Common name: Myclobutanil

Other name: myclobutanil (BSI, ANSI, draft E-ISO, (m) draft F-ISO)

Iupac name: 2-p-chlorophenyl-2-(1 H-1,2,4-triazol-l-ylmethyl)hexanenitrile; 2-(4-chlorophenyl)-2-(1 H-1,2,4-triazoN -ylmethyl) hexanenitrile

Chemical abstracts name:     α-butyl-α-(4-chlorophenyl)-l H-1,2,4-triazole-1 -propanenitrile

Type: Fungicide

CAS RN: [88671-89-0]

M.F.: C₁₅H₁₇ClN₄

Mol Wt: 288.8

 

Form (appearance): Pale yellow solid.

M.P.: 63-68℃ (tech.)

B.P.: 202-208℃/1 mmHg

V.P.: 0.213 mpa (25℃)

Solubility.: In water 142 mg/l (25℃). Soluble in common organic solvents, e.g. ketones, esters, alcohols and aromatic hydrocarbons, all 50-100 g/l. Insoluble in aliphatic hydrocarbons.

Stability: Stable under normal storage conditions. Aqueous solutions decompose on exposure to light, DT₅₀ 222 d (sterile water), 0.8 d (sensitized sterile water), 25 d (pond water); no hydrolysis (28℃) in 28 d (pH 5, 7, and 9).

Henry: 4.33 × 10^-4 Pa m³ mol^-1 (calc.)

K_owlogP: 2.94 (pH 7-8, 25℃)

 

Formulation types: EC; SC; WP; Seed treatment.

Biochemistry: Inhibits ergosterol biosynthesis (steroid demethylation inhibitor).

Mode of action: Systemic fungicide with protective and curative action.

Uses: Control of Asc0rnycetes, Fungi Imperfecti, and Basidiomycetes on a wide variety of crops. For example, used as a fo1iar treatment for control of scab and powdery mildew in apples and pears; powdery mildew, shot-hole, blossom blight, and rust in stone fruit; powdery mildew in vines and cucurbits; powdery mildew and rusts on ornamentals; rusts on perennial grasses grown for seed; and various diseases of wheat; as a seed treatment for control of seed- and soil-borne diseases in barley, maize, cotton, rice and wheat; and as a post-harvest drench or dip.

 

Reviews: AO/WHO 65, 67 (see part 2 of the Bibliography).

Oral: Acute oral LD₅₀ for male rats 1600, female rats 2290 mg/kg.

Skin and eye: Acute percutaneous LD₅₀ for rabbits >5000 mg/kg. Not irritating to their skin but mildly to their eyes; not a skin sensitiser to guinea pigs.

Noel: (90 d) for rats and female dogs 100, male dogs 10 mg/kg diet. No reproductive effects were observed in rats at 200 mg/kg, but there were some reproductive effects  in male rats at 1000 mg/kg.

ADI: (JMPR) 0.03 mg/kg b.w. [1992].
Other Non-teratogenic in rats and rabbits, and various mutagenicity tests proved negative. Not mutagenic in the Ames assay.

Toxicity: WHO (a.i.) III EC hazard R631 Xn; R221 Xl; R361 N; R51, R53

 

Birds: Acute oral LD₅₀ for bobwhite quail 510, grey partridges 1635 mg/kg.

Fish: LC₅₀ (96 h) for bluegill sunfish 2,4, rainbow trout 4.2 mg/l.

Daphnia: LC₅₀ (48 h) 11 mg/l.

Worms: Bees Non-toxic to bees.

 

Plant: In plants, metabolism is the same as in animals.

Animals: In animals, undergoes oxidation at the butyl group to a ketone and an alcohol, with partial conjugation to a glucoside. Following oral administration, rapidly excreted in the faeces and urine.

Soil/Environment: In soil, DT₅₀ 66 d (silt loam). Decomposition is through highly polar triazole compounds, with further degradation by ring splitting. No degradation under anaerobic conditions.