Chinese Journal of Chemistry

Formal synthesis of T-588 with asymmetric hydrogenation by Ru-SunPhos system.

Two colorimetric probes based on oxazine-thione 1a and 1b for the detection of Hg²⁺ were designed and synthesized. The probe 1a exhibits about a 70-fold enhancement in fluorescence and a color change after the addition of Hg²⁺ in acetonitrile/wate solvent. 1a was also highly selective to Hg²⁺ over other metal ions. Furthermore, DFT/TDDFT calculations were taken to explain the OFF-ON emission response.

Three hydrogen bond networks {[Co(btp)₂(H₂O)₂]·2(1,2-Hbdc)·2H₂O}_n (1), {[Co(btp)(1,3-bdc)(H₂O)]·1.5H₂O}_n (2) and {[Co(btp)₂(H₂O)₂]·(1,4-bdc)}_n (3) were synthesized. The structure of 2 is an undulated 2D (4,4) network. These [Co(btp)₂(H₂O)]_n²ⁿ⁺ 1D cations and 1,2-Hbdc⁻/1,4-bdc²⁻ anions form 2D hydrogen bond networks in 1 and 3. The thermal stabilities of 1, 2 and 3 were investigated.

A new class of quadruply hydrogen bonded supramolecular polymers is reported. The supramolecular polymers form gels and vesicles in both organic and aqueous media and the reversible conversion of the gels and vesicles are revealed in aqueous media.

A series of benzo[1,2-f:5,4-f′]diquinoline derivatives were synthesized. They showed a remarkably strong intramolecular CH···O hydrogen bond, and significant fluorescent changes in the presence of TFA.

A new type of one-pot, copper(II)-catalyzed domino process through a TBHP/I₂-mediated oxidative cyclization was developed for the synthesis of 5-trifluoromethyl-2,4-disubstituted oxazoles. The method provides advantages with regard to simplicity, mildness and efficiency.

The figure shows the double reciprocal curve of the action of the 4th-generation cephalosporin-class cefpirome with papain according to fluorescence enhancement Eq. (4), which is deduced by us. Even in the process of studying the fluorescence quenching between receptor-substrate, using the theoretical formula of fluorescence enhancement Eq. (4) can get more reliable results.

Phosphorylation partially suppressed the release of PsbO, PsbP, and PsbQ proteins from PSII membranes under light stress.

Two samnium(III)-bismuth(III) heterobimetallic complexes, SmBi(edta)(NO₃)₂·7H₂O (1) and SmBi(dtpa)(NO₃)·3.5H₂O (2) (edta=ethylenediaminetetraacetate, dtpa=diethylenetriaminepentaacetate), were synthesized and characterized. The two complexes exhibit one broad band of Bi 6s6p-6s² emission under UV excitation and the characteristic Sm³⁺ ion ⁴G_5/2→ ⁶H_J/2 (J=5, 7, 9, 11) transitions under visible light excitation, respectively.

A facile and efficient synthesis of 14-fluorophenyl-14H-dibenzo[a,j]xanthenes has been developed by one-pot condensation of fluorinated benzaldehydes with β-naphthol in the presence of p-TSA·H₂O under microwave irradiation and solvent-free conditions.

The novel three-dimension edta-linked heterometallic complex [Sb₂(edta)₂-µ₄-Co(H₂O)₂]·5.15H₂O has been synthesized and characterized by elemental analyses, FT-IR spectrum, X-ray single crystal diffraction analyses and TG-DSC.

A new thieno-[3,4-b]-pyrazine-cored dendrimer (see figure) was synthesized for use as red emitter in non-doped organic light-emitting diodes.

Polyaniline, synthesized in the presence of L-Asp as template molecules with subsequent extraction to create shape complementary cavities, was evaluated as MIP. The higher response and selectivity of the imprinted polyaniline for L-Asp over D-Asp can be assigned to the complementary cavities generated during extraction

The antipode of (+)-harzialactone A, an antitumor marine metabolite, was synthesized with the two stereogenic centers in the target structure taken from an optically active epoxy chiral building block.

In the presence of Cu(I) and triethyl amine, one-pot three-component reaction of fluoroalkanesulfonyl azides, alkynes and iminophosphoranes in CH₂Cl₂ at room temperature gave a novel class of fluorinated phosphorus amidines in good yields.

An efficient, highly selective method for polyfluoroalkylation of 2-aminothiazole derivatives was described. Specifically, a di-polyfluoroalkylated derivative was produced when 2-amino-4-chloromethylthiazole was reacted with perfluoroalkyl iodides under very mild conditions.

2-Ureido-4[1H]-pyrimidinone quadruple hydrogen-bonded assembly 1·1 containing N,N-dimethylaminophenyl moiety exhibits a sensitive response to fluoride anion and lead cation. Spectroscopic studies reveal that the presence of small amount of fluoride anions and lead cations can easily disassemble and intercalate 2-ureido-4[1H]-pyrimidinone hydrogen-bonded supramolecular architectures, respectively.

Aldol reaction between simple benzaldehydes and ketones successfully happened in solvent- and catalyst-free condition. Heat is assumed as the driving force for the reaction. This approach has obvious advantages to fully meet the requirement of the principles of green chemistry.

Fluorinated alkynyl ketones react with hydrazine to give fluorinated pyrazols in good to excellent yields with Au(I) as catalyst. All the reactions were carried out at room temperature with excellent regioselectivity.

The reactions of the cyclopentadienes functionalized by bis(3,5-dime-thylpyrazol-1-yl)methyl group with W(CO)₅THF have been investigated. These hybrid heteroscorpionate/cyclopentadienes coordinate to the tungsten atom in κ²-(N,N) bidentate or κ³-(π,N,N) tridentate mode.

The fluorine-containing trans-1,2-cyclopropane derivatives 4ba–4dd were synthesized from the fluorine-containing electron-deficient alkenes 3a–3d with semistabilized arsonium ylides 2b–2d, in biphasic system of dichloromethane-50% aqueous sodium hydroxide, generated in situ from the corresponding arsonium salts 1b–1d at room temperature in good yields with high stereoselectivity. The structures of fluorine-containing trans-1,2-cyclopropane derivatives were also studied.

Difluoromethyltri(n-butyl)ammonium chloride 1 was found to be an effective difluorocarbene reagent for O-, S-, N-, C-difluoromethylation under basic conditions. It is particularly remarkable that, when only 1.2 equiv. of reagent 1 was used, the difluoromethylated products were still obtained in high yields.

The diastereoselective three-component reaction of aldehydes, allyl bromide, and (S)-2-chlorotetrafluoroethanesulfinamide was achieved in the presence of zinc powder and titanium(IV) isopropoxide. Compared to (S)-tert-butanesulfinamide, the reaction used zinc powder instead of indium and better results were obtained with aromatic aldehydes. Moreover, opposite stereoselectivity is observed.

The reaction of chiral N-(tert-butanesulfinyl)ketimines and α,β-unsaturated trifluoromethyl ketones catalyzed by DBU was achieved under mild conditions. 1,2-Addition products, precursors of chiral trifluoromethylated 1,3-amino alcohols, were obtained diastereoselectively (dr value up to 95:5) in moderate yields (up to 76%). A possible catalytic cycle was proposed.

Aminochlorination of methylenecyclopropanes (MCPs) 1 can be achieved under CO₂ atmosphere using N,N-dichlorotoluenesulfonamine (TsNCl₂) as the nitrogen and halogen sources at room temperature.

A novel and facile preparation of 1,1-difluoroallyl substituted five-membered lactones or pyrrolidines in moderate yields through direct double electrophilic fluorination of 4,5-allenoic acids or tosylamides with Selectfluor^TM F-TEAD-BF₄ is described.

A trifluoethyl-substituted chiral thiourea catalyzed an enantioselective Michael addition of ethyl 4,4,4-trifluoro-3-oxobutanoate to α,β-unsaturated ketone esters to afford the corresponding α-trifluoromethyldihydropyrans with high enantioselectivity (up to 98% ee) under mild reaction conditions.

Through the chiral-pool based synthesis of both enantiomers of schweinfurthinol, it has been proven that this natural product isolated from the seeds of Canarium schweinfurthii possesses an (S) configuration. The optical rotation data for pure schweinfurthinol is also updated.

Seventeen novel gem-difluoromethylene-containing 1,2,3-triazoles were synthesized by the click reaction of ethyl 2-azido-2,2-difluoroacetate and terminal alkynes in the presence of 10 mol% CuI.

A new and efficient cascade synthesis of indazolo[2,1-a]indazole-6,12-diones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular CN coupling reaction. The methodology is applied to a wide range of 2-bromo and 2-chloro benzoyl chlorides to yield the indazolo[2,1-a]indazole-6,12-diones in good to excellent yields with high regioselectivities.

A new and efficient cascade synthesis of polycyclic fused imidazo[2,1-b][1,3]thiazinones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular CS coupling reaction. The methodology is applied to a wide range of 2-iodo, 2-bromo, and 2-chloro benzoyl chlorides to yield the polycyclic fused imidazo[2,1-b][1,3]thiazinones in good to excellent yields.

Synthesis of 1,3-diaryl-2-propen-1-one oxime via the condensation of 1,3-diaryl-2-propen-1-one with hydroxylamine hydrochloride in the presence of anhydrous sodium sulfate was carried out in refluxing EtOH for 2–4 h in 83%–93% yields. The significant features of the present procedure include higher yield, shorter reaction time, the apparently reduced molar ratio of hydroxylamine hydrochloride to substrate as compared to the reported literature method.

A novel palladium-catalyzed intramolecular aminofluorination by using NFSI as fluorinating reagent has been developed. This methodology provided a good route to synthesize 2-aryl-3-fluoropyrrolidine derivatives, albeit in a poor diastereoselectivity.

A novel well-defined triblock copolymer containing perfluorocyclobutyl group was prepared by the combination of mechanism transformation strategy, thermal cycloaddition [2π+2π] polymerization and atom transfer radical polymerization (ATRP). Firstly, a macroinitiator with two ATRP initiating end groups was synthesized by thermal polymerization of 4,4′-bis-(trifluorovinyloxy)biphenyl (BTFVBP) and sequential end-capping with a difunctional compound containing trifluorovinyl and ATRP initiation group. Secondly, this macroinitiator initiated ATRP of t-butyl acrylate to synthesize PtBA-b-PBTFVBP-b-PtBA triblock copolymer. This copolymer was hydrolyzed to afford PAA-b-PBTFVBP-b-PAA amphiphilic triblock copolymer. This kind of fluorine- containing well-defined structure should benefit the study of self-assembly behaviors.

A bioactive derivative of a natural diarylheptanoid containing a 1,3-anti diol motif was synthesized with the oxygen-carrying stereogenic centers taken from an enantiopure epoxy chiral building block derived from inexpensive and readily available D-glucolactone.

In pH 4.2–5.2 HOAc-NaOAc buffer solution, Ag⁺ reacted with dihalogenated fluorescein (DHF) dyes to form a 1:2 anionic complex. This anionic complex could further react with hyoscine butylbromide (HBB) to form 1:1 ion-association complex, which resulted in the significant enhancement of resonance Rayleigh scattering (RRS) intensity. Therefore, a novel method for the determination of HBB by resonance Rayleigh scattering (RRS) coupled with flow injection analysis (FIA) technique has been established.