Title: Marrubiin
CAS Registry Number: 465-92-9
CAS Name: [2aS-(2aa,5ab,6a,7a,8aa,8ba)]-6-[2-(3-Furanyl)ethyl]decahydro-6-hydroxy-2a,5a,7-trimethyl-2H-naphtho[1,8-bc]furan-2-one
Additional Names: 15,16-epoxy-6b,9-dihydroxy-8bH-labda-13(16),14-dien-19-oic acid g-lactone; 5-[2-(3-furyl)ethyl]decahydro-5,8-dihydroxy-1,4a,6-trimethyl-1-naphthoic acid g-lactone
Molecular Formula: C20H28O4
Molecular Weight: 332.43
Percent Composition: C 72.26%, H 8.49%, O 19.25%
Literature References: Diterpene lactone principle isolated from white horehound, Marrubium vulgare (Tourn.) L., Labiatae: Harms, Arch. Pharm. 83, 144 (1842); Ludwig, Kromayer, ibid. 158, 257 (1861); Nicholas, J. Pharm. Sci. 53, 895 (1964). Alternate view that marrubiin is an artefact generated from premarrubiin during the isoln: Henderson, McCrindle, J. Chem. Soc. C 1969, 2014. Structure and stereochemistry: Cocker et al., J. Chem. Soc. 1953, 2540; Chem. Ind. (London) 1954, 1561; 1955, 1484; Fulke, McCrindle, ibid. 1965, 647. Total stereochemistry: Wheeler et al., Tetrahedron 23, 3909 (1967); Appleton et al., J. Chem. Soc. C 1967, 1943. Synthesis: Mangoni et al., Tetrahedron 28, 611 (1972).
Properties: Crystals from alc, mp 160°. [a]D20 +35.8° (c = 3.1 in chloroform); [a]D24 +45° (acetone). uv max: 208, 212, 216 nm (log e 3.75, 3.75, 3.70). One gram dissolves in 60 ml alc. Freely sol in chloroform, acetone, hot alc, pyridine; sparingly sol in ether, benzene. Practically insol in water.
Melting point: mp 160°
Optical Rotation: [a]D20 +35.8° (c = 3.1 in chloroform); [a]D24 +45° (acetone)
Absorption maximum: uv max: 208, 212, 216 nm (log e 3.75, 3.75, 3.70) |