Emamectin benzoate

Emamectin

Names
Other names 4′′-Deoxy-4′′-epi-methylaminoavermectin B1; Epimethylamino-4′′-deoxyavermectin; MK 243; EMA; GWN 1972
Identifiers
CAS Number	119791-41-2 Y 155569-91-8 (Benzoate) Y
3D model (Jmol)	Interactive image
RTECS number	CL1203005
UNII	8C43B81H4W Y
SMILES C/C([C@](O[C@H]1C[C@H](OC)[C@](O[C@@H]2O[C@H](C)[C@@H](NC)[C@H](OC)C2)([H])[C@H](C)O1)([H])[C@@H](C)/C=C/C=C(CO3)/[C@@]([C@@]3([H])[C@H](O)C(C)=C4)(O)[C@@H]4C(O5)=O)=C\C[C@@H]6C[C@H]5C[C@]7(C=C[C@H](C)[C@]([C@@H](C)CC)([H])O7)O6
Properties
Chemical formula	C49H75NO13
Molar mass	886.13 g·mol−1
Appearance	White or faintly yellow powder
Melting point	141 to 146 °C (286 to 295 °F; 414 to 419 K)
Solubility in water	30-50 ppm (pH 7)
Pharmacology
ATCvet code	QP54AA06 (WHO)
Hazards
R-phrases	R25 R36 R50 R57 R58
S-phrases	S26 S36 S45 S60 S61
NFPA 704	2 2 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Emamectin is the 4”-deoxy-4”-methylamino derivative of abamectin, a 16-membered macrycyclic lactone produced by the fermentation of the soil actinomycete Streptomyces avermitilis. It is generally prepared as the salt with benzoic acid, emamectin benzoate, which is a white or faintly yellow powder. Emamectin is widely used in the US and Canada as an insecticide because of its chloride channel activation properties.

Emamectin, produced by the bacterium Streptomyces avermitilis, belongs to the avermectin family of compounds all of which exhibit toxicity for nematodes, arthropods, and several other pests. The benzoate salt of emamectin in particular has found widespread use as an insecticide and is approved by the EPA for use in prevention of emerald ash borer in ash trees. Emamectin is derived from avermectin B1, also known as abamectin, a mixture of the natural avermectin B1a and B1b. Emamectin has also shown promising applications in the eradication of fish lice and in fish farming.

Emamectin is derived from abamectin by replacement of an epi-amino-methyl (NHCH₃) group by a hydroxyl (-OH) group at the 4”-position. Emamectin, like abamectin, is a mixture of two homologue compounds termed B1a and B1b which differ on the C-25 side-chain by one methylene (CH2) group. B1a contains a sec-butyl group while B1b has an isopropyl group. Emamectin is a mixture, typically consisting of 10% B1b and 90% B1a.

Avermectin biosynthesis is classified into three stages: the formation of the polyketide-derived initial aglycone, modification of the initial aglycone to produce avermectin aglycones, and glycosylation of avermectin aglycones to generate avermectins.

Emamectin is widely used in controlling lepidopterous pests (order of insects that as larvae are caterpillars and as adults have four broad wings including butterflies, moths, and skippers) in agricultural products in the US, Japan, Canada, and recently Taiwan. The low-application rate of the active ingredient needed (~6 g/acre) and broad-spectrum applicability as an insecticide has gained emamectin significant popularity among farmers.

Emamectin has been shown to possess a greater ability to reduce the colonization success of engraver beetles and associated wood borers in loblolly pines (Pinus taeda L).6 A 2006 study regarding bolt-injections of four types of pesticides found emamectin to be the greatest reducer against these species with respect to the amount of larval feeding, length, and number of egg galleries.6 Formation of long vertical lesions in the phloem and xylem surrounding emamectin injection points were found indicating some level of tree-toxicity to the emamectin.