[New dimeric phthalide derivative from Angelica sinensis].

Aim: To study the chemical constituents of the roots of Angelica sinensis.

Methods: Silica gel column chromatography was used to separate the chemical constituents. Their structures were elucidated by chemical and spectral analysis (IR, MS, 1D and 2D NMR, etc.).

Results: Besides three known phthalide derivatives, one new dimeric phthalide derivative and a pair of epimer were isolated and their structures were identified as Z-3',8',3'a,7'a-tetrahydro-6,3',7,7'a-diligustilide-8'-one (1), Z,Z'-6,6',7,3'a-diligustilide (2) and the 8-epimer (3) of 2 on the basis of spectral data.

Conclusion: Compound 1 is a new dimeric phthalide derivative, and compound 3 was first reported from radix Angelica