Copper‐Catalyzed Selective Synthesis of Isoindolin‐1‐ones and Isoquinolin‐1‐ones from the Three‐Component Coupling of 2‐Halobenzoic Acid,Alkynylcarboxylic Acid and Ammonium Acetate

Isoindolin‐1‐ones and isoquinolin‐1‐ones were selectively synthesized from the reaction of 2‐halobenzoic acid, arylalkynylcarboxylic acid and ammonium acetate (NH₄OAc) in the presence of cesium carbonate (Cs₂CO₃) and a copper catalyst. Conducting the reaction under one‐pot conditions provided isoindolin‐1‐ones in good yields. Changing the addition sequence of ammonium acetate after all reagents had reacted at 120 °C for 6 h selectively produced isoquinolin‐1‐ones. A variety of arylalkynylcarboxylic acids produced the corresponding isoindolin‐1‐ones and isoquinolin‐1‐ones in good yields.

     

Ene‐Carbonyl Reductive Coupling for the Synthesis of 3,3‐Disubstituted Phthalide, 3‐Hydroxyisoindolin‐1‐one and 3‐Hydroxyoxindole Derivatives

An efficient method for the synthesis of three classes of heterocyclic derivatives such as 3,3‐disubstituted phthalides, 3‐hydroxyisoindolin‐1‐ones and 3‐hydroxyoxindoles, is reported. In the presence of the simple reductive system, zinc (Zn)/ammonia (NH₃) [or zinc‐copper (Zn‐Cu)/ammonia], a wide range of alkenes including acrylates, acrylonitrile, acrylamide and vinyl sulfoxide underwent reductive coupling with methyl 2‐acylbenzoates and subsequent lactonization to provide 3,3‐disubstituted phthalides in good to high yields at ambient temperature. In a similar manner, 3‐hydroxyisoindolin‐1‐one and 3‐hydroxyoxindole derivatives could also be easily prepared by direct reductive coupling of phthalimides and N‐substituted isatins with activated alkenes, respectively. Application of this methodology towards the synthesis of 1‐naphthol derivatives on a gram scale is also depicted. Furthermore, the intramolecular phthalimides–ene reductive coupling afforded the respective cyclization products with high diastereoselectivity.

     

Synthesis of α‐Arylphosphonates using Copper‐Catalyzed α‐Arylation and Deacylative α‐Arylation of β‐Ketophosphonates

Efficient methods for the direct arylation and deacylative arylation of β‐ketophosphonates with iodoarenes in presence of a copper(I) or a copper(II) salt as the catalysts have been developed. The corresponding α‐arylphosphonates were obtained in high yields. A tentative mechanism for the deacylative arylation reaction was proposed on the basis of the experimental data.     

1‐Amino‐1‐hydrazo‐2,2‐dinitroethene – a Hazard Warning

1‐Amino‐1‐hydrazo‐2,2‐dinitroethene ( 2 ) has been observed to spontaneously decompose with considerable violence during storage. Its preparation and handling should be regarded as potentially hazardous.     

马蔺子甲素的简易全合成

以3,5-二甲氧基溴苯为原料,经金属化、偶联、脱甲基化、Teuber氧化反应制得标题化合物.总收率74%.目标化合物的结构经核磁共振氢谱及元素分析确证.     

Highly (≥98%) Stereo‐ and Regioselective Trisubstituted Alkene Synthesis of Wide Applicability via 1‐Halo‐1‐alkyne Hydro‐ boration–Tandem Negishi–Suzuki Coupling or Organoborate Migratory Insertion

(Z)‐1‐Halo‐1‐alkenylboranes ( 7 ), preparable in 80–90% yields as ≥98% isomerically pure compounds via hydroboration of 1‐halo‐1‐alkynes, have been converted to a wide range of trisubstituted alkenes via three different routes in the tail‐to‐head ( T ‐to‐ H ) direction, i.e., (i) palladium‐catalyzed Negishi–Suzuki tandem alkenylation, (ii) treatment with organolithium or Grignard reagents to generate α‐bromo‐1‐alkenylboronate complexes that can undergo migratory insertion of a carbon group (R²) to form (E)‐alkenylboranes with inversion of alkene configuration (≥98% inversion), followed by fluoride‐promoted Suzuki alkenylation, and (iii) Negishi coupling to generate (Z)‐alkenylboranes in ≥98% retention of configuration, followed by treatment with organolithium or Grignard reagents to produce trisubstituted alkenes with reversed stereo configurations. The synthetic utility of the present methodology has been demonstrated in the highly selective synthesis of the side chain of scyphostatin in 28% yield over nine steps in the longest linear sequence from allyl alcohol. Thus, this new tandem protocol has been emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to prepare.     

Regioselective Addition of Organometallic Reagents to 2‐(1‐Alkynyl)‐2‐alken‐1‐ones for an Efficient Synthesis of Substituted 1,2‐Allenyl Ketones

Highly substituted 1,2‐allenyl ketones can be easily and efficiently prepared from organometallic reagents and readily available 2‐(1‐alkynyl)‐2‐alken‐1‐ones. The synthetic application of 1,2‐allenyl ketone products was also showcased by palladium‐catalyzed further transformation.     

Novel lipase isolated from a Pseudomonas strain and its application in the synthesis of S(+)‐2‐O‐benzylglycerol‐1‐acetate

Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the synthesis of optically pure 2‐O‐benzylglycerol‐1‐acetate, the building block for the preparation of many β‐blockers, phospholipase A2 inhibitors and other biologically active compounds was the aim of this investigation. A Pseudomonas (strain G6), recently isolated from soil, produced an extracellular lipase. SDS–PAGE analysis showed that the lipase protein was a hexamer. The molecular weight of the sub‐units of the lipase protein were 10, 19, 29, 30, 47 and 53. The catalytic activity of the lipase was exploited for the synthesis of 2‐O‐benzylglycerol‐1‐acetate from 2‐O‐benzylglycerol through transesterification using vinyl acetate as acylating agent. High selectivity of the lipase towards the monoacetate product was demonstrated. A 97% enantiomeric excess (ee) of S(+)‐2‐O‐benzylglycerol‐1‐acetate was obtained when the reaction was carried out at room temperature with shaking. The lipase was highly active in anhydrous organic microenvironments and in non‐polar organic solvents with log P values above 2.5. © 2002 Society of Chemical Industry     

Degradation of 1‐amino‐4‐bromoanthraquinone‐2‐sulfonic acid using combined airlift bioreactor and TiO2‐photocatalytic ozonation

BACKGROUND: Traditional treatment systems failed to achieve efficient degradation of anthraquinone dye intermediates at high loading. Thus, an airlift internal loop reactor (AILR) in combination with the TiO₂‐photocatalytic ozonation (TiO₂/UV/O₃) process was investigated for the degradaton of 1‐amino‐ 4‐bromoanthraquinone‐2‐ sulfonic acid (ABAS). RESULTS: The AILR using Sphingomonas xenophaga as inoculum and granular activated carbon (GAC) as biocarrier, could run steadily for 4 months at 1000 mg L^?1 of the influent ABAS. The efficiencies of ABAS decolorization and chemical oxygen demand (COD) removal in AILR reached about 90% and 50% in 12 h, respectively. However, when the influent ABAS concentration was further increased, a yellow intermediate with maximum absorbance at 447 nm appeared in AILR, resulting in the decrease of the decolorization and COD removal efficiencies. Advanced treatment of AILR effluent indicated that TiO₂/UV/O₃ process more significantly improved the mineralization rate of ABAS bio‐decolorization products with over 90% TOC removal efficiency, compared with O₃, TiO₂/UV and UV/O₃ processes. Furthermore, the release efficiencies of Br^? and SO₄^2? could reach 84.5% and 80.2% during TiO₂/UV/O₃ treatment, respectively, when 91.5% TOC removal was achieved in 2 h. CONCLUSION: The combination of AILR and TiO₂/UV/O₃ was an economic and efficient system for the treatment of ABAS wastewater. © 2012 Society of Chemical Industry     

Facile synthesis of 5,8‐linked quinoline‐based copolymers

Coupling quinoline at its 5,8‐positions provides a facile way to copolymerize quinoline with other conjugated moieties without breaking conjugation. Model compounds containing quinoline units, either at the periphery or in the core, were synthesized and one of them was characterized by X‐ray diffraction. Copolymers of quinoline and 9,9‐dialkylfluorene (R = n‐octyl or 2‐ethylhexyl) were synthesized in good yield by palladium‐catalysed Suzuki cross‐coupling. The copolymers are highly soluble in common organic solvents and gel permeation chromatography measurements against polystyrene standards showed the number‐average molecular weight to be in the range (1.02–2.06) × 10⁴ g mol^?1. Both copolymers emit in the blue region with an emission maximum centred at 435 nm. Copyright © 2012 Society of Chemical Industry     

2－戊基环成－2－烯酮的简易合成法

以正成醛与环戊酮为原料，经缩合、脱水得２－亚戊基环戊酮，再异构，得２－正成基环戊－２－烯酮。研究了在酸性条件下２－亚戊基环戊酮异构成２－正戊基环成－２－烯酮的反应条件。     

Effects of synthesis conditions on the pervaporation properties of poly[1‐(trimethylsilyl)‐1‐propyne] useful for membrane bioreactors

An integrated fermentation and membrane‐based recovery (pervaporation) process has certain economical advantages in continuous conversion of biomass into alcohols. This article presents new pervaporation data obtained for poly[1‐(trimethylsilyl)‐1‐propyne] (PTMSP) samples synthesized in various conditions. Three different catalytic systems, TaCl₅/n‐BuLi, TaCl₅/Al(i‐Bu)₃, and NbCl₅ were used for synthesis of the polymers. It was found that the catalytic system has a significant influence over the properties of membranes made from PTMSP. Although a combination of a high permeation rate and a high ethanol–water separation factor (not less than 15) was provided by all PTMSP samples, the PTMSP samples synthesized with TaCl₅/n‐BuLi showed significant deterioration of membrane properties when acetic acid was present in the feed. In contrast, the PTMSP samples synthesized with TaCl₅/Al(i‐Bu)₃ or NbCl₅ showed stable performance in the presence of acetic acid. When using a multicomponent mixture of organics and water, the copermeation of different organic components results in lower separation factor for both ethanol and butanol. These data are consistent with nanoporous morphology of PTMSP. It was demonstrated that pervaporative removal of ethanol improved the overall performance of the fermentation process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2271–2277, 2004     

Iodine‐Promoted Domino Reactions of 1‐Cyanocyclopropane 1‐Esters: A Straightforward Approach to Fully Substituted 2‐Aminofurans

A straightforward and efficient iodine‐promoted ring‐opening/cyclization domino reaction of 1‐cyanocyclopropane 1‐esters for the synthesis of fully substituted 2‐aminofurans is reported. This reaction involves the sequential ring‐opening/intramolecular cyclization reaction of 1‐cyanocyclopropane 1‐esters to give the corresponding 2‐amino‐4,5‐dihydrofurans, which were oxidized with I₂ and Et₃N in refluxing toluene to give the corresponding 2‐amino‐3‐furancarboxylates.

     

Yeast‐mediated enantioselective synthesis of chiral R‐(+)‐ and S‐(−)‐1‐phenyl‐1‐butanol from prochiral phenyl n‐propyl ketone in hexane–water biphasic culture

BACKGROUND: The hydrophobic phenyl n‐propyl ketone was used as a model compound to examine alcohol dehydrogenase activity in Saccharomyces cerevisiae mediated cell culture. Parameters such as pH, hexane‐to‐water volume percentage, and the amount of cofactor Zn²⁺ ion for either cell growth or reduction were studied to see their effect on the enantioselectivity toward the product R‐(+)‐ or S‐(?)‐1‐phenyl‐1‐butanol. RESULTS: The pH for cell growth in aqueous culture was 7.0, while the pH for reduction in the aqueous portion of the biphasic culture was 5.0. Without Zn²⁺ ion the biphasic cultures of middle to high hexane‐to‐water volume percentage exhibited an R‐(+)‐1‐phenyl‐1‐butanol enantiomeric excess of 53.7% to > 99%. Without Zn²⁺ ion the biphasic cultures at low hexane‐to‐water volume percentage possessed an S‐(?)‐1‐phenyl‐1‐butanol enantiomeric excess of 14.5–46.5%. Exclusively, the enantioselectivity for biphasic cultures containing Zn²⁺ ion was an S‐(?)‐1‐phenyl‐1‐butanol enantiomeric excess of 27.5% to > 99%. Reduction mediated in aqueous culture with varied amount of Zn²⁺ ion by the yeast Candida utilis also showed an S‐(?)‐1‐phenyl‐1‐butanol enantiomeric excess of 79.2–95.4%. CONCLUSION: The enantioselectivity of S. cerevisiae mediated biphasic culture reduction of phenyl n‐propyl ketone can be manipulated through the cofactor Zn²⁺ ion and the hexane volume percentage of the biphasic culture. Copyright © 2008 Society of Chemical Industry     

Microwave‐Accelerated Coupling‐Isomerization Reaction (MACIR) – A General Coupling‐Isomerization Synthesis of 1,3‐Diarylprop‐2‐en‐1‐ones

The microwave‐accelerated coupling‐isomerization reaction (MACIR) of (hetero)aryl halides and propargyl alcohols represents a general Pd/Cu and base‐catalyzed process for the synthesis of 3‐arylprop‐2‐en‐1‐ones in good yields.     

Palladium‐Catalyzed Synthesis of (Z)‐3‐Arylthioacrylic Acids and Thiochromenones

The three‐component reaction of aryl halides, sodium sulfide pentahydrate (Na₂S⋅5 H₂O), and propiolic acid in the presence of 2.5% bis(triphenylphosphine)palladium chloride [Pd(PPh₃)₂Cl₂], 5% 1,4‐bis(diphenylphosphino)butane (dppb) and 2 equivalents of 1,8‐diazabicycloundec‐7‐ene (DBU) produces stereoselectively (Z)‐3‐arylthioacrylic acids in good yields. A study of the reaction pathway suggested that the C S bond formation between aryl halides and Na₂S⋅5 H₂O proceeded first, and the resulting intermediate reacted with propiolic acid to produce the desired product. In addition, when the resulting product was treated with acid, the respective thiochromenones were formed in good yields.     

Assessment of commercial hydrate inhibitors using the 3‐in‐1 method

Phase equilibria, kinetics, and morphology studies of gas hydrates require separate pieces of equipment and experimentation times in the order of days. Recently, we designed a reactor that allows for tight control of the crystallization temperature. Coupled with a novel method, this reactor can screen the crystal morphology, phase equilibria, and apparent kinetics of gas hydrates. Compared to traditional multi‐trial methods, the main advantage of this method is that only a single experiment, completed in the order of hours, is required to assess: (a) the change in hydrate growth velocity with respect to temperature, (b) the HLV equilibrium temperature at the experimental pressure, and (c) the change in crystal morphology with respect to driving force. Using this 3‐in‐1 method, methane hydrate growth and dissociation was studied in the presence of four commercial inhibitors. Phase equilibria, kinetics, and morphology were obtained for all hydrate systems with inhibitors. The standard uncertainty for the HLV equilibrium temperature was 0.05 K and for pressure 0.005 MPa. The apparent rates of growth were measured for all systems (standard uncertainty was 0.008 mm · s^?1) and the difference between the inhibited systems and the pure system was very clear. Crystal habits varied considerably among inhibitors and radically with respect to the uninhibited system. Overall, we present an innovative technology to assess the morphology, kinetics, and thermodynamics of hydrate forming systems with a single apparatus. Furthermore, with little time investment, small sample sizes can be used to obtain replicates with minimum temperature and pressure uncertainties.     

Proton conducting polymer blends from poly(2,5‐benzimidazole) and poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)

Proton conducting polymer electrolyte membranes were produced by blending of poly(2,5‐benzimidazole) (ABPBI) and poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS) at several stoichiometric ratios with respect to polymer repeating units. The membranes were characterized by using Fourier transform infrared spectroscopy for interpolymer interactions and scanning electron microscope for surface morphology. Thermal stability of the materials was investigated by thermogravimetric analysis. Glass transition temperatures of the samples were measured via differential scanning calorimetry. The spectroscopic measurements and water uptake studies indicate a complexation between ABPBI and PAMPS that inhibited polymer exclusion up on swelling in excess water. Proton conductivities of the anhydrous and humidified samples were measured using impedance spectroscopy. The proton conductivity of the humidified ABPBI:PAMPS (1 : 2) blend showed a proton conductivity of 0.1 S/cm, which is very close to Nafion 117, at 20°C at 50% relative humidity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A Hofmann Rearrangement–Ring Expansion Cascade for the Synthesis of 1‐Pyrrolines: Application to the Synthesis of 2,3‐Dihydro‐1H‐pyrrolo[2,1‐a]isoquinolinium Salts

Treatment of cyclobutanecarboxamide with bis(trifluoroacetoxy)iodobenzene, PhI(OCOCF₃)₂, resulted in the formation of 1‐pyrroline via Hofmann rearrangement of the former followed by in situ ring expansion reaction of the cyclobutylamine intermediate. Further elaboration of this methodology to the synthesis of 2,3‐dihydro‐1H‐pyrrolo[2,1‐a]isoquinolinium salts has also been described.