Ditoluoyltartaric acid

The racemic 0-benzoyl- and 0-toluoylarmepavines (XXXIII R = PhCO or CH3C6H4CO) have been used in several attempts to resolve the base into its enantiomers 69,81). The best results were obtained with ditoluoyltartaric acid which resolved the racemic benzoyl base XXXIII (R = PhCO) into (+)- and (— )-armepavine with an optical purity of 84 % (mp 144 -145° [ocf -1-97.0°, - 98.2° in CHCI3). 

In another report by Aelterman et al., the development of a facile and large-scale preparation of the antitumor agent R116010 was demonstrated (Scheme 56.2). In their work, the key strategic improvement was the crystallization-induced diastereomeric dynamic resolution of the aminoketone rac-7, leading to the chiral ketone (S)-7 in 90% yield and 90% enantiomeric purity. After screening 22 chiral acids in numerous solvents, the resolution of aminoketone with ditoluoyltartaric acid in methanol was found to be the optimal process. This new process improves the overall yield from 0.26% to 18.8% without tedious chromatographic separations and hazardous reaction conditions. 

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