5′-脱氧-5′-氟-5-氟尿核苷的合成和性质

很多含氟核苷具有生理活性,因此,合成类似物引起人们的兴趣。5-氟尿核苷和5′-脱氧-5′-氟尿核苷的合成巳见报道。但是,5′-脱氧-5′-氟-5-氟尿核苷的合成及由于     

微波作用下1-苯基-5-[5-(芳胺羰基甲硫基)-4-苯基-1,2,4-三唑-3-甲硫基]四唑的合成及生物活性

采用微波和相转移催化法通过1-苯基-5-(4-苯基-1,2,4-三唑-5-巯基-3-甲硫基)四唑(2)与2-氯乙酰芳胺(3)反应高效、快速地合成了10种尚未见文献报道的1-苯基-5-[5-(芳胺羰基甲硫基)-4-苯基-1,2,4-三唑-3-甲硫基]四唑. 其结构经 IR, ¹H NMR, ¹³C NMR 和元素分析表征. 生物活性实验结果表明, 该类化合物在较低浓度下部分化合物对小麦芽有很好的促进作用.     

新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴

本文报道用新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴。配合物的表观摩尔吸光系数为1.31×10~5L·mol~(-1)·cm~(-1),Co∶5-NO_2-PAMB=1∶2,Co浓度在0～14μg/25mL范围内服从比耳定律。用于金属有机化合物中微量钴的测定,结果与理论值相符。     

2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4- 噻唑啉酮的合成

以2-氨基-5-取代苯氧甲基-1,3,4-噻二唑(1)为起始原料, 合成了中间体2-氯乙酰氨基-5-取代苯氧甲基-1,3,4-噻二唑)-2-乙酰亚胺(2)和2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-4-噻唑啉酮(3), 化合物3进一步与取代苯甲醛发生类Knoevenagle缩合反应, 得到了一系列2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4-噻唑啉酮类化合物4a～4p. 目标化合物4a～4p的结构经IR, ¹H NMR和元素分析确证.     

无催化剂条件下2-氨基-3-氰基-4-芳基-7,7-二甲基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃的合成

芳亚苄基丙二腈;二甲基环己二酮;无催化剂条件下2-氨基-3-氰基-4-芳基-7;7-二甲基-5-氧代-5;6;7;8-四氢-4H-苯并吡喃的合成     

新型5-取代吲哚-3-甲酰胺化合物的合成

以5-取代吲哚为原料,经维尔斯迈尔-哈克反应制得5-取代吲哚-3-甲醛(2a~2e); 2a~2e在DMF催化下,与盐酸羟胺反应制得5-取代吲哚-3-甲腈（3a~3e）; 3a~3e在H₂O₂和NaOH溶液中水解合成了5-取代吲哚-3-甲酰胺（4a~4e, 4b~4e为新化合物）,产率62.0%~75.0%,其结构经¹H NMR, ¹³C NMR和ESI-MS表征。     

5-乙基-2-吲哚酮的合成及其酰基化和N上烃基化反应研究

以4-乙基苯胺1为原料,经Sandmeyer反应得5-乙基靛红2;2经水合肼还原得到5-乙基-2-吲哚酮3;N,N-二甲基甲酰胺与三氯氧磷先形成Vilsmeier-Haack试剂,再与化合物3反应,合成2-氯-5-乙基-3-乙酰吲哚4;以丙酮为溶剂,对化合物4烃基化,以78.5%-95.6%的收率得到N-取代-2-氯-5-乙基-3-乙酰吲哚5a-5e。其中化合物4、5a-5e均未见文献报道,它们的结构均通过红外光谱、核磁共振氢谱(碳谱),质谱等确认。     

3-N-乙酰基-2-取代芳基-5-[5'-甲基-异噁唑-3']-Δ3-1,3,4－噁唑啉类化合物的合成

甲基-异噁唑甲酰肼;3-N-乙酰基-2-取代芳基-5-[5'-甲基-异噁唑-3']-Δ3-1;3;4－噁唑啉类化合物的合成     

5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯与铑显色反应的研究

本文报道以5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯(5-NO_2-PADAT)作分光光度法测定铑的新显色剂.结果表明,在PH 4.1及～6.5的乙酸-乙酸钠缓冲介质中,5-NO_2-PA-DAT与铑形成 2:1的紫红色络合物.该络合物在 1.8 mol/L高氯酸溶液中则转变为另一型体的蓝色络合物,最大吸收波长红移至583nm,表观摩尔吸光系数增至1.7×10_5L·mol_(-1)·cm(-1).以EDTA为掩蔽剂,大量的常见金属离子对测定无干扰.铑浓度在0～0.64μg/mL范围内遵守比尔定律.所建立的方法用于催化剂中微量铑的测定,结果满意.     

铀-2-(3,5-二溴-2-吡啶偶氮)-5-二乙氨基苯酚-Triton X-100析相体系的研究及应用

本文研究了铀-2-(3,5-二溴-2-吡啶偶氨)-5-二乙氨基苯酚(3,5-diBr-PADAP)-Triton X-100析相光度体系,建立了矿石中微量铀的测定方法,在pH 7.5三乙醇胺-盐酸介质中,将胶束溶液在 95±1℃加热 1h.络合物即被Triton X-100相完全富集.络合物最大吸收峰位于565nm.摩尔吸光系数为1.02×10～5L·mol～(-1)·cm～(-1),铀含量在0～12μg/5mL服从比耳定律.采用TBP萃淋树脂分离干扰离子,测定矿石中微量铀,结果满意.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.