- Simple and Efficient Synthesis of 5-Substituted-3-phenyl-2-thioxoimidazolidin-4-one Derivatives from S -Amino Acids and Phenylisothiocyanate in et 3N/DMF-H 2O
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A concise approach for the transformation of various S-amino acids into the 5-alkyl-3-phenyl-2-thioxoimidazolidin-4-one heterocycles using phenylisothiocyanate is described. Phenylthiohydantoins of amino acid were synthesized at room temperature in Et3N/DMF-H2O with easy workup and excellent yields.
- Jangale, Asha D.,Wagh, Yogesh B.,Tayade, Yogesh A.,Dalal, Dipak S.
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supporting information
p. 1876 - 1886
(2015/08/03)
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- Investigation of the diastereoselective Mannich reaction using imidazolidin-2-thione as a chiral auxiliary
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Titanium mediated asymmetric Mannich reactions using imidazolidin-2-thione as a chiral auxiliary proceeded in good yields and with high diastereoselectivity to afford the anti-products in the presence of PPh3 additive. A non-chelated transition state with the PPh3-bound titanium enolate was proposed to explain the stereochemistry of the product. Alcoholysis of the adducts with methanol cleaved the imidazolidin-2-thione auxiliary to give the methyl esters in good yields and with excellent ee values.
- Zhu, Liang,Lu, Cuifen,Chen, Zuxing,Yang, Guichun,Li, Yan,Nie, Junqi
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- Asymmetric induction by (S)-4-isopropyl-1-phenylimidazolidin-2-thione in titanium-mediated aldol reactions and its application in enantioselective synthesis of (R)-baclofen
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The usefulness of (S)-4-isopropyl-1-phenylimidazolidin-2-thione as a chiral auxiliary in stereoselective propionate and acetate aldol reactions is discussed. Further, the enantioselective synthesis of (R)-baclofen by acetate aldol reaction using the chiral auxiliary was demonstrated. Georg Thieme Verlag Stuttgart New York.
- Khatik, Gopal L.,Khurana, Ravi,Kumar, Varun,Nair, Vipin A.
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experimental part
p. 3123 - 3132
(2011/10/31)
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- Modulation of the pharmacological activities of secretory phospholipase A2 from Crotalus durissus cascavella induced by naringin
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In this work we have characterized the action of the naringin, a flavonoid found in grapefruit and known for its various pharmacological effects, which include antioxidant, blood lipid lowering and anticancer activity, on the structure and biochemical activities of a secretory phospholipase A (sPLA2) from Crotalus durissus cascavella, an important protein involved in the releasinge of arachidonic acid in phospholipid membranes. sPLA2 was incubated with naringin (mol:mol) at 37 °C and a discrete reduction in the UV scanning signal and a modification of the circular dichroism spectra were observed after treatment with naringin, suggesting modifications of the secondary structure of the protein. This flavonoid was able to decrease enzymatic activity and some pharmacological effects, such as myonecrosis, platelet aggregation, and neurotoxic activity caused by sPLA2, however, the inflammatory effect was not affected by naringin. In addition, small angle X-ray scattering (SAXS) data were collected for sPLA2 and naringin-treated sPLA2 to evaluate possible modifications of the protein structure. These structural investigations have shown that sPLA2 is an elongated dimer in solution and after treatment with naringin a conformational change in the dimeric configuration was observed. Our results suggest that structural modification may be correlated with the loss of enzymatic activity and alterations in pharmacological properties.
- Santos, Marcelo L.,Toyama, Daniela O.,Oliveira, Simone C. B.,Cotrim, Camila A.,Diz-Filho, Eduardo B. S.,Fagundes, Fabio H. R.,Soares, Veronica C. G.,Aparicio, Ricardo,Toyama, Marcos H.
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experimental part
p. 738 - 761
(2011/04/15)
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- Traceless approach for the synthesis of 3,5-disubstituted thiohydantoins on functionalized ionic-liquid support
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A traceless approach for the synthesis of 3,5-disubstituted thiohydantoins on a novel functionalized ionic-liquid support, 5, is described. Acylation of benzylamine functionalized ionic-liquid support with amino acids yielded ionic-liquid-supported amino acids, which reacted with isothiocyanates to afford ionic-liquid-supported thioureas. Following intramolecular cyclization cleavage from the ionic-liquid support by trifluoroacetic acid (TFA), the desired 3,5-disubstituted thiohydantoins were obtained in good yields and purities. The efficiency of this ionic-liquid-phase strategy facilitated isolation and analysis of intermediates and removal of excess reagents and by-products during the reaction process.
- Yao, Chao,Zhang, Yandong,Zhang, Guolin,Chen, Wenteng,Yu, Yongping,Houghten, Richard A.
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experimental part
p. 717 - 724
(2011/03/19)
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- Microwave-assisted traceless synthesis of thiohydantoin
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An efficient, microwave-assisted method for the liquid-phase combinatorial synthesis of 3,5-disubstituted-thiohydantoin has been developed. Fmoc-protected amino acids were coupled with HO-PEG-OH and after deprotection, reacted with various isothiocyanates
- Lin, Mei-Jung,Sun, Chung-Ming
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p. 8739 - 8742
(2007/10/03)
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