Short‐chain phorbol ester constituents of croton oil

Five phorbol diesters, three 4‐deoxy‐4α‐phorbol diesters, two phorbol monoesters, and one 4‐deoxy‐4α‐phorbol monoester were isolated from a commercial sample of croton oil and characterized spectroscopically. Their purification was achieved using combinations of droplet countercurrent chromatography, low‐pressure column chromatography over phase‐bonded silica gel, and preparative thin layer chromatography. All of these isolates were shown to possess short‐chain ester functionalities, with 12‐O‐tiglylphorbol‐13‐isobutyrate, 12‐O‐(2‐methyl)butyrylphorbol‐13‐isobutyrate, 12‐O‐(2‐methyl)butyrylphorbol‐13‐acetate, 12‐O‐tiglyl‐4‐deoxy‐4α‐phorbol‐13‐isobutyrate, 12‐O‐tiglyl‐4‐deoxy‐4α‐phorbol‐13‐acetate, 12‐O‐(2‐methyl)butyryl‐4‐deoxy‐4α‐phorbol‐13‐acetate, phorbol‐12‐tiglate and 4‐deoxy‐4α‐phorbol‐13‐acetate being new compounds.