Title: Avermectins
Additional Names: AVM
Literature References: A group of broad-spectrum antiparasitic antibiotics which are derivs of pentacyclic 16-membered lactones related to the milbemycins, q.v. Isoln from a novel actinomycete, Streptomyces avermitilis, and separation of major components A1a, A2a, B1a, B2a and minor components A1b, A2b, B1b, B2b: G. Albers-Schönberg et al., DE 2717040; eidem, US 4310519 (1977, 1982 both to Merck & Co.); R. W. Burg et al., Antimicrob. Agents Chemother. 15, 361 (1979); T. W. Miller et al., ibid. 368. Antiparasitic activity: S. R. Egerton et al., ibid. 372. Mechanism of action: L. C. Fritz et al., Proc. Natl. Acad. Sci. USA 76, 2062 (1979). Pesticidal activity: I. Putter et al., Experientia 37, 963 (1981). Structure determn: G. Albers-Schönberg et al., J. Am. Chem. Soc. 103, 4216 (1981). Absolute configuration of avermectin B1a and aglycon B2a: J. P. Springer et al., ibid. 4221. Prepn of aglycons: H. Mrozik et al., J. Org. Chem. 47, 489 (1982). Total synthesis of A1a (C49H74O14): S. J. Danishefsky et al., J. Am. Chem. Soc. 109, 8119 (1987). Biosynthetic studies: D. E. Cane et al., ibid. 105, 4110 (1983); M. D. Schulman et al., J. Antibiot. 39, 541 (1986); T. S. Chen et al., Arch. Biochem. Biophys. 269, 544 (1989). Reviews: W. C. Campbell et al., ACS Symp. Ser. 255, 1-20 (1984); M. H. Fisher, H. Mrozik, "The Avermectin Family of Macrolide Antibiotics" in Macrolide Antibiotics, S. Omura, Ed. (Academic Press, New York, 1984) pp 553-606; Southwest. Entomol. 1985, Suppl. 7, 1-51; J. R. Babu, ACS Symp. Ser. 380, 91-108 (1988). Review of syntheses: T. Blizzard et al., in Recent Prog. Synth. Antibiotics, G. Lukacs, M. Ohno, Eds (Springer-Verlag, Berlin, 1990) pp 66-102. Review of structure-activity relationships: W. L. Shoop et al., Vet. Parasitol. 59, 139-156 (1995). For related structures see abamectin, ivermectin.
Derivative Type: Avermectin A1a/b
Properties: [a]D27 +68.5 ± 2° (c = 0.77 in chloroform). uv max (methanol): 237, 243, 252 nm (e 28700, 31275, 20290).
Optical Rotation: [a]D27 +68.5 ± 2° (c = 0.77 in chloroform)
Absorption maximum: uv max (methanol): 237, 243, 252 nm (e 28700, 31275, 20290)
Derivative Type: Avermectin A2a/b
Properties: [a]D27 +48.8 ± 2° (c = 1.64 in chloroform). uv max (methanol): 237, 243, 245 nm (e 28800, 31740, 20425).
Optical Rotation: [a]D27 +48.8 ± 2° (c = 1.64 in chloroform)
Absorption maximum: uv max (methanol): 237, 243, 245 nm (e 28800, 31740, 20425)
Derivative Type: Avermectin B1a/b see Abamectin
Derivative Type: Avermectin B2a/b
Properties: [a]D27 +38.3 ± 2° (c = 0.87 in chloroform). uv max (methanol): 237, 243, 252 nm (e 27580, 30590, 20060).
Optical Rotation: [a]D27 +38.3 ± 2° (c = 0.87 in chloroform)
Absorption maximum: uv max (methanol): 237, 243, 252 nm (e 27580, 30590, 20060)
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