A total synthesis of (S)-(+)-ipalbidine

Liu, Zhu‐Jin; Lu, Ran; Chen, Qi; Hai, Hong

doi:10.1002/cjoc.19850030312

Cited by 201 publications

(298 citation statements)

References 8 publications

Supporting

Mentioning

267

Contrasting

Unclassified

Order By: Relevance

“…No dependence of these relationships on methods ͑Hartree-Fock or DFT͒ or basis sets has been verified. 14 Molecular acidity has also been of considerable study in the field of so-called conceptual DFT, [15][16][17][18] also called density functional reactivity theory. It concerns with the scenario when changes in the number of electrons ͑⌬N͒ and the external potential ͑⌬v͑r͒͒ take place, subsequent variations in the total energy of the system, E͓v͑r͒ ; N͔, which is the state function of the total number of electrons N and the external potential v͑r͒, will follow, obeying the following relationship:…”

Section: ͑3͒mentioning

confidence: 99%

“…[15][16][17][18] To that end, we will show that there exist similar linear relationships for the dissociating proton and that these correlations are the natural consequence of the Taylor expansion of the total energy of the system from conceptual DFT at the first-order approximation. We demonstrate the validity of these arguments with numerical data from 27 main groups and first, second, and third row transition metal-water complexes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Molecular acidity: A quantitative conceptual density functional theory description

Liu

Schauer

Pedersen

2009

The Journal of Chemical Physics

View full text Add to dashboard Cite

Accurate predictions of molecular acidity using ab initio and density functional approaches are still a daunting task. Using electronic and reactivity properties, one can quantitatively estimate pKa values of acids. In a recent paper ͓S. B. Liu and L. G. Pedersen, J. Phys. Chem. A 113, 3648 ͑2009͔͒, we employed the molecular electrostatic potential ͑MEP͒ on the nucleus and the sum of valence natural atomic orbital ͑NAO͒ energies for the purpose. In this work, we reformulate these relationships on the basis of conceptual density functional theory and compare the results with those from the thermodynamic cycle method. We show that MEP and NAO properties of the dissociating proton of an acid should satisfy the same relationships with experimental pKa data. We employ 27 main groups and first to third row transition metal-water complexes as illustrative examples to numerically verify the validity of these strong linear correlations. Results also show that the accuracy of our approach and that of the conventional method through the thermodynamic cycle are statistically similar.

show abstract

Section: ͑3͒mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular acidity: A quantitative conceptual density functional theory description

Liu

Schauer

Pedersen

2009

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…Los descriptores que fueron utilizados como variables independientes para construir el modelo QSAR pertenecen al contexto conceptual de la DFT; 23,24 estos han sido clasificados en descriptores globales y locales. Las cantidades globales dan información inherente al comportamiento reactivo de una molécula, son el potencial químico electrónico (µ), la dureza (h), la suavidad (S) y el índice de electrofilicidad (w).…”

Section: Fundamentos Teoricosunclassified

2D-QSAR ANALYSIS OF DERIVATIVES OF QUINOXALINE 1,4-DI-N-OXIDES WITH ACTIVITY AGAINST CHAGAS' DISEASE

Guerra¹,

López²,

Figueredo³

et al. 2016

Química Nova

View full text Add to dashboard Cite

publicado na web em 06/05/2016 2D-QSAR ANALYSIS OF DERIVATIVES OF QUINOXALINE 1,4-DI-N-OXIDES WITH ACTIVITY AGAINST CHAGAS' DISEASE. In the present work was performed a quantitative structure-activity relationship (QSAR) for a set of derivatives of 1,4-quinoxaline N-oxides with antichagasic activity based on reactivity descriptors from the frame conceptual DFT. QSAR models showed a good statistical quality and capacity internal prediction with R 2 > 0.6 and Q 2 > 0.5 respectively. QSAR model suggest that antichagasic activity of the studied compounds depends largely from the reactive behavior of N-oxide group (N-O). Also, reactivity descriptors showed that the N-oxide group is a reactive site in theses derivatives with nucleophilic characteristics. The results QSAR shed light on the understanding of the mechanism of action and design of new drugs based on derivatives of 1,4-di-N-oxides quinoxaline.Keywords: QSAR; Antichagasic; N-oxide group; Nucleophilic. INTRODUCCIONLa enfermedad de Chagas fue descubierta en 1909 por el medico brasileño Carlos Chagas mientras diagnosticaba a una joven paciente de dos años que presentaba parásitos en el torrente sanguíneo.1 Esta enfermedad, producida por el parásito protozoario Trypanosoma cruzi (T. cruzi), afecta actualmente entre 6 y 8 millones de personas en el mundo, 2 siendo endémica en América latina. No obstante, su incidencia en el continente europeo y algunos países de Norteamérica ha aumentado en los últimos años debido a los patrones de migración que provocan la diseminación de la enfermedad. 3,4 Aunque el principal modo de transmisión de T. cruzi hacia el ser humano ocurre por contacto con las heces de algunos hematófagos triatominos, 5 existen otros modos de infección asociados a transfusiones sanguíneas, 6 trasplantes de órganos, 7,8 contacto entre madre e hijo durante el parto, 9 y por vía oral. 10Con respecto a las manifestaciones clínicas, existen dos etapas que caracterizan la enfermedad de Chagas. La primera etapa comienza justo después de la infección (fase aguda), y aunque es asintomática, se han reportado casos con síntomas similares a los de una infección febril, dificultando así su correcto diagnóstico. 11La segunda etapa (fase crónica), que puede tardar hasta 15 años en aparecer, se caracteriza por cardiomiopatía dilatada 12,13 y afecciones del tracto digestivo 14 que representan un alto riesgo comprometiendo la vida de los pacientes. Desde el punto de vista farmacológico, el tratamiento actual de la enfermedad de Chagas se basa principalmente en dos fármacos nitro-heterocíclicos llamados Nifurtimox (Nfx) y benznidazol (Bz), descubiertos empíricamente entre 1960 y 1970; mostrando una efectividad en casi el 60% de los casos que son tratados durante la fase aguda. Sin embargo, el uso de Nfx y Bz para el tratamiento de la enfermedad durante la frase crónica es controversial debido a que estos nitro-heterociclos solo son eficaces contra la forma extracelular de T. cruzi que se desarrolla durante la fase aguda. Por lo tanto, la búsqueda de nuevos fármacos más...

show abstract

“…12 As it may interfere with fluorometric measurements, SOS is always minimized and if possible eliminated as a harmful phenomenon in the fluorometric determinations. 13 Since Liu et al first studied SOS as an analytical technique and applied it in the determination of metal ions in 1995, 14,15 however, it has been used as a new analytical technique with sensitive application prospects. 16,17 We have reported some flow-injection lanthanide-sensitized chemiluminescence (CL) [18][19][20] and electrochemiluminescence (ECL) 21,22 methods for the determination of other fluoroquinolones.…”

Section: Introductionmentioning

confidence: 99%

Determination of Ulifloxacin by Terbium-sensitized Fluorescence with Second-order Scattering and Its Applications

et al. 2007

View full text Add to dashboard Cite

IntroductionAs broad-spectrum antibiotics, fluoroquinolones (FQs) have gained increasing use and have become popular in clinical application thanks to their high bacteriologic and clinical cure rates and good pharmacokinetic profile. 1 Prulifloxacin (PUFX, Scheme 1), 6-fluoro-1-methyl-7-(4-[5-methyl-2-oxo-1,3-dioxolen-4-yl]-methyl-1-piprazinyl)-4-oxo-4H-(1,3)thiaceto(3,2-α)quinolone-3-carboxylic acid, is a new oral fluoroquinolone antibiotics. It is active against both gram-positive and gram-negative bacteria and several anaerobic and atypical bacteria associated with chronic bronchitis and urinary infections. 2After PUFX is administrated, it is immediately and quantitatively transformed to the active metabolite ulifloxacin (UFX, Scheme 1) which actually has antibacterial activity. Prulifloxacin is not detectable in the systemic circulation. 3 That is to say, PUFX is the prodrug of UFX. The oxodioxolenylmethyl group in the 7-piperazine ring helps PUFX to have an advantage over UFX on oral absorption.3 Thus, the main form existing in biological fluids, such as serum and urine, is UFX. It is thus necessary to develop rapid, selective and sensitive analytical methods for the determination and pharmacokinetic study of UFX.Analytical literature about the determination of UFX is seldom seen. There are a few papers that describe HPLC methods. 4-6The HPLC methods allow the separation and generally require expensive equipment and complicated procedures. The main advantages of fluorometry are simplicity and rapidity. Luminescence sensitization of lanthanide ions (especially Tb(III) and Eu(III)) allows their application as the luminescence probes. Lanthanide-sensitized luminescence provides a selective and sensitive approach that shows a large stokes shift, narrow emission bands and a long luminescence lifetime. The carboxylate and the keto oxygen atoms of FQs provide the chelated sites for Tb(III) or Eu(III) ion to form Ln(III)-FQ complex. When Tb(III)-FQ complex is excited, it gives rise to the characteristic luminescence of Tb(III) ion with maximum emission at 545 nm via intramolecular energy transfer. This terbium-sensitized method has been used in the determination of FQs. 7-11In recent years, the light scattering technique has been increasingly applied to analytical chemistry, the most common method used is resonance light scattering (RLS). In studying RLS, the strong scattering of light at double the wavelength of the incident light (λem = 2λex) is found, which is named as "second-order scattering (SOS)". 12 As it may interfere with fluorometric measurements, SOS is always minimized and if possible eliminated as a harmful phenomenon in the fluorometric determinations. 13 Since Liu et al. first studied SOS as an analytical technique and applied it in the determination of metal ions in 1995, 14,15 however, it has been used as a new analytical technique with sensitive application prospects. 16,17 We have reported some flow-injection lanthanide-sensitized chemiluminescence (CL) [18][19][20] and electrochemiluminescence ...

show abstract

A total synthesis of (S)-(+)-ipalbidine

Cited by 201 publications

References 8 publications

Molecular acidity: A quantitative conceptual density functional theory description

Molecular acidity: A quantitative conceptual density functional theory description

2D-QSAR ANALYSIS OF DERIVATIVES OF QUINOXALINE 1,4-DI-N-OXIDES WITH ACTIVITY AGAINST CHAGAS' DISEASE

Determination of Ulifloxacin by Terbium-sensitized Fluorescence with Second-order Scattering and Its Applications

Contact Info

Product

Resources

About