Triethylamine → (S,S)-2,4-dibenzylglutaric acid

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Reaction Steps

The chiral (S,S)-2,4-dibenzylglutaric acid is prepared as follows: To 5.0 g of (R*,R*)-2,4-dibenzylglutaric acid in 20 ml of isopropanol is added 0.81 g of triethylamine and the mixture is stirred for 20 minutes. To this mixture is added 0.97 g of d(+)-alpha-methylbenzylamine in 20 ml of isopropanol and the solution is stirred overnight. The solid is collected and recrystallized twice from isopropanol to yield (S,S)-2,4-dibenzylglutaric acid as the d(+)-alpha-methylbenzylamine salt melting at 201°-203°; [alpha]D =-20.4° (c=1 in methanol). To a warm solution of the above salt in 70 ml of water and 30 ml of ethanol is added 1 ml of concentrated hydrochloric acid. After standing 24 hours the solid is collected, washed with water and dried to yield (S,S)-2,4-dibenzylglutaric acid melting at 150°-152°; [alpha]D =+8.9° (c=2.0 in methanol).

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