By hydrolysis of scutellarin: Molisck, Goldschmidt, Monatsh. Chem. 22, 679 (1901); Marsh, Biochem. J. 59, 58 (1955). From Digitalis lanata Ehrh., Scrophulariaceae: Rangaswami, Rao, Proc. Indian Acad. Sci. 54A, 51 (1961), C.A. 56, 10076f (1962). Structure: Wessely, Moser, Monatsh. Chem. 56, 97 (1930). Synthesis: Sastri, Seshadri, Proc. Indian Acad. Sci. 23A, 262 (1946), C.A. 41, 449a (1947); Zemplén et al., Acta Chim. Acad. Sci. Hung. 16, 445 (1958); Jouanne, Mentzer, C. R. Seances Acad. Sci. Ser. C 263, 1022 (1966).
From leaves of Scutellaria altissima Linn., Labiatae: Goldschmiedt, Zerner, Monatsh. Chem. 31, 439 (1910); from Centaurea scabiosa L., Compositae: Charaux, Rabaté, J. Pharm. Chim. 9, 155 (1940); from Scutellaria spp.: Marsh, Biochem. J. 59, 58 (1955); Nature 183, 1824 (1959). Synthesis: Farkas et al., Ber. 107, 3878 (1974).