紫杉醇生物素标记衍生物的合成

以生物素、紫杉醇和6-氨基己酸为原料,经酰化、水解、酯化反应等步骤合成具有长臂连接的标题化合物。在三乙胺催化下,生物素与N-羟基琥珀酰亚胺反应生成N-羟基琥珀酰亚胺生物素酯。在氯化亚砜、甲醇反应体系下,由6-氨基己酸合成6-氨基己酸甲酯。在三乙胺作用下,N-羟基琥珀酰亚胺生物素酯和6-氨基己酸甲酯反应生成生物素-氨基己酸甲酯;生物素-氨基己酸甲酯在Li OH·H2O作用下,水解反应得到6-生物素氨基己酸。以DMF为溶剂,在N,N'-二环己基碳二亚胺(DCC)、4-二甲氨基吡啶(DMAP)作用下,6-生物素氨基己酸与紫杉醇反应,生成标题化合物。标题化合物和重要中间体化合物采用IR、1HNMR、MS进行了表征。     

d-生物素中间体合成工艺改进

原文节录：生物素又名维生素H或维生素B7，它作为成长素是整个生物界所必需的。自1941年从牛肝中分离得到生物素以来，它作为一种重要的维生素是各国科学家争相合成的对象。但反应步骤多、试剂昂贵、反应条件苛刻的问题难以解决。L-半胱氨酸和L-胱氨酸分子最符合生物素结构的要求，因此以其为起始原料合成生物素的研究一直很活跃。     

杀菌剂霜脲氰的生物素结合剂的合成

农用杀菌剂霜脲氰[1-(2-氰基-2-甲氧基亚胺乙酰基)-3-乙基脲](图1,1)对许多卵菌纲真菌,包括引起马铃薯晚疫病的疫霉属(Phytophthora infestans (Mont) de Bary)有很好的治疗活性。由于缺乏持效,霜脲氰的活性价值有所削弱,因此它常与其它杀菌剂混合使用。罗姆·哈斯公司的Karen A Evens等发现霜脲氰的靶标位置存在于尿苷的代谢或与     

N-羟基琥珀酰亚胺生物素酯的合成与应用

利用两种方法合成了N-羟基琥珀酰亚胺生物素酯，并用核磁共振谱进行了结构表征，N-羟基琥珀酰亚胺生物素酯的应用前景非常广泛。     

农药人工抗原合成的研究进展

综述了农药人工抗原合成、鉴定、偶联比测定和影响农药人工抗原质量的因素等方面研究进展。     

生物素的工业全合成

本文综述国内外学者在生物素合成方面所作的研究，筛选出两条适合工业合成的路线，即生物素的Sternbach生产技术和生物素的立体专一性全合成，为我国生物素的生产合成指明方向。     

d-生物素全合成研究进展

d-生物素目前大生产工艺以Sternbach合成路线为基础,加以不断优化形成以富马酸为起始原料,经溴代、苄胺化、环合、缩合、还原、水解、硫代、格氏、氢化、脱苄、精制得生物素。基于原料手性池的不对称合成方法发展迅速,取代Stembach合成路线有望成为可能。     

HCV核心抗原N-端片段生物素化表达质粒的构建及表达

目的构建HCV核心(C)抗原N-端1～130aa片段的生物素化表达质粒,并在大肠杆菌中进行表达。方法PCR扩增HCV C抗原N-端1～130aa片段的编码基因,拼接上生物素-蛋白连接酶底物肽序列(BSP),构建重组原核表达质粒pGEX4T-1-CN130BSP,转化大肠杆菌Rosetta,IPTG诱导表达。表达产物经SDS-PAGE后,电转至硝酸纤维素膜上,以抗HCVC抗原的单克隆抗体和辣根过氧化物酶标记的亲和素对表达产物进行分析。结果PCR扩增出约466bp的目的基因片段;质粒pGEX4T-1-CN130BSP经PCR及双酶切鉴定,与预期结果一致,测序鉴定基因无突变;SDS-PAGE显示表达产物相对分子质量约为42000,22℃诱导16h可溶性表达产物含量较高;表达的重组蛋白可被抗HCV C抗原的单克隆抗体所识别,并能特异性结合辣根过氧化物酶标记的亲和素。结论已成功构建了HCV C抗原N-端1～130aa片段生物素化表达质粒,并表达出带生物素标签的GST融合蛋白,为进一步研制HCV双抗原夹心检测试剂奠定了基础。     

生物素合成中的格利雅反应

研究了生物素合成中的格利雅反应,着重讨论了接侧链反应的工艺条件,优化并确立了反应条件,实现了工业化生产,解决了放大生产中产生的一系列问题,对溶剂进行了回收套用。研究表明,在多数情况下,绿色化学的目标与追求经济效益的目标是一致的。     

d-生物素中间体合成工艺改进

通过Zn/TiCl4、H4AlLi/TiCl4、Zn Cu/TiCl3低价钛催化剂比较,选择了稳定的Zn Cu/TiCl3为催化剂,反应制得生物素中间体(6aR) 1,3 二苄基 4 (4 甲氧羰基丁基) 二氢 噻吩并[3,4 d]咪唑 2 酮(Ⅵ)。改用异氰酸苄酯为关环试剂环化合成了(7aR) 3 苯基 6 苄基 1H,3H 咪唑并[1,5 c]噻唑 5,7 二酮(Ⅲ),选用CH3COOH/(CH3CO)2O代替CH3COOH作溶剂,反应时间由17h缩短为3h,产率从75%提高到93%。以L 半胱氨酸盐酸盐为原料,依次以苯甲醛、异氰酸苄酯为关环试剂环化合成Ⅲ,以锌为还原剂于90℃下开环合成了N,N′ 二苄基 L 巯基海因(Ⅳ),经与己二酸单甲酯酰氯于0℃下的酯化反应引入侧链,Zn Cu/TiCl3为催化剂,反应得到Ⅵ,5步反应建立了生物素所需骨架结构,总产率达56%。     

Chemobacterial Synthesis of a Sialyl‐Tn Cyclopeptide Vaccine Candidate

A conjugatable form of the tumour‐associated carbohydrate antigen sialyl‐Tn (Neu5Ac‐α‐2,6‐GalNAc) was efficiently produced in Escherichia coli. Metabolically engineered E. coli strains overexpressing the 6‐sialyltransferase gene of Photobacterium sp. and CMP‐Neu5Ac synthetase genes of Neisseria meningitidis were cultivated at high density in the presence of GalNAc‐α‐propargyl as the exogenous acceptor. The target disaccharides, which were produced on the scale of several hundreds of milligrams, were then conjugated by using copper(I)‐catalysed azide–alkyne cycloaddition click chemistry to a fully synthetic and immunogenic scaffold with the aim to create a candidate anticancer vaccine. Four sialyl‐Tn epitopes were introduced on the upper face of an azido‐functionalised multivalent cyclopeptide scaffold, the lower face of which was previously modified by an immunogenic polypeptide, PADRE. The ability of the resulting glycoconjugate to interact with oncofoetal sialyl‐Tn monoclonal antibodies was confirmed in ELISA assays.     

环境荷尔蒙邻苯二甲酸二甲酯的人工全抗原合成与表征

4-硝基邻苯二甲酸经过酯化、还原和与牛血清白蛋白偶联,成功合成了邻苯二甲酸二甲酯人工抗原,为其免疫分析方法的建立提供了条件。产物经红外光谱、紫外光谱和核磁共振鉴定分析确定。     

Carbohydrate array analysis of anti-Tn antibodies and lectins reveals unexpected specificities: implications for diagnostic and vaccine development

The Tn antigen is a carbohydrate antigen expressed in most carcinomas, during embryogenesis, on pathogenic parasites, and on HIV. It has been evaluated extensively as a potential diagnostic marker and several Tn-based vaccines are in clinical trials. Based on discrepancies in the literature regarding Tn expression, we began to question whether antibodies and lectins used routinely to detect the Tn antigen were providing accurate information. To investigate this possibility, a carbohydrate microarray and a highly sensitive assay were developed and three frequently used Tn receptors (HBTn1, Bric111, and VVL-B4) were evaluated. Carbohydrate-array analysis revealed unexpected cross-reactivity with other human carbohydrate epitopes. VVL-B4 bound the Tn antigen, GalNAcalpha1-6Gal, and GalNAcalpha1-3Gal. Bric111 bound the Tn antigen, blood group A, GalNAcalpha1-6Gal, and GalNAcalpha1-3Gal. HBTn1 showed the best selectivity, but still displayed moderate binding to blood group A. Implications for the development of Tn-based diagnostics and vaccines are discussed.     

Tn Antigen Expression Defines an Immune Cold Subset of Mismatch-Repair Deficient Colorectal Cancer

Colorectal cancer (CRC) cells often express Tn antigen, a tumor-associated truncated immature O-glycan (GalNAcα-O-Ser/Thr) that can promote tumor progression. Immunotherapies against Tn antigen have been developed and are being evaluated in clinical trials. Tn antigen can also be considered a novel immune checkpoint that induces immunosuppressive signaling through glycan-biding lectins to lead effector T cell apoptosis. We evaluated the correlation of Tn antigen expression by immunohistochemistry with mismatch-repair (MMR) status, tumor-infiltrating lymphocytes, tumor cell PD-L1 expression, and clinicopathological characteristics in 507 CRC patients. Although 91.9% of CRCs showed negative or weak Tn antigen staining (Tn-negative/weak), we identified a small subset of CRCs (8.1%) that displayed particularly intense and diffuse distribution of Tn antigen immunoreactivity (Tn-strong) that closely related to deficient MMR (dMMR). Moreover, 40 dMMR CRCs were stratified into 24 Tn-negative/weak dMMR tumors (60.0%) exhibiting dense CD8+ lymphocyte infiltrate concomitant with a high rate of PD-L1 positivity, and 16 Tn-strong dMMR tumors (40.0%) that demonstrated CD8+ T cell exclusion and a lack of PD-L1 expression, which was comparable to those of proficient MMR. Our finding suggests that the immune cold subset of patients with Tn-strong dMMR CRC may be effectively treated with immune checkpoint blockade therapy or cellular immunotherapy targeting Tn antigen.     

A Synthetic MUC1 Glycopeptide Bearing βGalNAc‐Thr as a Tn Antigen Isomer Induces the Production of Antibodies against Tumor Cells

This study presents the synthesis of the novel protected O‐glycosylated amino acid derivatives 1 and 2 , containing βGalNAc‐SerOBn and βGalNAc‐ThrOBn units, respectively, as mimetics of the natural Tn antigen (αGalNAc‐Ser/Thr), along with the solid‐phase assembly of the glycopeptides NHAcSer‐Ala‐Pro‐Asp‐Thr[αGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 3 ‐BSA) and NHAcSer‐Ala‐Pro‐Asp‐Thr[βGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 4 ‐BSA), bearing αGalNAc‐Thr or βGalNAc‐Thr units, respectively, as mimetics of MUC1 tumor mucin glycoproteins. According to ELISA tests, immunizations of mice with βGalNAc‐glycopeptide 4 ‐BSA induced higher sera titers (1:320 000) than immunizations with αGalNAc‐glycopeptide 3 ‐BSA (1:40 000). Likewise, flow cytometry assays showed higher capacity of the obtained anti‐glycopeptide 4 ‐BSA antibodies to recognize MCF‐7 tumor cells. Cross‐recognition between immunopurified anti‐βGalNAc antibodies and αGalNAc‐glycopeptide and vice versa was also verified. Lastly, molecular dynamics simulations and surface plasmon resonance (SPR) showed that βGalNAc‐glycopeptide 4 can interact with a model antitumor monoclonal antibody (SM3). Taken together, these data highlight the improved immunogenicity of the unnatural glycopeptide 4 ‐BSA, bearing βGalNAc‐Thr as Tn antigen isomer.     

Synthesis and antifungal activities of glycosylated derivatives of the cyclic peptide fungicide caspofungin

Diseases caused by systemic fungal infections have become a significant clinical problem in recent decades. A series of glycosyl derivatives of the approved cyclic peptide antifungal drug caspofungin conjugated with β‐D ‐glucopyranose, β‐D ‐galactopyranose, β‐D ‐xylopyranose, β‐L ‐rhamnopyranose, β‐maltose and β‐lactose units were designed, synthesized, and evaluated as new potential antifungal drugs. The compounds were obtained by coupling the corresponding glycosyl amines to the free primary amino groups of caspofungin through a bifunctional glutaryl linker. In contrast to caspofungin, these glycosylated derivatives are soluble in water, but are not hygroscopic and moreover, are more stable than caspofungin under high humidity and temperature. CD studies showed that glycosylation has very little impact on the conformation of the cyclic peptide of caspofungin. In vitro antifungal tests against seven human pathogenic fungi revealed that the caspofungin–monosaccharide conjugates, but not the disaccharide conjugates, have increased antifungal activities against the majority of tested fungus species relative to caspofungin. The β‐D ‐glucopyranosyl derivative 2 a showed the strongest and broadest antifungal activity, providing a lead for further studies.     

黄曲霉毒素G族人工抗原的合成与免疫效果研究

以黄曲霉毒素(Aflatoxin G1,AFG1)的半缩醛(Aflatoxin G2a,AFG2a)为中间物,通过还原烷基法,使黄曲霉毒素G1在8、9羟基上与牛血清白蛋白(BSA)实现偶联,得到偶联物。对偶联物进行紫外全波长扫描显示,其特征吸收峰与BSA和AFG1的特征吸收峰有明显差异。经完全透析后检测偶联物与BSA荧光强度差异,均表明BSA与黄曲霉毒素G1偶联,AFG1-BSA物质的量结合比为3.2∶1。以合成人工抗原免疫小鼠,用间接非竞争ELISA测得抗血清中抗体的效价可达1∶128 000,间接竞争ELISA测定抗体IC50为14.7 ng/mL。为下一步研制黄曲霉毒素G族单克隆抗体提供了关键试剂,为研究建立黄曲霉毒素G族免疫速测技术奠定了基础。     

氰戊菊酯免疫分析关键试剂人工抗原的合成与应用效果

以氰戊菊酸、间苯氧基苯甲醛为原料,利用酰氯与伯胺的活泼反应,合成了一种含有3个碳原子长度连接臂的氰戊菊酯半抗原,并通过核磁共振鉴定;用活泼酯法将合成的氰戊菊酯半抗原分别与牛血清白蛋白(BSA)和卵清白蛋白(OVA)偶联制备免疫抗原和检测抗原,紫外-可见连续光谱扫描结果显示,所制备的人工抗原的图谱具有载体蛋白和半抗原的特征峰叠加现象,表明偶联成功;人工抗原的免疫结果显示,以BSA偶联物免疫小鼠后获得抗血清效价分别为160 000、140 000和110 000,间接竞争ELISA(酶联免疫吸附分析)测定抗体IC50(半数抑制浓度)值为35.1 μg/L,与其他供试农药的交叉反应率均＜1%,为氰戊菊酯抗体研制及免疫分析检测技术研究提供了关键试剂.     

吗氯贝胺的合成工艺改进

以乙醇胺为起始原料,经亲核取代、肖特一鲍曼反应和缩合反应制得吗氯贝胺,总收率可达71.2%.     

甲基环己基二甲氧基硅烷的合成

报道了甲基环己基二甲氧基硅烷的格氏合成法。本方法简单、反应周期短、产率高,得到纯度达９８％的甲基环己基二甲氧基硅烷产品。