利用两种特殊起始材料l-半胱氨酸和d-青霉胺的相反手性,合成了多种噻唑烷基氨基醇。l-半胱氨酸衍生物是比d-青霉胺更有效的手性诱导剂,在苯甲醛的对映选择性乙基化中ee高达92%。使用几种芳族、杂芳族和脂肪族醛评估了最佳催化剂的范围,提供了出色的 ( S )-对映选择性。鉴于l-半胱氨酸和d的相反手性-青霉胺噻唑烷,预期使用一种或另一种类型的衍生物作为配体将允许形成烷基化产物的相反构型。然而,虽然l-半胱氨酸噻唑烷主要产生 ( S ) 形式的烷基化产物,但d-青霉胺导致两种配置。当由两种类型的配体催化时,该反应的立体化学结果的显着差异促使我们研究这种结果背后的原因。进行了广泛的量子化学计算,以确定在这些类型的氨基醇存在下苯甲醛的对映选择性乙基化可以进行的过渡态结构。还探索了速率确定步骤的替代路径,并发现对实验结果的合理化具有决定性作用。据观察,配体的类型决定了手性产物形成的可及反应路径,这最终决定了两种可能构型之间的平衡。
Novel thiazolidine derivatives as chiral catalysts in the enantioselective addition of diethylzinc to aldehydes
作者:Qinglin Meng、Yuelan Li、Yan He、Yedi Guan
DOI:10.1016/s0957-4166(00)00391-8
日期:2000.11
New chiral thiazolidine derivatives were synthesized conveniently from natural l-cysteine and showed good enantioselectivity (up to 90% ee) in the addition of diethylzinc to aldehydes. The catalytic efficiency of the thiazolidine derivatives is influenced by the different structures of the thiazolidine rings and the bulkiness of R moiety in the ester groups.
The steric effect and enantioselectivity of chiral 2,2-disubstituted thiaprolinol derivatives as ligands for borane reduction of aromatic ketones and for diethylzinc addition to aromatic aldehydes
作者:Hsiang-Ling Huang、Ya-Chuan Lin、Shyh-Fong Chen、Chia-Lin J. Wang、Lee Tai Liu
DOI:10.1016/0957-4166(96)00399-0
日期:1996.11
chiral amino alcohols 3a-e has been prepared from natural amino acid L-cysteine. These compounds have been used as chiral ligands for boranereduction of ketones and for diethylzinc addition to aldehydes. In the reduction of ketones, 3b-e have been used as the substitute of (R)-prolinol to provide (S)-alcohols in good yields and modest enantioselectivity (30–50% ee). In the diethylzinc addition to aldehydes
Design, Synthesis, and Safener Activity of Novel Methyl (R)-N-Benzoyl/Dichloroacetyl-Thiazolidine-4-Carboxylates
作者:Li-Xia Zhao、Hao Wu、Yue-Li Zou、Qing-Rui Wang、Ying Fu、Chun-Yan Li、Fei Ye
DOI:10.3390/molecules23010155
日期:——
A series of novel methyl (R)-N-benzoyl/dichloroacetyl-thiazolidine-4-carboxylates were designed by active substructure combination. The title compounds were synthesized using a one-pot route from l-cysteine methyl ester hydrochloride, acyl chloride, and ketones. All compounds were characterized by IR, 1H NMR, 13C NMR, and HRMS. The structure of 4q was determined by X-ray crystallography. The biological tests showed that the title compounds protected maize from chlorimuron-ethyl injury to some extent. The ALS activity assay showed that the title compounds increased the ALS activity of maize inhibited by chlorimuron-ethyl. Molecular docking modeling demonstrated that Compound 4e competed against chlorimuron-ethyl to combine with the herbicide target enzyme active site, causing the herbicide to be ineffective.
A compound represented by formula (I);
wherein ring A represents a nitrogen containing heterocyclic ring, ring B represents 5-membered heterocyclic ring which may have substituents, R represents a hydrogen atom or cyano and the other symbols represent as described in the specification; or a salt thereof. The compound represented by formula (I) has an inhibitory activity of DPP-IV, and therefore is useful as a preventive and/or treatment agent for type 2 diabetes mellitus, obesity, autoimmune disease, cancer metastasis, AIDS virus infection, dermatosis, prostatic hypertrophy and the like
A compound represented by formula (I);
wherein ring A represents a nitrogen containing heterocyclic ring, ring B represents 5-membered heterocyclic ring which may have substituents, R represents a hydrogen atom or cyano and the other symbols represent as described in the specification; or a salt thereof. The compound represented by formula (I) has an inhibitory activity of DPP-IV, and therefore is useful as a preventive and/or treatment agent for type 2 diabetes mellitus, obesity, autoimmune disease, cancer metastasis, AIDS virus infection, dermatosis, prostatic hypertrophy and the like