An improved synthesis of isonitrosoacetanilides

A novel two-step synthesis of isonitrosoacetanilides [2-(hydroxyimino)-N-phenylacetamides] has been developed, involving the initial acylation of aniline derivatives with 2,2-diacetoxyacetyl chloride, followed by reaction with hydroxylamine hydrochloride. The method works equally well with a variety of different aniline derivatives, including those with poor aqueous solubility and those containing electron rich ortho-substituents, neither of which react well under traditional conditions.     

Microwave assisted synthesis of some new heterocyclic spiro-derivatives with potential antimicrobial and antioxidant activity

Homophthalic anhydride reacts with different aromatic amines to produce N-substituted homophthalimides. Bromination of the latter produces 4,4-dibromo-homophthalimide derivatives that can be used as precursors for spiro-derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiro-isoquinoline derivatives. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro-derivatives. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, 1H-NMR and 13C-NMR. The newly synthesized compounds were tested for their antimicrobial and antioxidant activities, showing weak or no antimicrobial activity. On the other hand select compounds showed promising antioxidant activities.     

One-pot synthesis of tetrahydrochromene derivatives catalyzed by lipase

An efficient and green one-pot synthesis route for tetrahydrochromene derivatives was developed. Lipase from Porcine pancreas (PPL) shows excellent catalytic activity and exerts good adaptability to different substrates in the reaction. All the reactions go smoothly and provide tetrahydrochromene derivatives with isolate yield up to 97% under room temperature. This lipase-catalyzed multistep conversion method has provided a new strategy to synthesize chromene derivatives and expanded the application of enzyme in organic synthesis.     

Phenylglyoxal for polyamines modification and cyclam synthesis

The bis-aminals obtained by tetraamine and phenylglyoxal condensation display various behaviours such as equilibrium between different configurations, rearrangements that lead to lactam derivatives, or amine deprotection. Our investigations about them were focused on three different linear amines, and then extended to polyazacycloalkanes cyclen and cyclam. Cyclam was also synthesised with the bis-aminals issued from condensation of linear polyamines with phenylglyoxal. The lactam derivatives described here were moreover, employed for the mono-N-functionalisation of tetraamines by phenyl-acetic acid group.     

An efficient synthesis of mimetics of neamine for RNA recognition

As mimetics of neamine, several 4-heterocyclic 2-deoxystreptamine derivatives were chemically synthesized for RNA recognition. Conversion of 4-methylthiomethyl-5,6-di-O-acetyl-diazido-2-deoxystreptamine to the 4-chloromethyl derivative followed by reactions with different nuclophilic reagents gave the 4-heterocyclic 2-deoxystreptamine derivatives in satisfactory yields.     

Convenient synthesis of 5-azacoumarins

2-Formyl-3-hydroxypyridine and its 6-methyl derivative have been condensed with ethoxycarbonylmethyl-enetriphenylphosphorane and alkyl derivatives to afford 5-azacoumarins substituted in the second case by an alkyl group at 3-position by two different ways according to the used phosphorane.     

One-Pot synthesis of unsymmetrically substituted 2,4-dialkylisoflavenes

The trimethylsilyl derivative of formonometine reacts sequentially with two different organometallic derivatives to afford regiospecifically and with good yield 2,4-dialkylisoflavenes unsymmetrically substituted.     

Design and synthesis of two triazonine-carbaldehyde derivatives using several chemical tools

Several triazonine-carbaldehyde derivatives have been prepared using different protocols; however, some require special reagents and conditions. The aim of study involved the synthesis of two triazonine-carbaldehyde derivative using testosterone or OTBS-testosterone as chemical tool. Triazonine-carbaldehyde derivatives were prepared by a series of reactions that involve the following: (1) synthesis of two nitrobenzamide derivatives by reaction of testosterone or OTBS-testosterone with p-nitrobenzoyl azide using Copper(II) as catalyst; (2) reaction of the nitrobenzamides with ethylenediamine to form two triazonine derivatives using boric acid as catalyst; (3) preparation of hexynyl-triazonine derivatives by the reaction of two triazonines 6-chlorohex-1-yne in basic medium; (4) reaction of hexynyl-triazonine derivatives with benzaldehyde to form two triazoninol analogs; (5) preparation of triazoninynal derivatives through oxidation of triazoninol analogs with dimethyl sulfoxide; and (6) synthesis of triazonine-carbaldehyde derivatives by the reaction of triazoninynal derivatives with hexyne-1 using Copper(II) as catalyst. The chemical structure of compounds was determined by spectroscopic and spectrometric methods. In conclusion, in this work were prepared two triazoninone derivatives using several chemical techniques, which are simple procedures and easy to handle.     

Solid-phase synthesis of N-substituted 3,4-dihydroquinazolinone derivatives

An efficient solid-phase synthetic approach for the synthesis of N-substituted 3, 4-dihydroquinazolinone derivatives has been developed. Four different 2-nitrobenzoic acids and three different 2-phenylacetyl chlorides were employed in the synthesis of this library. After purification, all products were obtained in good yields.     

Straightforward acid-catalyzed synthesis of pyrrolyldipyrromethenes

Three for one: Pyrrolyldipyrromethenes having different functional groups were efficiently synthesized from POCl(3)-promoted condensations between 5-chloro-2-formylpyrrole or isoindole derivatives and suitable pyrrole or indole fragments through a novel nucleophilic aromatic substitution of the initially formed protonated azafulvene rings.     

Design and synthesis of two epoxide derivatives from 3-ethynylaniline

For several years ago, several epoxide derivatives have been prepared using different methods; however, some protocols use reagents which could be expensive and require specials conditions. The aim of this investigation was to prepare two new epoxide-derivatives from 3-ethynylaniline using some reactions such as oximation, acetylation, 2 + 2 addition, functionalized chloroamides, and epoxidation via Darzens reaction. The chemical characteristics of epoxide derivatives were determinate through a spectroscopic and spectrometric analysis. In conclusion, it is noteworthy that the reactions used in this study do not involve expensive reagents or special conditions for the synthesis of epoxide derivatives.     

Design and synthesis of novel cytotoxic podophyllotoxin derivatives

<正>In order to investigate the effect of different C4 linkage moieties on the cytotoxicity of podophyllotoxin derivatives,novel 4-Nand 4-C-substituted 4'-O-demethylepipodophyllotoxin derivatives were designed and synthesized.All the compounds were tested against A549 and MCF-7 tumor cells in vitro,and six compounds showed significant cytotoxicity.The most active compound 9f was superior to GL-331,and exhibited potent cytotoxicity with IC_(50) value at 10~(-7) mol/L level.     

Enzyme-catalyzed synthesis of natural and unnatural polysaccharides

Synthesis of natural and unnatural polysaccharide was achieved via “enzymatic polymerization” by utilizing a glycoside hydrolase as catalyst. Particularly, hyaluronan, chondroitin, and their derivatives belonging to glycosaminoglycans have been prepared using sugar oxazoline monomers designed on the basis of the concept “transition-state analogue substrate”. The oxazoline derivatives of N-acetylhyalobiuronate [GlcAβ(1→3)GlcNAc] and N-acetylchondrosine [GlcAβ(1→3)GalNAc], which have the repeating disaccharide structures of hyaluronan and chondroitin, respectively, were successfully polymerized by the catalysis of hyaluronidase, giving rise to synthetic hyaluronan and chondroitin. Their 2-substituted oxazoline derivatives were also polymerized to the corresponding N-acylated hyaluronan and chondroitin derivatives. Furthermore, N-acetylchondrosine oxazoline derivatives sulfated at the C4, the C6, and both the C4 and C6 of the GalNAc unit were catalyzed by hyaluronidase; the monomer sulfated at the C4 was polymerized to chondroitin 4-sulfate with well-defined structure, whereas the other two monomers were exclusively hydrolyzed to the corresponding disaccharides. These different kinds of natural and unnatural polysaccharides having relatively high molecular weights were produced in all cases by the catalysis of hyaluronidase. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5014–5027, 2006     

Eco-friendly synthesis of novel pyrimidine derivatives as potential anticancer agents

Herein, a rapid and highly efficient method for the synthesis of a new series of pyrimidine derivatives was demonstrated. The strategy was emanated from the reaction of hydrazinyl pyrimidine derivative ( 1 ) with different electrophilic species such as ethyl acetoacetate, ethyl 4,4,4-trifluoro acetoacetate, and phenyl isothiocyanate following cyclocondensation mechanism to afford the corresponding derivatives ( 2-6 ). Furthermore, condensation of hydrazine derivative ( 1 ) with different carbonyl compounds via conventional heating and microwave irradiation conditions was employed as a source of Schiff base derivatives bearing pyrimidine moiety ( 7-12 ). The structural features of all newly synthesized compounds were characterized by elemental and spectroscopic evidences. Some of the synthesized compounds were evaluated for in vitro cytotoxicity. The preliminary screening results showed that most of the tested compounds have moderate cytotoxic activity against HepG2 and HCT-116 cell lines. Finally, a molecular docking study was conducted to reveal the probable interaction with the thymidylate synthase enzyme.     

The synthesis of unusual isocoumarin derivatives: the chemistry of homophthalic acid

Homophthalic acid was reacted with thionyl chloride/DMF and ethyl chloroformate/NEt₃ in the presence and absence of NaN₃. In all cases completely different isocoumarin derivatives were obtained. These unusual isocoumarin derivatives were characterized and their mechanism of formation is discussed.     

Stereocontrolled one-pot synthesis of cycloalkane derivatives possessing a quaternary carbon using allyl phenyl sulfone

Stereocontrolled one-pot synthesis of cyclopentane derivatives possessing quaternary carbon using allyl phenyl sulfone and epoxyiodide was presented. Furthermore, application of this protocol to the synthesis of cycloalkane derivatives with different ring sizes was successful.     

Novel synthesis of N-substituted-calix[4](aza)crown derivatives

<正>A novel series of calix[4]azacrown derivatives with the reaction between calix[4]azacrown and the different fluorophore derivatives,which may be useful fluorescent receptors,have been synthesized and structurally characterized by IR,~1H NMR,~(13)C NMR and MS.From their analysis data,it was found those compounds adopted a cone conformation.     

Zr-promoted ‘pair’-selective and regioselective synthesis of penta-substituted benzene derivatives

Tetra-substituted zirconacyclopentadiene derivatives, obtainable via in situ generation of zirconacyclopropenes and their cyclic carbozirconation with alkynes, can be treated with alkynyllithiums to induce 1,2-migration accompanied by aromatization and protonolysis, leading to the formation of penta-substituted benzene derivatives, in which all five substituted may be different.     

Solid-phase synthesis of DOTA-peptides

A general synthetic route to two DOTA-linked N-Fmoc amino acids (DOTA-F and DOTA-K) is described that allows insertion of DOTA at any endo-position within a peptide sequence. Three model pentapeptides were prepared to test the general utility of these derivatives in solid-phase peptide synthesis. Both DOTA derivatives reacted smoothly by means of standard HBTU activation chemistry to the point of insertion of the DOTA amino acid, but extension of the peptide chain beyond the DOTA-amino acid insertion required the use of pre-activated C-pentafluorophenyl ester N-alpha-Fmoc amino acids. Three Gal-80 binding peptides (12-mers) were then prepared by using this methodology with DOTA positioned either at the N terminus or at one of two different internal positions;the binding of the resulting GdDOTA-12-mers to Gal-80 were compared. The methodology described here allows versatile, controlled introduction of DOTA into any location within a peptide sequence. This provides a potential method for the screening of libraries of DOTA-linked peptides for optimal targeting properties.     

Target-aimed synthesis of anion-deficient perovskites

The brownmillerite-type A 2B 2O 5 structure is considered as a parent one, giving rise to different derivatives: layered double perovskites, A-site and anion-vacancy-ordered perovskites, and the perovskite-like compounds with crystallographic shear planes. The structural relationships and synthesis pathways for these classes of materials are discussed with particular attention to the ordering at the A or B sublattices, anion vacancy ordering, and their mutual interaction.