Synthesis of new β- and γ-benzyloxy-S-glutamic acid derivatives and evaluation of their activity as inhibitors of excitatory amino acid transporters
作者:Lucia Tamborini、Paola Conti、Andrea Pinto、Simona Colleoni、Marco Gobbi、Carlo De Micheli
DOI:10.1016/j.tet.2009.05.054
日期:2009.8
enantiomerically pure diasteroisomers of γ-benzyloxy-S-glutamic acid was performed using trans-4-hydroxy-l-proline as a source of chirality, while the erythro and threo isomers of β-benzyloxy-S-glutamic acid were prepared starting from (R)-Garner's aldehyde. All new derivatives were tested for their inhibitory activity against excitatory amino acid transporters in a rat synaptosomal preparation and their
Synthesis of erythro-L-.BETA.-Hydroxyglutamic Acid Hydrochloride from L-Malic Acid.
作者:Sojiro SHIOKAWA、Tomihisa OHTA、Shigeo NOZOE
DOI:10.1248/cpb.40.1398
日期:——
Facile synthesis of erythro-L-β-hydroxyglutamic acid and its derivative, (2S, 3S)-3-acetoxypyroglutamate, from L-malimide is described. The Key reaction for the synthesis of 3-oxypyroglutamyl intermediate was the furylation of N-acylaminal acetate using zinc bromide-trimethylchlorosilane as an effective catalyst system. Oxidative cleavage of the furyl substituent afforded the 3-acetoxypyroglutamate, which on hydrolysis gave the title amino acid.
(S)‐malic acid is described. The chiral cyclic imide derived from (S)‐malic acid was converted to an acetoxylactam by reduction with sodium borohydride followed by acetylation. The obtained acetoxylactam was treated with trimethylsilylcyanide in the presence of boron trifluoride etherate to give the corresponding cyanolactam in high yield, even though the diastereoselectivity of the cyanation reaction was
Bioassay-guided fractionation of culture supernatants of the actinomycete Kutzneria sp. 744 resulted in the isolation of four new depsipeptides (1-4). Structure analysis revealed the general structure: cyclo[2-(I-methylcyclopropyl)-D-glycine-(2S,3aR,8aS)-6,7-dichloro-3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid-3-hydroxy-D-glutamic acid-o-methyl-L-serine-L-piperazie acid-(S)-2-hydroxy-3,3-dimethylbutanoic acid]. The 3-hydroxy-D-glutamic acid was present as its threo-isomer in 1 and 2 and as its erythro-isomer in 3 and 4. The piperazic acid was modified to its (R)-4-chloro analogue in 2 and to its C-5/N unsaturated analogue in 4. Compounds 1-4 displayed moderate spore germination inhibiting activity against several common root-rotting fungi.