Fungicide

MBI: dehydrase

NOMENCLATURE

Common name fenoxanil (BSI, pa ISO)

IUPAC name a mixture of 85% (R)-N-[(RS)-1-cyano-1,2-dimethylpropyl]-2-(2,4-dichlorophenoxy)propionamide and 15% (S)-N-[(RS)-1-cyano-1,2-dimethylpropyl]-2-(2,4-dichlorophenoxy)propionamide 

Chemical Abstracts name N-(1-cyano-1,2-dimethylpropyl)-2-(2,4-dichlorophenoxy)propanamide 

CAS RN [115852-48-7]  Development codes AC 382042; CL 382042; AC 901216 (all Cyanamid); WL 378309 (Shell); NNF-9425 (Nihon Nohyaku) 

PHYSICAL CHEMISTRY

Composition Material under development is a mixture of (R,R) and (R,S) diastereoisomers as major components, and (S,R and S,S) diastereoisomers as minor components.  Mol. wt. 329.2  M.f. C15H18Cl2N2O2  Form Off-white, odourless solid.  M.p. 69.0-71.5 °C  V.p. 0.21?.021 ´ 10-4 mPa (25 °C)  KOW logP = 3.53?.02 (25 °C)  S.g./density 1.22 (20 °C)  Solubility In water 30.7?.3 ´ 10-3 g/l (20 °C). Soluble in most organic solvents.  Stability Essentially stable within the relevant pH range. 

COMMERCIALISATION

History Discovered by Shell GmbH and acquired by American Cyanamid Co. (now BASF AG). Reported by E. Sieverding et al., (Proc. Br. Crop Prot. Conf. - Pests Dis., 1998, 2, 359). Under joint development by BASF and Nihon Nohyaku Co., Ltd. 

APPLICATIONS

Biochemistry Melanin biosynthesis inhibitor. Inhibits dehydratase enzymes which dehydrate scytalone to trihydroxynaphthalene and vermelone to dihydroxynaphthalene.  Mode of action Systemic, protective fungicide with residual effects.  Uses Under development for control of rice blast by foliar or into-water application.  Formulation types Dust; flowable. 

MAMMALIAN TOXICOLOGY

Oral Acute oral LD50 for male rats >5000, female rats 4211, male and female mice >5000 mg/kg.  Skin and eye Acute percutaneous LD50 for male and female rats >2000 mg/kg. Non-irritating to skin and eyes (rabbits); not a skin sensitiser (guinea pigs).  Inhalation LC50 >5.18 mg/l.  Other Non-mutagenic in Ames, DNA repair, chromosome aberration and mouse micronucleus tests. Non-teratogenic. 

ECOTOXICOLOGY