Compound can be prepared in three different ways all starting from 14-hydroxydihydronormorphinone (I): 1) The condensation of (I) with cyclobutanecarboxyl chloride (A) by means of triethylamine in CH2Cl2 gives the bis(cyclobutylcarbonyl) derivative (II), which is then reduced and hydrolyzed with LiAlH4 in THF. 2) The condensation of (I) with cyclobutylmethyl bromide (B) in DMF gives the N-cyclobutylmethyl derivative (III), which is then reduced with NaBH4 in ethanol. 3) The reduction of (I) with NaBH4 as before gives 14-hydroxydihydronormophine (IV), which is then alkylated with cyclobutylmethyl bromide (B) in DMF.