The topic is also of great interest for me, though from a different point of view. The resolution of racemic methamphetamine free base can be done without solvent through my favorite compound (grin):
O,O`(+)-dibenzoyl-d-tartaric acid in good yields. (80-85% ).
However, i wanted to ask if anybody has expierence with the so called RRR-process. RRR stands for resolution-racemisation-recycling, to re-racemise the unwanted l-isomer back to a 50:50 racemic mixture. This is conducted using small amount of a radical initiator like AIBN and a source of thiyl radicals (ie methyl thioglycolate). This way one can drive up yields from theoretical 50% to over 90% by running the process several times. I couldn´t find any reasonable procedure write down so far.
O,O`(+)-dibenzoyl-d-tartaric acid in good yields. (80-85% ).
However, i wanted to ask if anybody has expierence with the so called RRR-process. RRR stands for resolution-racemisation-recycling, to re-racemise the unwanted l-isomer back to a 50:50 racemic mixture. This is conducted using small amount of a radical initiator like AIBN and a source of thiyl radicals (ie methyl thioglycolate). This way one can drive up yields from theoretical 50% to over 90% by running the process several times. I couldn´t find any reasonable procedure write down so far.
- By 花谢花开
Which dibenzoyl tartaric acid do you use to split cas? Is it the liquid part or the crystal part? Can you explain it in detail? I agree with this method. I think it's better than tartaric acid. Thank you.
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- By OrgUnikum
Yes, the o,o-dibenzoyl-d-tartaric acid is the only one named in literature as working for chiral resolution of meth by the usual process. Search for "dutch resolution" for a description of how it is done. Plain tartaric acid shows no separation. The process which is supposed to work by solubility differences works by a complete different principle and It may work, or it may not. I do not know.
In the longer run any chiral synthesis will be more rewarding, no doubt about this.
Anybody planning to use AIBN should inform himself very well about how to handle this stuff, it is quite nasty.
In the longer run any chiral synthesis will be more rewarding, no doubt about this.
Anybody planning to use AIBN should inform himself very well about how to handle this stuff, it is quite nasty.
- By OrgUnikum
This is what you need to know....
Optical Resolution of N-methylamphetamine Via Diastereoisomeric Salt Formation With 2R,3R-O,O´-Di-p-toluoyltartaric Acid
DÁVID KOZMA, ZOLTÁN MADARÁSZ, CSABA KASSAI, AND ELEMÉR FOGASSY
Department of Organic Chemical Technology, Technical University of Budapest, Budapest, Hungary
CHIRALITY 11:373–375 (1999)
Optical Resolution of N-methylamphetamine Via Diastereoisomeric Salt Formation With 2R,3R-O,O´-Di-p-toluoyltartaric Acid
DÁVID KOZMA, ZOLTÁN MADARÁSZ, CSABA KASSAI, AND ELEMÉR FOGASSY
Department of Organic Chemical Technology, Technical University of Budapest, Budapest, Hungary
CHIRALITY 11:373–375 (1999)