Oxaziclomefone

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Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Oxaziclomefone

中文通用名

噁嗪草酮

IUPAC

3-[1-(3,5-dichlorophenyl)-1-methylethyl]-3,4-dihydro-6-methyl-5-phenyl-2H-1,3-oxazin-4-one

CAS

3-[1-(3,5-dichlorophenyl)-1-methylethyl]-2,3-dihydro-6-methyl-5-phenyl-4H-1,3-oxazin-4-one

CAS No.

153197-14-9

Molecular Formula

C₂₀H₁₉Cl₂NO₂

Molecular Structure

General Product Information

Category

Herbicides > Unclassified herbicides

Activity

Herbicide.Oxaziclomefone can be applied to rice paddies from pre-emergence to the 2.5 leaf stage of annual weeds. It is highly active against E. oryzicola and E. crusgalli up to the 3.0 stage at an application rate of 60 g a.i./ha. Following post-emergence applications to flooded paddies, the herbicide is taken up by the roots and shoots of weeds. This leads to discolouration of the leaves and shoots, necrosis and death, usually within two weeks of application. It has residual activity lasting up to 50 days after application.

Oxaziclomefone is applied to the flooded paddy and forms a layer near the surface. Due to its very low water solubility and positioning in the paddy soil surface, it is not absorbed by the roots of the rice plants and hence does not damage the crop. Rh?ne-Poulenc Yuka Agro describes this as physical selectivity rather than biological selectivity. The product is also safe to rotational crops.

High selectivity to transplanted rice and long residual activity has led to oxaziclomefone being considered for very early applications (including the day of transplanting of rice). This selectivity is physical: oxaziclomefone caused severe toxicity in 0 cm transplanted rice whereas this was not the case for rice transplanted at a depth of 1 or 3 cm.

Mode of action studies (BCPC 2001, J. Pestic. Sci.) confirmed that MY-100 has no inhibitory effects on known herbicide target sites; the exact site remains unknown. Although the morphological effects, particularly on root development, are similar to those produced by dichlobenil and oryzalin, the mode of action is dissimilar (i.e. no effect on cellulose biosynthesis and mitosis). Initial studies have shown that MY-100 does not inhibit asparagine synthetase, the proposed target site for cinnmethylin which also produces similar symptomology.

CropUse

CropUses:
rice

	30-80 g ai/ha (transplanted rice)
	25-50 g ai/ha (water-seeded rice)

Premix

Oxaziclomefone+clomeprop+bensulfuron-methyl

Physical & Safety Data

Physical Properties

Molecular weight:376.3; Physical form:White crystals. Melting point:149.5-150.5℃; Vapour pressure: 1.33 × 10-2 mPa (50 ℃); Partition coefficient(n-octanol and water):logP = 4.01; Solubility:In water 0.18 ppm (25℃).; Stability: DT50 30-60 d (50℃).

Toxicology

(Rat, Mouse): Oral LD₅₀ >5000 mg/kg. Dermal LD₅₀ >2000 mg/kg. (Rabbit) Minimal eye irritation, not a skin irritant; (Guinea Pig) Not a skin sensitizer.

Environmental Profile

HAZARDS: Fish: LC₅₀ (48 h) >5 ppm (carp) WATER SOLUBILITY: 0.18 ppm (25℃).

Transport Information

Hazard Class:O (Obsolete as pesticide, not classified)