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Efficient Resolution of Menthylamine with Inexpensive ( R , R )‐Tartaric Acid by Dielectrically Controlled Resolution (DCR)
Author(s) -
Schmitt Magdalena,
Schollmeyer Dieter,
Waldvogel Siegfried R.
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201301566
Subject(s) - chemistry , tartaric acid , diastereomer , methanol , yield (engineering) , aqueous solution , enantiomer , resolution (logic) , solvent , salt (chemistry) , sodium hydroxide , amine gas treating , nuclear chemistry , organic chemistry , materials science , artificial intelligence , computer science , metallurgy , citric acid
A practical procedure for the resolution of menthylamine 2 with ( R , R )‐tartaric acid [( R , R )‐ 3 ] as resolving agent is presented. Variation of the solvent system allows both enantiomers of 2 to be selectively crystallized. Performing the resolution in methanol containing 6 % water leads to (–) ‐2· ( R , R )‐ 3· MeOH. The other, less‐soluble diastereomeric salt is obtained by applying a solvent system consisting of methanol with 19 % water with a yield of 14 %. Subsequent basic workup with aqueous sodium hydroxide gave the free menthylamine compounds. Further workup of the mother liquors and an additional recrystallization step allowed the (–) ‐2· ( R , R )‐ 3· MeOH salt to be obtained in an overall yield of 22 %; the other salt (+) ‐2· ( R , R )‐ 3· MeOH · H 2 O was obtained in 23 % yield. This is another important example of the dielectrically controlled resolution of an interesting amine by using inexpensive ( R , R )‐tartaric acid as resolving agent.