An efficient and green preparation of 5-aminophosphonate substituted pyrimidine nucleosides under solvent-free conditions

An environmentally benign and highly efficient one-pot preparation of α-aminophosphonates under solvent-free conditions was developed. By employing this method, 5-aminophosphonate substituted pyrimidine nucleosides were synthesized in good to excellent yields starting from 5-forrnyl-2＇-deoxyuridine, aniline and dimethylphosphite.

Induction of Recombinant Uridine Phosphorylase and Its Application in Biosynthesis of Pyrimidine Nucleosides

Recombinant Escherichia coli pUDP,which overexpressed uridine phosphorylase（UPase）,was constructed.0.5 mmol·L 1lactose had a similar induction effect as the commonly used inducer IPTG during 2.5-5.5 h of cell growth.The lactose-induced UPase was stable at 50°C.Wet cells of pUDP was used as catalyst to biosynthesize 5-fluorouridine from 30 mmol·L 1uridine and 5-fluorouracil in phosphate buffer（pH 7.0）catalyzed at 50°C for 1.5 h and the yield of 5-fluorouridine was higher than 68%.Under the optimum reaction conditions for production of 5-fluorouridine,5-methyluridine and azauridine were synthesized from uridine by pUDP,the yield was 61.7%and 47.2%respectively.Deoxynucleosides were also synthesized by pUDP,but the yield was only about 20%.

Synthesis and antiviral activity of 4H-[1,2,5]oxadiazolo-[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides

A series of 4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides was designed, synthesized and evaluated against vesicular stomatitis virus （VSV） in Wish cell. The antiviral activities of all compounds were stronger than those of acyclovir, while their toxicities were similar to those of acyclovir.

Nucleosides 10: Synthesis of New Derivatives of Pyrimidine and Fused Pyrimidine Nucleosides of Expected Biological Activity

Pyrimidines, such as 6-amino-2-thio and 2-methylthiouracils and fused pyrimidines, such as thienopyrimidines reacted with 1-O-acetyl-2,3,5-tri-O- benzoyl-β-D-ribofuranose to get new derivatives of the corresponding nucleosides. The obtained protected nucleosides were deprotected by methanolic sodium methoxide to get the corresponding free uracil and thienopyrimidine nucleosides. The new nucleosides formed were tested for biological activity against some of microorganism (some fungi and bacteria species). Some of the tested products showed moderate activity and the results were reported.

Optimization, Spectroscopic(FT-IR, Excited States, UV/Vis) Studies, FMO, ELF, LOL, QTAIM and NBO Analyses and Electronic Properties of Two New Pyrimidine Derivatives

In the given research,the molecular structures of two new compounds,4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-amine(PM-1)and N-(4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-yl)-4,6-dichloro 1,3,5-1,3,5-triazin-2-amine(PM-2),have been studied with the use of density functional theory(DFT/B3LYP/MidiX)in dimethylformamide(DMF)for the first time.The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory(TD-DFT)method.The computed absorption spectral data of the title compounds are in good agreement with the experimental data,thus allowing an assignment of the UV/Vis spectra.The equilibrium geometry,the HOMO and LUMO molecular orbitals,excitation energies,oscillator strengths and Natural Bond Orbital(NBO)analysis for the molecules have also been calculated and presented.FT-IR spectra of the title molecules are recorded and discussed.The electron location function(ELF),localized orbital locator(LOL)and quantum theory of atoms in molecules(QTAIM)analyses were also carried out.On the basis of polyvinyl alcohol(PVA)and synthesized molecules,polarizer for UV/Vis region of the spectrum has been developed.

Novel Ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate Derivatives: Synthesis and Anticancer Activities

To explore the anticancer activity of 2, 4, 5, 6-substituted pyrimidines, several ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate?derivatives associated with the different substituted aromatic/aliphatic carboxamides?and sulfonamides were synthesized. Different groups and position on phenyl ring attached to the carboxamide?and sulfonamide of the pyrimidine led to two set of compounds. Their chemical structures were confirmed by IR,1H NMR and LC/MS analysis. Cytotoxicity of all the synthesized compounds were examined on human leukemia celllines (K562 and CEM). The preliminary results showed most of the derivatives exhibited good antitumor activity. Compound?with para chloro substitution among carboxamides and compound with meta dichloro substitution among sulphonamidesexhibited significant antitumor activity with IC50 value of 14.0 μM and 15.0 μM respectively against K562cell line. For comparison among electron donating groups between carboxamides and sulfonamides, compounds with?para tert-butyl substitution were chosen for further studies. Cell cycle analysis suggests that both tert-butyl substituted?compounds are able to induce apoptosis.

Molecular Dynamics Insights into Electron-Catalyzed Dissociation Repair of Cyclobutane Pyrimidine Dimer

Excess electrons are not only an important source of radiation damage,but also participate in the repair process of radiation damage such as cyclobutane pyrimidine dimer(CPD).Using ab initio molecular dynamics(AIMD)simulations,we reproduce the single excess electron stepwise catalytic CPD dissociation process in detail with an emphasis on the energy levels and molecular structure details associated with excess electrons.On the basis of the AIMD simulations on the CPD aqueous solution with two vertically added excess electrons,we exclude the early-proposed[2+2]-like concerted synchronous dissociation mechanism,and analyze the difference between the symmetry of the actual reaction and the symmetry of the frontier molecular orbitals which deeply impact the mechanism.Importantly,we propose a new model of the stepwise electron-catalyzed dissociation mechanism that conforms to the reality.This work not only provides dynamics insights into the excess electron catalyzed dissociation mechanism,but also reveals different roles of two excess electrons in two bond-cleavage steps(promoting versus inhibiting).

Synthesis, Spectroscopy and X-Ray Crystal Structure of 9-Methyl-3-Thiophen-2-Yl-Thieno [3, 2-e] [1, 2, 4] Triazolo [4, 3-c] Pyrimidine-8-Carboxylic Acid Ethyl Ester

The Preparation of 9-Methyl-3-thiophen-2-yl-thieno [3, 2-e] [1, 2, 4] triazolo [4, 3-c] pyrimi-dine-8-carboxylic acid ethyl ester is described. Elemental analysis, IR spectrum, 1H NMR, 13C NMR and X-ray crystal structure analyses were carried out to determine the composition and molecular structure of the title compound. There are two independent molecules in the asymmetric unit exhibiting intermolecular C-H…N, C-H…O interactions with additional π-π interaction that further helps in stabilizing the supramolecular structure. The results showed that the proposed method for synthesis is simple, precise and accurate which was further confirmed by crystal structure analysis.

基于液质联用法测定嘧啶核苷类化合物GY005在SD大鼠体内的药代动力学实验研究

建立LC-MS/MS法测定嘧啶核苷类化合物GY005在大鼠血浆中的浓度,并应用于大鼠体内的药代动力学研究。以特非那定为内标,经乙腈-甲醇沉淀蛋白后,采用ACE 5 C4 column(50 mm×2.1 mm,2.5μm)色谱柱,以0.1%甲酸水和0.1%甲酸乙腈为流动相,进行梯度洗脱分离,流速0.7 mL·min^(-1),进样量10μL;采用电喷雾离子源(ESI),正离子扫描方式,MRM扫描,分别以m/z 445.15→270.10和m/z 472.40→436.40作为化合物GY005和内标(特非那定)的质谱检测条件。大鼠灌服2 mg·kg^(-1)化合物GY005后,不同时间点取样测定其血浆浓度,计算药代动力学参数。雌雄SD大鼠单次静脉注射2 mg·kg^(-1)的受试品后,化合物GY005在雄性大鼠体内的暴露量(AUC_(last))为(228±44)h·ng·mL^(-1),消除半衰期(T_(1/2))为(0.30±0.01)h,清除率(CL)为(149±29)mL·min^(-1)·kg^(-1)。化合物GY005在雌性大鼠体内的暴露量(AUC_(last))为(215±158)h·ng·mL^(-1),消除半衰期(T_(1/2))为(0.32±0.03)h,清除率(CL)为(226±162)mL·min^(-1)·kg^(-1)。雌雄间暴露水平相当,没有显著性差异。这个方法具有简便、灵敏、快捷,适用于化合物GY005的药代动力学研究。

一测多评法测定美洲大蠊药材5种核苷类成分

目的建立高效液相色谱(HPLC)一测多评法同时测定美洲大蠊中尿嘧啶、尿苷、次黄嘌呤、肌苷及鸟苷5种成分的含量。方法采用Agilent ZORBAX SB-Aq色谱柱(250 mm×4.6 mm,5μm);以甲醇-0.01 mol·L^(-1)磷酸二氢钾溶液为流动相,梯度洗脱;流速:1.0 mL·min^(-1);柱温:20℃;检测波长:260 nm;进样量:10μL。计算内参物尿苷与其他成分的相对校正因子(fa/b)。一测多评法测定10批美洲大蠊中5种成分含量,并与外标法比较。结果5种核苷类在各自范围内线性良好(r>0.9995),平均加样回收率97.0%~100.8%。尿嘧啶、次黄嘌呤、肌苷、鸟苷的fa/b分别是0.9080、1.0053、1.9695、1.3034。结论所建立的方法准确稳定,可为美洲大蠊药材及提取物的质量控制提供理论参考。

不同产地太白贝母中11种核苷与碱基类成分分析及产地差异研究

目的对10批采自重庆、云南、陕西等5个省(市)的太白贝母样品中11种核苷和碱基类成分的含量进行测定,采用化学计量学分析法比较太白贝母中的核苷和碱基类成分的含量差异,对其质量进行综合评价,为规范化种植和产地优选提供参考。方法水超声提取太白贝母中的核苷和碱基类成分,采用高效液相色谱-二极管阵列检测器(HPLC-DAD)法测定样品中各成分含量,并采用主成分分析(Principal component analysis,PCA)、层次聚类分析(Hierarchical cluster analysis,HCA)对产地进行划分,偏最小二乘判别分析(Partial least squares discriminant analysis,PLS-DA)确定太白贝母中差异性的指标成分,比较指标性成分在不同产地样品间的含量差异。结果11种核苷和碱基类成分在不同产地太白贝母中存在显著差异;主成分分析和层次聚类分析可将样品聚为4类;PLS-DA鉴定出5个指标性成分,分别为尿嘧啶、胞嘧啶、尿苷、肌苷、腺苷,以重庆、湖北产地样品所含核苷和碱基成分相对较高,质量相对较优。结论该方法操作简单、重复性好、准确可靠,筛选出了鉴定不同产地太白贝母中的特征性核苷和碱基类成分,可用于初步阐明不同产地样品的差异性,并能够较好地反映太白贝母的品质,为太白贝母药材采购产地选择和质量控制提供参考。

HPLC法测定僵蚕5个核苷类成分的含量及聚类分析

目的建立同时测定僵蚕药材中5种核苷类成分含量的方法,并比较不同来源僵蚕药材中上述成分的差异性,为僵蚕药材的质量控制提供参考。方法采用月旭AQ-C_(18)(250 mm×4.6 mm,5μm)色谱柱;以纯水-甲醇为流动相,梯度洗脱,流速为0.8 mL/min;检测波长为260 nm,柱温为26℃;进样量为20μL。以21批不同来源的僵蚕药材为样品,测定上述5种成分含量,并采用SPSS 25.0统计学软件对21批不同来源的僵蚕药进行聚类分析。结果尿嘧啶、次黄嘌呤、尿苷、鸟苷及腺嘌呤分别在1~32μg/mL(r=1.0000)、0.3~9.6μg/mL(r=0.9999)、2~64μg/mL(r=0.9999)、5~160μg/mL(r=0.9998)、5~160μg/mL(r=0.9999)的浓度范围内与峰面积的线性关系良好,精密度、重复性、稳定性试验结果的RSD<3.00%,平均加样回收率为98.86%~101.73%,RSD<3.00%。不同来源僵蚕之间5个成分含量差异有统计学意义。经聚类分析,21批样品共聚为3类,产地样品即S1、S4、S5、S7、S8、S9聚类第Ⅰ类,市场样品聚为第Ⅱ类,产地样品S2、S3、S6聚为第Ⅲ类。结论该方法简便准确、重复性好,可用于同时测定僵蚕药材中上述5种核苷类成分的含量。同一产区僵蚕质量较为稳定,含量较高,市场僵蚕来源复杂,含量较低。

中医药联合核苷(酸)类似物治疗慢性乙型病毒性肝炎抗病毒疗效及安全性:基于随机、双盲、对照临床试验的Meta分析

目的中医药联合核苷(酸)类似物治疗慢性乙型病毒性肝炎抗病毒疗效仍存在争议,本文拟系统性评价中西医联合抗乙肝病毒效果及安全性。方法在中英文电子数据库(中国知网、万方、维普、中国生物医学等中文数据库和Embase、PubMed和Cocharane Library英文数据库)中检索中医药联合核苷(酸)类似物治疗慢性乙型病毒性肝炎的相关文献,筛选随机、双盲、对照临床试验文献进行统计分析。结果:共纳入随机、双盲、对照、临床试验文献9篇,共含2752例慢性乙型肝炎患者,试验组1376例,对照组1376例。结果与单用核苷(酸)类似物相比,试验组治疗能显著提高治疗(≥48周)结束时的乙肝病毒e抗原阴转率乙肝病毒e抗原血清转换率和乙型肝炎表面抗原转阴率。在治疗24周后的乙肝病毒的脱氧核糖核酸阴转率、谷丙转氨酶复常率方面,解毒类方试验组明显优于对照组。试验组与对照组两组在治疗(≥48周)结束时的乙肝病毒的脱氧核糖核酸阴转率、谷丙转氨酶复常率、肝脏炎症分级和纤维化分期变化率及不良反应发生率方面,差异无统计学意义。结论中医药联合核苷(酸)类似物治疗慢性乙型病毒性肝炎抗病毒疗效优于核苷(酸)类似物单药治疗,且不增加不良反应发生率。

甘草酸类制剂与核苷(酸)类似物联用对慢性乙型肝炎患者临床疗效与安全性的网状Meta分析

目的:比较与分析甘草酸类制剂与核苷(酸)类似物联用对慢性乙型肝炎(chronic hepatitis B,CHB)患者的临床疗效与安全性。方法:在Pubmed、Embase和中国知网、万方医学网、维普等数据库中,检索建库至2023年10月甘草酸类制剂与核苷(酸)类似物联用对CHB患者临床疗效与安全性的随机对照试验(randomized controlled trial)研究,采用Stata1和Revman等软件进行甘草酸类制剂与核苷(酸)类似物联用对CHB患者的临床疗效与安全性的网状Meta分析。结果:筛选后共纳入文献42篇,共涉及病例3991例;网状Meta分析结果显示,甘草酸类制剂与核苷(酸)类似物联用对CHB患者在丙氨酸转氨酶、天冬氨酸转氨酶、总胆红素等指标上的疗效均优于单用核苷(酸)类似物(P<0.05);在用药安全性方面,甘草酸类制剂与核苷(酸)类似物联用和单用核苷(酸)类似物的药物不良反应发生率经比较其差异无统计学意义(P>0.05)。结论:甘草酸类制剂与核苷(酸)类似物联用对CHB患者的疗效较为肯定,安全性也较高。

HPLC-FP法同时测定新品富硒竹笋中10种核苷类成分的含量

目的:建立同时测定不同品种富硒竹笋中胞嘧啶、尿嘧啶、胞苷、次黄嘌呤、尿苷、胸腺嘧啶、腺嘌呤、鸟苷、胸苷、腺苷10种核苷类化合物含量的方法。方法:运用HPLC法同时测定21种不同品种竹笋的核苷类化合物含量,色谱柱为InertsilODS-3C_(18),流动相为乙腈-水(梯度洗脱),检测波长为260nm,流速为0.8 mL·min~(-1),柱温为30℃,进样量为20μL。绘制21种富硒竹笋的指纹图谱进行相似度评价,确定共有峰,并用主成分分析、相关性分析和聚类分析对21种不同富硒竹笋的核苷类化合物含量测定结果进行分析。结果:10种核苷类成分在30 min内达到分离,线性关系良好(R2≥0.9990),精密度、稳定性、重复性、准确度试验RSD均小于2%。不同品种富硒竹笋中10种核苷类成分含量与结构比差异明显,并且核苷类化合物成分指标互相间存在着不同程度的相关性。通过主成分分析,提取了4个主成分,并确定了胸苷、胸腺嘧啶、腺苷、鸟苷为4项核心指标,可用于评价不同品种富硒竹笋的品质;通过相关性分析,得出尿嘧啶与胞苷、鸟苷与胸苷、胸苷与腺苷等指标间相关性较高,指标之间的含量会互相影响;通过聚类分析,得出新品富硒竹笋主要集中为一类,市场上常见的富硒竹笋主要分为两类。结论:该实验方法操作快速、简便,重现性好,可用于21种富硒竹笋中10种核苷类化合物的含量测定。同时,测定结果为竹笋的后期高效开发和利用提供理论依据。

Preparation of nucleoside-pyridine hybrids and pyridine attached acylureas from an unexpected uracil ring-opening and pyridine ring-forming sequence

Novel pyrimidine nucleoside-3,5-dicyanopyridine hybrids （4） or pyridine attached acylureas （5） were selectively and efficiently prepared from the reaction of 2′-deoxyuddin-5-yl-methylene malononitrile （1）, malononitrile （2） and thiophenol （3） or from an unexpected uracil ring-opening and pyddine ring-forming sequence via the reaction of 1 and 3. It is the first time such a sequence has ever been reported.

Klac PNP基因密码子优化及在枯草芽胞杆菌中的高效表达

嘌呤核苷磷酸化酶(purine nucleoside phosphorylase,PNP)是嘌呤补救合成途径中的关键酶,嘌呤降解途径涉及氧化嘌呤环裂解,在人体中形成尿酸作为最终产物,增加患痛风的风险。为提高PNP的发酵水平,将来源于乳酸克鲁维酵母的PNP基因进行密码子优化,分别将优化前后的目的PNP基因连接至分泌表达载体pBSA43,并在枯草芽胞杆菌WB600中重组表达PNP-YP-pBSA43、PNP-YO-pBSA43。结果显示,密码子优化前的酶活力为333.69 U/mL,优化后的酶活力达到351.61 U/mL。为进一步提高重组蛋白表达量,通过响应面分析得出优化后重组菌株产PNP的最佳发酵条件为初始pH为6.67、发酵时间55 h、发酵温度28.7℃。在该条件下,重组PNP活力为372.79 U/mL,相比未优化前提高了12%。来源于乳酸克鲁维酵母的PNP基因经密码子优化后重组表达,酶活力显著提高,对PNP在枯草芽胞杆菌中高效表达奠定了基础。

生物农药协同化学农药使用对番茄早疫病防治效果及经济效益的影响

本文以日光温室番茄为试验对象,设置不施药(CK)、80%代森锰锌可湿性粉剂2 250 g/hm^(2)(T_(1))、6%嘧啶核苷类抗菌素水剂1 875 mL/hm^(2)(T_(2))、6%嘧啶核苷类抗菌素水剂1 200 mL/hm^(2)+80%代森锰锌可湿性粉剂1 350 g/hm^(2)(T_(3))4个处理,研究了生物农药嘧啶核苷类抗菌素协同化学农药代森锰锌减量施用对番茄早疫病防治效果、营养指标及种植效益的影响。结果表明,与CK相比,生物农药与化学农药协同使用(处理T_(3))农药用量减少,对番茄早疫病防治效果显著,番茄生长旺盛,营养指标有明显改善,产量提高,值得大面积推广。

基于超高效液相色谱-三重四级杆串联质谱法的花椒中氨基酸和核苷类成分分析与评价

建立了UPLC-MS/MS法同时测定花椒中17种氨基酸和6种核苷的分析方法,并对不同产地的花椒样品进行主成分分析和聚类分析。样品经水提取后用超高效液相色谱-三重四级杆串联质谱仪测定,采用电喷雾电离源,多反应监测(MRM)模式检测,外标法定量。结果表明,17种氨基酸和6种核苷在各自的线性范围内线性良好,检出限为0.0013~0.0878μg/g,定量限为0.0045~0.2927μg/g;加标回收率为60.4%~120.4%,相对标准偏差(RSD)为0.6%~13.4%,操作方法简便快速,灵敏度和稳定性较好;14批次花椒样品中TAA在333.5~569.9 mg/kg之间,平均含量为451.3 mg/kg,其中S4氨基酸总量最高;氨基酸中精氨酸含量最高,平均含量为172.7 mg/kg,占TAA的38.3%;核苷总量在14.4~38.5 mg/kg之间,平均含量为27.7 mg/kg,其中S3核苷总量最高;核苷中尿苷含量最高,平均含量为21.6 mg/kg,占核苷总量的77.9%;通过主成分分析和聚类分析发现来自甘肃省陇南市西和县、甘肃省陇南市武都区、甘肃省天水市秦安区的花椒综合品质较高,位列该次测定的第一梯队,测定的数据可为甘肃地方特色产业的开发利用提供数据支持。

柴达木枸杞中8种核苷与碱基类成分分析及产地差异研究

为了明确柴达木枸杞优势及产地差异,本研究建立高效液相色谱法(HPLC)同时测定柴达木枸杞中8种核苷和碱基类成分的方法,并比较分析柴达木地区不同产地样品中核苷与碱基的组成和含量差异。结果显示:8种核苷与碱基类成分得到较好分离,线性关系良好,平均加标回收率在96.8%~98.9%之间,RSD均小于1.75%(n=6)。24批柴达木枸杞中均含有8种核苷和碱基类成分,其中:含量最高的为尿苷和鸟苷,其平均值分别为1.686 mg/g和1.614 mg/g;含量最低的为尿嘧啶,其平均值仅为0.014 mg/g,主成分分析和正交偏最小二乘判别分析结果显示德令哈、格尔木、都兰以及乌兰产地的枸杞具有较明显的差异;聚类分析将样品分为德令哈-乌兰分支和格尔木-都兰分支。主成分分析、正交偏最小二乘判别分析以及聚类分析较好地阐释了柴达木枸杞不同产地间的差异。该方法简单,重复性好,准确可靠。