3′-氧-叠氮甲基-β-胸苷的合成

以特戊酰基选择性保护β-胸苷的5′-羟基,再将3′-羟基硫甲基甲基化;然后以磺酰氯将硫甲基甲基氯代后再与叠氮钠反应,最后用碳酸钠脱掉保护基合成了3′-氧-叠氮甲基β-胸苷,其结构经1H NMR表征。     

含长碳烷基核苷氢亚磷酸酯衍生物的合成与表征

通过将抗病毒药物核苷(3'-叠氮-2',3'-二脱氧胸苷AZT或2',3'-二脱氢-2',3'-二脱氧胸苷d4T)与三氯化磷反应, 然后在不同的醇解试剂作用下, 一锅法合成得到6个含长链烷基的核苷氢亚磷酸二酯衍生物, 并采用³¹P NMR, ¹H NMR, ¹³C NMR和ESI-MS对其结构进行了表征.     

二胸苷二氨合铂的合成及其平衡常数的测定

用逐步中和法,在pH=9.0的条件下合成了二胸苷二氨合铂,用Sephadex G-10分离得到纯配合物,并用元素分析、TG、DTA和~(13)CNMR对此进行了表征。用~1H NMR法测定和计算了配位反应的平衡常数,其值为1gK_1=9.95,1gK_2=6.92。     

3’-叠氮-3’-脱氧胸苷-α-羟基膦酸酯衍生物的合成

在碱性条件下, 抗病毒核苷衍生物3’-叠氮-3’-脱氧胸苷(AZT)-5’-氢亚膦酸二酯与芳香醛加成反应得到4个3’-叠氮-3’-脱氧胸苷-α-羟基膦酸酯类衍生物, 通过31P NMR, 1H NMR, ESI-MS及元素分析对其结构进行了表征确认.     

使用新型芳基硼酸酯保护基高效合成双环肽BI-32169

芳基硼酸酯作为一种新型的多肽固相合成保护基,相比较烯丙基等传统保护基具有脱除条件简便、高效以及脱保护试剂绿色环保等优势.采用标准9-芴甲氧羰基（Fmoc）固相合成策略,通过固相环合方法,以芳基硼酸酯作为Asp侧链保护基成功首次合成具有独特双环结构的人胰高血糖素受体多肽类抑制剂BI-32169.该方法合成效率高,操作简便,能够为其他类似环肽的化学全合成提供参考.     

N,N'-二乙氧羰基-O,O'-烷基二硫氨酯的合成及表征

关于含有一个酯基和一个硫代酰胺基团的硫氨酯的合成研究已有大量报道,但含有两个酯基和两个硫代酰胺基团的硫氨酯的合成研究尚未见报道。由氯甲酸乙酯和硫氰酸钠经亲核取代反应和异构化合成N-烃氧羰基异硫氰酸酯中间体,再将该中间体与二醇经亲核加成反应,合成出了3种未见报道的N,N’-二乙氧羰基-O,O’-烷基二硫氨酯。经元素分析、红外光谱、核磁共振氢谱及碳谱分析,证实所合成的化合物即为目标产物。小型浮选实验表明,仅使用6 g/t的目标化合物a~c,铜的品位即可分别达到6.12%、6.35%、5.92%,回收率分别达到75.31%、76.50%、76.35%,用量远低于丁基黄药,且铜的品位和回收率都有不同程度的提高,可作为一种新型捕收剂应用到硫化铜类的矿物浮选中。     

苯丙素苷Acteoside,Isoacteoside和Ligupurpuroside J的全合成

发展了一条合成苯丙素苷类化合物的通用路线,并依据此路线完成了苯丙素苷毛蕊花糖苷（Acteoside）和异毛蕊花糖苷（Isoacteoside）的全合成及紫茎女贞苷J（Ligupurpuroside J）的首次全合成.其中的关键步骤是应用金（Ⅰ）催化的鼠李糖邻炔基苯甲酸酯给体与多羟基裸露的2-苯乙基葡萄糖苷进行区域选择性糖苷化反应,成功构建天然苯丙素苷中常见的α-（1→3）糖苷键.该合成路线减少了保护基的使用,简洁高效.     

α-羰基水合醛及水合醛酯在水相中的烯丙基化反应

在水相中,α-羰基水合醛及水合醛酯与二溴二烯丙基锡作用可较高产率地生成α-羰基和α-酯基高烯丙基醇。     

DAP改性DAIP树脂体系

通过邻苯二甲酸二烯丙基酯(DAP)与间苯二甲酸二烯丙基酯(DAIP)共聚,再与增韧剂共固化,对DAIP 树脂体系进行改性研究.结果表明:DAP的引入可降低体系的交联密度,显著改善固化产物的冲击及弯曲强度.当共聚液中DAP质量百分数达到40%时,体系的冲击强度比原DAIP增韧体系提高了67%,弯曲强度提高了30%,同时改性后体系仍然保持较高的热变形温度及优良的介电、耐水性能.     

大豆苷元苯磺酸酯衍生物的细胞代谢研究

该文研究了大豆苷元苯磺酸酯衍生物D1~D3在人主动脉血管平滑肌细胞中的代谢途径。利用高效液相色谱-质谱(HPLC-MS)检测了大豆苷元苯磺酸酯衍生物的细胞代谢产物,初步推断出苯磺酸酯衍生物的体外代谢途径。研究发现,大豆苷元苯磺酸酯衍生物D1~D3水解代谢产物的进一步葡萄糖醛酸苷化和硫酸化是其主要代谢途径,二者存在竞争关系,衍生物均可以代谢成先导物大豆苷元（DD）。其中化合物D2是先发生苯磺酸酯基的水解,然后甲基醚水解生成DD的代谢途径,表明在细胞内水解酶的作用下苯磺酸酯键比甲基醚键更易发生水解。而化合物D1、D3则存在两种可能的代谢途径,表明在细胞内水解酶的作用下,乙酰基、乙基和苯磺酸酯基可以同时发生水解。该体外代谢途径的研究可为化合物D1~D3的整体实验提供可靠的理论依据。     

Improved synthesis of oligonucleotides containing 2-thiouridine derivatives by use of diluted iodine solution

It is known that the 2-thiocarbonyl group of 2-thiouridine (s²U) derivatives reacts easily with various oxidizing agents used in oligonucleotide synthesis to give a complex mixture. In this letter, we report an improved method for the synthesis of oligonucleotides containing s²U derivatives. It turned out that the 2-thiocarbonyl group of oligonucleotides containing s²U derivatives was stable in a 0.02 M solution of iodine in pyridine-THF-H₂O. These conditions were successfully applied to the synthesis of oligonucleotides containing s²U derivatives on an automated DNA/RNA synthesizer. Moreover, no undesirable side reactions were detected so that these modified oligonucleotides could be obtained in markedly improved yields.     

Palladium-catalyzed direct N-arylation of nucleosides, nucleotides, and oligonucleotides for efficient preparation of dG-N2 adducts with carcinogenic amino-/nitroarenes

A method for direct palladium-catalyzed N-arylation reaction of nucleobases was developed for the convenient synthesis of DNA adducts with carcinogenic compounds. Using xantphos as the phosphine ligand and tetraethylammonium fluoride as the base in DMSO, several o-iodonitroarenes could be efficiently coupled with 2'-deoxyguanosine, 2'-deoxyadenosine, and 2'-deoxycytidine. The presence of a 3'-phosphate group in the deoxyribose moiety was found to be compatible with this N-arylation reaction; further, oligonucleotides could serve as substrates. The facile nitroreduction of the coupling compounds (12) yielded 2'-deoxyguanosin-N2-ylarylamine adducts, which are known to be biologically important. Compound 12 was easily converted to phosphoramidite derivatives, allowing the preparation of site-specific modified oligonucleotides with arylamine after the nitroreduction.     

Spatial photorelease of oligonucleotides, using a safety-catch photolabile linker

[reaction: see text] We report the development of a safety-catch photolabile linker that allows the light-directed synthesis and spatially selective photorelease of oligonucleotides from microarrays. The linker remains stable to light during DNA synthesis, and is activated for photorelease after acidic hydrolysis. We demonstrate that the photoreleased oligonucleotides can be amplified by PCR to produce double stranded DNA. The advantages offered by this linker could aid the development of an automated gene synthesis platform.     

Green-Light Activatable BODIPY and Coumarin 5’-Caps for Oligonucleotide Photocaging

We synthesized two green-light activatable 5’-caps for oligonucleotides based on the BODIPY and coumarin scaffold. Both bear an alkyne functionality allowing their use in numerous biological applications. They were successfully incorporated in oligonucleotides via solid-phase synthesis. Copper-catalyzed alkyne-azide cycloaddition (CuAAC) using a bisazide photo-tether gave cyclic oligonucleotides that could be relinearized by activation with green light and were shown to exhibit high stability against exonucleases. Chemical ligation as another example for bioconjugation yielded oligonucleotides with an internal strand break site. Irradiation at 530 nm or 565 nm resulted in complete photolysis of both caging groups.     

Linkers for oligonucleotide microarray synthesis

A number of linkers for microchip-based (microarray) synthesis of oligonucleotides were synthesized here using photolabile intermediates. The resulting linkers are designed for covalent immobilization on slides containing both hydroxyl and amino groups.The first series of linkers was intended for the synthesis of oligonucleotide arrays for hybridization analysis. These linkers provide a strong covalent bond with the slide surface when amino groups in oligonucleotide heterocyclic bases are deprotected.The second series of linkers allows to cleave the synthesized oligonucleotides from the support on which they were synthesized. Furthermore, the use of such linkers yields oligonucleotides devoid of the phosphate group at their 3′ end.The obtained linkers were successfully tested in the synthesis of oligonucleotides on a microchip for subsequent hybridization analysis and assembly of a DNA fragment.     

New method to prepare peptide-oligonucleotide conjugates through glyoxylic oxime formation

A new method to prepare peptide-oligonucleotide conjugates through chemoselective glyoxylic oxime linkage is reported. A novel phosphoramidite reagent, readily accessible from serine, was prepared and used in automated DNA synthesis to prepare oligonucleotides carrying a glyoxylic aldehyde functionality at the 5' terminus. This was efficiently coupled to a peptide functionalized with an aminooxy group. The method could be of general use to prepare a broad range of oligonucleotide conjugates.     

New phosphoramidite derivatives for the preparation of oligonucleotides containing a hydrazide group in any specified position of the oligonucleotide chain

A new versatile method for the preparation of oligonucleotides containing hydrazide groups in any position of the oligonucleotide chain by standard phosphoramidite automated oligonucleotide synthesis is proposed. The method is based on the use of a series of new modified components for oligonucleotide synthesis. An original protecting group for the hydrazide group is proposed. The presence of the hydrazide group in the obtained oligonucleotides and its high reactivity were demonstrated by the reaction with 4-methoxybenzaldehyde in solution. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2585–2595, November, 2005.     

The 2-(N-formyl-N-methyl)aminoethyl group as a potential phosphate/thiophosphate protecting group in solid-phase oligodeoxyribonucleotide synthesis

[reaction in text] The 2-(N-formyl-N-methyl)aminoethyl deoxyribonucleoside phosphoramidite 1 has been synthesized and used in the solid-phase synthesis of an octadecathymidylic acid as a cost-efficient monomer for potential application in the preparation of therapeutic oligonucleotides. The 2-(N-formyl-N-methyl)aminoethyl group can be cleaved from oligonucleotides according to a unique thermolytic cyclodeesterification process at pH 7.0. In addition to being cost-effective, the use of 1 simplifies oligonucleotide postsynthesis processing by eliminating the utilization of concentrated ammonium hydroxide in oligonucleotide deprotection.     

A New and Efficient Method for Synthesis of 5′‐Conjugates of Oligonucleotides through Amide‐Bond Formation on Solid Phase

An efficient method for synthesis of oligonucleotide 5′‐conjugates through amide‐bond formation on solid phase is described. Protected oligonucleotides containing a 5′‐carboxylic acid function were obtained by use of a novel non‐nucleosidic phosphoramidite building block, where the carboxylic acid moiety was protected by a 2‐chlorotrityl group. The protecting group is stable to the phosphoramidite coupling conditions used in solid‐phase oligonucleotide assembly, but is easily deprotected by mild acidic treatment. The protecting group may be removed also by ammonolysis. 5′‐Carboxylate‐modified oligonucleotides were efficiently conjugated on solid support under normal peptide‐coupling conditions to various amines or to the N‐termini of small peptides to yield products of high purity. The method is well‐suited in principle for the synthesis of peptide‐oligonucleotide conjugates containing an amide linkage between the 5′‐end of an oligonucleotide and the N‐terminus of a peptide.     

Characterization and sequence verification of thiolated deoxyoligonucleotides used for microarray construction

During synthesis of thiolated deoxyoligonucleotides, side products can be formed. When used in the fabrication of microchips, the oligonucleotides have to be of high purity. We demonstrated the presence of impurities, which were not failure sequences from the synthesis. These products were identified and characterized using high-performance liquid chromatography (HPLC) and electrospray MS(/MS). The presence of the free thiol group was assessed by acrylamide derivatization. After reaction with acrylamide the correct compounds showed a 71 u mass shift and the major fragment ions could be assigned as 5' a-base and 3' w ions, similar as for unmodified DNA. The side products were unaffected by acrylamide, suggesting that the thiol group was modified. The oligonucleotide containing a species with a mass of 32 u higher was identified as 5' sulfinic acid containing molecule and was found as 45% of the total amount of a DNA 25 mer. Other components appeared to be dithio-linked oxidation products, present about 1 to 5% in a 10 mer and 15 mer deoxyoligonucleotide. The analyses were useful for optimizing the synthesis protocols.