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A series of functionalized pillar[5]arenes mono-pyridylimine derivatives with different lengths of diaminoalkylene units as the side chains on the pillar[5]arene's rim were conveniently synthesized. The investigation of 1 H NMR spectra and single crystal structures indicated that the formation of free forms or pseudo[1]rotaxanes turned out to be controlled by both the axle lengths of diaminoalkylene chains and the solvent effect. The pillar[5]arene mono-pyridylimines with short hydrazinyl and diaminoethylene chains exist in free form. On the other hand, pillar[5]arene mono-pyridylimines with longer than diaminopropylene chains formed stable pseudo[1]rotaxanes both in solution and in the crystal state. [ABSTRACT FROM AUTHOR]

In the presence of hexamethylphosphorous triamide, the reaction of isatin with arylidene pivaloylacetonitriles in dry methylene dichloride afforded functionalized spiro[cyclopropane-1,3′-indolines] in good yields and with high diastereoselectivity. Moreover, the similar reaction of isatins with isatylidene malononitriles predominately gave spiro[indoline-3,1′-cyclopropane-2′,3″-indolines] in very high yields with two indoline moieties in trans -configuration. [ABSTRACT FROM AUTHOR]

An MS guided fractionation of the alkaloidal constituents of Flueggea virosa has yielded nine new Securinega alkaloid oligomers, fluevirosinines B–J ( 1 – 9 ). The absolute structures of these oligomers have been characterized on the basis of spectroscopic data and biogenetic consideration. Fluevirosinines B–E ( 1 – 4 ) are four tetramers with new connecting sequences or new oligomerizing patterns, and fluevirosinines G–J ( 6 – 9 ) represent the first examples of pentamers of the Securinega alkaloid family. Among these alkaloids, fluevirosinine B ( 1 ) showed the best anti-HIV activity with an EC 50 value of 14.1±1.2 μM. [ABSTRACT FROM AUTHOR]

Abstract: In the presence of methanesulfonic acid as catalyst, the condensation reactions of 5,5′-dialkyldipyrromethanes with p-hydroxyacetophenone in methanol resulted in a mixture of the unexpected polysubstituted 15α,20α-di(4-hydroxylphenyl)calix[4]pyrroles and the expected 10α,20β-di(4-hydroxylphenyl)calix[4]pyrroles in comparable lower yields. The crystal structures of the new calix[4]pyrroles and their oxyacetate derivatives were successfully determined by X-ray diffraction and the intermolecular interactions in the solid state is briefly discussed. [Copyright &y& Elsevier]

Abstract: A couple of self-folding A-D-A guests were synthesized, and it was found that the guests could be included by the pentiptycene-based tweezer-like hosts to form stable 1:1 complexes in solution, which have been evidenced by the 1H NMR, ROESY 2D NMR and ESI MS spectra. Moreover, a potassium ion-controlled switchable process between the host and the self-folding guest was further achieved. [Copyright &y& Elsevier]

Abstract: In the presence of p-toluenesulfonic acid as the catalyst the three-component reactions of arylamines, acetylenedicarboxylates, and isatins showed very interesting molecular diversity. When equal amount of arylamine was used, the three-component reaction resulted in the high yields of functionalized 3′-hydroxyspiro[indoline-3,5′-pyrroline]-2,2′-dione derivatives. On the other hand the functionalized 3′-N-arylaminospiro[indoline-3,5′-pyrroline]-2,2′-diones were also successfully prepared in satisfactory yields by using 2M arylamine in the reaction. [Copyright &y& Elsevier]

Abstract: An efficient synthetic method for the pentasubstituted pyrroles was successfully developed via the one-pot domino reactions of arylamines, acetylenedicarboxylates, and 3-phenacylideneoxindoles. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ generated β-active enamino ester. [Copyright &y& Elsevier]

Abstract: A sequential one-pot two-step tandem reaction for selective and efficient synthesis of pyrrolo[2,1-a]isoquinoline and its dihydro- and tetrahydro-derivatives has been developed. The tandem reactions of isoquinoline, α-halogenated methylene compounds, aromatic aldehydes, and cyanoacetamide firstly give tetrahydropyrrolo[2,1-a]isoquinolines as main products. The corresponding pyrrolo[2,1-a]isoquinolines and dihydropyrrolo[2,1-a]isoquinolines can be obtained directly by controlling oxidation with DDQ. The mechanism of this tandem reaction involved the 1,3-dipolar cycloaddition of isoquinolinium ylide as the key step. A unique elimination of the amido group preferring to the cyano group has been observed. [Copyright &y& Elsevier]

Abstract: New zwitterionic salts of pyridinium–Meldrum acid and pyridinium–barbituric acid are conveniently synthesized from the three-component reactions of 2-, 3-, or 4-pyridacylpyridinum iodides, aromatic aldehydes, and Meldrum acid or N,N-dimethylbarbituric acid in the presence of triethylamine as base promoter in acetonitrile. [Copyright &y& Elsevier]

Abstract The fluorinative alkoxylation of simple alkenes under catalyst-free conditions was achieved. Various substituted olefins, including terminal and internal alkenes, and oxygen-containing nucleophiles were compatible with the standard conditions, and gave a variety of β-fluoroethers in good to excellent yields. Notably, the alkynyl and chloride-containing nucleophiles were well tolerated. In addition, acetic acid and TsNH 2 could be also used as nucleophiles and successfully afforded the desired products in good yields. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

A novel and operationally simple visible-light induces oxidative ring opening of imidazo[1,2-a]pyridines accessed to esters has been discussed. Notably, the method uses C 6 F 5 I(OCOCHF 2) 2 as free radical initiator, combining O 2 to promote the cleavage of C–C and C–N bonds under ambient conditions. The reaction also presents favorable selectivity and good groups tolerance. Besides, the possible reaction mechanism is proposed based on the preliminary control experiments. [Display omitted] [ABSTRACT FROM AUTHOR]

A simple and efficient protocol for cyclization between formamidines and ethyl isocyanoacetate has been described in the absence of metal catalyst and solvent. A series of 1-substituted-4-imidazolecarboxylates were synthesized in moderate to good yields with DABCO as base additive. Image 1 • A novel and green protocol for synthesis of 1-substituted-4-imidazolecarboxylates. • This cycloaddition reaction in the presence of DABCO under metal-free and solvent-free conditions. • Novel applications of formamidine for synthesis of heterocyclic compounds. [ABSTRACT FROM AUTHOR]