- Synthesis of C2-symmetric bisthiazolidine ligands derived from L-cysteine
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Treatment of L-cysteine esters and thiazolidine-4-carboxylic esters with an excess of paraformaldehyde in the presence of trifluoroacetic acid provides C2-symmetric N,N′-methylene-bisthiazolidines in good yield.
- Diaz,Gonzalez
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- Industrialized scale preparation method for pidotimod
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The invention discloses an industrialized scale preparation method for pidotimod, and belongs to the technical field of medicine synthesis. The industrialized scale preparation method comprises the following steps of performing ring closure and esterification on L-cysteine, so as to obtain L-thiazolidine-carboxylic ester; then, condensing with L-pyroglutamic acid under the action of a condensing agent; then, performing ester hydrolysis, and crystallizing, so as to obtain a product meeting the medicinal standard. The industrialized scale preparation method has the advantages that the intermediate, such as L-thiazolidine-carboxylic ester hydrochloride, is not separated, the water is removed by a co-boiling method in the condensing reaction process, and the separating and drying steps of theintermediate are omitted; compared with other preparation methods, the technology is optimized, so as to shorten the large-scale production time, improve the yield rate, and reduce the production cost; the operability in the scale production of the pidotimod is realized.
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Paragraph 0018; 0021; 0023; 0025; 0027
(2018/11/03)
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- Thiazolidine esters: New potent urease inhibitors
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A variety of esters of thiazolidine-4-caboxylic acid were synthesized and investigated for their urease inhibitory properties. A significant increase in urease inhibitory activities of these ester derivatives has been observed. The order of activity increases from methyl ester to heptyl ester but further prolongation of the alkyl chain was proved to be detrimental for receptor binding. These findings provide evidence that the nature of the alkyl chain has a significant impact on the coordination of thiazolidine esters with bi-metallic nickel center of urease. It was also observed that inhibition potentiated by lower pH and with increase in time.
- Lodhi, Muhammad Arif,Shams, Sulaiman,Khan, Khalid Mohammad
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p. 858 - 864
(2015/01/30)
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- New dipeptides containing thiazolidine-4-carboxylic acid derivatives: Synthesis and characterization using NMR techniques and X-ray data
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New dipeptides, structural analogues of known immunomodulating agents, were prepared by stereospecific condensation between 2-substituted thiazolidine-4-carboxylate esters with N-substituted L-proline or L- thiaproline. The structure of these compounds has been elucidated by combination of NMR methods and X-ray analysis. In addition, NMR measurements on dipeptides indicated the presence of S-cis and S-trans conformers around the amide bonds.
- Pellegrini, Nadia,Refouvelet, Bernard,Crini, Gregorio,Blacque, Olivier,Kubicki, Marek M.,Robert, Jean-Francois
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p. 950 - 955
(2007/10/03)
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- Sulfur-containing β-amino alcohols as catalysts in enantioselective synthesis
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Oxazaborolidine catalysts generated in situ from cyclic or acyclic sulfur containing (R)-cysteine, (S)-penicillamine and (S)-methionine derivates and BH3 have been applied successfully to the enantiocontrolled, catalytic reduction of aromatic ketones. The corresponding sec alcohols could be obtained in excellent enantiomeric excess, up to 100% ee. Using these chiral auxiliaries in the enantioselective addition of diethylzinc to aldehydes afforded optically active sec alcohols in enantiomeric excess up to 93% ee.
- Trentmann, Wilhelm,Mehler, Thomas,Martens, Juergen
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p. 2033 - 2043
(2007/10/03)
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- Protected Derivatives of (R)-Cysteine and (R)-Cysteinol
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The synthesis of N, O, S protected forms of (R)-cysteine and (R)-cysteinol as bicyclic derivatives is described.The reactivity and the preparation of substituted derivatives of these systems is also discussed.
- Gonzalez, Asensio,Lavilla, Rodolfo,Piniella, Juan F.,Alvarez-Larena, Angel
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p. 3015 - 3024
(2007/10/02)
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- Immunomodulatory agents: Dioxothiadiazabicyclo[3.3.0]octanes and their 2- spiro derivatives
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A series of 6,8-dioxo-3-thia-1,7-diazabicyclo[3.3.0]octanes and a series of 6,8-dioxo-3-thia-1,7-diazabicyclo[3.3.0]octane 2-spiro derivatives were synthesized from L-(-)-R-cysteine ethyl ester in two steps. The synthetic route involved condensation of the amino acid with an appropriate aldehyde or ketone, then a further condensation of the resultant ethyl thiazolidine-4- carboxylate with an isocyanate or an isothiocyanate. The proliferative response to human lymphocyte mitogen (phytohemagglutinin) was used as a primary screening assay for most of the thiadiazabicyclic compounds in comparison with levamisole. Furthermore, the most active compounds were tested for ability to release soluble receptors (sRIL-2) after mitogenic stimulation of T cells and for ability to activate macrophage oxidative metabolism measured by chemiluminescence. Most compounds were active in all three tests and some showed dose-dependent activity.
- Refouvelet,Harraga,Nicod,Robert,Seilles,Couquelet,Tronche
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p. 1076 - 1083
(2007/10/02)
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