合成乙拉西坦的方法改进

以2-吡咯烷酮为起始原料,经成盐与缩合反应合成了乙拉西坦,总收率60.2%.其结构经1H NMR, IR和MS确证.     

液相色谱–质谱法测定血清中左乙拉西坦含量

建立测定血清中左乙拉西坦浓度的液相色谱–质谱方法。血清样品用甲醇提取,离心分离除去蛋白,采用液相色谱–质谱法测定其中左乙拉西坦的含量。流动相为甲醇–0.1%甲酸(体积比为80∶20),色谱柱为Agilent C18柱(100 mm×4.6 mm,3.5μm)。左乙拉西坦含量在1 000~100 000 ng/m L范围内与色谱峰面积线性关系良好,线性相关系数r2=0.999,检出限为10 ng/m L。测定结果的相对标准偏差为0.93%(n=6),样品加标回收率为99.4%~101.3%。该方法具有较高的灵敏度、准确度和良好的精密度,适合血清中左乙拉西坦含量的测定。     

乙拉西坦的合成

2-吡咯烷酮经N-烷基化、氨解反应合成了乙拉西坦,总收率42．6％。其结构经^1H NMR,^13C NMR和IR表征。     

离子色谱-电导检测法测定左乙拉西坦中四丁基溴化铵残留

建立了左乙拉西坦原料药中痕量四丁基溴化铵测定的离子色谱方法。以Dionex IonPac CS17阳离子交换色谱柱为分析柱,15 mmol/L甲磺酸溶液-乙腈淋洗液,流速为1.0 mL/min,抑制型电导检测器。样品基质及常见阳离子对测定无干扰,四丁基溴化铵质量浓度在0.5～20 mg/L范围内与峰面积线性关系良好,相关系数为0.9997,定量限(LOQ)为0.5 mg/L,检出限(LOD)为0.15 mg/L,加标回收率为98.0%～103.7%。方法可用于左乙拉西坦原料药中痕量四丁基溴化铵的检测。     

一种新型荧烷染料的合成

以间二乙氨基苯酚(1)和邻苯二甲酸酐(2)为原料制得2一羧基-4'-二乙氨基-2'-羟基二苯甲酮(3);在浓硫酸作用下,3与2-甲基-5-对甲氧基苯基-1,3,4-噁二唑(4)反应合成了一种新型的荧烷染料--2-(5-甲基-1,3,4-噁二唑-2-基)-6-二乙氨基荧烷,其结构经1H NMR,IR和元素分析表征.合成3的较适宜条件为:132mmol,n(1):n(2)=1.0:1.2,36%NaOH 60 mL,反应时间10 h,分解时间6 h,收率71.8%,纯度83.4%(HPLC).     

新型苯乙酰脒类化合物的合成及其感光性能

以氢化铝锂为还原剂,甲基叔丁基醚为溶剂,1,5-二氮杂双环[4.3.0]-5-壬烯(1)于55℃反应9 h制得1,5-二氮杂双环[4.3.0]壬烷(2),收率87.9%,纯度95.0%。2分别与溴代苯乙酮(3a),对甲氧基溴代苯乙酮(3b)和对溴基溴代苯乙酮(3c)进行消除反应合成了3个新型的苯乙酰基潜双环脒类化合物(4a~4c),其结构经1H NMR和LC-MS表征。采用正交实验对合成4a~4c的反应条件进行了优化。在最佳反应条件[以甲苯为溶剂,3a 25.2 mmol,n(3a)∶n(K2CO3)∶n(2)=1.0∶2.0∶1.4,于15℃反应24 h]下,1,5-二氮杂双环[4.3.0]-5-苯乙酰基壬烷(4a)收率89.0%,纯度87.9%。感光性能研究结果表明,1,5-二氮杂双环[4.3.0]-5-(4-甲氧基)苯乙酰基壬烷(4b)经紫外曝光400 mJ·cm-1,其引发性能最强,分解转化近45%;曝光2 000 mJ·cm-1,4b分解转化近90%。     

一种合成拉坦前列素的新方法

拉坦前列素是治疗青光眼和高眼压症的首选药物.现有合成方法存在路线长、收率低、异构体杂质难以分离等问题.本研究以苯甲酰基科里内酯为原料,氧化后与2-氧代-4-苯丁基膦酸二甲酯通过改良Horner-Wadsworth-Emmons反应形成ω侧链,经还原、脱保护、氢化、四氢吡喃基(THP)保护、还原内酯得到内半缩醛,然后以(4-羧基丁基)三苯基溴化鏻与六甲基二硅基胺基钠(NaHMDS)形成磷叶立德通过Wittig反应形成α侧链,经酯化、脱保护基后,合成了拉坦前列素,并用正相液相色谱法纯化,制得终产物,产物用1H NMR,13C NMR,IR和HRMS进行了结构表征.结果表明,拉坦前列素纯度达99.91%,总收率为19.2%.为拉坦前列素的合成提供一种高收率、高纯度、可大批量合成的新方法.     

HPLC法测定(S)-2-氨基丁酰胺对映异构体

使用高效液相色谱-柱前衍生化法测定了(S)-2-氨基丁酰胺盐酸盐的对映异构体。采用梯度洗脱;流动相A为0.1 mol/L乙酸铵溶液,流动相B为乙腈溶液;流速1.5 m L/min;波长336 nm;柱温为40℃。(S)-2-氨基丁酰胺盐酸盐对映异构体的检出限和定量限分别为0.0085μg/m L和0.0319μg/m L。对映异构体的浓度在0.03~3.0μg/m L范围内线性关系良好(r2=0.9992),回收率在91.8%~104.6%之间。方法能够有效控制左乙拉西坦重要中间体(S)-2-氨基丁酰胺的光学纯度。     

3-氯-5-(三氟甲基)-2-乙胺基吡啶的合成

以2,3-二氯-5-三氟甲基吡啶为起始原料,经亲核取代、脱羧、加氢还原及酰胺水解等4步反应合成了3-氯-5-(三氟甲基)-2-乙胺基吡啶,纯度97.4%,总收率61.36%,其结构经1H NMR确证。     

2,3-二甲基-4-氯吡啶-N-氧化物的合成工艺改进

对2,3-二甲基-4-氯吡啶-N-氧化物(4)的合成工艺进行了改进。以2,3-二甲基吡啶为原料,经氧化(钨酸钠为催化剂,双氧水为氧化剂,收率96.5%),硝化(65%的浓硝酸为硝化剂,收率86.3%,纯度99.0%)及氯化(乙酰氯为氯化剂,收率86.8%,纯度98.6%)合成了4,总收率72.2%,4的结构经1H NMR表征。     

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.