Chemical Properties
Flumioxazin pure is off-white odorless solid, melting point 135.5℃. Vapor pressure 1×10-7mPa(20/25℃). Partition coefficient Kow lgP=0.037(pH 7).Henry's constant <7×10-5Pa -m3/ mol(20℃). Relative density 0.24 (25°C). Solubility in water (25°C, mg/L): 63 (pH 5), 5850 (pH 7), 100546 (pH 9). Hydrolyzed DT50: 13d (pH 5), 24d (pH 7), 26d (pH 9). Aqueous photolysis of DT50: 7d (pH 5), 17d (pH 7), 13d (pH 9). pKa3.18.
Uses
Diflufenzopyr (SAN 835H) is an auxin transport inhibitor. Diflufenzopyr can enhance the activity of auxin herbicides, such as quinclorac (HY-B0871) and picloram (HY-B2034), and of the synthetic auxin, 1-naphthaleneacetic acid (HY-18570)[1][2].
Synthesis
Diflufenzopyr was prepared as follows: 5 ml of methanol solution containing 4-phenylaminourea (0.37 g, 2.4 mmol) was added to an aqueous solution of 2-acetylnicotinic acid (0.40 g, 2.4 mmol) in 7 ml of methanol, the mixture was stirred at room temperature overnight, thereafter the solid precipitate was collected by filtration, washed with ethanol, and dried to afford 4-phenylsemicarbazone 2-acetylnicotinic acid with a melting point of 174 (decomposition).
References
[1] Sikkema P H, et al. Biologically effective dose and selectivity of SAN 1269H (BAS 662H) for weed control in corn (Zea mays).[J]. Weed Technology, 1999, 13(2):283-289.
[2] Grossmann K, et al. On the mechanism of selectivity of the corn herbicide BAS 662H: a combination of the novel auxin transport inhibitor diflufenzopyr and the auxin herbicide dicamba. Pest Manag Sci. 2002 Oct;58(10):1002-14. DOI:
10.1002/ps.549
