Fungicide Cyproconazole

NOMENCLATURE Cyproconazole

Common name cyproconazole (BSI, draft E-ISO, (m) draft F-ISO)

IUPAC name (2RS,3RS;2RS,3SR)-2-(4-chlorophenyl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol 

Chemical Abstracts name a-(4-chlorophenyl)-a-(1-cyclopropylethyl)-1H-1,2,4-triazol-1-ethanol 

CAS RN [94361-06-5] for (2RS,3RS;2RS,3SR) isomers; [113096-99-4] for unstated stereochemistry; [94361-07-6] for (2RS,3SR) isomers Development codes SAN 619 F (Sandoz) 

PHYSICAL CHEMISTRY Cyproconazole

Composition It is a mixture (c. 1:1) of 2 diastereoisomers. Mol. wt. 291.8 M.f. C₁₅H₁₈ClN₃O Form Colourless solid. M.p. 106-109 ºC B.p. >250 ºC V.p. 3.46 ´ 10^-2 mPa (20 ºC) K_OW logP = 2.91 (pH 7) S.g./density 1.259 g/cm³ Solubility In water 140 mg/l (25 ºC). In acetone 230, ethanol 230, dimethyl sulfoxide 180, xylene 120 (all in g/l, 25 ºC). Stability Decomposition is <5% after storage for 2 years. Stable in aqueous solutions at pH 1-9 for a test period of 35 days (50 ºC) or 14 days (80 ºC). Slowly hydrolysed in 1N HCl and NaOH. pKa No acid or base properties in range pH 3.5-10. F.p. No reaction up to 360 ºC 

APPLICATIONS Cyproconazole

Biochemistry Steroid demethylation inhibitor. Mode of action Systemic fungicide with protective, curative, and eradicant action. Absorbed rapidly by the plant, with translocation acropetally. Uses Foliar, systemic fungicide for control of Septoria, rust, powdery mildew, Rhynchosporium, Cercospora, and Ramularia in cereals and sugar beet, at 60-100 g/ha; and rust, Mycena, Sclerotinia and Rhizoctonia in coffee and turf. Formulation types SC; SL; WG. Selected tradenames: 'Alto' (Bayer, Syngenta); 'Shandon' (Barclay); mixtures: 'Radius' (+ cyprodinil) (Syngenta)

MAMMALIAN TOXICOLOGY Cyproconazole

Oral Acute oral LD₅₀ for male rats 1020, female rats 1333, male mice 200, female mice 218 mg/kg. Skin and eye Acute percutaneous LD₅₀ for rats and rabbits >2000 mg/kg. Non-irritating to skin and eyes (rabbits). Non-irritating to skin, and not a skin sensitiser (guinea pigs). Inhalation LC₅₀ (4 h) for rats >5.65 mg/l air. NOEL (1 y) for dogs 1 mg/kg b.w. daily; (2 y) for rats 1 mg/kg b.w. daily. Other Not mutagenic in the Ames assay. Toxicity class WHO (a.i.) II EC hazard (R22) 

ECOTOXICOLOGY Cyproconazole

Birds Acute oral LD₅₀ for Japanese quail 150 mg/kg. Dietary LC₅₀ (8 d) for Japanese quail 816, mallard ducks 1197 mg/kg diet. Fish LC₅₀ (96 h) for carp 18.9, trout 19, bluegill sunfish 21 mg/l. Daphnia LC₅₀ (48 h) 26 mg/l. Bees LD₅₀ (contact) >0.1 mg/bee; (oral) >1 mg/bee. 

ENVIRONMENTAL FATE Cyproconazole

Animals In mammals, following oral administration, cyproconazole is rapidly absorbed, extensively metabolised and excreted, DT₅₀ c. 30 h. No bioaccumulation. Plants In different crops, metabolic pathways are similar and the major residue is cyproconazole itself. Soil/Environment In soil, cyproconazole degrades moderately quickly, DT₅₀ c. 3 mo. No accumulation and leaching potential. Soil adsorption, Freundlich K 4.1 (loam, pH 6.4, o.m. 2.3%), 16 (loamy sand, pH 5.1, o.m. 3.9%).