Diastereoselective Synthesis of 4-Substituted L-Prolines by Intramolecular Radical Cyclization ofN-Aryl sulphonyl-N-allyl 3-bromoalanines: Interesting Dependence of Selectivity on the Nature of Sulphonamido Groups
Diastereoselective Synthesis of 4-Substituted L-Prolines by Intramolecular Radical Cyclization ofN-Aryl sulphonyl-N-allyl 3-bromoalanines: Interesting Dependence of Selectivity on the Nature of Sulphonamido Groups
five-step-reaction procedure and 19 novel conjugates N-[2-chloro-9-(tetrahydropyran-2-yl)-9H-purin-6-yl]-N-cyclopropylglycylamino acid benzylesters were provided. On mouse-tail flick model their in vivo analgesic activities were assayed. The results indicate that introducing Gly-OC2H5 into the 6-position of the substituted purine leads to ambiguous increase of the analgesic activity, while introducing Gly-AA-OBzl
针对慢性疼痛的化学疗法,通过五步反应方法和19种新型缀合物N- [2-氯-9-(四氢吡喃-2-)偶联了两种止痛药,取代的嘌呤和Gly-AA-OBzl。提供了(yl)-9 H-嘌呤-6-yl] -N-环丙基糖基氨基酸苄酯。在鼠尾轻弹模型上,测定了它们的体内止痛活性。结果表明,将Gly-OC 2 H 5引入取代的嘌呤的6-位导致镇痛活性的模棱两可的增加,而将Gly-AA-OBzl引入该位置导致镇痛活性的显着增加。
High yielding synthesis of dehydroamino acid and dehydropeptide derivatives
作者:Paula M. T. Ferreira、Hernâni L. S. Maia、Luís S. Monteiro、Joana Sacramento
DOI:10.1039/a904730a
日期:——
By using a 4-dimethylaminopyridine (DMAP) catalysed reaction of β-hydroxyamino acid derivatives with tert- butyl pyrocarbonate [(Boc)2O], dehydroamino acid derivatives are obtained in high yields. The same methodology applied to dipeptides with a β-hydroxyamino acid residue gives the corresponding dipeptides with a dehydroamino acid residue.
Asymmetric Synthesis of β
<sup>2</sup>
‐Aryl Amino Acids through Pd‐Catalyzed Enantiospecific and Regioselective Ring‐Opening Suzuki–Miyaura Arylation of Aziridine‐2‐carboxylates
作者:Youhei Takeda、Tetsuya Matsuno、Akhilesh K. Sharma、W. M. C. Sameera、Satoshi Minakata
DOI:10.1002/chem.201902009
日期:2019.8
A Pd‐catalyzed enantiospecific and regioselective ring‐opening Suzuki–Miyaura arylation of aziridine‐2‐carboxylates was developed. The cross‐coupling allows for the asymmetric preparation of enantioenriched β2‐aryl amino acids, starting from commercially available enantiopure d‐ and l‐serine esters. The mechanism and selectivity of the reaction was rationalized based on computational models.
Diastereoselective Synthesis of 4-Substituted L-Prolines by Intramolecular Radical Cyclization of<i>N</i>-Aryl sulphonyl-<i>N</i>-allyl 3-bromoalanines: Interesting Dependence of Selectivity on the Nature of Sulphonamido Groups
Enantiopure 4-substituted L-proline derivatives have been prepared via intramolecular radical cyclization of N-aryl sulphonyl-N-allyl-3-bromo-L-alanines in high yields. Surprisingly, the extent of selectivity was found to be primarily dependent on the nature of sulphonamido aryl group and could be as high as 33:1 using naphthyl sulphonamide.