Reaction of Perfluoroalkanesulfinyl Chlorides with Enamines: A Facile Synthesis of α-Perfluoroalkanesulfinyl Ketones and Aldehydes

The reaction of perfluoroalkanesulfinyl chlorides with enamines was achieved in the presence of triethylamine, and α-perfluoroalkanesulfinyl carbonyl compounds were obtained in moderate to good yields after hydrolysis of the reaction intermediates with dilute hydrochloric acid.     

Solid—phase Synthesis of α—Haloaldehydes form Polymer—supported 4—（Phenylseleno）morpholine

Polystyrene-supported 4-(phenylseleno)morpholine was synthesized and could be used as an efficient α-selenenylating agent for saturated aldehydes.α-Haloaldehydes were prepared by reaction of polystyrene-supported α-selenoaldehydes with bromine or sulfuryl chloride in good yield and high purity.     

非烯胺途径有机催化醛醇缩合反应立体选择性合成邻卤代醇和Knoevenagel产物（英文）

Stereoselective synthesis by an aldol reaction between chloroacetone and aldehyde was studied using a synthesized chiral organocatalyst and triethylamine. The reaction gave α-chloro-β-hydroxy ketones in excellent yield with high anti selectivity and enantioselectivity. The chiral organocatalyst was also used in the Knoevenagel reaction, which gave α-cyano-β-hydroxy ketones at a low temperature and the usual Knoevenagel product at a high temperature. Both products were obtained in good to moderate yield with good anti selectivity in the case of α-cyano-β-hydroxy ketone derivatives.     

Synthesis of novel fullerene α-amino acid conjugates

Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.     

A new variant of Knorr''''s pyrrole synthesis

The reaction between ethyl 3-bromopyruvate and p-substituted anilines was found to involve the unexpected participation of acetone (solvent) forming N-aryl-5-methyl-pyrrole-3-carboxylates.The influence of p-substituents of aniline and the feasibility with other ketones were studied.N-aryl-indole-3-carboxylate (17) was synthesized successfully with this method.The unique character of p-methoxy-aniline in this reaction was discussed.     

Asymmetric hydroazidation of α-substituted vinyl ketones catalyzed by chiral primary amine

We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts.A simple chiral primary-tertiary diamine catalyst derived from lphenylalanine was found to readily promote this aza-Michael addition reaction with enamine protonation as the key stereogenic step,thus enabling the effective synthesis of α-chiral β-azido ketones with good yields and moderate enantioselectivities.     

Stereoselective synthesis ofvic-halohydrins and an unusual Knoevenagel product from an organocatalyzed aldol reaction：A non-enamine mode

Stereoselective synthesis by an aldol reaction between chloroacetone and aldehyde was studied using a synthesized chiral organocatalyst and triethylamine. The reaction gave α-chloro-β-hydroxy ketones in excellent yield with highantiselectivity and enantioselectivity. The chiral organocatalyst was also used in the Knoevenagel reaction, which gave α-cyano-β-hydroxy ketones at a low tem-perature and the usual Knoevenagel product at a high temperature. Both products were obtained in good to moderate yield with goodanti selectivity in the case of α-cyano-β-hydroxy ketone deriva-tives.     

Sulfamic acid as a cost-effective and recyclable solid acid catalyst for Friedel–Crafts alkylation of indole with α,β-unsaturated carbonyl compound and benzyl alcohol

Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole withα,β-unsaturated carbonyl compound and benzyl alcohol.Various indoles,α,β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction,and the corresponding products were obtained in good to excellent yields.     

Kinetics of the Inactivation of Creatine Kinase During Inhibition by Planar Anions

The kinetic theory of the substrate reaction during the modification of enzyme activity previously described by Tsou has been applied to a study on the kinetics of slow irreversible inhibition of creatine kinase by planar anions. Kinetic equation of substrate reaction was derived according to the theoretical analysis and experiment data, and then was simplified. From the simplified equation for the substrate reaction in the presence of the inhibitors, the microscopic rate constants for the reaction of the inhibitors with enzyme were obtained. The mechanism of inhibition of enzyme activity was discussed.     

A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone~

When ketones were treated with ammonium chloride and Oxone~ in MeOH at room temperature,a directα-chlorination of ketones was occurred and a series of the corresponding a-chloroketones were obtained in moderate to good yields after 24 h.In this reaction,ammonium chloride was used as the source of chlorine and Oxone~ was used as an oxidant.This method was simple, convenient and providing a novel procedure for preparation of a-chloroketones.     

Stereoselective Synthesis of Sulfonyl-substituted trans-2,3-Dihydrofuran Derivatives via Reaction of Arsonium Ylides with α,β-Unsaturated Ketones

Trans-2,3-dihydrofuran derivatives 3 or 4 substituted with a sulfonyl group were prepared with high chemoselectivity and good yields by [1＋4]-addition reaction of α,β-unsaturated ketones 1 with arsonium bromide 2 in CH2Cl2 in the presence of potassium carbonate at room temperature.The structures of the products were characterized by IR,MS,^1H NMR,elemental analysis and single crystal X-ray diffraction analysis.A mechanism for the formation of products was also proposed.     

Preparation and Peactions of Pyridinium Ylids via Decarboxylation of Pyridinium Betaines

Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium betaines 3, which were prepared from the reactions of α-amino acid ester hydrochlorides with 2,4,6-triphenylpyrylium tetrafluoroborate. Protonation,addition and substitution reactions of 4 with electrophiles were studied in this paper.     

Synthesis of New Benzoimidazole Derivatives

The reactions of cryptotanshinone and tanshinone llA with cadaverine and putrescine were investigated. Six new compounds, four with imidazole functional groups and two with oxazole groups, were obtained. The possible reaction mechanism was proposed.     

Appraisal of an oligomerization behavior of unprotected carbohydrates induced by phosphorus reagent

In this article, a novel oligomerization behavior of unprotected monosaccharides was discovered in a one-pot reaction induced by phosphorus reagent at room temperature. The inherent characteristics of the oligomerization reaction were dissected in detail by mass spectrometry based method combined with NMR technology. It was found that the main glycosidic bonding pattern is (1→6) linkage with 66% regioselectivity for each step. The ratio of α-(1→6) and β-(1→6) glycosidic bonds formed is around 1:1. The reactivity of 1-OH group from aldoses and the driving force from penta-coordinated phosphorus intermediates are the two critical factors for the oligomerization, according to the monitoring experiments by ESI-MS and NMR. Besides, the oligomerization reaction has good compatibility for various aldoses and could expand to O-glycosylated modification of peptides in vitro. The above results will provide a novel enlightenment to develop more convenient and higher-efficient methods for the synthesis of oligosaccharide library.     

Modification of Sugar Chains in Glycoalkaloids and Variation of Anticancer Activity

To study the effect of the sugar chains in glycoalkaloids against cancer cells, 6-O-sulfated solamargine and acid-catalyzed hydrolytic products of α-solamargine and α-solasonine were prepared. The sulfation at O-6 of solamargine was proceeded in five steps. The 6-OH group was first selectively protected with DMT-Cl, and then the secondary hydroxyl groups on the sugar ring were acetylated. After the protective group DMTr was removed, the free 6-OH group was sulfated. Finally, the acetyl groups were removed to give 6-O-sulfated solamargine in a good yield. The hydrolyses of solamargine and solasonine were performed in diluted hydrogen chlorede. Three and two hydrolyzed products were obtained from solamargine and solasonine, respectively. The antiproliferative activities against HCT-8 tumor cells of two glycoalkaloids and their derivaties were examined via a MTT assay. The results show that α-solamargine and α-solasonine exhibit strong cytotoxic activities with an IC50 of 10.63 and 11.97 μmol/L, respectively, wheras their derivaties seem to be less activities.     

Inhibitory effect of H_(3 + x)PMo_(12－x)V_xO_(40)-Ton the self-polymerization of methyl methacrylate

In this work,a series of molybdovanadophosphoric heteropoly acid quaternary ammonium salts H_(3+x)PMo_(12 -x)V_xO40-T were synthesized and employed as a reaction inhibitor in the selfpolymerization of methyl methacrylate(MMA).The polymerization inhibition effect of H_(3+x)PMoPMo_(12 -x)V_xO40-T)with different number of vanadium atoms and reaction dosages was investigated using differential scanning calorimetry(DSC).It shows that the inhibitory effect was improved with the increasing dosages of H_(3+x)PMoPMo_(12 -x)V_xO40-T),and the polymerization inhibition was also affected by the number of vanadium atoms in the H_(3+x)PMo_(12 -x)V_xO40-T .Furthermore,cyclic voltammograms(CV)was used to probe the mechanism of the inhibition reaction with H3+xPMo12xVxO40-T.The result of CV indicates that the inhibition reaction is an oxidation–reduction reaction.H_(3+x)PMo_(12 -x)V_xO40-T can react directly with the MMA monomer radicals,which eliminated the MMA monomers,and therefore the self-polymerization of the MMA can be effectively inhibited by H_(3+x)PMo_(12 -x)V_xO40-T.     

Solid state reactions of nitrogenous heterocyclic compounds (Ⅱ)——Solid state reactions of indole with carbonyl compounds

Solid state Michael addition reaction of indole with α,β-unsaturaled carbonyl compounds was carried out,by which a series of compounds containing three different heterocyclic groups binding to one carbon atom were obtained.In the presence of Lewis acid,indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones.The solid state reaction showed higher selectivity and yield than solution reaction The structures of products were identified by IR,1H NMR,MS,elemental analysis and X-ray crystal analysis.The reaction mechanism was also proposed.     

Block Copolymer Networks Composed of Poly(ε-caprolactone) and Polyethylene with Triple Shape Memory Properties

In this contribution, we reported a novel synthesis of block copolymer networks composed of poly(ε-caprolactone)(PCL) and polyethylene(PE) via the co-hydrolysis and condensation of α,ω-ditriethoxylsilane-terminated PCL and PE telechelics. First, α,ω-dihydroxylterminated PCL and PE telechelics were synthesized via the ring-opening polymerization of ε-caprolactone and the ring-opening metathesis polymerization of cyclooctene followed by hydrogenation of polycyclooctene. Both α,ω-ditriethoxylsilane-terminated PCL and PE telechelics were obtained via in situ reaction of α,ω-dihydroxyl-terminated PCL and PE telechelics with 3-isocyanatopropyltriethoxysilane. The formation of networks was evidenced by the solubility and rheological tests. It was found that the block copolymer networks were microphase-separated. The PCL and PE blocks still preserved the crystallinity. Owing to the formation of crosslinked networks, the materials displayed shape memory properties. More importantly, the combination of PCL with PE resulted that the block copolymer networks had the triple shape memory properties, which can be triggered with the melting and crystallization of PCL and PE blocks. The results reported in this work demonstrated that triple shape memory polymers could be prepared via the formation of block copolymer networks.     

Asymmetric catalytic 1,3-dipolar cycloaddition of α-diazoesters for synthesis of 1-pyrazoline-based spirochromanones and beyond

A highly enantioselective 1,3-dipolar cycloaddition of α-substituted diazoesters with exocyclic enones was achieved with chiral scandium(III)/N,N′-dioxide complex as the catalyst. This protocol provided a facile and efficient route to optically active 1-pyrazoline-based spirochromanones and others with good outcomes(up to 97% yield, 98% ee with 95:5 dr). Moreover,enantioenriched 2-pyrazoline-based spirochromanones were also accessible by switching α-substituted diazoesters to α-diazoacetates. The further specific transformations of chiral pyrazoline-based spiro-compounds to spirocyclopropane derivatives were disclosed as well.     

Solid State Photochemistry of Nitrobenzaldehydes

The photochemical reaction of nilrobenzaldehyde with indole and antipyrine was investigated in solid state.The structures of the new products were identified by means of IR,MS,'H NMR and elemental analysis,and the crystal structure of audition product 2c was determined by X-ray diffraction analysis.The mechanism of this reaction was also proposed.