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Kekulé, skeletal formula of myclobutanil
Kekulé, skeletal formula of myclobutanil
IUPAC name
3D model (JSmol)
ECHA InfoCard 100.101.000 Edit this at Wikidata
EC Number
  • 410-400-0
MeSH Systhane
RTECS number
  • XZ5257000
UN number 3077
  • InChI=1S/C15H17ClN4/c1-2-3-8-15(9-17,10-20-12-18-11-19-20)13-4-6-14(16)7-5-13/h4-7,11-12H,2-3,8,10H2,1H3 ☒N
  • CCCCC(Cn1cncn1)(C#N)c1ccc(Cl)cc1
Molar mass 288.78 g·mol−1
Appearance Pale, yellow, translucent crystals
Melting point 63 to 68 °C (145 to 154 °F; 336 to 341 K)
Boiling point 202 to 208 °C (396 to 406 °F; 475 to 481 K) at 130 Pa
142 mg⋅dm−3
GHS labelling:
GHS07: Exclamation mark GHS08: Health hazard GHS09: Environmental hazard
H302, H319, H361, H411
P273, P281, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Flash point > 100 °C (212 °F; 373 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Myclobutanil is a triazole chemical used as a fungicide. It is a steroid demethylation inhibitor, specifically inhibiting ergosterol biosynthesis.[1] Ergosterol is a critical component of fungal cell membranes.


Myclobutanil (2 stereoisomers)


The Safety Data Sheet indicates the following hazards:

  • Suspected of damaging fertility or the unborn child.
  • Toxic to aquatic life with long lasting effects.[2]

The first hazard has caused this chemical to be placed on the 1986 California Proposition 65 toxics list.

When heated, myclobutanil decomposes to produce corrosive and/or toxic fumes, including carbon monoxide, carbon dioxide, hydrogen chloride, hydrogen cyanide, and nitrogen oxides.[3][4]

Banned for cannabis cultivation[edit]

Myclobutanil is banned in Canada, Colorado, Washington, Oregon, and Oklahoma for the production of medical and recreational cannabis. In 2014, a Canadian news investigation by The Globe and Mail reported the discovery of myclobutanil in medical cannabis produced by at least one government licensed grower.[5] In September 2019, NBC News commissioned CannaSafe to test THC cartridges for heavy metals, pesticides, and residual solvents like Vitamin E; pesticides, including myclobutanil, was found in products from unlicensed dealers.[6] In Michigan, the current state action limit for myclobutanil is 200 ppb in cannabis products.[7]


  1. ^ "Myclobutanil Product Sheet". Kingtai Chemicals Co.
  2. ^ "SAFETY DATA SHEET Myclobutanil" (PDF). Cayman Chemical Company. Retrieved 11 August 2021.
  3. ^ GOV, NOAA Office of Response and Restoration, US. "MYCLOBUTANIL - CAMEO Chemicals - NOAA".{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ^ "Product Safety Assessment: Myclobutanil".
  5. ^ "Canadians not told about banned pesticide found in medical pot supply" – via The Globe and Mail.
  6. ^ "Tests show bootleg marijuana vapes tainted with hydrogen cyanide". NBC News.
  7. ^ "Technical Bulletin".

External links[edit]