Chirospecific Synthesis of (S)-(+)- and (R)-(-)-5-Amino-4-hydroxypentanoic Acid from L- and D-Glutamic Acid via (S)-(+)- and (R)-(-)-5-Hydroxy-2-oxopiperidine
Enantioenriched N-(2-chloroalkyl)-3-acetoxypiperidines as potential cholinotoxic agents. Synthesis and preliminary evidence for spirocyclic aziridinium formation
作者:Nam Huh、Charles M. Thompson
DOI:10.1016/0040-4020(95)00285-g
日期:1995.5
The syntheses of six enantioenriched analogs representing cyclic forms of acetylcholine are reported. (S)- and (R)-N-(2-chloroethyl)-3-acetoxypiperidine and (R,R)-, (R,S)-, (S,R)-, and (S,S)-N-(2-chloropropyl)-3-acetoxypiperidine have been synthesized from (R)- or (S)-3-hydroxypiperidine in five steps. (R)- and (S)-3-hydroxypiperidine were accessed via parallel stereospecific routes from d- and 1-glutamic
报道了代表乙酰胆碱的环状形式的六个对映体富集的类似物的合成。(S)-和(R)-N-(2-氯乙基)-3-乙酰氧基哌啶和(R,R)-,(R,S)-,(S,R)-和(S,S)-N从(R)-或(S)-3-羟基哌啶经五步合成了-(2-氯丙基)-3-乙酰氧基哌啶。(R)-和(S)-3-羟基哌啶可通过平行的立体定向途径从d-和1-谷氨酸进入,并通过非对映异构的tartranilic酸盐的分级重结晶而获得。((S)-N-(2-氯乙基)-3-乙酰氧基哌啶与高氯酸银反应形成乙酰胆碱的螺环叠氮基类似物,这是由叠氮基亚甲基的特征性1 H NMR位移所证明的。
Diastereoselective Synthesis of Nonracemic 2-Alkyl-5-Hydroxypiperidines with (2R,5S)-Configuration via a Tandem Wittig [2+3] Cycloaddition Reaction. Synthesis of epi-Pseudoconhydrine and Its Homologs
作者:Claus Herdeis、Thomas Schiffer
DOI:10.1055/s-1997-1366
日期:1997.12
A diastereoselective synthesis of cis-2-alkyl-5-hydroxypiperidines is presented, starting from enantiopure azidolactone 1. The key step of the reaction sequence is the tandem Wittig [2+3] cycloaddition reaction of lactol 2 to give triazolines 5a,b which are in equilibrium with the diazoamines 6a,b. Thermolysis of the mixture of 5 and 6 provides enantiopure 7, which is O-protected, diastereoselectively hydrogenated, and N-protected to 9. Further transformation of 9 yields epi-pseudoconhydrine (14) and its homologs.
Synthesis of carbohydrate-based monomers that are precursors for the preparation of stereoregular polyamides
作者:Francisca Zamora、Manuel Bueno、Inmaculada Molina、Hernán A. Orgueira、Oscar Varela、Juan A. Galbis
DOI:10.1016/0957-4166(96)00216-9
日期:1996.6
ic acid and (S)-5-amino-4-hydroxypentanoic acid have been performed in several steps from L-arabinose, D-xylose and (S)-(+)-glutamic acid, respectively. These ω-aminoacids are precursors of bifunctional monomers that could be used for the preparation of opticallyactivepolyamides.
Cyclopropane-Derived Peptidomimetics. Design, Synthesis, and Evaluation of Novel Enkephalin Analogues
作者:Stephen F. Martin、Michael P. Dwyer、Benoît Hartmann、Kyle S. Knight
DOI:10.1021/jo991288h
日期:2000.3.1
lactones with dipeptides, and a novel method for the synthesis of substituted diaminocyclopropanes was also developed. The Leu-enkephalin analogues were tested in a panel of binding and functional assays, and although those derivatives containing cyclopropane replacements of the Gly(2)-Gly(3) exhibited low micromolar affinity for the mu-receptor, analogues containing such replacements for the Phe(4)-Leu(5)
The newly constructed reactor for hydrogenations in microwave fields allows to work out the syntheses up to 25 bar. This is shown for the synthesis of intermediates of active agents. In order to demonstrate the superiority of the microwave-assisted hydrogenation, the reactions are compared with classical hydrogenations. The following reactions were carried out: dearomatization, debenzylation, azide hydrogenation and the hydrogenation of strychnine. (C) 2005 Elsevier Ltd. All rights reserved.