34592-47-7Relevant articles and documents
Asymmetric Michael reaction promoted by chiral thiazolidine-thiourea catalyst
da Silva, Tiago Lima,Rambo, Raoni Scheibler,Jacoby, Caroline Gross,Schneider, Paulo Henrique
supporting information, (2019/12/27)
In this work, we report the synthesis and characterization of three new thiazolidine- and thiourea-based chiral organocatalysts. These compounds were successfully applied in asymmetric Michael addition reactions between different ketones and nitrostyrenes leading to products in up to 85% yield, >96:4 r.d. and 97% e.e. Computational studies were used to better visualize the proposed transition state and explain the observed stereoselectivities. One of the new catalysts was also successfully applied in an aldol addition between cyclohexanone an p-nitrobenzaldehyde leading to product in 80% yield, >96:4 d.r. and 80% e.e.
Industrialized scale preparation method for pidotimod
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Paragraph 0018; 0020; 0022; 0024; 0026, (2018/11/03)
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.
New aspects of the formation of 2-substituted thiazolidine-4-carboxylic acids and their thiohydantoin derivatives
Mahdy, Ahmed R.E.,Elboray, Elghareeb E.,Fandy, Ragab F.,Abbas-Temirek, Hussien H,Aly, Moustafa F.
, p. 105 - 121 (2018/05/14)
Aromatic aldehydes reacted readily with (R)-cysteine in boiling acidified methanol to give diastereomeric mixtures of the corresponding 2-(aryl substituted) thiazolidine-4-carboxylic acids. 4-Nitrobenzaldehyde under similar conditions afforded one isomer of 2-(4-nitrophenyl)-thiazolidine-4-carboxylic acid, which epimerized in the NMR solvents into a diastereomeric mixture. 2-Nitrobenzaldehyde reacted with (R)-cysteine to afford 3,5-bis-(2-nitrophenyl)-tetrahydro-1H-thiazolo[3,4-c]oxazol-1-one as the sole product, which collapsed in the NMR solvent into a diastereomeric mixture of the thiazolidine-4-carboxylic acids. The thiazolidine derivatives reacted smoothly with phenyl isothiocyanate to give single isomers of the corresponding thiohydantoins.
