Title: Abamectin
CAS Registry Number: 71751-41-2
CAS Name: Avermectin B1
Additional Names: 5-O-demethylavermectin A1a and 5-O-demethyl-25-de(1-methylpropyl)-25-(1-methylethyl)avermectin A1a (4:1); avermectin B1a/b
Manufacturers' Codes: MK-936
Trademarks: Agri-Mek (Syngenta); Avid (Syngenta); Zephyr (Syngenta)
Literature References: Mixture of avermectins, q.v., containing at least 80% of avermectin B1a (C48H72O14) and not more than 20% of avermectin B1b (C47H70O14). Isoln from Streptomyces avermitilis: G. Albers-Schönberg et al., DE 2717040; eidem, US 4310519 (1977, 1982 both to Merck & Co.). Separation of components: T. W. Miller et al., Antimicrob. Agents Chemother. 15, 368 (1979); by semi-preparative HPLC: C. C. Ku et al., J. Liq. Chromatogr. 7, 2905 (1984). Structure determn: G. Albers-Schönberg et al., J. Am. Chem. Soc. 103, 4216 (1981). Absolute configuration: J. P. Springer et al., ibid. 4221. Partial synthesis of B1a: K. C. Nicolaou et al., ibid. 106, 4189 (1984). Total synthesis: S. Hanessian et al., ibid. 108, 2776 (1986). Anthelmintic activity: L. S. Blair, W. C. Campbell, J. Parasitol. 64, 1032 (1978); J. R. Egerton et al., Antimicrob. Agents Chemother. 15, 372 (1979); K. S. Todd et al., Am. J. Vet. Res. 45, 976 (1984). Pesticidal activity: I. Putter et al., Experientia 37, 963 (1981); R. A. Dybas, A. St. J. Green, Proc. Br. Crop Prot. Conf. - Pests Dis. 1984, 947. Control of red imported fire ants: J. A. Greenblatt et al., J. Agric. Entomol. 3, 233 (1986). Interaction with GABA receptors: S. S. Pong et al., J. Neurochem. 34, 351 (1980); T. N. Mellin et al., Neuropharmacology 22, 89 (1983). Receptor binding studies: S. S. Pong, C. C. Wang, ibid. 19, 311 (1980); G. Drexler, W. Sieghart, Eur. J. Pharmacol. 99, 269 (1984). Fate in soil and plants: D. L. Bull et al., J. Agric. Food Chem. 32, 94 (1984); H. A. Moye et al., ibid. 35, 859 (1987); M. S. Maynard et al., ibid. 37, 178, 184 (1989). Review: J. R. Babu, ACS Symp. Ser. 380, 91-108 (1988). Reviews of modes of action: C. C. Wang, S. S. Pong, Prog. Clin. Biol. Res. 97, 373-395 (1982); D. J. Wright, Biochem. Soc. Trans. 15, 65-67 (1987); of insecticidal activities and use: L. Strong, T. A. Brown, Bull. Entomol. Res. 77, 357-389 (1987). Book: Ivermectin and Abamectin, W. C. Campbell, Ed. (Springer-Verlag, New York, 1989) 363 pp.
Properties: Odorless, off-white to yellow crystals from methanol, mp 150-155° (dec). [a]D +55.7 ±2° (c = 0.87 in CHCl3). uv max (methanol): 237, 245, 253 nm (log e 4.48, 4.53, 4.34). Vapor pressure: 1.5 ´ 10-9 torr. Soly at 21° (mg/l): water 10; (mg/ml): acetone 100; n-butanol 10; chloroform 25; cyclohexane 6; ethanol 20; isopropanol 70; kerosene 0.5; methanol 19.5; toluene 350. Hydrolysis does not occur in aq soln at pH 3, 5, 7. LD50 (technical grade) orally in sesame oil in mouse, rat: 13.5, 10.0 mg/kg; dermally in rabbit: >2000 mg/kg. LD50 in mallard duck, bobwhite quail: 84.6, >2000 mg/kg. LC50 (96 hr) in rainbow trout, bluegill: 3.6, 9.6 mg/l; LC50 (48 hr) in Daphnia magna: 0.34 mg/l (Merck Technical Data Sheet).
Melting point: mp 150-155° (dec)
Optical Rotation: [a]D +55.7 ±2° (c = 0.87 in CHCl3)
Absorption maximum: uv max (methanol): 237, 245, 253 nm (log e 4.48, 4.53, 4.34)
Toxicity data: LD50 (technical grade) orally in sesame oil in mouse, rat: 13.5, 10.0 mg/kg; dermally in rabbit: >2000 mg/kg; LD50 in mallard duck, bobwhite quail: 84.6, >2000 mg/kg; LC50 (96 hr) in rainbow trout, bluegill: 3.6, 9.6 mg/l; LC50 (48 hr) in Daphnia magna: 0.34 mg/l (Merck Technical Data Sheet)
Use: Acaricide; insecticide.
Therap-Cat-Vet: Anthelmintic. |