... Tetrahedron. Volume 56, Issue 20, 12 May 2000, Pages 3181–3187. Cover image Cover image. ... The optical rotation ([α] D 20 =+37° (c 1, CHCl 3 )) confirmed that this compound has the absolute configuration of the unnatural isomer of huperzine A. 1.2. Crystal structure of 12 25. ...
[West, Scott P.; Bisai, Alakesh; Lim, Andrew D.; Narayan, Raja R.; Sarpong, Richmond Journal of the American Chemical Society, 2009 , vol. 131, # 31 p. 11187 - 11194]