A diester resulting from the formal sequential esterification of the hydroxy group of one molecule of (3R)-3-hydroxybutyric acid with the carboxy group of a second, followed by the esterification of the hydroxy group of the product with the carboxy group of a third molecule of (3R)-3-hydroxybutyric acid. Isolated from the Japanese inedible mushroom Hypoxylon truncatum and also the sponge-derived actinomycete Micromonospora sp. RV43.