Diterpenes from leaves of Juniperus chinensis

Sixteen diterpenes, a norditerpene and a secoditerpene were isolated from the leaves of Juniperus chinensis. The structures of new compounds abieta-8,11,13-trien-7β-ol, 13β-hydroxy-7-oxoabiet-8(14)β-en-19,6β-olide (juniperolide), 6,13β-dihydroxy-7-oxoabieta-5,8(14)-dien-19-al (juniperal), 15-oxo-16-norabieta-7,13-dien-19,6β-olide (norjuniperolide), 13β,14β-epoxy-8-oxo-7,8-secoabietan-7,19-olide (secojuniperolide) and 11β-hydroxy-14-oxochinan-19-al (chinanoxal) were determined by spectral methods and X-ray crystallography. Besides the sempervirane, abietane and totarane types having the isopropyl group, respectively, at the C-12, C-13 and C-14 positions, the remaining chinanetype diterpene having an isopropyl group at C-11 is first reported. Occurrence of all four types of diterpenes in this plant is significant.