8026. Quassin

Nomenclature

CAS number: 76-78-8
2,12-Dimethoxypicrasa-2,12-diene-1,11,16-trione; 3aβ,6aβ,7,7aα,8,11a,11bα,11c-octahydro-2,10-dimethoxy-3,8α,11aβ,11cβ-tetramethylphenanthro[10,1-bc]pyran-1,5,11(4H)-trione; nigakilactone D.
C22H28O6; mol wt 388.45.
C 68.02%, H 7.27%, O 24.71%.

Description and references

One of the bitter constituents of the wood of Quassia amara L., Simaroubaceae known in commerce as Surinam quassia. Obtained by the resolution of the mixture of bitter constituents of quassia wood: E. P. Clark, J. Am. Chem. Soc. 59, 927 (1937); London et al., J. Chem. Soc. 1950, 3431. Structure: Valenta et al., Tetrahedron Lett. no. 20, 25 (1960); Carman, Ward, ibid. 1961, 317; Valenta et al., Tetrahedron 15, 100 (1961). Stereochemistry: Valenta et al., ibid. 18, 1433 (1962). Identity with nigakilactone D: Murae et al., ibid. 27, 1545 (1971). Synthetic approach: Stojanac et al., Can. J. Chem. 53, 619 (1975); P. A. Grieco et al., Tetrahedron Lett. 21, 1619 (1980). Total synthesis of dl-form: eidem, J. Am. Chem. Soc. 102, 7586 (1980).

Chemical structure

Properties

Very bitter rectangular plates from dilute methanol, mp 222°. [α]D20 +34.5° (c = 5.09 in CHCl3). uv max: ≈255 nm (ε ≈11,650). Sol in benzene, alc, acetone, chloroform, pyridine, acetic acid, hot ethyl acetate. Sparingly sol in ether, petr ether. Bitterness threshold 1:60,000.