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AbstractAn efficient one-step procedure for the synthesis of a new series of multifunctional olefins by condensation of α-substituted β-diketones as well as β-phosphonoesters and benzoylated β-ketoesters with formaldehyde, using potassium carbonate in refluxing THF, followed by a deacylation reaction, is herein described. In contrast, the α-substituted β-keto esters, bearing an acyl moiety, only undergo a hydroxymethylation reaction, with no metal catalysts/activating agents, as is usually required for the process, affording the corresponding α-hydroxymethyl β-keto esters in high yields. [ABSTRACT FROM AUTHOR]

Ten novel 4-esterchalcones, licochalcone analogues, were strategically synthesized to study the effect of electro-donating or electro-withdrawing substituents in the aryl enone moiety on their pharmacological and photoprotective properties. 4-Esterchalcones had their drug-like character evaluated, which demonstrated positive characteristics for the development of novel drug candidates. In the in vitro antimicrobial evaluation, isovaleryl 4-esterchalcones showed activity against strains of Staphylococcus aureus, Candida albicans and C. tropicalis with minimum inhibitory concentration (MIC) in the range of 2.64-3.32 µmol mL−1, and the isobutyryl 4-esterchalcone 5d (4'-Br) presented antimicrobial activity against all strains tested, with a MIC of 2.74 µmol mL−1. In the UV-Vis study, λmax were observed at 312-327 nm, the UVB range, mainly. The best SPF-UVB results ranged from 18.04 to 21.06, with high εmax values, indicating that 4-esterchalcones have the potential to act as sunscreens. Furthermore, along with the environmental concern, halogenated compounds demonstrated slightly toxic on Artemia salina. [ABSTRACT FROM AUTHOR]

A series of novel 2-oxo-2-(arylamino)ethyl 4-formylbenzoates were prepared via the reaction of the potassium salt of p-formylbenzoic acid with 2-chloro-N-aryl-acetamide in DMF at reflux. A new series of 1,4- dihydropyridin-3,5-dicarbonitriles, hexahydroacridine-1,8-diones, decahydropyrimido[4,5-b]quinolines, and hexahydrobenzo[4,5]imidazo[2, 1-b]quinazolines which are linked to N-aryl-benzoyloxyacetamide were obtained through the Hantzsch reaction of various 2-oxo-2-(arylamino)ethyl 4-formylbenzoate with the respective 3-aminocrotononitrile or a mixture of 1,3-dicarbonyl compounds and amine source. The structures of the novel compounds were confirmed using a variety of spectra. [ABSTRACT FROM AUTHOR]

We describe herein the design and synthesis of new isoxazolidin-5-carboxylates by microwave-assisted 1,3-dipolar cycloadditions of aldonitrones, derived from five fragrant aldehydes, with methacrylate esters. The reaction proceeded regioselectively providing mostly endo- diastereomers and in some cases an inseparable mixture of endo-exo products. The structures of target compounds were identified on the basis of IR, NMR, and TOF-MS measurements. Besides, both aldonitrone and isoxazolidine derivatives were subjected to olfactory evaluation by an expert nose. Diverse fragrance notes were observed in each series of isoxazolidines bearing different groups from aldonitrones. However, their odor ranges were found as animalic, medical, waxy, and ozonic undertones in common. [ABSTRACT FROM AUTHOR]

An approach for the synthesis of pyrazolo[4,3-c]quinoline derivatives has been developed by the combination of pyrazole-arylamines and β-keto esters via cleavage of C–C bonds. The strategy shows good tolerance and compatibility with a wide range of functional groups. Moreover, this method features simple conditions, generates a series of alkyl substituted pyrazolo[4,3-c]quinoline, and provides the desired products in moderate to good yields. [ABSTRACT FROM AUTHOR]

An efficient heterogeneous palladium-catalyzed Suzuki coupling of aromatic triazine esters with arylboronic acids has been developed. The reaction proceeds smoothly in toluene at 110 °C using 2 mol% of MCM-41-bound bidentate phosphine palladium complex [MCM-41-2P-Pd(OAc)2] as catalyst and provides a novel and practical method for the synthesis of aryl ketones starting from readily available aromatic acids in a one-pot procedure with moderate to excellent yields. The MCM-41-2P-Pd(OAc)2 catalyst can be reused at least seven times without any apparent decrease in its catalytic activity. [ABSTRACT FROM AUTHOR]

The first mild, in situ, single-pot, high-yielding well-screened copper (II) salt-based catalyst system utilizing the hydrogen surrogacy of sodium borohydride for selective hydrogenation of a broad range of nitro substrates into the corresponding amine under habitancy of water or methanol like green solvents have been described. Moreover, this catalytic system can also activate various functional groups for hydride reduction within prompted time, with low catalyst-loading, without any requirement of high pressure or molecular hydrogen supply. Notably, this system explores a great potential to substitute expensive traditional hydrogenation methodologies and thus offers a greener and simple hydrogenative strategy in the field of organic synthesis. [ABSTRACT FROM AUTHOR]

Efficient procedures have been developed for the synthesis of novel series of bis(9,10-diaryl-hexahydroacridine-1,8-diones) in which the two acridine moieties were linked to aliphatic, aromatic, or heteroaromatic spacers via ether or ester linkages. The target products were obtained in good to excellent yields via a multi-component reaction of the appropriate aromatic amine, 5,5-dimethyl-1,3-cyclohexanedione, and the corresponding bis-aldehydes. The reactions were also proceeded to give the target products in good yields via a multi-component reaction of the appropriate cyclic enamines, and the corresponding bis-aldehydes under similar conditions. Bis-alkylation of the appropriate hexahydroacridine-1,8-dione with the corresponding dihalo compound in a basic medium was also proved to be an effective strategy for the synthesis of the target products. The multi-component reaction of the aromatic amine, bis-aldehydes, and barbituric acid or 1,3-dimethylbarbituric acid, instead of 5,5-dimethyl-1,3-cyclohexanedione, afforded the corresponding Knoevenagel condensation adducts in good yield and unfortunately, the expected bis-tetrahydropyrimido[4,5-b]quinolines could not be isolated. [ABSTRACT FROM AUTHOR]

The current study describes an efficient environmental benign synthetic route of N-aryl substituted c-fused pyrrole derivatives via neat approach. It also provides base-mediated intramolecular macrolactamization using amine ester amidation reaction and leads to fused diazocine-6(5H)-one with effective yields. [ABSTRACT FROM AUTHOR]

N-alkylation of amines by the reaction with xanthate esters in the presence of acetic acid catalyst in ethanol is reported. Short reaction time, high yield, general applicability and environmentally benign nature are the noteworthy features of our protocol. The probable mechanism for the formation N-alkylation of amines is proposed. [ABSTRACT FROM AUTHOR]

We report a two-step rapid and efficient synthesis of β-amino-α,β-unsaturated esters. Microwave-assisted synthesis was used throughout the process. Seventeen β-amino-α,β-unsaturated esters were produced in excellent yields and short reaction times. The effects of the heating method and substituents, especially the o-substituted group of the phenols or thiophenols, were investigated. A plausible reaction mechanism is also proposed. [ABSTRACT FROM AUTHOR]

The Huisgen zwitterionic intermediates, generated in situ from N-heterocycles and acetylenic esters were intercepted by tryptanthrins to afford novel spiroindolo[2,1-b]quinazoline-6,2'-pyrido[2,1-b][1,3]oxazines in CH2Cl2 at room temperature. Clear evidence for the structure of a derivative was obtained from single-crystal X-ray analyses. The most important feature of this reaction is the fact it forms two stereogenic centers, one of which is quaternary with remarkable diastereoselectivity. [ABSTRACT FROM AUTHOR]

Green synthesis of novel bis(hexahydro-1H-xanthene-1,8(2H)-diones) which are linked to aliphatic or aromatic spacers via ether or ester linkages were performed in good to excellent yields by the reaction of 5,5-dimethyl-1,3-cyclohexanedione with the appropriate bis-aldehydes using p-TSA as an organic acid solid catalyst. The reaction of the bis-aldehydes with barbituric acid or 1,3-dimethylbarbituric acid instead of 5,5-dimethyl-1,3-cyclohexanedione afforded the corresponding Knoevenagel condensation adducts in good yield. [ABSTRACT FROM AUTHOR]

Herein a practical and convenient procedure for the one-step synthesis of quinoline-3,4-dicarboxylate derivatives from isatins and β-keto esters in alcohols by sulfuric acid-catalyzed was described. This novel protocol offers the advantages of high conversion rates, short reaction times, and easy handling. [ABSTRACT FROM AUTHOR]

The efficient synthesis of the ester side chains of homoharringtonine and harringtonine using lactones as building blocks has been developed. The synthesis used classic reactions from readily available starting materials. Reactions of the lactone bearing an oxo-containing α-tetrasubstituted center with MeOH and cephalotaxine, respectively, proceeded smoothly to give the corresponding ring-opening products in 80% and 65% yield. [ABSTRACT FROM AUTHOR]

4,7-Dihydroazolo[1,5-a]pyrimidin-5-ylmethanesulfonamides are side-products of the three-component Biginelli-like reaction of aminoazoles, aldehydes and N,N-dialkyl-2-ketomethanesulfonamides. Herein, we report a straightforward synthesis of 5-sulfonamidomethyl substituted 4,7-dihydroazolo[1,5-a]pyrimidines by a two-component condensation of aminoazoles and N,N-dialkyl(cinnamoyl)methanesulfonamides in DMF at reflux. The starting N,N-dialkyl-2-ketomethanesulfonamides can be obtained by either lithiation of N,N-dialkylmethanesulfonamides and reaction with aldehydes followed by oxidation of the resulting alcohols or by Claisen condensation of N,N-dialkylmethanesulfonamides with the corresponding esters. The chemical structures of all synthesized compounds are supported by 1H and 13C NMR-spectroscopy, mass spectrometry and elemental analysis. [ABSTRACT FROM AUTHOR]

UV curing of photopolymerizable monomers, like (meth)acrylates, has been utilized for coatings for more than half a century and more recently in further developed areas such as tissue engineering. However, these monomers have major disadvantages, e.g., high irritancy and cytotoxicity, which leads to limited use in tissue engineering regarding health issues. Vinyl esters (VE) and vinyl carbonates (VC) can compete with (meth)acrylates in terms of material properties and have significantly lower toxicity, but lack in cost efficient synthesis methods. The purpose of this communication is to establish new pathways to overcome this drawback. It was shown that VEs can be synthesized either by vinyloxy trimethylsilane or by acetaldehyde in excellent yields. Moreover, a new method to synthesize vinyl chloroformate as precursor for VCs in lab scale was evolved by a catalyzed reaction of vinyloxy trimethylsilane with a phosgene solution. Finally, the cytotoxicity tests showed auspicious results. [ABSTRACT FROM AUTHOR]

A direct metal-free approach for the synthesis of alpha-cyanoalkylboronic esters from bis-diboron ester and azobis-nitrile compound is reported under ambient temperature and pressure via a free radical procedure. [ABSTRACT FROM AUTHOR]

An efficient and simple approach for the direct synthesis of aryl and heteroaryl sulfonic esters was developed using DMS and DES as alkoxysulfonylation reagents. The reaction is operationally simple and scalable. This protocol does not require solvent, expensive catalysts, base, ligand additives or other reagents. A wide range of sulfonic esters were synthesized in moderate to good chemical yields. This method has the advantage of low cost, facile and tolerated a wide range of substrates. [ABSTRACT FROM AUTHOR]

An efficient and operationally simple method for the preparation of phenylvinyl-1,2-diamines by the Rh(II)-catalyzed C–N coupling of 1-sulfonyl-1H-1,2,3-triazoles with secondary amines (e.g., N-aryl glycine esters, diarylamines or 1-phenyl-2-(p-tolylamino)ethanone) via the 1,3-insertion of Rh(II)-azavinyl carbenes into sp3 N-H bond process has been developed. The optimized conditions tolerate various functional groups and afford the diverse (Z)-phenylvinyl-1,2-diamines in good to excellent yields with high regioselectivity. The method was also successfully extended to the synthesis of functional tertiary amines having a Z configuration of the (1-aryl-2-(sulfonamido)vinyl) substituent and two aryl groups. [ABSTRACT FROM AUTHOR]

The reaction between dialkyl 8-oxo-8H-cyclopenta[a]acenaphthylene-7,9-dicarboxylates and zwitterionic intermediates, generated in situ from alkyl isocyanides and dialkyl acetylenedicarboxylates, is described. This reaction leads to the formation of tetraalkyl 5′-(alkylimino)-5′H-spiro[cyclopenta[a]acenaphthylene-8,2′-furan]-3′,4′,7,9-tetracarboxylates. The structure of a typical product was confirmed by X-ray crystallographic analysis. [ABSTRACT FROM AUTHOR]

A metal-, oxidant-, and additive-free conversion of hydroxamates to esters have been achieved using molecular iodine as the reagent using a novel but not-so-explored heron-type rearrangement. The reaction proceeds with almost equal facility with substrates having either electron-donating or electron-withdrawing substituent. Similarly, α,ß-unsaturated, and sterically hindered ortho-substituted hydroxamates also undergo the desired transformation smoothly. [ABSTRACT FROM AUTHOR]

A series of seven coumarinyl-amino acid ester conjugates have been synthesized and characterized by NMR (1H and 13C) and mass spectra. Further, the compounds were investigated for their therapeutic applications such as anti-inflammatory and antioxidant activities. Among the synthesized compounds most of the analogs showed good efficiency compared with the standard. [ABSTRACT FROM AUTHOR]

Novel chromenyl α-aminophosphonic acid 4 and dialkyl chromenyl phosphonate 6 have been obtained. In addition, some novel types of chromene fused with phosphorus heterocycles such as chromeno[4,3-c][1,2]azaphospholes 5 and 7, chromeno[2,3-d][1,3,2]diazaphosphinine 8 and 1,2-oxaphosphinino[3,4-c]pyridine 10 have been synthesized. The methodology depended on treatment of 2-imino-2H-chromene-3-carboxamide (1) with some phosphorus esters. The synthesized compounds were evaluated for antioxidant and cytotoxic activities. Among the synthesized compounds, compound 5 exhibited the most antioxidant activity with IC50 = 2.8 μg/mL in comparison with ascorbic acid as standard antioxidant. Also, compound 5 had significant cytotoxic effects against four cancer cell lines. Its IC50 values ranged between 4.96 and 7.44 μg/mL in comparison to doxorubicin (IC50 = 0.426–0.493 μg/mL). [ABSTRACT FROM AUTHOR]

A highly efficient method has been developed for the synthesis of diphenylmethyl (DPM) esters from 2-diphenylmethoxypyridine. Various carboxylic acids readily reacted with 2-diphenylmethoxypyridine in the presence of FeCl3 as a catalyst to provide the desired DPM esters with high yields. The procedure is facile and enables effective synthesis of a variety of esters for the protection of carboxylic acids. [ABSTRACT FROM AUTHOR]

Some novel compounds of bis/mono 1-aryl-1H-tetrazole-5-carboxylic acid are synthesized by the hydrolysis of two different synthesized esters, they are ethyl-1-aryl-1H-tetrazole-5-carboxylate and ethyloxo(1-aryl-1H-tetrazol-5-yl)acetate. The ethyl-1-aryl-1H-tetrazole-5-carboxylate is resistant to get hydrolyzed, whereas the ethyloxo(1-aryl-1H-tetrazol-5-yl) acetate undergoes hydrolysis process and converts the ester to title compound. All the synthesized compounds are characterized by IR, 1H and 13C NMR, mass and elemental analysis.The ethyl-1-aryl-1H-tetrazole-5-carboxylateis optimized by DFT B3LYP method and the HOMO and LUMO energy is 5.14 eV and also there is a formation of a weak bond between O18 and C8 as observed from the AIM analysis result. [ABSTRACT FROM AUTHOR]

Nucleosides are valuable biologically active compounds, which display antitumour and antiviral activities. Various types of bioactive nucleosides are designed to improve their therapeutic efficacy, However this strategy faces the difficult selectivity issues of nucleoside chemistry. Therefore, the goal of this review is to give an idea of the opportunities provided by biocatalyst CAL-B procedures in the preparation of different types of bioactive nucleoside compounds. The function of Candida Antarctica lipase-B (CAL-B) in organic synthesis is reviewed. This enzyme has been found to be a principally efficient and robust lipase catalyzing an unexpected variety of reactions including many different regio- chemo, and diastereo-selective synthesis. Moreover, the structure of Candida Antarctica lipase-B is an example of an enzyme for which its specificity has been predicted based on acylation and deacylation mechanism on substrates. [ABSTRACT FROM AUTHOR]

A green and cost-effective Pummerer-type rearrangement between readily accessible carboxylic acids and DMSO has been achieved under metal-free conditions in satisfactory to excellent yields. The transformation for the synthesis of valuable methylthiomethyl esters is shown to be a convenient strategy for various (hetero)aromatic acids, α,β-unsaturated carboxylic acids and saturated alkyl carboxylic acids with good functional group tolerance. [ABSTRACT FROM AUTHOR]

A copper-catalyzed α-cyanoisopropylation reaction of β-keto esters using azo compounds as cyanoalkylating agents is presented, providing an easy access to β-dicarbonyls containing an α-tertiary nitrile moiety with adjacent tertiary and quaternary carbon centers. It is remarkable because a tremendous steric conflict is involved during reaction. Such nitriles were otherwise unavailable, and the reaction features simple and relatively mild conditions and good functional-group tolerance. [ABSTRACT FROM AUTHOR]

Facile and efficient synthesis of sulfoxide esters using menthols as chiral auxiliary is described. Phenylthio/benzylthio/naphthylthioacetic esters act as an efficient substrate for chiral sulfoxides via oxidation in one step. The structural and stereochemical aspects of target product were established on the basis of various spectroscopic studies, namely FT-IR, NMR (1H NMR and 13C NMR) and elemental analysis. This method is simple, fast, convenient and very efficient. [ABSTRACT FROM AUTHOR]

A concise synthesis of both enantiomers of γ-valerolactone has been developed from commercially available Alanine. The key steps in the synthesis of these γ-Lactones are DIBAL-H reduction of ester (9) followed by in situ Wittig reaction with EtO2CCH = PPh3 ylide (13) (Z/E = 1: 3.5) and one pot lactonization triggered by deprotection of O-TBS ether (14). [ABSTRACT FROM AUTHOR]

A facile phosphine-promoted [2 + 3] cycloaddition of dialkyl azodicarboxylates with β,γ-unsaturated α-keto esters was developed, and a series of pyrazoline derivatives were obtained with good yields under mild conditions. Furthermore, the scope of the cyclizations was investigated. [ABSTRACT FROM AUTHOR]

3,4-Dihydropyrimidin-2-ones act as a versatile scaffold in organic synthesis, which serves as a significant template for the development of various therapeutic agents and shows a wide spectrum of activities. The attractive application of 3,4-dihydropyrimidin-2-ones in organic synthesis is undoubtedly owing to C-5 ester group, which is responsible for the change in its bioactivity. Introduction of various groups like electron-withdrawing and electron-donating groups at positions 1, 2, 3, 5, and 6 greatly increased biological activity. Significant efforts have been undertaken to exploit different synthetic routes to synthesize various derivatives of 3,4-dihydropyrimidin-2-ones. This review article gives a comprehensive account of the synthetic utility of C-5 substitution of 3,4-dihydropyrimidin-2-ones used in the design and synthesis of different types of compounds with greater emphasis on recent literature. [ABSTRACT FROM AUTHOR]

Esters of 3-alkyl-4-oxo-2-butenoic acid, which are very important synthons, are not equally accessible in both E and Z configurations. The (Z)-isomers can be easily obtained from 3-alkyl-4-hydroxybutenolides, in turn prepared by aminoalkylation of aliphatic aldehydes with glyoxylic acid. The (E)-isomers, on the contrary, result from laborious procedures: the condensation of aldehydes with glyoxylic acid, followed by separation from γ -hydroxybutenolide by-product and esterification, or of aldehyde enamines with glyoxylic esters, followed by Z ester by-product conversion into γ -aminobutenolide and purification. Here, we describe a straightforward route to the title compounds, applied to methyl (E)-3-propyl-4-oxo-2-butenoate, avoiding any problematic by-product or isomer chromatographic separation: pentanal and glyoxylic acid are condensed to 3-propyl-4-hydroxybutenolide, which is converted to methyl (Z)-3-propyl-4-oxo-2-butenoate and then isomerized to E ester under acidic conditions. [ABSTRACT FROM AUTHOR]

The preparation of novel 3-, 4-, 6-, and 13-amino-tetradecanoic acid methyl esters (2a–d) obtained by the reduction of 3-, 4-, 6-, and 13-oximino-tetradecanoic acid methyl esters (1a–d), was investigated. Oximino esters were reduced to afford the corresponding amino esters using NaBH4–ZrCl4 reducing system with good yields (58–82%). However, the reduction of oximino esters with LiAlH4 and BH3. Tetrahydrofuran gave the corresponding novel 3-, 4-, 6-, and 13-oximino alcohols (3a–d), and 3-, 4-, 6-, and 13-amino alcohols (4a–d) respectively with good chemical yields. [ABSTRACT FROM AUTHOR]

A new reagent, tert-butyl (2,4-dioxo-3-azaspiro [5,5] undecan-3-yl) carbonate (Boc-OASUD) for the preparation of N-Boc-amino acids is described. The Boc-OASUD reacts with amino acids and their esters at room temperature in the presence of a base and gives N-Boc-amino acids and their esters in good yields and purity. Introduction of the Boc group takes place without racemization. The Boc-OASUD, being a solid and more stable, is a better alternative to di-tert-butyl dicarbonate which is low melting and has to be dispensed in plastic containers than glass because of its poor stability. [ABSTRACT FROM AUTHOR]

(E)-2-(6-((E)-2-carboxyvinyl)-2,3-dihydroxyphenyl)-3-(3,4-dihydroxyphenyl) acrylic acid, designated SMND-309, was synthesized starting from 2-hydroxy-3-methoxybenzaldehyde in 12 steps and with an overall yield of 44%. The synthetic key features were the conversion of aryl aldehyde into aryl acetic acid for one-carbon extended, the Perkin condensation, and the Heck coupling for construction of α , β -unsaturated ester. [ABSTRACT FROM AUTHOR]

The present work describes the origin, control, and synthesis of two potent impurities of dabigatran etexilate1, dabigatran dimer2, and dabigatrann-propyl ester3from the commercially available raw materials 2-[(4-cyanophenyl)amino]acetic acid (4) andN-[3-amino-4-(methylamino)benzoyl]-N-2-pyridinyl-β-alanine ethyl ester (5). These impurities are the process-related impurities and may affect the quality of drug substance, during its manufacturing in large scale. These impurities are not only the crucial components in determining the quality and safety of the drug substance1but also provide a better understanding of impurity profiling. [ABSTRACT FROM PUBLISHER]

In the present work, we determined and evaluated the stereochemical outcome of the Horner–Wadsworth–Emmons (HWE) reaction of 2-oxoalkylphosphonates with different ester functions (bis(2,2,2-trifluoroethyl), 2,2,2-trifluoroethyl methyl, dimethyl) and side chains (aliphatic, aromatic) with three different aldehydes (benzaldehyde, THP- and PPB-protected Corey aldehydes) under two reaction conditions. The “trans” protocol is generally used in theE-selective HWE reactions, while “cis” protocol promotes theZ-selectivity. [ABSTRACT FROM PUBLISHER]

Several low-melting sugar mixtures (LMMs) were synthesized and used for preparation of 1,4-dihydropyridines with aldehydes, 1,3-dicarbonyl compounds, and a nitrogen source as starting materials. Good yields, low reaction times, recyclability of LMMs, and catalyst-free methodology are some of the highlights of this new protocol. [ABSTRACT FROM PUBLISHER]

An efficient synthesis ofα,β-unsaturated esters is achieved via a one-pot reaction in the presence of aC3-symmetric arsine. The key advantages are the short reaction time, simple workup, mild reaction conditions, and high yields. [ABSTRACT FROM PUBLISHER]

The direct acylation of sulfonamides by esters represents an attractive strategy in organic chemistry, being an interesting alternative to classical approaches toN-acylsulfonamides. Here is described a simple and effective method to obtainN-acylsulfonamides of pharmaceutical interest, in a reaction promoted by titanium(IV) chloride. This strategy was successfully applied to the synthesis of a peroxisome proliferator–activated receptorαantagonist with a benzenesulfonimide moiety, ensuring an excellent yield of product. The reaction was further studied to explore the behavior of differentα-bromoesters and esters and the effects ofpara-substitution in the benzenesulfonamide moiety. [ABSTRACT FROM AUTHOR]

Friedel–Crafts reaction of indoles to aromaticα-ketimino esters was found to be catalyzed by camphorsulfonic acid with good yields (up to 98%) under ambient temperature. This process provides an efficient method for the synthesis of unnatural amino acid derivatives that bear quaternary carbon centers. [ABSTRACT FROM PUBLISHER]

The benzofuran skeleton is commonly found in a wide variety of natural products that display a wide range of biological activities. For this reason, benzofuran has a high potential for use as a scaffold in both chemical and pharmaceutical syntheses of natural products. This work describes the development of a novel asymmetric synthetic method of benzofuran-derivedβ-amino esters via K2CO3-promoted domino reactions ofortho-hydroxyl aromaticN-tert-butylsulfinyl imines and diethyl bromomalonate. A small library of target compounds was prepared under optimized reaction conditions in moderate to good yields with high distereoselective and enantioselective properties. The newly generated chiral carbon center was of an (S)-configuration as determined by x-ray diffraction. [ABSTRACT FROM AUTHOR]

A novel procedure for the preparation of organic ammonium tribromides (OATBs) is described from their corresponding bromides. Quaternary ammonium bromides (QABs) and a N,N′-heterocyclic dibromide are efficiently oxidized to their corresponding monotribromides and bistribromide bym-chloroperbenzoic acid (MCPBA) in the presence of 2 and 4 equiv of KBr, respectively. The reactions are carried out in an aqueous medium without the use of any mineral acid or metal catalyst/promoters. A variety of tribromides are synthesized in very good yields including a hitherto unknown reagent, 1,10-(ethane-1, 2-diyl)phenanthrolinediium bistribromide (EPDBT). EPDBT is investigated as brominating agent and found to be highly effective for selective bromination of active methylene groups of a variety of 1,3-diketones and β-ketoesters. [ABSTRACT FROM AUTHOR]

Oxidation of nitrogen-containing heteroaryl-2-methanols to esters with Ag2O and isopropyl iodide is reported. This methodology is very mild and can tolerate many functional groups. [ABSTRACT FROM AUTHOR]

Various substituted benzaldehydes were converted into benzoate esters with household bleach and sodium iodide in an alcohol solvent. The reaction works best with methanol. Only 4-chlorobenzaldehyde, 3-nitrobenzaldehyde, and 4-nitrobenzaldehyde reacted completely with 1-propanol under these conditions. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications®for the following free supplemental resource(s): Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

2,6-Dimethyl-3,5-bis(ethoxycarbonyl)-1,4-dihydropyridine (dihydropyridine Hantzsch ester, DHPHE) and CuSO4 · 5H2O efficiently accelerated azide–alkyne cycloaddition reactions of both aliphatic and aromatic substrates and gave 1,4-disubstituted 1,2,3-triazoles as the only isomer in good to excellent yields at room temperature with 1 mol% of CuSO4 · 5H2O/DHPHE (1:1 in molar ratio). The reaction could be carried out smoothly in methanol in air with high efficiency. DHPHE may play multiple important roles in the reaction: a reducing reagent to generate the catalytic center copper(I) from CuSO4, a base to help form the intermediate acetylide, and a ligand to stabilize the catalytic copper(I) species via coordination after being transformed to pyridine derivative. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

Herein we have reported a facile solvent-, catalyst-, and aldehyde-free, one-pot synthesis of 3,4-dihydropyridin-2-one from 1,3-diones using simple and mild reaction conditions. The substrate scope has been also extended toβ-ketoesters. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications®for the following free supplemental resource: Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

An efficient route to the synthesis of 1,3-dienylphosphonates (1) has been developed for the first time by the substitution of propargylic esters (2) to the diethyl phosphite (3) nucleophile in the presence of Pd2(dba)3 · CHCl3(2 mol %) and 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (4 mol%). Both the alkyl and aryl 1,3-dienylphosphonates can be prepared from this transformation. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthetic Communications®to view the free supplemental file. [ABSTRACT FROM PUBLISHER]