کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1347587 | 1500351 | 2013 | 5 صفحه PDF | دانلود رایگان |
The diastereomeric salts of (R)- and (S)-2-aminomethyl-1,4-benzodioxane with unichiral mandelic acid form a simple eutectic, whose binary phase melting point diagram shows the unique eutectic at 0.35 M ratio of the less soluble diastereomer. Such an eutectic composition, near to 0.5, is consistent with the modest efficiency previously reported for their separation via crystallization from ethanol/ethyl acetate. However, the ternary solubility phase diagram, obtained from solubility measurements in methanol, shifts the eutectic to a lower molar ratio (0.10) of the less soluble diastereomer, thus indicating an optimal resolvability of the diastereomeric mandelates. This was confirmed by the highly efficient resolution of racemic 2-aminomethyl-1,4-benzodioxane with (R)-mandelic acid via a single crystallization from methanol. The ready availability of both the racemic substrate and the resolving acid makes this simple and efficient resolution procedure very attractive to obtain the enantiomers of 2-aminomethyl-1,4-benzodioxane, which are important synthetic intermediates.
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(S)-2-Aminomethyl-1,4-benzodioxaneC9H11NO2Ee = 97.2%[α]D25=-56.9 (c 1, CHCl3)Source of chirality: resolution with (R)-mandelic acidAbsolute configuration: (S)
(S)-2-Aminomethyl-1,4-benzodioxane (R)-mandelateC17H19NO5[α]D25=-94.9 (c 1, MeOH)Source of chirality: diastereoselective crystallizationAbsolute configuration: (S)·(R)
Journal: Tetrahedron: Asymmetry - Volume 24, Issues 13–14, 31 July 2013, Pages 796–800