Earlier communications (1,2) have reported the structural elucidation and total synthesis of eritadenine, 4-(6-amino-9H-purin-9-yl)-2(R),3(R)-dihydroxybutyric acid (I), isolated as a major component from Lentinus edodes. In the course of continuing search for new constituents, an extensive analysis of eritadenine fraction was carried out, leading to the isolation of two new substances, deoxyeritadenine (II) and 4-(6-amino-9H-purin-9-yl)-propionic acid (III). This communication deals with their structures and syntheses. Deoxyeritadenine (II) was isolated by preparative TLC after conversion of crude eritadenine to methyl ester; its structure was determined by spectrometric and NMR data as 4-(6-amino-9H-purin-9-yl)-2(R)-hydroxybutyric acid, with R-configuration confirmed synthetically via resolution of 2-hydroxybutyrolactone-derived intermediates, condensation with 4-amino-6-chloro-5-nitropyrimidine, and reduction, yielding a product identical to natural II. The second new substance (III), isolated in minute quantities, had a structure deduced from NMR (showing an ethylene group) and verified by comparison with an authentic specimen synthesized from adenine and ethyl acrylate.