Nanoparticle-stabilized Alkenyl Succinic Anhydride(ASA)Emulsions:A Review

Alkenyl succinic anhydride(ASA) is a popular paper-sizing agent that is generally added to papermaking systems as an aqueous emulsion. Herein, we reviewed the recent work focusing on ASA emulsions stabilized by solid particles. Solid particle-stabilized ASA emulsions generally possess high ASA content and exhibit good sizing performance. The particles that have been used to stabilize ASA emulsions typically include montmorillonite, laponite, alumina, TiO_2, Fe_3O_4, polyaluminum sulfate(PAS), and cellulose nanocrystals(CNCs). Montmorillonite is the first extensively studied particle stabilizer for ASA emulsions. Laponite is undoubtedly the most competent particle stabilizer for preparing ASA emulsions with high sizing efficiency. Montmorillonite and laponite can be used individually as stabilizers after modification or as co-stabilizers with other particles or polymers. TiO_2, alumina, PAS, and CNCs are commonly used as stabilizers either individually or with other particles.

Solvent-Free Synthesis of 5-Alkenyl-2,2-butylidene-1, 3-dioxane-4,6-diones under Ultrasonic Irradiation with o-Phthalimide-N-Sulfonic Acid as Catalyst

5-Alkenyl-2,2-butylidene-1,3-dioxane-4,6-diones were synthesized by the Knoevenagel condensation reaction of aromatic aldehydes with 2,2-butylidene-1,3-dioxane-4,6-dione using o-phthalimide-N-sulfonic acid as catalyst, without solvent under ultrasonic irradiation. The present method has some notable advantages such as mild reaction conditions, short reaction times, less catalyst dosage and high yields with the green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused for five times without any noticeable decrease in the catalytic activity.

(Z)-a-Selanyl Alkenyl Grignard Reagents as Convenient Precursors for Stereoselective Synthesis of Trisubstituted Alkenes

Z)-a-Selanyl alkenyl Grignard reagents 2 were prepared conveniently by treatment of a-bromovinylselenides 1 with magnesium filings in THF. Intermediates 2 were reacted with alkyl iodides in the presence of CuI or Pd(PPh3)4 to afford (Z)-1,2-disubstituted vinylselenides 3, which were cross-coupled with Grignard reagents in the presence of (PPh3)2NiCl2 to give trisubstituted alkenes 4 stereoselectively in good yields.

New 5-Alkenyl Resorcinols from <i>Lithraea molleoides</i>(Vell). Eng.

Lithraea molleoides (Anacardiaceae) is a tree that grows in South America including Southern Brazil, Southern, and Eastern Bolivia, Southern Paraguay, Northern, and Central Argentina. Infusions, decoctions, or tinctures from its aerial parts (leaves, buds, and young stems) are employed in ethnomedicine mainly against respiratory, and digestive inflammations and illnesses. Antibacterial, antiviral, antioxidant, anti-inflammatory, and antinociceptive activities, among others, have been reported for L. molleoides. Many of its biological activities have been associated with the reported presence of 5-alkenyl resorcinols. Alkyl/alkenyl catechols and alkyl/alkenyl resorcinols are very common in members of the Anacardiaceae family and several activities have been attributed to them. This work describes the isolation and the structural elucidation of three new 5-alkenyl resorcinols isolated from Lithraea molleoides reported in nature for the first time.

Regioselective Synthesis of Two Novel 4-alkenyloxy-2,6-dihydroxyacetophenones

Two novel Acetophenones, 4-(1'-geranyloxy)-2,6-dihydroxyacetophenone 1 and 4-(1'-farnesyl)-2,6-dihydroxyacetophenone 2 isolated from the fruit of Evodia merrillii and from the aerial parts of Borronia ramosa respectively, have been synthesized by starting from 2,4,6-trihydroxyacetophenone 3.

Strain-promoted S-arylation and alkenylation of sulfinamides using arynes and cyclic alkynes

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.

Chemoselective and Living/Controlled Polymerization of Alkenyl Methacrylates by the Phosphonium Ylide/Organoaluminum Lewis Pairs

Chemoselective,living/controlled polymerizations of allyl methacrylate(AMA) and vinyl methacrylate(VMA) with/without methyl methacrylate(MMA) by using the phosphonium ylide/organoaluminum based Lewis pairs(LPs) have been realized.The P-ylide-2/AIMe(BHT)_(2)(Pylide-2=Ph_(3)P=CHMe and BHT=2,6-iBu_(2)-4-MeC_(6)H_(2)O) was demonstrated to be superior by which homopolymers PAMAs(M_(n)=27.6-111.5kg/mol and ■=1.14-1.25) and PVMAs(M_(n)=28.4-78.4 kg/mol and ■=1.12-1.18) and block copolymers PMMA-b-PAMA,PAMA-b-PVMA,PAMA-bPMMA,PMMA-b-PAMA-b-PMMA,PAMA-b-PMMA-b-PAMA,and PAMA-b-PVMA-b-PAMA were synthesized.In the polymerizations,all of the monomers were reacted by the conjugated ester vinyl groups leaving intactly the nonconjugated acryloxy groups.The pendant acryloxy groups attached to the main chain enable further to post-functionalization by the AIBN-induced radical "thiol-ene" reaction using PhCH_(2)SH.The thiolether side group-containing polymers PAMA-SCH_(2)Ph and PAMA-SCH_(2)Ph-b-PMMA-b-PAMA-SCH_(2)Ph were thus prepared.

Asymmetric Two-Component Alkenyl Catellani Reaction for the Construction of C—N Axial Chirality

Herein,we report an asymmetric two-component alkenyl Catellani reaction for the construction of C—N axial chirality through a palladium/chiral norbornene cooperative catalysis and an axial-to-axial chirality transfer process.Various partially aromatic iodinated 2-pyridones,quinolones,coumarin and uracil substrates react with 2,6-disubstituted aryl bromides with a tethered amide group,to afford a wide variety of polycyclic C—N atropisomers(38 examples,up to 97%e.e.).The obtained C—N axial chirality originates from the preformed transient C—C axial chirality with high fidelity.The synthetic utility of this chemistry is demonstrated by facile prepa-ration of complex quinoline and pyridine based C—N atropisomers through a N-deprotection and aromatization sequence.In addi-tion,a remote axial-to-central diastereoinduction process dictated by C—N axial chirality is observed with excellent diastereocontrol.

Asymmetric alkenylation reaction of benzoxazinones with diarylethylenes catalyzed by B(C_(6)F_(5))_(3)/chiral phosphoric acid

Catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive challenge.Herein,we reported an asymmetric alkenylation of benzoxazinones with diarylethylenes by utilizing a B(C_(6)F_(5))_(3)/chiral phosphoric acid catalyst.A broad of benzoxazinones and diarylethylenes with electron-withdrawing and electron-donating groups were tolerated(up to 95%yield and 97.5:2.5 e.r.)in the methodology under mild reaction conditions.Moreover,the synthetic utility was confirmed by the scaled-up reaction and transformations of the products.The mechanism was preliminarily explored by control reactions,nonlinear effect experiment and DFT calculations.

Aromatic and olefinic C–H alkenylation by catalysis with spirocyclic NHC Ru(Ⅳ) pincer complex

Catalyst innovation lies at the heart of transition-metal-catalyzed reaction development. In this article, we have explored the C(sp2)–H alkenylation activity with novel spirocyclic N-heterocyclic carbene(NHC)-based cyclometalated ruthenium pincer catalyst system, SNRu-X. After screening catalyst and condition, a high valent Ru(Ⅳ) dioxide(X = O_(2)) species has demonstrated superior reactivity in the catalytic alkenylation of aromatic and olefinic C–H bonds with unactivated alkenyl bromides and triflates. This reaction has achieved the easy construction of a wide range of(hetero)aromatic alkenes and dienes, in good to excellent yields with exclusive selectivity. Preliminary mechanistic studies indicate that this reaction may proceed through a single electron transfer(SET) triggered oxidative addition, by doing so, providing valuable complementary to classical alkenylation reactions that are dependent on activated alkenyl precursors.

高氯酸银催化炔丙醇与酸酐反应制备烯二酮

烯二酮类化合物是一类重要的工业原料和多功能的有机合成中间体,在制药工程、香料加工和化学合成中有着广泛的应用.利用高氯酸银(AgClO_(4))催化炔丙醇与酸酐的反应,首次合成了几种此前从未报道过的新型烯二酮类化合物.该反应过程无需溶剂,且具有操作简单、条件温和、绿色环保、底物普适性广等优点,这表明了该方法在烯二酮合成领域巨大的应用潜力.

Rhodium-Catalyzed Direct C-H Alkenylation of Indoles with Alkenyl Borates

Main observation and conclusion A new Rh(Ⅲ)-catalyzed direct C—H alkenylation of 2,3-unsubstitued indoles with alkenyl borates through C—H activation followed by transmetallation was described.This protocol provides an efficient method for the synthesis of terminal C2-alkenylindoles under mild conditions,and also shows broad substrate scope and high functional group tolerance with respect to both components.Furthermore,the C2-alkenylated indole can be easily transformed into carboline derivative,which is an important polycyclic indole moiety in natural products and drug molecules.

Spherical hollow mesoporous silica supported phosphotungstic acid as a promising catalyst for α-arylstyrenes synthesis via Friedel-Crafts alkenylation

In this work, a spherical hollow mesoporous silica(SHMS) with high surface area(902 m^2/g) and large mesopore volume(1.31 cm^3/g) was prepared via a facile and scalable two-step soft-hard dual templateassisted sol-gel approach(OSDSG) by using glucose-derived carbon nano/micro particles(NMCP) as a hard template and cetyltrimethylammonium bromide(CTAB) as a soft template,respectively,in which the size-preselected carbon submicro-particle was used to replace ploymer sphere, and no extra precious additives like n-octadecyltrimethoxysilane(C18TMS). Supported phosphotungstic acid(PTA) catalysts on SHMS(PTA/SHMS) and on previously reported spherical mesoporous silica(PTA/SMS) with 25 wt% of PTA loading were prepared and employed as solid acid catalysts for diverse reactions. Transmission electron microscopy(TEM),N_2 adsorption-desorption, X-ray diffraction(XRD), and NH_3 temperatureprogrammed desorption(NH_3-TPD) techniques were employed to characterize the nature of carriers and supported PTA catalysts for revealing the structure-performance relationship. The developed PTA/SHMS catalyst demonstrates much higher catalytic activity than PTA/SMS for diverse reactions including alkenylation, esterification, alkylation, and benzylation, ascribed to the strengthened mass transfer and enlarged exposure degree of acidic sites to reactants those resulting from unique hollow and mesoporous morphology. Moreover, PTA/SHMS catalyst also exhibits outstanding catalytic performance for the diverse a-arylstyrenes via solid acid-mediated alkenylation. PTA/SHMS could be considered as a practical solid acid catalyst for diverse transformations.

TMSCI Promoted Direct sp3 C-H Alkenylation to Construct （E）-2-Styryl-tetrahydrobenzo[d]thiazoles

A high-efficient and stereo-specific approach for the preparation of biologically important （E）-2-styryl-tetra- hydrobenzo[d]thiazoles has been developed via TMSC1 promoted direct sp3 C-H alkenylation of 2-methyl-5,6-di- hydrobenzo[d]thiazol-7（4H）-one under metal-free conditions. Seventeen target compounds were synthesized in ex- cellent yields of 82%--98% under the optimal conditions of 300 mol% TMSCI at 110℃ for 2 h, and their chemical structures were elucidated by IR, NMR, ESI-MS, elemental analyses and X-ray crystallography analysis. A plausible mechanism was also proposed, and this method provided a good functional group conversion for the sp3 C-H substrates.

Silicotungstic acid-derived WO_(3) composited with ZrO_(2) supported on SBA-15 as a highly efficient mesoporous solid acid catalyst for the alkenylation of p-xylene with phenylacetylene

Highly dispersed silicotungstic acid-derived WO_(3) composited with ZrO_(2) supported on SBA-_(15) (WZ/SBA-_(15)) as an ordered mesoporous solid acid catalyst was prepared via a facile incipient wetness impregnation (IWI) method that active ingredients, ZrO_(2) and WO_(3), were impregnated into the channels of SBA-_(15) simultaneously with a subsequent calcination process. The relationship between catalyst nature and performance was explored by high resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N_(2) adsorption-desorption, NH_(3) temperature-programmed desorption (NH_(3)-TPD), and FT-IR of pyridine adsorption (Py-IR) characterization techniques. The catalytic performance of W_(12)Z_(15)/SBA-_(15) is not only greater than that of single component solid acid catalysts, WO_(3)/SBA-_(15) and ZrO_(2)/SBA-_(15), but also W_(12)/Z_(15)/SBA-_(15) prepared by impregnating active ingredients, ZrO_(2) and WO_(3), into SBA-_(15) in sequence. The outstanding performance of W_(12)Z_(15)/SBA-_(15) is derived from the strong interaction between ZrO_(2) and WO_(3), which results in more acid sites, and relatively high specific surface area, large pore volume, and ordered mesoporous structure of SBA-_(15). The characterization and reaction results clearly demonstrate that the synergy of ZrO_(2) and WO_(3) has a clear boost for the alkenylation. The optimized W_(12)Z_(15)/SBA-_(15)-500 achieves a 99.4% conversion of phenylacetylene and a 92.3% selectivity of main product α-arylstyrene for the alkenylation of p-xylene with phenylacetylene, with very low level of oligomers producing at the same time. Moreover, W_(12)Z_(15)/SBA-_(15)-500 shows excellent catalytic stability and regeneration. Therefore, W_(12)Z_(15)/SBA-_(15)-500 is a promising solid acid catalyst for the alkenylation.

Lewis Acid Enables Ketone Phosphorylation:Synthesis of Alkenyl Phosphonates

Main observation and conclusion An efficient Lewis acid enabled ketones phosphonylation to synthesize vinylphosphonates has been developed.This method relays on ketone hydrophosphonylation/α-hydroxy phosphonates unimolecular elimination(E1)dehydration cascade reaction sequence.

α-烯基磺酸钠在酸性体系中的增稠性能研究

研究了α-烯基磺酸钠在盐酸、硫酸、磷酸、氨基磺酸、草酸、柠檬酸和羟基乙酸溶液中的增稠性能,并考察了不同浓度的氯化钠和硫酸钠对体系黏度的影响。结果表明:α-烯基磺酸钠在盐酸和硫酸溶液中有自增稠作用,在其他几种酸性溶液中需要添加氯化钠或硫酸钠才能使体系增稠。

A one-pot protocol for copper-mediated azide–alkyne cycloaddition using alkenyl triflate precursors

On the basis of the mild transformation of alkenyl triflates into alkynes promoted by LiCl, a one-pot protocol using alkenyl triflate precursors was developed for copper-mediated azide–alkyne cycloaddition. This protocol may provide an opportunity of sequentially click reactions for the construction of bifunctional probes in chemical biology studies.

Discovery of Novel Long-Chain Alkenyl Diacid Derivatives as ACLY Inhibitors

ATP citrate lyase(ACLY)synthesizes cytosolic acetyl coenzyme A(acetyl-CoA),an essential biosynthetic precursor for lipid synthesis and the acetyl donor required for protein acetylation.The aberrant expression and activity of ACLY has been documented in multiple human cancers.ETC-1002 is an indirect ACLY inhibitor,and it has recently been approved by the FDA as an additional therapeutic option in high-risk hypercholesterolemia patients unable to meet goals with standard therapy.In this work,we identified a series of novel long-chain alkenyl diacids as potent direct ACLY inhibitors,and comprehensive structure-activity relationship analysis showed that compound 18f was the most potent ACLY inhibitor with an IC50 value of 1.5μmol/L.Subsequent ester formation of 18f gave a new series of compounds such as 25f that maintained ACLY inhibitory activity and improved antitumor cell proliferation effects.

Construction of chiral 3-alkenyl-3-substituted oxindoles by stereoselective direct alkenylation of isatin derivatives and 3-vinylindoles

An efficient asymmetric alkenylation between 3-vinylindoles and isatin derivatives was developed under catalysis of a chiral copper complex.A series of optically active 3-alkenyl-3-substituted oxindoles were obtained in excellent yields and stereoselectivities.The reaction mechanism was proposed and supported by DFT calculation.