It is known that morphine-6-glucuronide is more potent than morphine, but it is difficult and expensive to produce. Our aim was to synthesise an analogue(s) of morphine-6-glucuronide which would have similar or enhanced properties, but that could be obtained via a simple synthetic route. It is hoped that such a compound could be used to treat terminally ill cancer patients. Due to the enhanced potency a smaller dose of the drug would be required to effect the same analgesic effect as morphine, and this may help to reduce the effect of morphine tolerance.