ADENINE, or 6-AMINO-PURIN, C5H5N5, in chemistry, a basic substance which has been obtained as a decomposition product of nuclein, and also from the pancreatic glands of oxen. It has been synthesized by E. Fischer (Berichte, 1897, 30, p. 2238) by heating 2.6.8-trichlorpurin with to times its weight of ammonia for six hours at roo° C.; by this means 6-amino-2.8-dichlorpurin is obtained, which on reduction by means of hydriodic acid and phosphonium iodide is converted into adenine. In 1898 E. Fischer also obtained it from 8-oxy-2.6-dichlorpurin ,Berichte, 1898, 31, p. 104). It crystallizes in long needles; forms salts C5H5N5.2HI and (C5H5N5)2.HsSO4.2H20, and is converted by nitrous acid into hypoxanthine or 6-oxypurin. On heating with hydrochloric acid at 18o-2oo° C. it is decomposed; the products of the reaction being glycocoll, ammonia, formic acid and carbon dioxide. Various methyl derivatives of adenine have been described by E. Fischer (Berichte, 1898, 31, p. 104) and by M. Kruger (Zeit. fur physiol. Chemie, 1894, 18, p. 434). For the constitution of adenine see PURIN.