Return to Pyridalyl Adverse Effects

ACTIVITY: Iinsecticide (unclassified)

CAS Name: 2-[3-[2,6-dichloro-4-[(3,3-dichloro-2-propenyl)oxy]phenoxy]propoxy]-5-(trifluoromethyl)pyridine


Adverse Effects:

Body Weight Decrease
Endocrine: Adrenal
Endocrine: Ovary

Endocrine: Testes


Environmental - persistence in soil

Regulatory Information
(only comprehensive for the US)
US EPA Registered: Pending 
Japan: Maximum Residue Levels (MRLS) Cabbage • Chinese cabbage • Eggplant • Japanese radish (including Radish) (leaf and root) • Lettuce (Cos and Leaf) • Pimento (Sweet pepper) • Strawberry • Tomato • Welsh (including Leek)
Other Information
Molecular Formula: C18H14Cl4 F3 NO3 
Entry Year: 2001   
Inventing Company: Sumitomo  
Manufacturers: Valent 
Other Names: Pyridanil
Of special interest:
PAN Data
2004: Evaluation Report. PYRIDALYL. January 14, 2004. Japan Food Safety Commission. Pesticides Expert Committee.
2004 - Abstract: The discovery of pyridalyl: a novel insecticidal agent for controlling lepidopterous pests by N Sakamoto et al. Pest Management Science, January 2004, vol. 60, no. 1, pp. 25-34(10).
Dec 5, 2003 - Valent petitioned EPA for first time tolerances for food commodities in the US. See Federal Register below.
USDA- funded field trials for new pesticide Pyridanil (now Pyridalyl) from Sumitomo Chemical
August, 2001 - IR-4 New Products/Transitional Solution List. This list contains brief descriptions of numerous new pest control materials that have been introduced over the last several years. Additionally, it contains information on some "older" crop protection chemicals that are believed to have room for new uses. This List includes Pyridalyl (S-1812)

- abbreviations
Chemical name
S-1812-Py-OH 2-[3-[2,6-dichloro-4-[(3,3,-dichloroallyloxy)]phenoxy]propoxy] -5-(trifluoromethyl)-3-pyridynol
S-1812-DP 3,5-dichloro-4- [3-(5-trifluoromethyl-2-pyridyloxy)]- propoxyphenol
[The unchanged form of the compound was the main components in the feces, and a major metabolite]
[detected in the extracts of rat liver, kidney, lung, whole blood, and fat]
S-1812-DP-Me 2-[3-(2,6-dichloro-4-methoxyphenoxy)propoxy]-5- (trifluoromethyl)pyridine
S-1812-Ph-CH2COO H 2-[3,5-dichloro-4-[3-(5-trifluoromethyl-2-pyridinoxy)]-propoxy]phe noxy]acetic acid
[detected in the extracts of rat liver, kidney, lung, whole blood, and fat]
HPHM 3-[2,6-dichloro-4-(3,3-dichloroprop-2-enyloxy)phenoxy]- propanol
[detected in the extracts of rat liver, kidney, lung, whole blood, and fat]
DCHM 3-[2,6-dichloro-4-(3,3-dichloroprop-2-propanil)oxy]phenol
S-1812-PYP 3-(5-trifluoromethyl-2-pyridyloxy)propanol
TPPA 3-(5-trifluoromethyl-2-pyridyloxy)propionic acid
HTFP 5-trifluoromethyl-2-hydroxypyridine
HPDO 5-trifluoromethyl-3-hydroxy-2-pyridone
N-methyl-HTFP 5-trifluoromethyl-N-methyl-2-pyridone
N-methyl-HPDO 5-trifluoromethyl-3-hydroxy-N-methyl-2-pyridone
Ref: Evaluation Report. PYRIDALYL. January 14, 2004. Japan Food Safety Commission. Pesticides Expert Committee.

US Federal Register
Date Published Docket Identification Number Details

Dec 5, 2003








Valent USA Corp. Two Pesticide tolerance petitions: PP 2F6459 and PP 2E6592

Commodity PPM
Cottonseed 0.4
vegetable, fruiting, group 8 1.1
vegetable, leafy,
except Brassica, group 4
Brassica, head and stem,
subgroup 5A
Brassica, leafy greens, subgroup 5B 30.0
turnip greens 30
meat 0.04
meat by-products 0.05
animal fat 1.0
whole milk 0.1
and to establish tolerances for residues of the insecticide chemical pyridalyl plus the metabolite
S-1812-DP, 3,5-dichloro-4-[3-(5-trifluoromethyl-2-pyridyloxy)]propoxy phenol,
cotton gin by-products 23.0

Genotoxicty... The test systems assayed did not show any evidence of pyridalyl genotoxicity except the in vitro mammalian cytogenetics (chromosome aberration) assay.
Subchronic toxicity.
-- Pyridalyl technical was tested in rats in a 3-month feeding study. Effects included
decreased body weight gain, altered blood biochemistry, increased relative liver weight and histopathological changes in the liver, ovary, adrenal and lung. The NOAEL is 100 ppm (5.56 mg/kg/day in males and 6.45 mg/kg/day in females).
-- A 13-week feeding study in mice was conducted. Effects included decreased body weight gain, hematological and blood biochemical effects,increased liver weight, decreased kidney and ovary weights and histopathological changes in liver, kidney, ovary and adrenal. The NOAEL is 70 ppm in males (8.169 mg/kg/day) and 700 ppm in females (86.78 mg/kg/day).
-- A 13-week oral (capsule) toxicity study was conducted in
dogs. Effects included decreased body weight gain, clinical signs indicative of respiratory distress, hematological and blood biochemistry effects, increased liver, lung and kidney weights and histopathological alterations of the lung, kidney, adrenal and liver. The NOAEL was 10 mg/kg/day.
Chronic toxicity.
In a 104-week combined chronic/oncogenicity study in rats,
effects included decreased body weight gain, increased frequency of rearing (high dose females only), hematological alterations and histopathological alterations of the spleen. No oncogenicity was found. The NOAEL for this study is 100 ppm (3.4 mg/kg/day in males and 4.1 mg/kg/day in females).
-- Pyridalyl was administered in the diet to mice for 78-weeks. Effects included decreased body weight gain and food consumption/efficiency, and increased liver and kidney weights. The NOAEL of the study was 50 ppm (5.04 mg/kg/day in males and 4.78 mg/kg/day in females)
-- Pyridalyl was administered for 12-months by capsule to
dogs. There were alterations in blood biochemistry (alkaline
phosphatase and alanine aminotransaminase) and increased liver weights. The NOAEL of the study was 20 mg/kg/day.
Metabolite toxicology. Two metabolites of pyridalyl, 2-hydroxy-5-trifluoromethylpyridine (HTFP) and HPDO that occur in extremely low levels in plants and animals, were also tested for genetic toxicity. Both metabolites were positive in the bacterial assay, but were negative in the mammalian mutagenesis assay. One metabolite, HPDO, was positive in the chromosome aberration test.
Endocrine disruption. Data from the rat reproduction and subchronic studies indicated that pyridalyl may effect lipid metabolism and, consequently, hormone levels. These in vivo results suggested that S-1812 may have a modulating activity on steroid biosynthesis at doses generally exceeding MTD... studies support the conclusion that S-1812 is not an endocrine disruptor in in vivo mammalian systems. Although, very weak inhibition of a single steroid biosynthesis pathway was observed in the in vitro study, effects possibly related to this conversion in mammalian systems were observed only at dose levels that greatly exceeded the maximum tolerated dose.


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