Occurs in the bark of Samanea saman Merr. (formerly Pithecolobium saman Benth.), bark and seed of P. bigeminum Mart. and P. lobatum Benth., Leguminosae. Isoln: Greshoff, Ber. 23, 3541 (1890); K. Wiesner et al., Can. J. Chem. 30, 761 (1952). Structure: eidem, J. Am. Chem. Soc. 75, 6348 (1953); D. E. Orr, K. Wiesner, Chem. Ind. (London) 1959, 672; K. Wiesner, D. E. Orr, Tetrahedron Letters no. 16, 11 (1960); K. Wiesner et al., Can. J. Chem. 46, 1886, 3617 (1968).