Search results for "Amide"
showing 10 items of 3119 documents
An Efficient Synthesis of Tenofovir (PMPA): A Key Intermediate Leading to Tenofovir-Based HIV Medicines
2020
Abstract: Herein, we report further improvements to the synthesis of tenofovir 1, the precursor to tenofovir disoproxil fumarate and tenofovir alafenamide fumarate. Starting from acyclic precursor diaminomalononitrile 12, a four-step protocol to tenofovir 1 will allow for vertical integration for more manufacturers. The key transformation is a more convergent one step procedure from 6 as compared to the current commercial process, with an improved yield from 59% (two steps) to 70%. Further improvements include eliminating the need for problematic magnesium tert-butoxide (MTB) and significant solvent reduction by eliminating the need for an intermediate workup. With the costs of HIV/AIDS tre…
Metalation and N-alkylation of some polyamides
1981
Totally N-substituted polyamides were synthesized starting from poly(2,4,4-trimethylhexamethylene terephthalamide) by metalation of the amide groups and subsequent reaction with several electrophiles. Polyamides of this structure are not available from terephthalic acid and the corresponding diamines by polycondensation. This N-alkylation reaction can be used for the synthesis of comb-like graft copolymers. The solubilitity and the thermal properties of these polyamide derivatives are described.
Isobaric vapor-liquid equilibria for the extractive distillation of 2-propanol + water mixtures using 1-ethyl-3-methylimidazolium dicyanamide ionic l…
2017
Abstract Isobaric vapor–liquid equilibria for the binary systems 2-propanol + water, 2-propanol + 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), and water + [emim][DCA] as well as the vapor–liquid equilibria for the 2-propanol + water + [emim][DCA] ternary system have been obtained at 100 kPa using a recirculating still. The electrolyte nonrandom two-liquid (e-NRTL) model was used for fitting successfully the experimental data. The effect of [emim][DCA] on the 2-propanol + water system has been compared with that produced by other ionic liquids reported in the literature. From the results, [emim][DCA] appears as a good entrainer for the extractive distillation of this solvent mixtur…
Isobaric vapor-liquid equilibria for the 1-propanol + water + 1-ethyl-3-methylimidazolium dicyanamide system at 100 kPa
2017
Abstract Isobaric vapor–liquid equilibria for the 1-propanol + 1-ethyl-3-methylimidazolium dicyanamide ([emim [DCA] binary system and for the 1-propanol + water + [emim] [DCA] ternary system have been obtained at 100 kPa using a recirculating still. The electrolyte nonrandom two-liquid (e-NRTL) model was used for fitting successfully the experimental data. The effect of [emim][DCA] on the 1-propanol + water system has been compared with that produced by other ionic liquids reported in the literature. From the results, [emim][DCA] appears as a potential entrainer for the extractive distillation of this solvent mixture, causing the azeotrope to disappear at 100 kPa when the ionic liquid mole …
Evaluation of thermodynamic parameters for blends of polyethersulfone and poly(methyl methacrylate) or polystyrene in dimethylformamide
1998
Liquid-liquid phase separation phenomena have been investigated for a ternary system containing two polymers and a solvent. Namely, dimethylformamide (DMF)/polyethersulfone (PES)/poly(methyl methacrylate) (PMMA) and DMF/PES/Polystyrene (PS). The composition of the three components in the two phases in equilibrium has been determined by size exclusion chromatographic (s.e.c.) analysis. The lattice-based mean-field theory, first developed by Flory and Huggins, has been modified to adequately describe these systems. In this respect, we have assumed that the parameters depend on the polymer concentration, and we have included a ternary parameter. The phase equilibrium compositions have been use…
ChemInform Abstract: Ring-Opening Aminolysis of Sesquiterpene Lactones: An Easy Entry to Bioactive Sesquiterpene Derivatives. Synthesis of (+)-β-Cype…
2010
Abstract Santonin ( 1 ) and other sesquiterpene lactones ( 2–3 ) react with pyrrolidine and other cyclic secondary amines to afford γ-hydroxyamides, which by elimination with mesyl chloride in pyridine-benzene at 80°C give unsaturated amides 4a-4c, 5a-5c and 6 . Starting from amides 5a-5c a series of bioactive compounds against Locusta migratoria have been prepared, differing in the oxidation states of the C-3 and C-12 carbon atoms. Starting from amides 5a and 6 two conjugated diene eudesmanes (+)-β-cyperone ( 15 ) and (−)eudesma-3,5-diene ( 19 ) have been prepared involving an elaboration of the amide group of the side chain of the eudesmane skeleton.
Comparative studies of the Pschorr reaction in the pyrazole series. Access to the new dibenzo[e,g]pyrazolo[1,5-a][1,3]diazocine system of pharmaceuti…
2008
The diazonium tetrafluoroborate 11 obtained from 2-amino-N-methyl-N-(1-phenyl-3- methylpyrazol-5-yl)benzamide was transformed in dry acetonitrile via an ionic or radical pathway. Differences were observed with respect to ionic or radical transformations in aqueous media of the analogous diazonium hydrogen sulfate 1 derived from the same amine. In acetonitrile solution, the ionic pathway was characterized by an increased yield of 1,4-dimethyl- 3-phenyl-pyrazolo(3,4-c)isoquinolin-5-one 4 and by the formation of its isomer, the new derivative 7,9-dimethyldibenzo(e,g)pyrazolo(1,5-a)(1,3)diazocin-10(9H)-one 12. When the reaction followed a radical pathway, the pyrazolo(3,4-c)isoquinoline derivat…
IR fingerprints of U(VI) nitrate monoamides complexes: a joint experimental and theoretical study.
2010
Infrared spectra of 0.5 mol·L-1 uranium(VI) nitrate monoamide complexes in toluene have been recorded and compared with infrared spectra calculated by DFT. The investigated monoamides were N,N- dimethylformamide (DMF), N,N-dibutylformamide (DBF), and N,N- dicyclohexylformamide (DcHF). The validity of DFT calculations for describing uranium nitrate monoamide complexes has been confirmed as a fair agreement between experimental and calculated spectra was obtained. Furthermore, a topological analysis of the electron density has been carried out to characterize monoamide-uranium interactions. From this work, it appears that the increase of stability of uranylmonoamide complexes may be directly …
1,4-Dimethyl-3-phenyl-3H-pyrazolo[3,4-c]isoquinolin-5(4H)-one
2008
The title compound, C18H15N3O, is the product of the thermal decomposition of the diazonium salt derived from 2-amino-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)benzamide. It is characterized by a trans orientation of the methyl groups with respect to the tricyclic ring system. The molecule has a nearly planar phenylpyrazolo[3,4-c]isoquinolin-5-one system, the largest deviation from the mean plane being 0.066 (2) angstrom for the O atom. The dihedral angle between the phenyl substituent and the heterotricycle is 67 (1)degrees. The packing is stabilized by C-H center dot center dot center dot N hydrogen-bond interactions, with the formation of molecular chains along the c axis.
Thermal Denaturation of Pea Globulins (Pisum sativum L.)—Molecular Interactions Leading to Heat-Induced Protein Aggregation
2013
The heat-induced denaturation and aggregation of mixed pea globulins (8%, w/w) were investigated using differential scanning calorimetry (DSC), SDS-PAGE, and size-exclusion chromatography (SEC-HPLC). DSC data showed that the pea proteins denaturation temperature (T(d)) was heating-rate dependent. The T(d) value decreased by about 4 °C by lowering the heating rate from 10 to 5 °C/min. The SDS-PAGE analysis revealed that protein denaturation upon heating at 90 °C was mainly governed by noncovalent interaction. The SEC-HPLC measurements indicated that low-denatured legumin (≈350-410 kDa) and vicilin/convicilin (≈170 kDa) globulins were heat-denatured and most of their subunits reassociated int…