Wakeman—Pigments of Flowering Plants . 
815 
diet 4 in 1877 confirmed the work of Hlasiwetz and Pfaundler, 
Ciamician and Silber 5 in 1894 attacked the problem of its con¬ 
stitution and partially elucidated its structure. Koenig and 
Kostanecki 6 in the same year completed this task. Other studies 
of maclurin have been made by Delffs 7 in 1862; Liebig 8 in 
1860; Bedford and Perkin 9 in 1895; and by Perkin in 1897. 
Maclurin forms fine pale yellow crystals which melt at 200°. 
It dissolves in caustic alkalies forming a yellow solution which 
turns brown upon exposure to the air. Lead acetate gives a 
yellow precipitate. 
Kinoin, — Tetrahydroxy — 2, 3, 4 2' — metlnoxy-3' — diphenyl 
methanone. 
Kinoin * 1 occurs in the dried juice of Pterocarpus erinaceus, 
Pterocarpus marsupium, and Coccoloba uvifera, also in several 
species of Eucalyptus, and in Butea frondosa. 
In 1879, Etti 2 isolated from green kino a substance which he 
called kinoin and to which he assigned the formula C 14 H 12 0 6 . 
This substance contains a hydroxy group and upon hydrolysis 
yields pyrocatechin and gallic acid. Thomas 3 in his book on 
the natural dyestuffs has suggested for kinoin the structural for¬ 
mula given above. 
A considerable number of investigations of the various species 
of kino have been made. The results of most of these investiga¬ 
tions do not agree with those of Etti, phloroglucin, pyrocatechin, 
* Ann., 185, p. 117. 
6 Ber., 27, p. 1627; 28, p. 1393. 
«Ber., 27, p. 1996. 
7 Chem. Centrlbl., 1862, p. 284. 
8 Jahresber. d. Chem., 1860, p. 278. 
9 Jr. Chem. Soc., 67, p. 933. 
10 Jr. Chem. Soc., 71, p. 186. 
1 Pharm. Jr., 16, p. 676; Pharm. Ztg., 58, p. 593. 
2 Ber., 11, p. 1876; 17, II, p. 2241. 
8 Les Matieres Colorantes Naturelles, p. 22. 
