(1S,4S)-4-[(4-hydroxyphenyl)methyl]-2-methyl-2,5-diazaspiro[bicyclo[3.2.1]octane-6,1'-cyclohexan]-4'-one + S-adenosyl-L-methionine <=> (1S,4S)-4-[(4-methoxyphenyl)methyl]-2-methyl-2,5-diazaspiro[bicyclo[3.2.1]octane-6,1'-cyclohexan]-4'-one + S-adenosyl-L-homocysteine + H(+)