfoxide and sulfone, and their oxo-tetrahydrobenzoxazole and desethoxyl derivatives, and further to the conjugates of these compounds.

The residue levels of apparent alloxydim-sodium (ADS), sodium salt of 2-(1allyloxyaminobutylidene)-5, 5-dimethyl-4-methoxycarbonylcyclohexane-l, 3-dione, in soybean seeds were studied using 14C-ADS compounds labeled at either C-7 or C-1, 5 position. The 14C-ADS was applied on the first trifoliate at the second trifoliate stage of the plant. One group of the treated plants was kept under the condition preventing from rainfall. Another group was showered artificially 3 or 7 days after treatment of 14C-ADS and then kept outdoors for 9 or 10 weeks.The residue levels equivalent to alloxydim-sodium in the seeds were 0. 022-0. 039 ppm at 9 weeks and 0. 024-0. 050 ppm at 10 weeks for all samples. So neither the difference in the condition such as artificial rain nor the difference in the position of 14C-label affected the residue levels in the seeds. About 10% of the radioactivity in seeds harvested 9 weeks after treatment was found in lipid fraction. Most of the radioactivity was detected in the water soluble fraction after precipitating protein fraction, in which about 28% and 5% of the radioactivity were found in case of 7-14C and 1, 5-14C, respectively. Thus the dimedone moiety of ADS was only a little incorporated into proteins.