Haloxyfop-R-methyl

Common name haloxyfop (BSI, ANSI, draft E-ISO, (m) draft F-ISO, WSSA)

IUPAC name (RS)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionic acid 

Chemical Abstracts name (?-2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid 

CAS RN [69806-34-4] unstated stereochemistry; [95905-78-5] racemate   

haloxyfop-etotyl

IUPAC name ethoxyethyl (RS)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate 

Chemical Abstracts name 2-ethoxyethyl (?-2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoate 

CAS RN [87237-48-7] unstated stereochemistry 

haloxyfop-P-methyl

IUPAC name methyl (R)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate 

Chemical Abstracts name methyl (R)-(+)-2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoate 

Other names haloxyfop-R (methyl ester) 

CAS RN [72619-32-0]; acid [95977-29-0]   

PHYSICAL CHEMISTRY

haloxyfop

Mol. wt. 361.7  M.f. C15H11ClF3NO4  Form Colourless crystals.  M.p. 107-108 ºC  V.p. <1.33 ´ 10-3 mPa (25 ºC)  KOW logP = 1.34 (20 ºC, unstated pH)  S.g./density 1.64  Solubility In water 43.4 mg/l (pH 2.6, 25 ºC); 1.590 (pH 5), 6.980 (pH 9) (both in mg/l, 20 ºC). In acetone, methanol, isopropanol >1000, dichloromethane 459, ethyl acetate 518, toluene 118, xylene 74, hexane 0.17 (all in g/l).  Stability DT50 in water 78 d (pH 5), 73 d (pH 7), 51 d (pH 9).  pKa 2.9 

haloxyfop-etotyl

Mol. wt. 433.8  M.f. C19H19ClF3NO5  Form Colourless crystals.  M.p. 58-61 ºC  V.p. 1.64 ´ 10-5 mPa (20 ºC) (OECD 104)  KOW logP = 4.33 (20 ºC) (OECD 107)  S.g./density 1.34  Solubility In water 0.58 (unbuffered), 1.91 (pH 5), 1.28 (pH 9.2) (all in mg/l, 20 ºC). In dichloromethane 2760, xylene 1250, acetone, ethyl acetate, toluene >1000, methanol 233, isopropanol 52, hexane 44 (all in g/l, 20 ºC).  Stability Hydrolysed to haloxyfop under acidic and alkaline conditions. In water, DT50 33 d (pH 5), 5 d (pH 7), a few h (pH 9) (all 25 ºC). 

haloxyfop-P

Mol. wt. 361.7  M.f. C15H11ClF3NO4  Form Colourless crystals.  M.p. 70.5-74.5 °C  V.p. 3.5 ´ 10-3 mPa (25 °C)  KOW logP = 0.27 (pH 7)  Solubility In water 375 mg/l (20 ºC). In acetone, dichloromethane, methanol, xylene >639 g/l (20 ºC).  pKa 4.27 

haloxyfop-P-methyl

Composition The (R)- isomer of haloxyfop-methyl.  Mol. wt. 375.7  M.f. C16H13ClF3NO4  Form Clear brown, odourless liquid.  B.p. >280 ºC  V.p. 0.328 mPa (25 ºC)  KOW logP = 4.00  Henry 1.1 ´ 10-3 Pa m3 mol-1 (20 °C, calc.)  S.g./density 1.372 (20 °C)  Solubility In water 9.08 mg/l (25 ºC). In acetone, cyclohexanone, dichloromethane, ethanol, methanol, toluene, xylene >1 kg/l (20 ºC).  Stability DT50 in water 100 d (pH5), 48 d (pH7), 52 h (pH9) (all 25°C).  F.p. 186 °C 

APPLICATIONS

Biochemistry Fatty acid synthesis inhibitor, by inhibition of acetyl CoA carboxylase (ACCase). 

Mode of action Haloxyfop-etotyl and haloxyfop-P-methyl are selective herbicides, absorbed by the foliage and roots, and hydrolysed to haloxyfop, which is translocated to meristematic tissues, and inhibits their growth. 

Uses Haloxyfop-etotyl and haloxyfop-P-methyl are used post-emergence for control of annual and perennial grasses in sugar beet, fodder beet, oilseed rape, potatoes, leaf vegetables, onions, flax, sunflowers, soya beans, vines, strawberries, and other crops. Applied at 104-208 g a.e./ha (-etotyl) and 52-104 g a.e./ha (-P-methyl).