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Graphical abstract Highlights • Practical one-pot reaction for preparation of 5-substituted-1 H -tetrazoles. • Without using high boiling point or volatile organic solvents in the reaction. • Easy reaction set-up and multigram scale. Abstract A series of 5-substituted-1 H -tetrazoles have been efficiently synthesized in moderate to excellent yields (68–90%) under mild reaction conditions by combining aryl aldehydes, hydroxylamine hydrochloride with sodium azide in the presence of catalytic amount of Cu(OAc) 2 in deep eutectic solvent (DES). The new synthetic method has many advantages, such as high conversion, green reaction medium, easy work-up, low cost, and environment friendly. [ABSTRACT FROM AUTHOR]

Abstract: We have developed an efficient one-pot, two-step reaction protocol for the synthesis of eight-membered 1,5-benzodiazocine-2-ones by Ugi four-center three-component coupling reaction (U-4C-3CR) and subsequent reductive cyclization using Fe/NH4Cl in protic solvent. [Copyright &y& Elsevier]

Abstract: Modified nucleobases and nucleic acids have found many biological and pharmaceutical applications. Here we report a microwave-directed synthesis of a variety of modified uracil and cytosine nucleobases with high yields under solvent-free conditions. The reaction yields were further improved by addition of Lewis acid. The crystal structures of 5-isopropyl-6-methyluracil and 6-phenyluracil were also determined. [Copyright &y& Elsevier]

Abstract: The improved preparation of 1-substituted-β-carbolines is reported using microwave-assisted aza-Wittig/electrocyclic ring-closure reaction with ionic liquids as solvent. In all cases an unprecedented N-methoxymethyl group (MOM) deprotection is observed. [Copyright &y& Elsevier]

Abstract: Two novel star-shaped π-conjugated oligomers bearing a triphenylpyridine moiety as peripheral units and triphenylamine as a core have been synthesized via the threefold Heck/Sonogoshira coupling reaction protocol and their absorption and fluorescence properties have been examined. These oligomers showed excellent solubility in common organic solvents, emit light in blue and violet regions, and have high thermal stability. [Copyright &y& Elsevier]

Abstract: A simple and facile synthesis of 12-aryl-12H-indeno[1,2-b]naphtho[3,2-e]pyran-5,11,13-trione derivatives was accomplished via the one-pot condensation of 2-hydroxynaphthalene-1,4-dione, aldehydes, and 2H-indene-1,3-dione at 100°C under solvent-free conditions in the presence of the solid acid catalyst, poly(4-vinylpyridinium) hydrogensulfate. This method has the advantages of high yields, clean reactions, simple methodology, and short reaction times. The catalyst could be recycled and reused four times without significant loss of activity. The structures of the novel compounds were confirmed by IR, 1H NMR, and elemental analysis. [Copyright &y& Elsevier]

Abstract: Two new conjugated dendrimers bearing a tetraphenylethylene moiety as dendrons and triphenylamine as a core have been synthesized through a convergent synthetic strategy using threefold Heck/threefold Sonogashira coupling reaction. These dendrimers showed excellent solubility in common organic solvents and emit light in the blue and violet regions. [Copyright &y& Elsevier]

Abstract: A new multi-branched fluorophore derived from tetra-quinoxalinylethylene as the core with diphenylaminofluorene units incorporated at the peripheral positions has been synthesized via Pd-catalyzed Suzuki coupling and experimentally shown to possess strong solvent effect on its fluorescence emission and lifetime behaviors. The initial characterization also found that this dye molecule exhibits two-photon activities and effective optical power limiting properties in the near-IR region under the irradiation of nanosecond laser pulses. [Copyright &y& Elsevier]

Abstract: The syntheses and spectroscopic properties of a series of pegylated zinc(II)-phthalocyanines (Zn-Pcs) containing one, two, or eight tri(ethylene glycol) chains are described. The single molecular structure of a phthalonitrile precursor containing one hydroxyl and one PEG group, and its unique intermolecular hydrogen bonding are presented. The pegylated Pcs are highly soluble in polar organic solvents and have fluorescence quantum yields in the range 0.08–0.28. [Copyright &y& Elsevier]

Abstract: N-Aryl-2-nitrosoanilines, available from the reaction of nitroarenes with anilide anions, undergo cyclization to furnish substituted phenazines. The reaction is promoted by potassium carbonate in methanol, N,O-bis(trimethylsilyl)acetamide (BSA) in aprotic solvents, and by acetic acid. The method is illustrated by the synthesis of 1-methoxyphenazine, a precursor of pyocyanine, starting from the appropriate nitroarene–aniline pairs. [Copyright &y& Elsevier]

Abstract: Polyethylene glycol functionalized phosphonium salt (Br−Ph3 +PPEG600P+Ph3Br−) was found to be an efficient, homogenous, recyclable catalyst for coupling of CO2 with a variety of aziridines producing corresponding 5-aryl-2-oxazolidinones with good yields and excellent regioselectivity under relatively mild and solvent free conditions. Furthermore, the catalyst was effectively recycled for four consecutive cycles without any significant loss in its catalytic activity and selectivity. [Copyright &y& Elsevier]

Abstract: We report on synthesis and photophysical properties of a new class of fluorescent dyes. They are characterized by large Stokes-shifts, long fluorescence lifetimes in organic solvents and a pronounced dependency of the fluorescence lifetime on the solvent polarity. Also worthy of note is the high bleaching stability. To provide access to biochemical and medical applications a series of derivatives were prepared, which exhibit specific reactivity towards different biologically relevant functional groups (carboxylic acids, amines, maleimides, N-hydroxysuccinimide esters). Furthermore, two alkynes were prepared, which could be used in ‘Click’ chemistry. [Copyright &y& Elsevier]

Abstract: A new cascade strategy to the synthesis of 2,3-diarylated indoles via the metal-free reaction of aryl aldehyde and aryl amine triggered by N-heterocyclic carbene (NHC) under solvent-free conditions, has been disclosed. The protocol has the advantages of easy work-up, high yields, wide application scope, and an environmentally benign procedure compared with the reported methods. [Copyright &y& Elsevier]

Abstract: Diversely substituted hydantoins have been synthesized by new strategy from cyanamide based precursor, that is, methyl N-cyano-N-alkyl/arylaminoacetate. Dialkylphosphates were employed as the mild reagent to hydrolyze and cyclize the substrate in one step to give quantitative yields of the desired products. Syntheses of multivalent hydantoins viz bis-hydantoin, bicyclohydantoin have potentially widened the scope and applicability of the present method. Solvent-free conditions and very easy work-up procedure make the reaction convenient and eco-friendly. Single crystal structures of some of the representative compounds are also reported. [Copyright &y& Elsevier]

Abstract: A straightforward, efficient and more sustainable catalyst-free method has been developed for the synthesis of quinoxaline, benzoxazole, and benzimidazole ring system in glycerol to achieve yields that were comparable to or better than, those in conventional media. It is noteworthy that the reaction was exclusively carried out in glycerol–water system, rendering the methodology highly valuable from both environment and economic points of view. [Copyright &y& Elsevier]

Abstract: We report the synthesis and photophysical properties of N-alkyl- or N,N-dialkyl-pyrene-1-carboxamide. These derivatives, as well as pyrene, exhibited blue emission. N-Alkyl-type derivatives exhibited strong fluorescence emission (Φ fl =0.61 in EtOH) in both nonpolar and polar solvents. On the other hand, N,N-dialkyl-type derivatives showed weak fluorescence emission (Φ fl <0.01) due to vibrational deactivation. However, in highly viscous solvents such as glycerin, the quantum efficiencies of N-alkyl-type (Φ fl =0.91) and N,N-dialkyl-type (Φ fl =0.082) derivatives were increased. We also investigated the fluorescence mechanism of these compounds using time-dependent density-functional theory (TD-DFT). From these results, we find that highly fluorescent pyrene-1-carboxamide derivatives can be designed by introducing an appropriate functional group at the nitrogen atom of the amide. Thus, N,N-dialkyl-type pyrene-1-carboxamide has considerable potential for use in applications such as environmental response sensors and probes. [Copyright &y& Elsevier]

Abstract: Wells-Dawson heteropolyacids (H6P2W18O62·24H2O) were used as catalysts in the Hantzsch-like multicomponent condensation reaction with 3-formylchromones as aldehyde component, a β-ketoester and ammonium acetate, under solvent-free conditions at 80°C. Although the desired products were obtained, functionalized pyridines were the main reaction product and became the alternative route to dihydropyridine ring formation. Based on the proposed mechanisms for the formation of each of the obtained products, the multicomponent reaction was modified to afford only the functionalized pyridines (60–99%). Our procedure represents a clean alternative for the synthesis of several highly functionalized pyridines. [Copyright &y& Elsevier]

Abstract: The reaction of anilines, benzaldehydes, and ethyl 3,3-diethoxypropionate in the presence of Yb(OTf)3 proceeded under mild reaction conditions to give dihydropyridines (DHPs). We have found that the reaction depended on the solvent and the DHPs were obtained selectively in 1,4-dioxane as a solvent. Various 2,6-unsubstituted DHPs were synthesized in one pot in satisfactory yields. [Copyright &y& Elsevier]

Abstract: 1,2-Dihalogenation and oxy-1,1-dihalogenation of alkynes by N-halosuccinimides can be selectively realized through using different reaction conditions. α,β-Dihalo alkenes were obtained exclusively using THF as solvent without using any catalyst, while α,α-dihalo ketones were synthesized using a mixed solvent of THF and H2O in the presence of FeCl3·6H2O. Terminal aromatic alkynes are smoothly transformed into α,α-dihalo ketones on water without a catalyst. [Copyright &y& Elsevier]

Abstract: We described herein the use of glycerol as solvent in the catalyst-free synthesis of benzodiazepines and benzimidazoles. This simple and efficient method furnishes the corresponding 1-H-1,5-benzodiazepines and 1,2-disubstituted benzimidazoles in good yields by the condensation of o-phenylenediamine with several ketones and aldehydes, respectively. In addition, glycerol can be easily re-utilized for further condensation reactions up to four times without lost of activity. [Copyright &y& Elsevier]

Abstract: Proof-of-concept has been demonstrated for the biocatalytic transformation of aciclovir into valaciclovir, attaining high conversions from a solid-to-solid biotransformation in l-valine methyl ester using various formulations of Subtilisin Carlsberg activated for use in organic solvent. [ABSTRACT FROM AUTHOR]

Abstract: One-pot, three-component coupling reactions of indole, aromatic aldehydes, and heteroaryl amines under solvent-free conditions lead to the formation of the corresponding novel 3-[(N-heteroaryl)(aryl)methyl]indoles in moderate to high yields. The key features of this multi-component reaction are the simple reaction procedure, no organic solvent or acid catalyst, and easy product separation without further purification. [Copyright &y& Elsevier]

Abstract: Four new well-defined monodisperse linear oligofluorenes with anthracene core An-OFVn (n =1–4) have been synthesized through Heck and Wittig reaction. These conjugated oligomers exhibit good solubility in common organic solvents. It is found that the conjugation length of the oligomers can be extended and the formation of excimers can be suppressed with increasing the number of fluorene–vinylene units linked in the 9,10-positions of anthracene. [Copyright &y& Elsevier]

Abstract: A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoximes using an ionic liquid, 1-pentyl-3-methylimidazolium tetrafluoroborate, [pmim]BF4 under organic solvent-free condition, has been developed. A variety of aromatic, heteroaromatic and aliphatic aldoximes are converted to the corresponding nitriles. The ionic liquid is recovered and reused for subsequent reactions. [Copyright &y& Elsevier]

Abstract: A series of novel oligo(p-phenylenes) (OPPs) derivatives with bisdiene side-chains are synthesized and fully characterized. These cruciforms are soluble in common organic solvents and show good thermal stability. Absorption and emission spectra are recorded to study the effect of different electron-withdrawing and electron-donating groups on photophysical properties. Powder XRD shows crystalline structures for all the cruciforms. Single crystal XRD studies show tight-packing along the planar bisdiene axis but significant twisting along phenylene units, which correlate the role of functionalization along the bisdiene axis in tuning the band gaps of the cruciforms. [Copyright &y& Elsevier]

Abstract: A novel [2]catenane is synthesized in good yield from an upper-rim functionalized calix[4]arene macrobicycle and a nitro-substituted isophthalamide threading component in the presence of a chloride anion template via a ring-closing metathesis (RCM) reaction. After halide anion template removal the resulting catenane host exhibits a high degree of selectivity for chloride in competitive organic solvent mixtures. [Copyright &y& Elsevier]

Abstract: An efficient method for the conjugate addition of unactivated alkyl iodides to α,β-unsaturated carbonyl compounds using indium/copper in water is described. The reactions proceed more efficiently in water than in organic solvents. In, CuI, and InCl3 are all essential for efficient reaction. Formation of a symmetrical vic-diarylalkane is observed when an aryl-substituted alkene is used as substrate. [Copyright &y& Elsevier]

Abstract: A task-specific basic ionic liquid, [Bmim]OH, has been introduced as a catalyst for the aza-Michael addition of aromatic amines and N-heterocycles to cyclic or acyclic ketones under neat conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency. [Copyright &y& Elsevier]

• Lemon juice has been explored as catalyst and green solvent in organic synthesis. • Naturally occurring lemon juice is biodegradable, cheap and non-toxic. • Organic transformations can be mediated by lemon juice effectively and selectively. • Lemon juice is a suitable substitute for many toxic metal catalysts. • Lemon juice generates lower waste than traditional chemical methods. Lemon juice has been extensively explored recently as highly selective and efficient biocatalyst as well as green solvent in organic synthesis. Lemon juice holds considerable promise as cheap, easily available, biodegradable, nontoxic and easy-to-construct alternative to well-studied metal-based catalysts and also it is well consistent with green chemistry theme. The present digest paper primarily aims to illustrate the progress of lemon juice mediated organic transformations towards the synthesis of a wide variety of important organic compounds. The mechanistic aspects of the reactions have been highlighted as well. [ABSTRACT FROM AUTHOR]

Abstract: Multi-component synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines has been developed by using the reaction of aldehydes, malononitrile, and thiophenols in the presence of a Zn(II) or a Cd(II) metal–organic framework (MOF) as the heterogeneous catalyst. This protocol tolerates different functional groups on the substrates and does not require the use of any organic solvent. Moreover, the Zn(II) and Cd(II) MOF catalysts can be recovered and reused for a number of runs without loss of activity. [Copyright &y& Elsevier]

Abstract: 2-Amino-4-arylthiazoles were prepared in a one-pot solvent-free procedure by reaction of p-substituted acetophenones with thiourea and iodine under microwave irradiation. [Copyright &y& Elsevier]

Abstract: Nitrocylcohexadienones have been applied as nitration reagents for mild, mono-nitrating reactions. The original synthesis of 2,3,5,6-tetrabromo-4-methyl-4-nitrocylcohexa-2,5-dien-1-one appeared to be difficult to pursue due to both the solvent system and reaction conditions. Therefore, we applied a modified solvent system and optimized the reaction conditions to prepare the dienone at 0°C, to eventually overcome the difficulties. [Copyright &y& Elsevier]

Abstract: In this Letter we present the synthesis of hitherto unreported 1-aryl-2-alkyl-1,4,5,6,7,8-hexahydro-1,3-diazocines 1. Cyclic amidines 1 were synthesized by PPSE promoted ring closure of N-acyl-N′-arylpentamethylenediamines 2. The cyclodehydration reaction was performed under microwave irradiation in solvent-free conditions. Precursors 2 were prepared by selective functionalization of N-arylcadaverines 3. [Copyright &y& Elsevier]

Abstract: An efficient and general method has been described for the synthesis of 3-hydroxy-3-(nitromethyl)indolin-2-one by the reaction of isatins with nitromethane/nitroethane in the presence of DABCO. The reaction is catalytic, very rapid, yields are very high and avoids the use of solvents for reaction. The protocol is applicable for substituted isatins as well as substituted nitroalkanes. [Copyright &y& Elsevier]

Abstract: Baker’s yeast catalyzed one-pot three-component cyclocondensation of aryl aldehydes, malononitrile, and β-dicarbonyls in organic medium has been carried out to obtain polyfunctionalized 4H-pyrans. The reaction has been carried out at room temperature in organic solvent, dimethylacetamide and the products obtained in good to moderate yields with simple work up procedure. [Copyright &y& Elsevier]

Abstract: A novel task-specific ionic liquid, 1-butyl-3-methylimidazolium p-toluenesulfinate, [bmim][p-TolSO2] has been synthesized and used as a nucleophile for the reaction with alkyl bromides and phenacyl bromides to prepare sulfones and β-ketosulfones in excellent yields (80–93%) in [bmim][BF4] ionic liquid. The isolated yields of sulfones and β-ketosulfones were higher in [bmim][BF4] than other organic solvents at room temperature. [Copyright &y& Elsevier]

Abstract: Convenient simple and suitable methods for the synthesis of carbamates, N,N′-unsymmetrically disubstituted ureas, and S-alkyl thiocarbamates derived from CH3OC(O)SNCO in one-step are provided. Reactions are operationally simple and have high selectivity toward nitrogen, oxygen, and sulfur nucleophiles. The absence of solvents coupled with high yields and short reaction times make these procedures very attractive for synthesis. [Copyright &y& Elsevier]

Abstract: The synthesis of 2,6-bis-hydrazonopyridines from 2,6-bis-hydrazinopyridine and the conversion of these bis-hydrazones into 2,6-bis-indazol-1-ylpyridines were studied. The conversion of bis-haloarylhydrazones to bis-indazoles was systematically optimized using iron and copper mediated reactions and various bases and ligands. By varying solvent, base, transition metal, and ligand, a novel regiospecific route to the 2,6-bis-indazol-1-ylpyridine class of ligands was developed. [Copyright &y& Elsevier]

Abstract: A simple and efficient trans-acetoacylation method for the synthesis of β-keto ester derivatives has been described using ytterbium(III) triflate as a new catalyst under solvent-free condition. This method was found to be efficient and convenient for the synthesis of a wide variety of β-keto ester derivatives. [Copyright &y& Elsevier]

Abstract: An efficient one-pot method has been developed for the synthesis of α-oxycarbanilinophosphonates via a one-pot reaction of an aldehyde with diethyl phosphite in the presence of magnesium oxide followed by reaction with an isocyanate under solvent-free conditions using ultrasonic irradiation. This method is simple, rapid and good yielding. [Copyright &y& Elsevier]

Abstract: The solvent-free reaction of oligoethylene glycol diglycidyl ethers with dimercaptoethane in the presence of benzyltrimethylammonium hydroxide (Triton B) gave, via regiospecific epoxide opening reactions, dihydroxy dithiacrown ethers in excellent yields and in short reaction times. [ABSTRACT FROM AUTHOR]

Abstract: Formamide derivatives have been synthesized in excellent yields from amine and formic acid in the presence of a catalytic amount of thiamine hydrochloride (VB1) at 80°C. The advantages of this method are the use of a cheap, stable, non-toxic, and readily available catalyst, easy work-up, improved yields, and solvent-free conditions. [Copyright &y& Elsevier]

Abstract: An environmentally benign aqueous Biginelli protocol for the synthesis of substituted 3,4-dihydropyrimidin-2(1H)-ones using thiamine hydrochloride as a catalyst has been achieved. These ultrasound-assisted reactions proceed efficiently in water in the absence of organic solvent. Utilization of ultrasound irradiation, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective. [Copyright &y& Elsevier]

Abstract: A novel cyclic trimer of imidazole 1, in which imidazole rings are connected by amide bonds, has been synthesized with the help of LiCl as a template for the cyclization. The absorption spectra of 1 indicate the extension of conjugation between imidazole rings and amide bonds. The addition of 3Mequiv of MgCl2 solubilizes 1 in polar organic solvent, suggesting the chelating ability of 1 to Mg cation. [Copyright &y& Elsevier]

Abstract: The cyclocondensation of 2-aminothiophenol and aldehydes has been carried out in dichloromethane using bakers’ yeast as a catalyst for obtaining 2-aryl/heteryl benzothiazoles in good yields. [Copyright &y& Elsevier]

• Novel aromatic ambidextrous gelators have been discovered. • The glutamic-based gelators show an ambidextrous properties. • The aspartate-based gelator exhibits no ambidextrous properties. Although large amounts of organogelators and hydrogelators have been available, the ambidextrous gelators that can gelate both organic solvents, especially, apolar solvents and water are very limited. Furthermore, most of them have been found out incidentally. In order to create powerful ambidextrous gelators it should be necessary to tackle a bottom-up approach based on organic synthesis. Thus, according to molecular design the amphiphilic aromatic compounds consisting of glutamate- or aspartate-based structure having two long alkyl chains and some ethylene glycol units have been prepared. The glutamate-based amphiphilic compounds having one ethylene glycol unit or two ethylene glycol units exhibited an excellent ambidextrous capability because they can only gelate benzene, toluene and water, however, introduction of three ethylene glycol units prevented gelating water. On the other hand the corresponding aspartate-based amphiphilic compound showed no such ambidextrous properties. [ABSTRACT FROM AUTHOR]

Abstract: New amphiphilic oximes of galactose and glucosamine have been synthesized and characterized. The oxime functionality has been introduced to the first and sixth positions of a nonionic surfactant, consisting of a sugar polar head and a lipophilic side chain. The compounds are soluble in pyridine and sparingly soluble in other polar organic solvents and water. [Copyright &y& Elsevier]

Abstract: The iodide salt of the pyrylium dye Cy39 (Cy39I, 1) has been suggested as an alternative of its perchlorate salt, which is widely used for biolabeling applications. A new efficient organic solvent-free procedure for synthesis of 1, allowing for a greener approach to the cyanine dyes, is suggested. The unique combination of solubility and thermostability of both the starting materials and the target Cy39 salt made the performance of the synthesis in an aqueous solution as well as reusing of unreacted starting materials possible. [Copyright &y& Elsevier]