Structurally the only difference between JWH-133 and dimethylbutyl-D8-THC is that JWH-133 lacks the hydroxy group seen on dimethylbutyl-D8-THCs phenol structure (the C1 position of the A ring), turning this group into a phenyl (JWH-133) instead of phenol.
JWH-133 and dimethylbutyl-D8-THC differ structurally only in that JWH-133 lacks the hydroxy group found on dimethylbutyl-D8-THCs phenol structure (the C1 position of the A ring), transforming it into a phenyl group instead of a phenol.