A cyclic Leu-enkephalin mimetic containing a 7-membered ring, and two linear analogues, has been prepared on solid phase. In the cyclic mimetic the intramolecular (1–4) hydrogen bond found in crystalline Leu-enkephalin has been replaced by an ethylene bridge. In addition, the amide bond between Tyr1 and Gly2 has been replaced by a methylene ether isostere and Gly3 has been deleted. The two linear analogues both contain the methylene ether isostere instead of the Tyr1-Gly2 amide bond and the shorter of the two lacks Gly3. The three compounds, and a β-turn mimetic analogous to the 7-membered turn mimetic but with Gly3 included, were evaluated for specific binding to μ- and δ-opioid receptors in rat brain membranes. With the exception of the β-turn mimetic the three other Leu-enkephalin analogues all bound with varying affinity to the μ- and δ-opioid receptors. From the results it could be concluded that Leu-enkephalin binds in a turn conformation to the opiate receptors, but that this conformation is not a (1–4) β-turn.
The dihydropyran 3 reacts with sulfonyl azides to give the known (sulfonylimino)-ethers ( = lactone sul-fonylimines) 4 and 18. Reaction of 4 with NH2NH2 · H2O leads to the aminoiriazole-dibulanol 5, characterized as its tetraacetate 8, and not, as previously claimed, to 6 or 7. Similarly, the dihydrofuran-derived (tosylimino)-ether 10 yields 11 The structure of 5 was established by X-ray analysis,
Triazole Ligands Reveal Distinct Molecular Features That Induce Histamine H<sub>4</sub> Receptor Affinity and Subtly Govern H<sub>4</sub>/H<sub>3</sub> Subtype Selectivity
作者:Maikel Wijtmans、Chris de Graaf、Gerdien de Kloe、Enade P. Istyastono、Judith Smit、Herman Lim、Ratchanok Boonnak、Saskia Nijmeijer、Rogier A. Smits、Aldo Jongejan、Obbe Zuiderveld、Iwan J. P. de Esch、Rob Leurs
DOI:10.1021/jm1013488
日期:2011.3.24
a peripheral imidazole group. The imidazole ring posed some problems in the click chemistry putatively due to Cu(II) coordination, but Boc protection of the imidazole and removal of oxygen from the reaction mixture provided effective strategies. Pharmacological studies revealed two monosubstituted imidazoles (6h,p) with <10 nM H4R affinities and >10-fold H4R/H3R selectivity. Both compounds possess
组胺H 3(H 3 R)和H 4(H 4 R)受体引起了药物化学界的极大兴趣。鉴于它们相对较高的同源性,但治疗前景却大相径庭,因此对两种受体的配体选择性至关重要。我们使用具有[1,2,3]三唑核心的配体询问H 4 R / H 3 R的选择性。Cu(I)辅助的“点击化学”被用来组装各种[1,2,3]三唑化合物(6a - w和7a - f),许多含有外围咪唑基团。咪唑环可能由于Cu(II)配位而在点击化学中造成了一些问题,但是咪唑的Boc保护和从反应混合物中除去氧气提供了有效的策略。药理研究表明,两种单取代的咪唑(6h,p)的亲和力<10 nM H 4 R和H 4 R / H 3 R选择性> 10倍。两种化合物均具有环烷基甲基,并且似乎靶向H 4中的亲脂性口袋R具有很高的空间精度。[1,2,3]三唑支架的使用进一步证明了以下概念,即间隔区长度或外围基团的简单改变可以逆转对H 3 R的选择性。提
Simple Conversion of Aromatic Amines into Azides
作者:Qi Liu、Yitzhak Tor
DOI:10.1021/ol034919+
日期:2003.7.1
[reaction: see text] A straightforward and highly efficient synthesis of aromatic azides from the corresponding amines is accomplished using triflyl azide under mild conditions.
[反应:见正文]使用三氟叠氮化物在温和的条件下,可以从相应的胺中直接高效地合成芳族叠氮化物。
Solid-phase Total Synthesis of (−)-Apratoxin A and Its Analogues and Their Biological Evaluation
Two approaches for the solid‐phasetotalsynthesis of apratoxin A and its derivatives were accomplished. In synthetic route A, the peptide was prepared by the sequential coupling of the corresponding amino acids on trityl chloride SynPhase Lanterns. After cleavage from the polymer‐support, macrolactamization of 10, followed by thiazoline formation, provided apratoxin A. This approach, however, resulted