Aminocyclopyrachlor

Aminocyclopyrachlor

Names
Preferred IUPAC name 6-Amino-5-chloro-2-cyclopropylpyrimidine-4-carboxylic acid
Identifiers
CAS Number	858956-08-8 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:62952
ChemSpider	21442054
ECHA InfoCard	100.121.525
PubChem CID	17747875
UNII	O19K7667GO Y
CompTox Dashboard (EPA)	DTXSID0074683
SMILES C1CC1C2=NC(=C(C(=N2)N)Cl)C(=O)O
Properties
Chemical formula	C8H8ClN3O2
Molar mass	213.62 g·mol−1
Appearance	Brown liquid[2]
Density	1.134 g/ml
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Aminocyclopyrachlor (AMCP) is a selective, low-toxicity, auxin-mimicking herbicide that provides pre- and post-emergent control of broadleaf weeds on several non-food use sites including rights of way, wildlife management areas, recreational areas, turf/lawns, golf courses and sod farms. It was conditionally registered as Imprelis by DuPont in August 2010, and first used in Fall 2010.^[3] The chemical is a systemic herbicide and acts by disrupting gene expression. Aminocyclopyrachlor belongs to the pyrimidine carboxylic acid chemical family and mimics auxin which is a growth-regulating hormone in dicots including broadleaf terrestrial plants.^[4] This causes undifferentiated cell division and elongation, with resulting appearance characteristic of auxin herbicide damage such as leaf twisting and curling.^[5][6]

Although auxin-mimicing herbicides are selectively toxic to dicots, some angiosperms are also affected. Due to the emergence of damage to some conifer species, the United States Environmental Protection Agency and DuPont advised professional applicators and residential consumers to not use Imprelis where Norway spruce or white pine trees are present on or near the property being treated.^{[3] [7]}

Tomato plants are the preeminent bioassay platform for testing auxin herbicide damage because they are extremely sensitive to it.^[8][9] In a controlled greenhouse test, tomato plants were mulched with the remains of Norway spruce and honey locust trees that were damaged from exposure to AMCP that had been applied to adjacent turf grass more than a year prior to the tomato tests. The mulch (i.e. shredded foliage and stems) contained 4.7 to 276 ppb of AMCP. All of the AMCP-exposed tomato plants sustained visible damage while the unexposed controls showed no damage. Residual AMCP in the exposed tomato plants ranged from 0.5 to 8.0 ppb.^[10]

As with aminopyralid, AMCP-contaminated soil, mulch, or compost should be excluded from sensitive crops or gardens. The dissipation half-life (DT₅₀) time of AMCP has been measured at between 3 and >112 days in four soils from the Northern Great Plains.^[11] More recently, the time required for 90% degradation (DT₉₀) was found to be 622 to 921 days.^[12] As a practical matter, all material in AMCP-treated areas should be regarded as permanently poisonous to tomatoes and other nightshades until proven safe.