Patent ID: 8901356

Claim:
A method of producing ingenol-3-angelate (I) from ingenol (II): the method comprising the steps of: (a) reacting one or both hydroxyl groups in positions 5 and 20 of ingenol (II) with suitable hydroxyl protecting agents, which may be the same or different, to obtain a compound of the general formula (III) or (IV) wherein R 1 represents hydrogen or a hydroxyl protective group and R 2 represents hydrogen or a hydroxyl protective group, with the proviso that R 1 and R 2 are not both hydrogen, and wherein D represents a dihydroxyl protective group; (b) esterifying the hydroxyl group at the 3-position of the compound of formula (III) or (IV) to obtain a compound of the general formula (V) or (VI) wherein R 1 , R 2 and D are as described above; and (c) removing the hydroxyl protective groups R 1 or R 2 , or R 1 and R 2 , or D from the compound of formula (V) or (VI) to obtain ingenol-3-angelate (I).