Two New Neolignans from the Stems of Syringa pinnatifoliaHemsl. var. alashanensis

Two new neolignans, syripinnalignins A and B (1 and 2, resp.), were isolated from the 95% EtOH extract of the stem of Syringa pinnatifolia Hemsl. var. alashanensis. The structures of 1 and 2 were elucidated by spectroscopic methods, including UV, IR, HR-ESI-MS, and extensive 1D- and 2D-NMR techniques.