Happyman reads from Amination/demethylation process Ellis K. Fields
http://www.google.com/patents/about?id=pIQ3AAAAEBAJ&output=text
"SUMMARY OF THE INVENTION
OH 0 OH OCH,
According to the invention, it has now been found that selective demethylation of compounds of the formula (II) can be achieved by treating such compounds
35 with an aluminum halide, such as aluminum chloride or bromide in a homogeneous solution in chlorobenzene, bromobenzene or nitrobenzene, preferably, nitrobenzene, to produce compounds of the formula (I) in high yield and in a single step. The amount of aluminum
40 halide used is not critical and can be from 1 to 20 moles per mole of compound of formula (II), but the best results are obtained with 4—8 moles of aluminum halide. The temperature at which the reaction is conducted can be varied from 0° to 50°C., but the best
45 results are obtained at temperatures of 20°C. or less. Another important advantage of the procedure of the invention is the possibility, owing to the mild conditions employed therein, of using optically active intermediates without any loss of optical activity; thus the separa- tion of optical isomers can be performed, with advantage, at an earlier stage of the synthetic sequence."
This seem feasible? Hypothetically applied to lets say 4-MAR? May I also throw HBr demethylations in there. HBr/NaI is the only I got the patent for.
http://www.google.com/patents/about?id=pIQ3AAAAEBAJ&output=text
"SUMMARY OF THE INVENTION
OH 0 OH OCH,
According to the invention, it has now been found that selective demethylation of compounds of the formula (II) can be achieved by treating such compounds
35 with an aluminum halide, such as aluminum chloride or bromide in a homogeneous solution in chlorobenzene, bromobenzene or nitrobenzene, preferably, nitrobenzene, to produce compounds of the formula (I) in high yield and in a single step. The amount of aluminum
40 halide used is not critical and can be from 1 to 20 moles per mole of compound of formula (II), but the best results are obtained with 4—8 moles of aluminum halide. The temperature at which the reaction is conducted can be varied from 0° to 50°C., but the best
45 results are obtained at temperatures of 20°C. or less. Another important advantage of the procedure of the invention is the possibility, owing to the mild conditions employed therein, of using optically active intermediates without any loss of optical activity; thus the separa- tion of optical isomers can be performed, with advantage, at an earlier stage of the synthetic sequence."
This seem feasible? Hypothetically applied to lets say 4-MAR? May I also throw HBr demethylations in there. HBr/NaI is the only I got the patent for.