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Spiroxamine

Spiroxamine 98%TC
Spiroxamine 75%WG
Spiroxamine 50%WG

Fungicide
FRAC 5, G2; morpholine: spiroketalamine

Spiroxamine NOMENCLATURE
Common name spiroxamine (BSI, pa ISO)
IUPAC name 8-tert-butyl-1,4-dioxaspiro[4.5]decan-2-ylmethyl(ethyl)(propyl)amine
Chemical Abstracts name 8-(1,1-dimethylethyl)-N-ethyl-N-propyl-1,4-dioxaspiro[4,5]decane-2-methanamine
CAS RN [118134-30-8] Development codes KWG 4168 (Bayer)

Spiroxamine PHYSICAL CHEMISTRY
Composition Comprises 2 diastereoisomers, A and B, in the proportions 49-56% and 51-44%, respectively. Mol. wt. 297.5 M.f. C18H35NO2 Form Faintly yellowish liquid; (tech. is a light brown, oily liquid). M.p. <-170 °C (separate diastereoisomers, spiroxamine A, spiroxamine B, and tech. mixture of both diastereoisomers) B.p. Decomp. c. 120 °C V.p. A: 9.7 mPa (20 °C); B: 17 mPa (25 °C) (both extrapolated) KOW A: logP = 2.79; B: logP = 2.92 (unstated pH) Henry A: 2.5  10-3; B: 5.0  10-3 (both in Pa m3 mol-1, 20 °C, calc.) S.g./density A and B both 0.930 (20 °C) Solubility In water, mixture of A and B: >200  103 mg/l (pH 3, 20 °C); A: 470 (pH 7), 14 (pH 9); B: 340 (pH 7), 10 (pH 9) (both diastereoisomers in mg/l, 20 °C). Stability Stable to hydrolysis and photodegradation; provisional photolytic DT50 50.5 d (25 °C). pKa 6.9, base F.p. 147 °C

COMMERCIALISATION
History Discovered in 1987. Reported by S. Dutzmann et al. (Proc. Br. Crop Prot. Conf. - Pests Dis., 1996, 1, 47).First sold in 1997. Manufacturers Bayer CropScience

Spiroxamine APPLICATIONS
Biochemistry Sterol biosynthesis inhibitor, acting mainly by inhibition of 14-reductase. Mode of action Protective, curative and eradicative systemic fungicide. Readily penetrates into the leaf tissue, followed by acropetal translocation to the leaf tip. Uniformly distributed within the whole leaf. Uses Control of powdery mildew in cereals (Erysiphe graminis), at 500-750 g/ha, and in grapes (Uncinula necator), at 400 g/ha. Also gives good control of rusts (Rhynchosporium and Pyrenophora teres), together with certain side-effects against Septoria diseases. Penetration studies have shown that tank mixes of spiroxamine and triazoles can positively influence the uptake of triazoles in plants. Formulation types EC; EW. Selected products: 'Impulse' (Bayer CropScience); 'Prosper' (Bayer CropScience); mixtures: 'Pronto Plus' (+ tebuconazole) (spray, Germany) (Bayer CropScience)