Diastereospecific synthesis of new 4-substituted l-theanine derivatives

Considering the biological activity of l-theanine as a potent agonist of NMDA receptors, impacting on glutamatergic synapse activity, we have developed an asymmetric synthesis of new enantiomerically pure 4-substituted l-theanine derivatives. The key step is a stereospecific alkylation on a previously synthesized and correctly protected (S)-pyroglutamate.

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(2S,4R)-4-Benzyl-di-tert-butyl-5-oxopyrrolidine-1,2-dicarboxylateC21H29NO5de >99%[α]D20=-4.0 (c 1.0, CH2Cl2)Source of chirality: (2S)-Boc-Pyr-OtBu.absolute configuration: (2S,4R)

(2S,4R)-4-(4-Isopropylbenzyl)-di-tert-butyl 5-oxopyrrolidine-1,2-dicarboxylateC24H35NO5de >99%Source of chirality: (2S)-Boc-Pyr-OtBu.[α]D20=-3.4 (c 1.0, CH2Cl2).absolute configuration: (2S,4R)

(2S,4R)-4-(4-tert-Butylbenzyl)-di-tert-butyl 5-oxopyrrolidine-1,2-dicarboxylateC25H37NO5de >99%Source of chirality: (2S)-Boc-Pyr-OtBu.[α]D20=-2.9 (c 1.0, CH2Cl2).absolute configuration: (2S,4R)