[The isolation and structure of argutone--a new bacteriostatic constituent of Incarvillea arguta]

Argutone——a new constituent having bacteriostatic and sedative activities was isolated from the foliage of the Incarvillea arguta (Royle) Royle. Its structure was evidenced by UV IR ~1H-NMR ~(13)C-NMR MS and X-ray diffraction etc as 2-ethoxymethylene-3,5-dihydroxy-γ-pyrone. Both of pyrane ring and two side chain hydroxy groups (C_3-OH, C_5-OH) form a plane structure, and side chain -CH_2OCH_2CH_3 with folding form extends toward a vertical position from this plane. It has weak intra-molecular hydrogen bond and the molecules are held together by Van Der Waals force in the solid state.