Succinimide tartaric acid

Resorcinol Sorbic acid Succinimide Tartaric acid... 

Dihydroxypyrrolidinones, which can be considered as cyclic GABA derivatives, are potential nootropic drug candidates. All four possible diastereomers 794—797, as shown in Scheme 174, can be prepared from tartaric acid. Treating L-tartaric acid sequentially with acetyl chloride, methyl glycinate, and then acetyl chloride provides in 81% overall yield the C2-symmetric succinimide 790. In order not to reduce the methyl ester, the very mild treatment with sodium borohydride at —40 °C is employed to prepare the cw-hydroxylactam 791 in an 80% isolated yield. Esterification of 791 with trifiuoroacetic anhydride followed by triethylsilane reduction yields to the extent of 79% the pyrrolidinone 792. This is deprotected with sodium methoxide to provide in 97% yield (3i ,45)-3,4-dihydroxy-A -methoxy-carbonylmethyl-2-pyrrolidinone (793). Ammonolysis of 793 affords (3i ,4 S)-3,4-dihydroxy-2-oxopyrrolidine-A -acetamide (794) in 60% yield. Subsequent modifications to 793 allow for the preparation of (35, 4S)-3,4-dihydroxy-2-oxopyrrolidine-A/-acetamide (795), (3R,4R)-3,4-dihydroxy-2-oxopyrrolidine-A -acetamide (796) and (35, 47 )-3,4-dihydroxy-2-oxopyrrolidine-7V-acetamide (797) [234]. 

The two enantiomers of tra i -3,4-difluoropyrrolidine, (3/f,4/f)-9 and (35, 45)-9, were prepared from d- and L-tartaric acids. Figure 3.5 illustrates the sequence starting with L-tartaric acid to produce (3/f,4/f)-9. This was conceptually similar to the first enantioselective syntheses of vicinal A -substituted dilluoropyrrohdines carried out previously. In this previous work, the requisite fra x-2,3-dihydroxypyrrolidine derivatives were made by reduction of diacetoxy succinimides. 

---