ABSTRACT: The title compound, C29H36O4 [systematic name (4aR,5R,6aS,7R,11aS,11bR)-4a-hydroxy-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophen-anthro[3,2-b]furan-5-yl cinnamate], a natural diterpene known as pulcherrin J, was isolated from stem barks of medicinally important Caesalpinia pulcherrima (L.). The crystal structure of pulcherrin J shows it to be composed of a central core of three trans-fused cyclo-hexane rings and a near planar five-membered furan ring, along with an axially oriented cinnamate moiety and an -hydroxy substituent attached at positions 4a and 5 of the steroid ring system, respectively. The absolute structure was established with the use of Cu Kα r
