Synthesis of a Pair of Derivatives of N-Methylpyrrole Polyamide

A pair of derivatives of tetrameric N-methylpyrrole polyamide were synthesized in order to develop a new method for the study of interaction of the polyamide derivatives with DNA. Indole acetic acid and nicotinic acid were introduced to the polyamide in the synthesized compound, which showed an expected red shift in the UV spectrum. These compounds may function as a potential tool in the detection of the polyamide binding to DNA.     

Molecular recognition of a self-assembled monolayer of a polydithiocarbamate derivative of β-cyclodextrin on silver

The synthesis and molecular recognition properties of a new sulfur containing β-cyclodextrin (β-CD) derivative chemisorbed on a silver surface are described. Hepta-6-amino-6-deoxy-β-CD was allowed to react with CS₂ in the presence of ammonia to give a mixture of partially substituted dithiocarbamate derivatives with an average degree of substitution of 4.5. A modified silver electrode with this derivative is capable of discriminating between the three positional isomers of nitrobenzoate ion and nitrophenol, as determined by cyclic voltammetry. Only the meta- and para-isomers give a signal corresponding to the reduction of the nitro group. This is attributed to the different orientations of the nitro group with respect to the silver surface after inclusion in the CD cavity. Experiments in the presence of cyclohexanol showed a decrease in signal intensity of the meta- and para-isomers which is associated with the competitive complexation of this guest, suggesting that the electroactive probe is complexed to the cavity.     

The Synthesis of a Series of Phosphoryl Coumarins

Different hydroxy substituted coumarins were successfully phosphorylated with diisopropylphophite （DIPPH） by the Atherton-Todd reaction in 76-89% yields. Moreover, the reaction activities of different hydroxys of the coumarins in the Atherton-Todd reaction were studied.     

Synthesis of a Novel Type of Glycophosphate Mimics

A series of novel type of glycophosphate mimics are synthesized by Todd reaction and their structure were determined on the basis of NMR,ESI-MS.     

Simulation of a flow of a “Sedate” reaction mass in a screw reactor with a thin wall layer

A transition to a flow virtually non-gradient in a screw reactors of heavy sedate liquid with thin wall layer is considered. The graphs of the differential response functions of the known models based on the ideal gas law for structures of flows (ideal mixture, ideal displacement, laminar and turbulent flows) in comparison with the response function of the sedate reaction mass were presented. The flow structure corresponds to the regime of the ideal displacement in the screw reactor at a treatment of the sedate reaction mass when air, water or other thin liquid are fed as lubricant in the wall layer.     

Synthesis of a new series of anti-rhinovirus compounds

The synthesis of a series of 3,6-dichloropyridazine derivatives was described.In vitro experiment,all compounds exhibited ananti-rhinovirus activity,and one of the compounds 6g showed the comparable activity as our lead compound pirodavir.     

The cuticle of the cactusCereus peruvianus as a source of a homo-α-d-galacturonan

The waxy pecto-cellulosic cuticle of cladodes of the columnar cactusCereus peruvianus (19% of the whole phytobiomass; dry wt) is a source of an α-d-polygalacturonic or pectic acid (35–40% yield, on a dry wt based on the wax-free pectocellulose layer). Warm EDTA/oxalate or room temperature strong acid/alkali cycles are efficient for pectic acid extraction, since divalent cation (mainly Ca²⁺) is a barrier to be removed within the native and compact architecture of the cuticle. Despite some molecular dispersion arising from the application of strong mineral acid in the first extraction step, the pectic material appears to be quite homogeneous and, on acid or enzymatic analyses, was shown to contain onlyd-galacturonic acid as its monomer.Cereus cuticle pectate (sodium salt) tends to gel above a concentration of 1%, a useful property that can be more easily obtained by the inclusion of sucrose, light addition of calcium salt, and/or mild acidification.     

Synthesis of amine-phenol ligands in water – a simple demonstration of a hydrophobic effect

Abstract

The synthesis in water of a series of tetradentate amine-phenol ligands derived from formaldehyde, 2,4-disubstituted phenols and amines is presented. These molecules, which are used in catalyst development, include 4,6-di-alkyl-2-bis(2-methoxyethyl)aminomethylphenols and 4,6-di-tert-amyl-2-bis(3-(dimethylamino)propyl)aminomethylphenols. Yields were generally greater than reactions performed in methanol and near quantitative for hydrophobic phenols.     

Synthesis of a highly functionalized γ-lactone as a precursor of 9-pentyl anthracyclines

The synthesis of non racemic chiral γ-lactone 7 from α-D-isosaccharino-1,4-lactone (+)-8, as a precursor of the A-ring of the targeted 3′-morpholinyl-9-pentyl anthracycline 6, is described.     

Implementation of a quality system in a clinical laboratory – Evaluation of quality indicators

 The aim of this study was to evaluate the primary experience of implementing a quality system in a clinical laboratory. The second interrelated aim was to evaluate the quality and financial indicators needed for continuous measurement of quality, decision making in the laboratory management and everyday process control in analytical work. The quality process itself should be evaluated because the building up of a quality system requires a considerable amount of resources. The most effective and practical ways of using a quality system as a management tool should be found and the need for financial appraisal when the quality system is implemented is stressed. According to our study, when the effects of the quality system were evaluated, the managers of the laboratory had not considered the appropriate financial indicators. The quality indicators considered to be the best were internal quality control, external quality assessment and customer satisfaction surveys. The first benefits of the quality system evaluated by the personnel were other than the purely financial benefits, they include a more systematic and empowering approach to laboratory management, better working instructions, better knowledge of the methods and equipment, and fewer errors. The financial evaluation of a quality process in a public-owned clinical laboratory is complicated due to the fact that financial indicators are not as far developed and diverse as in industrial organisations. When starting to implement a quality system, it is important to pay attention to all measures that motivate the staff and help them benefit from the practical effects of the system. Received: 10 November 1999 / Accepted: 12 January 2000     

First Synthesis of a Series of New Natural Glucosides

Alkyl glucoside 1 and aryl glycosides 2-4 were highly stereospecifically synthesized over 4-6 steps from commercially available starting materials. The coupling reaction of the acetobromo-α-D-glucose with the unprotective dihydroxy aglycon in the presence of silver oxide, or with aromatic aglycon in the presence of sodium hydroxide produced the key intermediate. Only β-configuration glycosides were formed in this procedure. The synthesis of all these glycosides was reported for the first time.     

Synthesis of 2,15-Hexadecanedione as a Precursor of Muscone

Muscone is a precious fragrant compound scarce in nature. Many synthetic attempts for this unique natural product have been carried out. In this work, the one-carbon unit transfer reaction of tetrahydrofolate coenzyme was initialed. Bisbenzimidazolium salt was used as tetrahydrofolate coenzyme model, and thus the biomimetic synthesis of 2,15-hexadecanedione, a precursor of muscone, was successfully accomplished by using the addition-hydrolysis reaction of bisbenzimidazolium salt with methyl magnesium iodide.     

Synthesis of a New Series of Bone Affinity Compounds

As known that tetracycline possesses bone affinity1, which can be used as carrier of bone-targeting drugs. Chrysophanol is one of the anthraquinone components isolated from Rheum palmatum L., its structure is similar to tetracycline. The bone affinity of …     

Crystallization of polypropylenewith a minute amount of β-nucleator

Triammonium-N-dithiocarboxyiminodiacetate, (NH₄)₃L, a new dithiocarbamato derivative of iminodiacetate, has been synthesized. The coordination properties of the ligand were tested in reactions with copper(II), nickel(II) and palladium(II) salts in acidic solutions. Complexes with a general formula M(H₂L)₂ were obtained, with the coordination taking place through the sulfur atoms of the dithiocarbamate moiety. The new compounds were characterized by elemental analysis, UV/VIS and IR spectroscopy, thermal analysis and magnetic measurements. In addition, the ligand was characterized by ¹H- and ¹³C-NMR spectroscopy and molar conductivity measurements. The copper(II) complex is paramagnetic, while the nickel(II) and palladium(II) compounds are diamagnetic. The thermal decomposition of all compounds is continuous and the thermal stability of the complexes is higher than that of the ligand, as expected.     

Synthesis of a Dopamimetic Thionated Dipeptide Prodrug of L-DOPA

L-DOPA has gained widespread credit over the past decades as being the mainstay of the pharmacological treatment of Parkinson‘s disease. However, there are many adverse effects associated with the use of L-DOPA. The prodrug approach is the most promising way to solve the problem. In this article, a thionated dipeptide prodrug of L-DOPA 11 was synthesized via 10 steps in a total yield of 26.5% from L-DOPA.     

Preparation of a New Polyoxometalate-based Nanoparticles

Polyoxometalates (POMs) α-K8H6[Si2W18Ti6O77] (Si2W18Ti6) loaded starch nanoparticles have been prepared and structurally characterized by elemental analyses, IR spectra and ^29Si spectroscopy. The particle size of Si2W18Ti6/starch was estimated by a Transmission electron microscope (TEM) and a 1000HSA MALVIRN Zetasizer instrttment. The result shows that the polyoxometalate retained the parent structure after encapsulated by starch microspheres.     

Measurement of the Bulk Modulus of a Liquid Using a Pump–Probe Laser Technique

We describe an undergraduate laboratory experiment that uses a time-resolved laser technique. Using pump-probe in a novel way, students determined the bulk modulus of a liquid. Employing the fourth harmonic from a pulsed Nd:YAG laser, an elastic wave is generated in an aqueous solution of N-acetyltryptophan, and the wave propagation is probed by a He-Ne laser. This experiment serves as a rare example of how a bulk property of a condensed phase can be measured using time-resolved optical measurements having relevance to undergraduate physical chemistry or material science laboratory.     

Development of a scalable palladium-catalyzed α-arylation process for the synthesis of a CGRP antagonist

The Pd-catalyzed α-arylation of cycloheptapyridyl ketone is a key complexity-building step in the synthesis of BMS-846372, a CGRP antagonist. A first-generation process utilized Pd(OAc)₂/P^tBu₃·HBF₄ catalyst system with a strong base NaO^tBu. Although this process was demonstrated on multi-kilo scale, the harsh conditions led to non-selective metal catalyzed processes, which generated several operational, quality, and throughput issues. By acquiring detailed knowledge around several important process parameters, we were able to design an efficient and scalable second-generation α-arylation process using a Pd(OAc)₂/RuPhos catalyst system with the weaker base, K₃PO₄ in tert-amyl alcohol. This new weak base process was high yielding, efficient, and superior in several respects compared to the strong base process. The strategy behind the reaction and isolation development and the process considerations important to scaling a catalytic reaction from laboratory to manufacturing scale will be discussed.     

Stereoselective synthesis of a β-D-phosphatidylgalactose

The stereoselective synthesis of a -D-phosphatidylgalactose has been achieved by the interaction of a benzyl phosphatidate with D-galactose tert-butyl orthoacetate or trichloroacetimidate.M. V. Lomonosov Institute of Fine Chemical Technology, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 16–19, January–February, 1991.