5,9,11-Trihydroxy-2,2-dimethyl-3-(2-methylbut-3-en-2-yl)pyrano[2,3-a]xanthen-12(2H)-one from the Stem Bark of Calophyllum tetrapterum Miq - Tjahjandarie, Tjitjik Srie (MDPI AG, Basel, Switzerland, 2017)