五元氮杂糖衍生物的实用有效合成方法

以D-葡萄糖为原料, 经具有降冰片烷结构的双环缩醛中间体, 合成了部分羟基保护的1-脱氧-D-氮杂阿拉伯糖衍生物, 提供了一种合成五元氮杂糖衍生物的简便有效方法.     

微波促进1,3-偶极环加成反应合成氮杂糖苷衍生物

利用微波促进氮杂糖硝酮(2)与丙烯酸类衍生物(3)发生1,3-偶极环加成反应,立体选择性地得到了一系列新的含异噁唑烷的氮杂糖衍生物(4),反应效率显著提高,反应时间由95h缩短为5～15min,收率由67%提高到78%～88%.利用NMR和HRMS等方法结合化合物(4d-1)的单晶结构确定了产物的结构和相对构型.     

含醛基及叠氮基氮杂糖中间体的合成

以D-甘露糖为原料,分别利用苄胺双取代和aza-Wittig反应,再经氧化和亲核取代反应,合成了带保护基的含叠氮基及醛基的五元及六元氮杂糖中间体,对相关反应条件、基团保护及反应机理等进行了探讨,并提供了一种选择性脱除三苯甲基保护基的方法.     

苄连氮桥联双硫杂杯[4]芳烃的合成

硫杂杯[4]二醛基衍生物(1)在水合肼中肼解,合成了新化合物硫杂杯[4]二醛腙基衍生物(2);1和2在弱酸的催化下反应合成了新的具有对称结构的苄连氮双硫杂杯[4]芳烃(3);2和3的结构经1H NMR,IR,ESI-MS和元素分析表征.     

一些新型含氮、硫杂官能团的杯[4]芳烃衍生物的合成

以杯[4]芳烃-1,3-二溴乙氧基衍生物1为合成平台,在K2CO3/MeCN体系中分别与乙醇胺、L-亮氨醇、2-巯基苯并咪唑、巯基乙酸乙酯反应,以49%～76%的产率合成了4种新型含氮、硫杂官能团的杯[4]芳烃衍生物2,4,5和6.化合物2进一步与异硫氰酸苯酯反应,以84%的产率得到了新型树枝状杯[4]芳烃氮、硫杂衍生物3.新化合物的结构与构象经元素分析、质谱、核磁共振谱等表征证实.     

新型硫杂杯[4]芳烃衍生物的合成

在对叔丁基硫杂杯[4]芳烃(1)的下缘1,3-位引入芳醛基制得硫杂杯[4]二醛基衍生物(3);3在水合肼中肼解制得硫杂杯[4]二醛腙基衍生物(4);4与5,5'-亚甲基二水杨酰基二水杨酰氯经缩合反应合成了具有桥连结构的硫杂杯[4]芳烃桥联氮杂衍生物(6),3,4和6为新化合物。其结构经1H NMR,IR,ESI-MS和元素分析表征。     

季戊四醇衍生物为骨架的糖簇、糖树枝状分子的合成与应用

综述了以季戊四醇衍生物为骨架的糖簇、糖树枝状分子的合成与应用. 由于季戊四醇衍生物本身所具备的结构特点, 这类分子非常适合于合成新型的糖簇分子和糖树枝状分子. 同时, 由于季戊四醇衍生物在有机合成领域应用广泛, 很多有机合成方法都可以应用到这类糖缀合物的合成中.     

氮杂二烯光化学反应合成喹啉衍生物

综述了以氮杂二烯为原料,光化学反应合成喹啉衍生物的最新进展.参考文献18篇.     

3-杂环基硫取代-1,3,4,5-四氢-2-氧代-苯并氮杂衍生物的合成

以芳酰肼为原料,合成了一系列3-巯基-5-芳基-1,2,4-三唑、2-巯基-5-芳基-1,3,4-噁二唑和2-巯基-5-芳基-1,3,4-噻二唑,并通过硫原子对3-溴-2-氧代-苯并氮杂3-位上的亲核取代反应将杂环化合物引入了苯并氮杂的结构当中,合成了32个新的苯并氮杂杂环衍生物.为提高其在有机溶剂中的溶解性,在苯并氮杂的N原子上引入乙酸乙酯和乙酸叔丁酯基取代基,合成了36个新衍生物.所有化合物经质谱、核磁共振谱及元素分析确证了结构并初步测定了抗菌活性.     

3-杂环基硫取代-1,3,4,5-四氢-2-氧代-苯并氮杂衍生物的合成

以芳酰肼为原料, 合成了一系列3-巯基-5-芳基-1,2,4-三唑、2-巯基-5-芳基-1,3,4-噁二唑和2-巯基-5-芳 基-1,3,4-噻二唑, 并通过硫原子对3-溴-2-氧代-苯并氮杂3-位上的亲核取代反应将杂环化合物引入了苯并氮杂的结构当中, 合成了32个新的苯并氮杂杂环衍生物. 为提高其在有机溶剂中的溶解性, 在苯并氮杂的N原子上引入乙酸乙酯和乙酸叔丁酯基取代基, 合成了36个新衍生物. 所有化合物经质谱、核磁共振谱及元素分析确证了结构并初步测定了抗菌活性.     

Stereoselective synthesis of partially protected azasugar derivatives

Five-membered azasugar derivatives with partially protected hydroxyl groups, and their fluorinated derivatives were synthesized via the key intermediates of norbornyl-like bicyclic acetals using d-xylose and d-glucose as starting materials. The glycosylation of the azasugar intermediate and 1-methylenesugar was also explored. Translated from Chemical Journal of Chinese Universities, 2006, 27 (4) (in Chinese)     

An Efficient Route to Emodic Amine and Analogous <Emphasis Type="Italic">O</Emphasis>-Methyl Protected Derivatives Starting from Emodin

Summary. Emodic amine could be synthesized in a five-step approach in excellent overall yield by following a modified Curtius rearrangement strategy, starting from the naturally occurring emodin. This unique emodin derived 6-amino substituted polyhydroxylated anthraquinone may serve as a promising synthon for a new class of amino functionalized photodynamically active hypericin derivatives. In addition, the partially O-methyl protected 6-amino- and 6-carboxy-anthraquinones could be synthesized in high yields via selective O-methyl ether cleavage from the corresponding tri-O-methyl derivatives.     

An Efficient Route to Emodic Amine and Analogous O-Methyl Protected Derivatives Starting from Emodin

Emodic amine could be synthesized in a five-step approach in excellent overall yield by following a modified Curtius rearrangement strategy, starting from the naturally occurring emodin. This unique emodin derived 6-amino substituted polyhydroxylated anthraquinone may serve as a promising synthon for a new class of amino functionalized photodynamically active hypericin derivatives. In addition, the partially O-methyl protected 6-amino- and 6-carboxy-anthraquinones could be synthesized in high yields via selective O-methyl ether cleavage from the corresponding tri-O-methyl derivatives.     

Synthesis of septanosides through an oxyglycal route

A new route to synthesize septanoside derivatives from protected 2-hydroxyglycals is reported. Ring expansion of a pyranoside to a septanoside was achieved through key reactions of a cyclopropanation, ring opening, oxidation, and reduction. Methyl septanoside derivatives, namely, methyl alpha-D-glycero-D-talo-septanoside and methyl alpha-D-glycero-l-altro-septanoside, were synthesized in an overall yield of 35% and 46%, respectively, from the corresponding protected 2-hydroxy glycals.     

Synthesis of protected α-alkyl lanthionine derivatives

Protected α-alkyl lanthionine derivatives were synthesized in five steps starting from a known phenyloxazoline precursor. This approach involved the synthesis of a family of substituted cyclic sulfamidates and their regioselective opening by nucleophilic attack with a protected cysteine. This efficient multistep strategy affords various α-alkylated lanthionine derivatives in high yields.     

β-Fluorinated proline derivatives: potential transition state inhibitors for proline selective serine dipeptidases

Three new types of β-fluorinated proline derivatives were synthesized as potential transition state inhibitors for proline selective serine dipeptidases. The fluorophosponate derived from protected proline was tested as a Wadsworth-Horner-Emmons reagent for the synthesis of fluoro-olefin-containing pseudodipeptides.     

Design and Synthesis of Some New α‐Phenyl Cinnamoyl Derivatives for Selective Protection of Purine Nucleosides

Three new α‐phenylcinnamic acid derivatives [4‐methoxy‐α‐phenylcinnamic acid, α‐(4‐methoxyphenyl)‐cinnamic acid, and 4,4′‐bismethoxy‐α‐phenylcinnamic acid] were synthesized, characterized, and selectively used for protecting the exocyclic amino function of purine nucleosides (2′‐deoxyadenosine and 2′‐deoxyguanosine) via active ester generation. The acids were first activated using p‐nitrophenol, and these activated esters were used subsequently for the selective protection of amino groups. The N‐protected derivatives of 2′‐deoxyguanosine and 2′‐deoxyadenosine have been found to be sufficiently stable toward acids, thus minimizing depurination under oligodeoxyribonucleotide synthesis protocol. The ease of syntheses of N‐protected purine nucleosides, their stability under an acidic environment, and mild deprotection conditions are the key advantages of the new protecting groups.     

The concept of internal solubilization in peptide synthesis: ethylene glycol-based protecting groups

A novel, ethylene glycol-based protecting group is designed and synthesized for use in solid phase peptide synthesis. Ether and ester type protected amino acids are prepared. The acid stability of the new protecting group showed complete Fmoc/t-Bu compatibility. The new derivatives are tested in solid phase peptide synthesis, with a ‘difficult’ sequence to examine the disruption of peptide aggregation.     

DABCO: an efficient promoter for the acetylation of carbohydrates and other substances under solvent-free conditions

A simple, mild and efficient solvent-free method for the acetylation of carbohydrates, and their partially protected derivatives, as well as non-carbohydrate substances in excellent yields in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is described with the advantage of tolerance to various functional groups, short reaction time and ease of product isolation.     

An efficient regioselective synthesis of endocrocin and structural related natural anthraquinones starting from emodin

Endocrocin and related naturally occurring anthraquinone pigments like cinnalutein could be synthesized regioselectively via a Marschalk type reaction, starting from the natural hydroxy anthraquinone emodin. Furthermore, the new tri-O-methyl protected emodin-2-carbaldehyde may serve as a promising synthon for new bathochromically shifted, higher generation photodynamically active hypericin derivatives.