Chiral separation of raltitrexed by cyclodextrin-modified micellar electrokinetic chromatography

A rapid and effective method was developed for the chiral separation of raltitrexed (RD) enantiomers by carboxymethyl-beta-cyclodextrin (CM-β-CD)-modified micellar electrokinetic chromatography (MEKC). Optimization of conditions including the type and concentration of the chiral selector, concentration of sodium dodecyl sulfate (SDS), pH and concentration of the background electrolyte (BGE), capillary temperature, and applied voltage was investigated. The enantiomers of raltitrexed could be separated with satisfactory resolution and linear response by using 75 mM Tris-phosphate at pH 8.0 containing 30 mM SDS and 8 mM CM-β-CD as buffer system. Furthermore, the usefulness of this method was demonstrated in a purity test of a real synthetic drug sample. Figure Chiral separation of raltitrexed by CM-β-CD MEKC was optimized and applied to test the purity of a synthetic drug sample     

A study of nicotinic acid synthesis on a pilot installation and its simulation

Technological process parameters of the nicotinic acid synthesis by oxidation of β-picoline on a vanadium-titanium catalyst in a unit tube of a pilot installation were determined: conversion of β-picoline, yield and selectivity for products, and parametric sensitivity of the "hot point" temperature to variation of parameters at the reactor inlet. A mathematical simulation of the process was carried using the model of heat-and-mass transfer in a bed of a tubular reactor and the kinetic model of oxidation of β-picoline.     

Regioselective alkanoylation of cyclodextrins

The regioselective transesterification of native α- and β-Cyclodextrins (CDs) with vinyl acetate and vinyl laurate is presented in this paper. The reactions were carried out in dimethyl sulfoxide by using low molecular weight salts (Na₂HPO₄ and NaCl, respectively). MALDI-TOF mass spectrometry and NMR analysis were applied to investigate the chemical structure and the degree of the modification of the final products. Results show that these salts catalyze regioselective transesterification between β-CDs and vinyl laurate aiming for the secondary C-2 hydroxyl group. The synthesis and separation of β-CD-laurate derivatives leads to a mixture of mono-2-O-dodecanoyl-β-CD and native β-CDs. Unreacted β-CDs could be selectively removed enzymatically by cyclodextrin glucosyl-transferase (CGTase) and β-amylase.     

Supramolecular assembly system depended on guest species based on bis-naphthane modified β-cyclodextrin dimer

The supramolecular assembly system based on bis naphtahlene modified β-cyclodextrin dimer linked with ethylenediamine unit was studied. The synthesis of the titled compound (β-1) was succeeded in a 7% synthetic yield. It was observed that β-1 showed monomer emission, which was decreased concurrently with appearance of excimer emission in an addition of guest species such as 1-adamantanol or ursodeoxycholic acid. When γ-CyD was added to the system, two types of fluorescent spectra were obtained, which was depended on guest species. It was indicated that both of naphthalene units of β-1 were included in the γ-CyD cavity in the presence of 1-adamantanol in a fashion of 2:1 complex. On the other hand, an addition of ursodeoxycholic acid gave disappearance of the excimer emission as well as increase of monomer emission. In the system, each of the appended units was trapped by the each of two γ-CyDs, which is 2:2 complex formation.     

Oligosaccharide tagged β-cyclodextrins: synthesis and biological affinity towards Concanavalin A

An original synthetic route based on multi-glycosylation and selective protection–deprotection steps has been developed which allows a fast access to complex oligomannosides with both α-(1,3),α-(1,6) and α-(1,3),α-(1,4) cores. The later have been linked to modified β-cyclodextrins bearing spacing arms of varying chemical structure and length through peptidic-like coupling, leading to the formation of a range of oligomannosyl cyclodextrin conjugates. Complexation studies with sodium anthraquinone-2-sulfonate (ASANa) and sodium adamantane 1-carboxylate (ACNa) as guest molecules demonstrated that the β-cyclodextrin inclusion properties are preserved. Binding affinity studies using the mannose specific lectin Concanavalin A (Con A) demonstrated the key role of the density and tridimensional structure of the sugar ligand in recognition events.     

A new sprout inhibitor of potato tuber based on carvone/β-cyclodextrin inclusion compound

A monoterpene, D-carvone or (4S)-(+)-carvone, present in the essential oil of caraway seeds (Carum carvi L.), acts as a sprouting inhibitor agent for potato tubers in storage. The aim of the present study was to investigate the possibility of using carvone/β-cyclodextrin inclusion compound as a sprout inhibitor agent for potato tubers. A Raman study of the interactions between β-cyclodextrin (β-CD) and included carvone molecule in solid state is also reported; the results confirm the synthesis of inclusion compound at pilot scale level.     

Synthesis of p-nitrophenyl glycosides of N-aminoacyl derivatives of D-glucosamine. II

1. A method has been developed for the synthesis of p-nitrophenyl β-D-glucosaminides acylated with glucine and alanine. 2. p-Nitrophenyl N glycyl-β-D-glucosaminide has been found to be a substrate of a neutral β D-hexosaminodase.     

Synthesis of 3β-hydroxy-20-oxo-30-norlupan-28-oic (platanic) acid and its glycosides

All available literature data on the chemical synthesis and isolation from natural sources of 3β-hydroxy-20-oxo-30-norlupan-28-oic (platanic) acid and its derivatives and their biological activity were reviewed. A one-step synthesis of platanic acid from betulin was developed. Its glycosylation by α-acetobromoglucose (ABG) catalyzed by Ag₂O in various solvents such as pyridine, CH₂Cl₂, and their mixture was studied. The optimal synthetic schemes for platanic acid monoglucosides and diglucoside were found. NMR spectra of platanic acid and its glycosides were studied.     

Steroids modified at C<Superscript>15</Superscript>. Synthesis and spectra-structure correlations

A synthesis of 15-benzoyloxybutyl-20-hydroxymethylpregn-16-enes, the intermediates in the synthesis of brassino- and ecdysteroids modified in the D ring was performed starting with 2α,3α-isopropylidenedioxy-6,6-ethylenedyoxy-5α-androst-15-ene-17-one and its 2β,3β-isomer through a sequence of reactions involving Michael addition, Wittig reaction and ene reaction. Structures of the compounds were proved by the methods of two-dimensional NMR spectroscopy.     

Selective hydrogenations of steroids catalyzed by heterogenized Ru complexes

Summary [RuCl₂(PPh₃)₃], [{RuCl₂(TPPMS)₂}₂] and their heterogenized analogs were applied in the selective hydrogenation of 17-keto- and α,β-unsaturated ketosteroids. In basic conditions these complexes selectively hydrogenated the C=O bonds, similarly to the results obtained in the case of α,β-unsaturated aldehydes. A new method was developed for the synthesis of an expensive steroid alcohol, which can be prepared traditionally in a more complicated way.     

Beta-D-galactopyranosyl azide: its one-step quantitative synthesis using E461G-beta-galactosidase (Escherichia coli) and a demonstration of its potential as a reagent for molecular biology

A simple one-step synthesis of β-d-galactopyranosyl azide from 0-nitrophenyl-β-d-galactopyranoside and azide catalyzed by E461G-β-galactosidase is described. The synthesis is quantitative in the presence of excess azide and only the β anomer is produced. The product was purified (71% yield) from the other reaction components by extraction with ethyl acetate, silica gel chromatography, and crystallization. The purity was verified by GLC, TLC, and NMR. Thus, E461G-β-galactosidase is able to specifically and quantitatively from β-d-galactopyranosyl-azide. The purified β-d-galactopyranosylazide inhibited the growth of Escherichia coli that express β-galactosidase but not of E. coli that do not. Growth is stopped because β-galactosidase catalyzes the hydrolysis of the β-galactopyranosyl-azide, and the azide that is produced inhibits cell growth. This selective inhibition of growth has potential application in molecular biology screening.     

Synthesis of methyl 2,6-dideoxy-β-D-arabino-, 3,6-dideoxy-β-D-ribo-, and 4,6-dideoxy-β-D-xylo-hexopyranosides

A convenient method is proposed for the synthesis of methyl 1,6-dideoxy-β-D-arabino-, 3,6-dideoxy-β-D-ribo-, and 4,6,dideoxy-β-D-xylo-hexopyranosides by the partial deoxygenation of methyl β-D-quinovopyranoside followed by liquid chromatography of the dideoxysugars. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 741–743, November–December, 1991.     

A new era for organic synthesis—highlights of the recent progress

The major progress in organic synthesis since 2005 is briefly surveyed in two parts. The first part deals with some of the most impressive advances in the synthetic methodology, which includes: (1) metal-mediated synthetic reactions, with an emphasis on the olefin metathesis and gold-mediated reactions; (2) free radical-based organic synthesis; (3) synthetic transformations performed in a “one-pot” manner involving either tandem reactions or multicomponent reactions; (4) asymmetric reactions catalyzed by metal and organo-catalysts. The major advances in total synthesis of some complex natural products with significant biological activities are presented in the second part, with detailed illustrations of ten selected molecules, including dragmacidin F, abyssomicin C, 11-acetoxy-4-deoxyasbestinin D, pentacycloanammoxic acid, UCS1025A, (−)-merrilactone A, nigellamine A₂, (+)-saxitoxin, and Tamiflu (an artificially designed natural product-like molecule). An array of complicated structures of the natural products synthesized over the last two years is also listed to serve as a convenient lead to the original literature for the prospective interested readers. Translated from Progress in Chemistry, 2007, 19(1): 6–34 [译自: 化学 进展]     

New nematogenic β-diketones for synthesis of lanthanidomesogens

A series of new β-diketones containing in their structure cyclohexane and benzene ring was obtained. The effect of the terminal substituents in the molecules of β-diketones on their liquid crystal and optical properties was studied. The absorption spectra of all β-diketones practically do not overlap with the emission spectrum of polymer PFO but have good overlapping with that of PVC. The obtained compounds are promising ligands for synthesis of liquid crystal adducts of lanthanide β-diketonates with the Lewis bases, polyfunctional luminescent materials.     

Synthesis of bis-β,β′-spiro-pyrrolidinyl-oxindoles,containing a rhodanine fragment

The synthesis of isatilidene derivatives of N-alkylrhodanines has been carried out with dipolarophiles and unstable azomethine ylides, generated in situ from sarcosine and paraformaldehyde. A series of chiral pyrrolidinyl-oxindoles spirofused in the β,β′-positions has been synthesized in the result of cycloaddition in high yield and diastereoselectivity.     

ZrCl4-Catalyzed Efficient Synthesis of Enaminones and Enamino Esters under Solvent-free Conditions

Summary. A facile synthesis of β-enaminones and enamino esters by condensation of β-dicarbonyl compounds with differently substituted amines in the presence of ZrCl₄ under solvent-free conditions is reported.     

α- and β-scopodonnines from Datura inoxia seeds

A mixture of two alkaloids, d, ℓ-α- and β-scopodonnines, known earlier as synthetic products, has been isolated for the first time from the seed ofDatura inoxia. The spatial structure of β-scopodonnine dimethiodide has been established by the x-ray structural method. Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 532–537, July–August, 1991.     

One-pot synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans

A “one pot” method for the synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans from β-aryl- and 4-β-hetaryl-β-oxo acid esters was developed. Dedicated to Corresponding Member of the Russian Academy of Sciences E. P. Serebryakov on the occasion of his 70th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1030–1032, April, 2005.     

Triterpene glycosides ofTragacantha and their genins. Cyclostipulosides A and B fromTragacantha stipulosa

Two new triterpene glycosides of the cycloartane series, which have been called cyclostipulosides A and B, have been isolated in the individual form from the roots ofTragacantha stipulosa Boviss. Their structures have been established by physicochemical methods. Cyclostipuloside A is 24R-cycloartane-3β,6α,16β,24,25-pentaol 16-O-β-D-glucopyranoside 3-O-β-D-xylopyranoside, and cyclostipuloside B is 24R-cycloartane-3β,6α,16β,24,25-pentaol 6-O-α-L-arabinopyranoside 16-O-β-D-glucopyranoside 3-O-β-D-xylopyranoside. By the acid hydrolysis of cyclostipulosides A and B we have obtained the new glycoside 24R-cycloartane-3β,6α,16β,24,25-pentaol 16-O-β-D-glucopyranoside. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 670–674, September–October, 1998.