21411-81-4Relevant articles and documents
Efficient resolution of menthylamine with inexpensive (r,r)-tartaric acid by dielectrically controlled resolution (DCR)
Schmitt, Magdalena,Schollmeyer, Dieter,Waldvogel, Siegfried R.
, p. 1007 - 1012 (2014/03/21)
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·H2O 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. With the same inexpensive resolving agent, (R,R)-tartaric acid, both antipodes of menthylamine can be selectively crystallized as diastereomeric salts. The concentration of water determines which salt is formed. In a few simple resolution steps, good yields and high enantiomeric excess can be achieved. Copyright
Direct amination of bio-alcohols using ammonia
Pingen, Dennis,Diebolt, Olivier,Vogt, Dieter
, p. 2905 - 2912 (2013/10/21)
A slightly adapted catalyst system has been successfully applied in the direct amination of primary and secondary alcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammonia used are highly important in this system, especially for higher substrate loadings. The catalyst was employed on a larger batch scale for the conversion of isomannide to the corresponding diamine. Additionally, it was shown that the catalyst is stable for at least six consecutive runs. No significant loss of activity and selectivity was observed.
Direct amination of secondary alcohols using ammonia
Pingen, Dennis,Mueller, Christian,Vogt, Dieter
supporting information; experimental part, p. 8130 - 8133 (2011/02/22)
Hydrogen shuttle: For the first time secondary alcohols and ammonia can be directly converted into primary amines with a selectivity of up to 99% by using a simple ruthenium/phosphine catalyst (see scheme; R1, R2= alkyl, aryl, alkenyl; M=[Ru3(CO)12]; and L=phosphine ligand).
Practical synthesis of optically pure menthylamines starting from racemic neomenthol
Welschoff, Nina,Waldvogel, Siegfried R.
experimental part, p. 3596 - 3601 (2010/12/19)
A reliable and scalable route to racemic and highly enantiomerically enriched menthylamines exploits the technical product rac-neomenthol as the starting material. The elaborated protocol is based on nucleophilic substitution of the hydroxy moiety by azide. Subsequent reduction and resolution with tartaric acid provides the desired optically enriched menthylamines.
A new novel and practical one pot methodology for conversion of alcohols to amines
Vidya Sagar Reddy,Venkat Rao,Subramanyam,Iyengar
, p. 2233 - 2237 (2007/10/03)
A convenient and efficient one pot sequence has been developed for the transformation of alcohols to amines using sodium azide, triphenylphosphine in CCl4-DMF.
