Silyl modification of biologically active compounds. 12. Silyl group as true incentive to antitumour and antibacterial action of choline and colamine analogues

A series of triorganylsilyl(β‐dialkylaminoethoxy)silanes was prepared and characterized by elemental analysis, ¹H, ¹³C, ²⁹Si NMR and mass spectroscopy. Comparative study of ²⁹Si resonance of newly synthesized compounds showed correlation between its value and substituent nature at the silicon atom, and is shifted upfield for β‐triorganyl(N,N‐dialkylaminoethoxy)silanes in comparison with corresponding methiodides, revealing weak N^…Si interaction for proper silanes. In vitro antitumour and antimicrobial properties were investigated. The biological activity data exhibited a marked enhancement of inhibitory activity on trialkylsilylation against tumour cell lines and all the test bacterial/fungal strains. Copyright © 2006 John Wiley & Sons, Ltd.     

Interaction of 1-acylamino-2,2-dichloroethenyl(triphenyl)phosphonium chlorides with alkanolamines

Abstract

It is shown that the interaction of 1-acylamino-2,2-dichloroethenyl(triphenyl)-phosphonium chlorides with alkanolamines having a primary amino group results in the formation of 4-oxazolylphosphonium salts containing hydroxyalkylamine substituents at position 5 of the oxazole cycle. Under similar conditions the reaction of N-substituted alkanolamines with 1-acylamino-2,2-dichloroethenyl-(triphenyl)phosphonium chlorides leads to the formation of 1,3-oxazolidin-2-ylidene derivatives, in which the triphenylphosphonium group is located in the side chain. The structure of the new synthesized compounds has been reliably proven by elemental analysis, IR, ¹Н, ¹³С, ³¹Р NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction.     

Reactive kinetics of carbon dioxide loaded aqueous blend of 2-amino-2-ethyl-1,3-propanediol and piperazine using a pressure drop method

In this study, a new pressure drop method has been used to investigate the kinetics of carbon dioxide reaction with aqueous blend of 2-amino-2-ethyl-1,3-propanediol (AEPD) with piperazine (PZ). The blending of a small amount of PZ with AEPD has a significant effect on the observed rate constant, k_obs. It was observed that k_obs values of the blend increased more than twice than the summation of k_obs values of individual alkanolamines. The reaction kinetics in this study were modeled by assuming a termolecular mechanism. The addition of 0.1 mol/L of PZ to 1 mol/L AEPD exhibited an observed rate constant, k_obs of 8824.1 s⁻¹, which is comparable to other alkanolamine mixtures. Hence, PZ/AEPD mixtures can be potentially used for rapid carbon dioxide capture.     

Accurate pKa Calculation of the Conjugate Acids of Alkanolamines,Alkaloids and Nucleotide Bases by Quantum Chemical Methods

The pK_a of the conjugate acids of alkanolamines, neurotransmitters, alkaloid drugs and nucleotide bases are calculated with density functional methods (B3LYP, M08‐HX and M11‐L) and ab initio methods (SCS‐MP2, G3). Implicit solvent effects are included with a conductor‐like polarizable continuum model (CPCM) and universal solvation models (SMD, SM8). G3, SCS‐MP2 and M11‐L methods coupled with SMD and SM8 solvation models perform well for alkanolamines with mean unsigned errors below 0.20 pK_a units, in all cases. Extending this method to the pK_a calculation of 35 nitrogen‐containing compounds spanning 12 pK_a units showed an excellent correlation between experimental and computational pK_a values of these 35 amines with the computationally low‐cost SM8/M11‐L density functional approach.     

Improving the Capture of CO2 by Substituted Monoethanolamines: Electronic Effects of Fluorine and Methyl Substituents

The influence of electronic and steric effects on the reaction between CO₂ and monoethanolamine (MEA) absorbents is investigated using computational methods. The pK_a of the alkanolamine, the reaction enthalpy for carbamate formation, and the hydrolytic carbamate stability are important factors for the efficiency of CO₂ capture. The steric and electronic effects of CH₃, CH₂F, CHF₂, CF₃, F, dimethyl, difluoro, and bis(2‐trifluoromethyl) substituents at the α carbon of MEA on this reaction are investigated. Density functional theory (DFT) (B3LYP, M06‐2X, M08‐HX and M11‐L) and ab initio methods [spin component‐scaled second‐order Møller‐Plesset theory (SCS‐MP2), G3], each coupled with solvent models [conductor‐like polarizable continuum model (CPCM) and universal solvation models (SM8 and SMD)], are shown to yield accurately calculated pK_a values of the substituted MEAs. Specifically, G3, SCS‐MP2, and M11‐L methods coupled with the SMD and SM8 solvation models perform well with a mean unsigned error (MUE) of only 0.15, 0.24 and 0.25 pK_a units, respectively. SCS‐MP2 is used to calculate the reaction enthalpy for carbamate formation and the carbamate stability towards hydrolysis. With the introduction of β‐fluoro substituents (especially the CH₂F moiety) the reaction enthalpy for the formation of carbamates can be fine‐tuned to be less exothermic than that using the unsubstituted MEA. This implies a reduced energy requirement for the solvent‐regeneration step in the post‐combustion carbon‐capture method, which is currently the energy‐limiting step in efficient CO₂ capture. β‐Fluoro‐substituted MEAs are also shown to form less stable carbamates than MEA. Thus, β‐fluoro‐substituted MEAs display a great potential for the use in the post‐combustion carbon‐capture process. Finally, a clear correlation is observed between the gas‐phase basicity and the tendency to form carbamates. This allows for the rapid prediction of which species will be formed experimentally, and thus the CO₂‐absorbing capacities of alkanolamines can be estimated.     

醇胺分子结构及其CO2捕集能力

研究了一乙醇胺及其衍生物的非环状醇胺的分子结构与其吸收捕集CO2性能之间的关系．通过实验测定了在313．15K和393．15K两个温度下,CO2分压从1kPa到700kPa条件下,CO2在不同醇胺水溶液中的溶解度,分析研究了羟基与烷基间的链长、取代烷基位置、氨基上烷基链数目及烷基羟基链数目、羟基位置和两个羟基的影响．结果表明,不同分子结构的醇胺水溶液对CO2的吸收能力有明显差别．根据CO2的捕集分离要求,选择合适的溶剂,可大幅度提高溶剂的CO2捕集能力．     

齐墩果酸-烷醇胺复合物的制备及性能

采用超声法制备齐墩果酸(OA)与烷醇胺(EAs)[单乙醇胺(MEA)、二乙醇胺(DEA)或三乙醇胺(TEA)]复合物,利用差示扫描量热、X射线衍射、红外光谱和拉曼光谱等技术手段对复合物进行了表征。 发现OA与EA之间无新的化学键形成,它们以分子间力结合形成复合物。 OA与EA复合物提高了OA的溶解度,为OA新型给药系统提供新思路和理论依据。     

离子色谱法同时测定脱硫液中的四种醇胺

建立了同时分离测定异丙醇胺(IPA)、三异丙醇胺(TIPA)、N-甲基二乙醇胺(MDEA)、N,N-二甲基二乙醇胺(DMAE)和6种阳离子的离子色谱法。色谱柱为TSKgelSuperIC-CR阳离子交换柱,流动相为冠醚(2.0mmol/L)、甲基磺酸(2.2mmol/L)、L-组氨酸(0.5mmol/L)混合溶液,流速为0.5mL/min,抑制电导检测。DMAE、MDEA、TIPA、IPA的检出限分别为0.48、36.9、47.04和1.39μg/L;样品中DMAE、MDEA、TIPA、IPA平均回收率为103.15%,95.48%,97.64%,92.41%。方法具有简单、快速、灵敏、抗干扰等优点,用于测定脱硫液中的DMAE、MDEA、TIPA和IPA,结果令人满意。     

Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance for CO2 Capture

The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO₂ with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11‐L, MP2, and spin‐component‐scaled MP2 (SCS‐MP2) methods were used, coupled with SMD and SM8 solvation models. A reduction in carbamate stability leads to an increased CO₂ absorption capacity of the amine and a reduction of the energy required for solvent regeneration. Important factors for the reduction of the carbamate stability were an increase in steric hindrance around the nitrogen atom, charge on the N atom and intramolecular hydrogen bond strength. The present study indicates that secondary ethanolamines with sterically hindering groups near the N atom show significant potential as candidates for industrial CO₂‐capture solvents.     

Synthesis,physico‐chemical and biological study of trialkylsiloxyalkyl amine coated iron oxide/oleic acid magnetic nanoparticles for the treatment of cancer

New original water‐soluble magnetic nanoparticles based on natural components, magnetite–oleic acid–biologically active silyl modified alkanolamine, were synthesized. Physico‐chemical characterization, i.e. magnetic properties, concentration of magnetite, size of iron oxide core, of the nanoparticles synthesized and the corresponding magnetic fluids obtained, was carried out. Magnetic fluids were screened for in vitro cytotoxicity concerning human fibrosarcoma (HT‐1080), mouse hepatoma (MG‐22A) monolayer tumour cell lines and normal mouse fibroblasts (NIH 3T3). They possess low or moderate cytotoxic effects, are non‐toxic, exhibit high NO‐induction ability and strongly change tumour cell morphology. Copyright © 2008 John Wiley & Sons, Ltd.