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Aims: Synthesis of dihydropyrimidinones derivatives. Background: carrying out reactions in the green route and organic solvent-free conditions. Objective: Regioselective Michael addition of dihydropyrimidinones to acrylic esters. Methods: The reaction proceeded in the presence of K2CO3/TBAB, a media of inorganic base K2CO3 and organic ionic salt TBAB (tetrabutylammonium bromide) at 100oC. Results: A series of new dihydropyrimidinone derivatives using aza-Michael addition reaction were synthesized under solvent-free conditions. Conclusion: The reaction is characterized by high efficiency, relatively short reaction time, high yields, simple environmentally friendly reaction conditions. Other: The reaction of acrylic esters with dihydropyrimidinones produced N3-substituted derivative of dihydropyrimidinones with 85-95% yields in 6 h.

In this work, new pyrazole derivatives were prepared by one-pot three-component reaction emloying symmetric and asymmetric 1,2-disulfonyl-hydrazines, cyclohexyl isocyanide, and dialkyl acetylenedicarboxylates. Reactions with asymmetric 1,2-disulfonylhydrazines led to two regioisomers, which were distinguished by density functional theory calculations and the major isomer attributed to the energically more stable one.

Laccase/DDQ as a new bioinspired quinone-based cooperative catalytic system was used for the biomimetic aerobic oxidative synthesis of 2-substituted quinazolines and Hantzsch pyridines from the oxidative cyclocondensation of 2-aminobenzylamine and aldehydes and the oxidative aromatization of 1,4-dihydropyridines, respectively. The products were obtained in good to high yields in a phosphate buffer (0.1 M, 12.5 mL, pH 4.5) and acetonitrile (4 vol%) mixture as a solvent. These methods are more eco-friendly, efficient, simple, and practical than other currently available ones because of mild reaction conditions and because they are free from any halide and toxic and expensive transition metals. Therefore, these methods can be applied in pharmaceutical and other sensitive synthetic procedures.

In this research paper, for the first time laccase from Trametes Versicolor was used as a electron-transfer biocatalyst for the aerobic regeneration of DDQ as a high reduction potential organic oxidant. Laccase/DDQ as a new bioinspired quinone-based cooperative catalytic system was used for the aerobic oxidation of sulfides and oxidative coupling of thiols with high yields at room temperature. The herein presented method is more eco-friendly and practical than other currently available methods as it is free from any toxic transition metals or halides and provides quantitative conversion under mild reaction conditions.

A manipulative simple and efficient green methodology for the synthesis of β-sulfonyl esters from sulfonyl hydrazides and acrylic esters promoted by DABCO (1,4-diazabicyclo[2.2.2]octane) is described. The reaction is conducted through sulfa-Michael addition reaction in the absence of solvent at 75°C within 2–3 h. The effects of different bases, molar ratio of DABCO, temperature and time parameters on yield of reaction were investigated.

In the present paper, silver nanoparticles (AgNPs) were synthesized using the Brassica oleraceae fruit extract under the simple and eco-friendly conditions. The reaction between silver nitrate, as metal source, and aqueous extract of Brassica oleraceae fruit, as reductant agent, produced AgNPs in high yield. The formation of AgNPs was confirmed by means of UV-Vis spectroscopy and scanning electron microscopy (SEM) was used for characterization of morphology and size of silver nanoparticle products. The investigation of diverse reaction parameters revealed that reductant concentrations, reaction pH, mixing ratio of the reactants and interaction time affected the size and morphology of synthesized AgNPs. AgNPs with 32.74 nm size and amorphous, based on SEM images, were produced within 24 h interaction period. AgNPs also showed a good antibacterial activity against Escherichia coli.

A new series of pyrrolo[3,4-b]quinolin-2(3H)-yl)benzamides were designed based on molecular hybridization approach and synthesized by reaction of benzohydrazide derivatives with 9-phenylfuro[3,4-b]quinoline-1,3-diones in the presence of an Et3N catalyst. Simple reaction, excellent yield, simple separation process and eco-friendly approach by minimizing the chemical waste renders this protocol particularly attractive. The series 9a–g was evaluated for in vitro antibacterial activity against (+ve bacteria) Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212, (−ve bacterium) Escherichia coli ATCC 25922. In vitro minimum inhibitory concentration (MIC) evaluations showed that the compound 9a was effective against E. coli (MIC: 0.25 mg/mL) S. aureus (MIC: 0.25 mg/mL) and E. faecalis (MIC: 0.5 mg/mL).

In this paper, we offered a green, environment-friendly, novel and inexpensive method for the synthesis of a series of pyrazole derivatives. The reaction took place in the presence of tetrabutylammonium bromide, a commercially available organic ionic salt, at room temperature under solvent-free conditions. All products were confirmed by infrared radiation, nuclear magnetic resonance and elemental analysis. Yields of products were 75–86%.

In this paper, C–N bond formation between 2,3-dihydrophthalazine-1(4H),4-dione (phthalhydrazide) and α,β-unsaturated esters was investigated and a new series of phthalazine derivatives was synthesized using an efficient and simple method under solvent-free conditions. An aza-Michael addition of phthalhydrazide to both acrylic and fumaric esters led to N-mono-substituted phthalhydrazides (as mono-Michael adduct) in the presence of tetrabutylammonium bromide as a high polar media, and 1,4-diaza-bicyclo[2,2,2]octane as an available organic base. In this reaction, the N1,N2-bis-Michael adduct was not observed at all. Also, reactions were performed at 90°C and yields of products were good to excellent.

A simple, efficient and clean procedure has been developed for the cleavage of imines C=N bond. Deprotection of imines to their parent carbonyl and amine compounds was achieved using p-toluenesulfonic acid in the solid state condition at 25-45 ˚C. The salient features of this methodology are shorter reaction times, cheap processing, high yields of product and easy availability of the catalyst. These features make this method an attractive alternative to existing routes for deprotection of iminesA simple, efficient and clean procedure has been developed for the cleavage of imines C=N bond. Deprotection of imines to their parent carbonyl and amine compounds was achieved using p-toluenesulfonic acid in the solid state condition at 25-45 ˚C. The salient features of this methodology are shorter reaction times, cheap processing, high yields of product and easy availability of the catalyst. These features make this method an attractive alternative to existing routes for deprotection of imines

A new series of spiro[[1,3]dithiolane-2,3′-indolines]-2′-one derivatives was synthesized using Michael addition reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one to various α,β-unsaturated esters as well as direct alkylation of this compound with alkyl dihalides. Michael reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one and α,β-unsaturated esters produced related Michael adduct in the presence of tetrabutylammonium bromide and base 1,4-diazabicyclo[2.2.2]octane in good to excellent yields at 80°C under solvent-free conditions. Also, direct alkylation of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one by dihaloalkanes in the presence of base K2CO3 afforded the corresponding products in good yields under the same conditions.

An unexpected reaction between 4-phenylurazole and fumaric esters which led to the formation of 5-alkylidene derivatives of hydantoin is described in this paper. The reaction takes place in the presence of tetrabutylammonium bromide (TBAB), and 1,4-diaza-bicyclo[2,2,2]octane (DABCO) at 70 °C under solvent-free conditions.

The adsorption behavior of H2S gas on the P‒doped, V/P, Nb/P, and Ta/P‒codoped g-C3N4 were theoretically investigated using density functional theory. The computed adsorption energy of H2S molecules over the P‒doped, V‒embedded, Nb‒embedded, Ta‒embedded, V/P‒codoped, Nb/P‒codoped, and Ta/P‒codoped g-C3N4 systems are −0.188, −3.141, −2.850, −3.388, −3.263, −2.970, and −3.523 eV, respectively. These results revealed that with embedding and codoping of g-C3N4, the interaction energy between H2S and V/P, Nb/P, Ta/P‒modified g-C3N4 systems significantly enhances. Furthermore, the band structure results exhibited that with adsorption of H2S on g-C3N4 and also embedded and codoped systems, the electrical conductivity of the g-C3N4 systems remarkably decreases owing to the induced new impurity energy states near the Fermi energy level. Also, the results of the relaxed structures displayed that with adsorption of H2S molecules on g-C3N4 and also the modified g-C3N4 with V, Nb, and Ta and also P elements, the initial planar structure of the pristine g-C3N4 automatically become buckle because the stability of wrinkles structure of g-C3N4 is more than that of the flat structure. Additionally, the results of the Lowdin charge analysis revealed that electron transfer occurs from orbitals of transition metals to the orbitals of H2S molecules for all of the g-C3N4 systems. Finally, current research introduces Ta/P‒codoped g-C3N4 system with adsorption energy of −3.523 eV as the highest sensitive, and low-cost gas sensor candidate for sensing and removing H2S gas from the atmosphere.

A quantum mechanical density functional theory (DFT) was successfully developed for the estimation of pKa values of chlorinated phenols in aqueous solution with a precision of 0.9 pKa units. The MP2/6-311++G(d,p)//B3LYP/6-31+G(d) level of theory was used for the gas phase calculation. For computation in the solution phase and to calculate the energy difference of the acid-base, the polarized continuum model (PCM) at the HF/6-31G(d,p) level was used. The pKa value was computed for each involved species using pentachlorophenol (PCP) as a reference molecule. Natural bond orbital (NBO) analysis considering the natural resonance theory (NRT) was carried out on an optimized geometry of studied compounds to give information about the nature of bonds. Graphical abstract Chlorinated phenols.

The highly regioselective C-N bond formation between phenytoin and acrylic/fumaric esters was accomplished. Solvent-free media Michael addition of phenytoin to acrylic esters led to the selective synthesis of N3-substituted phenytoins (as mono-Michael adducts) in the presence of tetrabutylammonium bromide (TBAB) and potassium carbonate under ultrasonic irradiation conditions at room temperature. These reactions produced N1,N3-disubstituted phenytoins (as bis-Michael adducts) at 70 oC. Surprisingly, the addition of phenytoin to fumaric esters, instead of acrylic esters, selectively provided only N3-substituted phenytoins at both room temperature and 70 oC under the same conditions.

The direct polycondensation of a monomer derived from l-aspartic acid together with adipic acid as a modifier co-monomer with aromatic diamines was studied to synthesize co-poly(amide-imide)s (CPAIs). The relative reactivity of the co-monomers and the manner of their insertion into polymer chains were evaluated using a model reaction and 1H NMR spectroscopy, respectively. The synthesized polymers depicted optical rotations similar to those of the monomer precursor and inherent viscosities in the range of 0.13–0.95 dl/g. Thermal stability and behavior as well as the weight-loss pattern of the CPAIs were studied by thermo-analytical techniques (thermogravimetric analysis-differential thermal analysis, dynamic mechanical thermal analysis and differential scanning calorimetry). Onset decomposition temperatures >300°C and carbonization residues of more than 50% at 600°C were detected for the treated polymers. Almost all of the copolyamides were noncrystalline solids, as illustrated in the X-ray diffraction patterns, and had good levels of solubility in a variety of polar organic solvents. These polymers could afford transparent and flexible to brittle films in solution casting on glass plates. Scanning electron microscopy on the polymer films showed a uniform and continuous morphology, indicating good film forming ability.

Trisubstituted quinolines and acylhydrazones were unexpectedly prepared from a reaction of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides with acetylenic esters. Using of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides led to obtain not only quinoline, but also a second pharmaceutical important product acylhydrazone. Notably, excellent yields, operational simplicity, short reaction times, and the avoidance of the use of catalysts make this approach an attractive complementary method to produce quinoline-2,3-dicarboxylates. The crystal structure of 5a was determined using single-crystal X-ray crystallography. The results showed that crystal packing diagram of 5a is of two pairs of molecules that have two independent alternate intermolecular 1D-polymeric H-bonds between two perpendicular molecules.

A series of polymer–clay nanocomposite (PCN) materials consisting of polyimide and typical clay were prepared by solution dispersion. Quaternary alkylammonium modified montmorillonite, Cloisite 20A, was used as organoclay. Poly(amic acid) solution was prepared from the reaction of benzophenone-4,4′,3,3′-tetracarboxylic dianhydride and 2-(5-(3,5-diaminophenyl)-1,3,4-oxadiazole-2-yl) pyridine in dimethylacetamide. Thermal imidization was performed on poly(amic acid)/organoclay dispersion in a regular temperature-programmed circulation oven. The study of interlayer d-spacing with X-ray diffraction pattern indicates that an exfoliated structure may be present in the nanocomposite 1%. Intercalated structures were obtained at higher organoclay loadings. Nanocomposites were studied using thermogravimertic analysis and differential scanning calorimetry. Nanocomposites exhibit higher glass transition temperature and improved thermal properties compared to neat polyimide due to the interaction between polymer matrix and organoclay particles. The results are also compared with data of a similar work. Morphology study with scanning electron microscopy showed that the surface roughness in nanocomposite 1% increased with respect to pristine polyimide. Solvent uptake measurements were also carried out for the prepared materials. Maximum solvent adsorption was observed for dimethyl sulfoxide (DMSO). It was found that the solvent uptake capacity decreased with increasing clay content.

A simple, efficient and clean procedure has been developed for the C -alkylation of barbituric acid. The Michael addition of barbituric acid to α,β-unsaturated esters by employing K 2 CO 3 in the nano-mordenite media (K 2 CO 3 /nano-MOR), as catalyst, gave C -alkylated barbituric acid in good to excellent yield. Nano-MOR showed good reusability. K 2 CO 3 /nano-MOR catalyst has been found to be an excellent catalyst for the reaction under solvent-free conditions at 80-90 ˚C. Keywords : Solvent-free, C -Alkylation, Barbituric Acid, α,β-Unsaturated Esters, Nano-Mordenite (Nano-MOR), INTRODUCTION Barbiturates, that are derivatives of barbituric acid (pyrimidine-2,4,6-trione), belong to one of the most important classes of drug molecules. 1-7 -Alkylation of barbituric acid in the presence and absence of These compounds were first introduced for medical use in 1911. 8 More than 2500 barbiturates have been synthesized and in the height of their popularity about 50 were marketed for human use.

The reaction of 4-phenylurazole and fumaric esters in the presence of tetrabutylammonium bromide results in the formation of 5-alkylidene derivatives of hydantoin under solvent-free conditions.

A regioselective N3-alkylation of 5,5-diphenyl-2-thiohydantoin (2-thiophenytoin) using a very efficient mild base K2CO3 and α,β-unsaturated esters in the presence of organic salt TBAB (tetrabutylammonium bromide) at room temperature has been reported (3b–3h). The selectivity of this reaction is excellent and products have been produced in good yields under solvent-free conditions. The increase of the reaction temperature to 70°C mostly disappeared this selectivity and afforded only the N1,N3-dialkylated derivatives of 2-thiophenytoin in good yields (4b–4g). We were unable to selectively N3-alkylate 2-thiophenytoin with ethyl acrylate at both room temperature and 70°C under the same conditions (4a). Dimethyl and diethyl fumarates cannot work as Michael acceptors and were hydrolyzed to fumaric acid under reaction conditions.

An account of the experiments on preparing polystyrene (PS) nanocomposites through grafting the polymer onto organophilic montmorillonite is reported. Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety. Because the reaction may liberate HCl, it was performed in the presence of sodium hydrogencarbonate to prevent the exchange of quaternary alkylammonium cations with H+ ions. Only the silanol groups on the edge of the clay react with vinyltrichlorosilane. The radical polymerization of the product with styrene as a vinyl monomer leads to chemical grafting of PS onto the montmorillonite surface. The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhlet extraction. Chemical grafting of the polymer onto Cloisite 20A was confirmed by infrared spectroscopy. The prepared nanocomposite materials and the grafted nano-particles were studied by XRD. Exfoliated nanocomposites may be obtained for 0.5 wt%–1 wt% clay content. The nanocomposites were studied by thermogravimertic analysis (TGA) dynamic thermal analysis (DTA) and dynamic mechanical analysis (DMTA).

New, thermally stable polyimides and a poly(amide-imide) containing a 1,3,4-oxadiazole-2-pyridyl pendant group based on 2-[5-(3,5-diaminophenyl)-1,3,4-oxadiazole-2-yl]pyridine were synthesized. The synthesis and characterization of the model compound 2-{5-[(3,5-bistrimellitimido)phenyl]-1,3,4-oxadiazole-2-yl}pyridine (DIDA) were also investigated, and DIDA was used in the preparation of the poly(amide-imide) in an ionic liquid, 1-butyl-3-methylimidazolium bromide, as a polymerization solvent. The polymers were characterized by separating and characterizing the poly(amic acid) intermediates using infrared and elemental analyses. The prepared polymers were soluble in polar and aprotic solvents, such as dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone and dimethylacetamide. Thermal behaviour of the polymers was studied using thermogravimetric analysis and differential scanning calorimetry. The inherent viscosities of the polyimide and poly(amide-imide) solutions were in the range 0.34–0.85 dL g−1 (in concentrated sulfuric acid with a concentration of 0.125 g dL−1 at 25 ± 0.5 °C). The removal of Co(II) from aqueous solutions was performed using one of the polyimides. It was found that this polymer had a maximum adsorption capacity and efficiency at pH = 10.0. Copyright © 2012 Society of Chemical Industry

An efficient and simple procedure for the synthesis of novel isatin derivatives is described. Michael addition of aniline Schiff bases of isatin or p-toluidine Schiff bases of isatin to fumaric esters affords the Michael adduct compounds in good to high yields in the presence of K2CO3 and tetrabutylammonium bromide (TBAB) under solvent-free conditions. Repeating of this reaction about spiro[1,3-dioxolane-2,3′-indol]-2′(1′H)-one, as a Michael donor, in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) gives Michael adducts in remarkable yields under the same conditions.

An organophilic clay has been obtained via cation exchange reaction between sodium montmorillonite and the hydrochloride salt of 2-(5-(3,5-diaminophenyl)-1,3,4-oxadiazole-2-yl)pyridine, POBD. Thermogravimetric analysis (TGA) showed that thermal decomposition of the organophilic clay starts at about 350°C, which shows that it is quite thermally stable compared with conventional montmorillonite modified with aliphatic long chain surfactants. POBD-modified organoclay almost quantitatively removed the Co(II) ion from aqueous solution at pH = 10.0 (Qt = 3.00 mg g−1, R = 98.2%). A series of polyimide/clay nanocomposite materials (PCNs) consisting of POBD and benzophenone-3,3′,4,4′-tetracarboxylic dianhydride, BTDA were also prepared by an in situ polymerization reaction via thermal imidization. POBD-modified organoclay was used as a surfactant at different concentrations. Intercalation of polymer chains within the organoclay galleries was confirmed by WXRD. Both the glass transition temperature and thermal stability are increased with respect to pristine PI at low clay concentrations. At high clay loadings, the aggregation of organoclay particles results in a decrease in Tg and thermal stability. In the SEM images of PCN 1 and 3%, too many micro cracks are observed in the background, and a flower-shape pattern spreads uniformly over the entire surface. The maximum Co(II) uptake capacity and efficiency were observed at pH 10.0 within a 40-h period for both PI and PCN films. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

1,5-Naphthene dioxy diacetic acid was synthesized from the reaction of 1,5-naphthalene diol and chloroacetic acid. It was used then as a bi-functiona l monomer in polycondensation reaction with aromatic diamines in the presence of tripnenylphosphite to produce poly(amide-ether)s. All the obtained polymers were characterized by IR and elemental analysis; their solubility behaviour was evaluated in polar organic solvents as well as in concentrated H2SO4. The extent of thermal stability and phase transitions of poly(amide- ether)s were investigated by thermogravimetric analysis and differential scanning calorimetry respectively; while the morphology was estimated by X-ray powder diffraction patterns. Besides, the fu-fu stacking character of polymer chain interactions in the solid state was confirmed by absorption spectra of solid thin films.

Zosima absinthifolia belongs to the Apiaceae family and is found in Iran, Turkey, Iraq and different countries of the Caucasus, Middle East and Central Asia. The fruits are used as food flavoring and as a food spice in Iran. In the present work, an n-hexane extract of the plant seeds was purified by vacuum liquid chromatography and preparative TLC for affording a furanocoumarin named imperatorin and two known coumarins, 7-prenyloxy coumarin and aurapten. The compound structures were elucidated by UV, 1H and 13C NMR data. Our results indicated that all tree compounds, especially imperatorin exhibited fungi toxic activity against Sclerotinia sclerotiorum, a common plant pathogen. The compounds also displayed phytotoxic effects and stunted seed germination, shoot and root growth of lettuce. It could be concluded that the purified compounds play allelopathic roles for the plant and could protect the plant against pathogens and competing herbs.

In the present work, new thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent. The obtained polymers are insoluble or slightly soluble in polar aprotic solvents such as DMSO and DMF. Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers had improved thermal stabilities. The model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compounds were characterized by conventional spectroscopic methods.

Highly efficient aza-Michael additions of isatin and phthalimide to symmetrical fumaric esters in ionic liquid media to produce the corresponding Michael adducts in excellent yields are described which were performed at 100 °C for 1–5 h. The results show that these aza-Michael additions are not effective with fumaric esters containing sterically hindered alkoxy groups.

Esterification or transesterification reactions are usually carried out in the presence of homogeneous or heterogeneous catalysts. However, recently a new method was reported for the esterification of carboxylic acids by tributyl borate under solvent- and catalyst-free conditions. In order to show the synthetic ability of trialkyl borate esters in the esterification reactions, here, the esterification of other carboxylic acids and diacids by tributyl-, triisoamyl-, and tribenzyl borate under the same conditions were reported. Some of the prepared ester and diester products have found wide applications as plasticizers and synthetic ester base lubricants. The esterification reactions have been cleanly carried out in the absence of any solvent under catalyst-free conditions. The maximum rate belongs to isoamyl trichloroacetate (VIb) which reached about 76% within about 6.5 h. On the basis of obtained findings, it seems that electron withdrawing groups on carboxylic acid facilitate the esterification reaction.

were monitored and linear working ranges of 0.3-12.0 and 0.7-20 µg mL −1 with detection limits of 0.07 and 0.10 µg mL −1 were obtained, respectively. Also, recoveries in the range of 92.8 to 100.1% and relative standard deviations in the range of 0.4 to 7.1% were obtained. First derivative spectrophotometry has also been applied for palladium determination under the optimum condition. The linear dynamic range of 0.2-24.0 µg mL −1 palladium with relative standard deviations of 0.6-6. 9% and recoveries in the range of 94.9-102.5% has been obtained by first derivative spectrophotometry. The method shows high selectivity because of the high concentration of acid used, which prevents formation of complexes of α -benzilmonoxime with the other cations. The palladium complex formed was stable at least one day. The method was successfully applied to the determination of palladium in some synthetic palladium alloys and palladium-charcoal powder.

A manipulatively simple and rapid method for conversion of oximes to the corresponding carbonyl compounds is described. The reaction is conducted under solvent-less conditions using alumina-supported permanganate. According to the reaction system and conditions used, different ketones and aldehydes are obtained in moderate and good yields.

In an extremely fast, high efficient and novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under solventless 'dry' condition gave oximes in quantitative yield

Oxidation of series of various primary and secondary alcohols to corresponding carbonyl compounds with ammonium persulfate in aqueous media was described. No over oxidation of primary alcohols to carboxylic acids and secondary alcohols to esters was observed. Under such conditions benzoin was converted to benzoic acid.

An efficient, mild, inexpensive and eco-friendly protocol for the synthesis of p-toluenesulfonamide derivatives by aza-Michael addition reaction of p-toluenesulfonamide to fumaric esters using potassium carbonate under ultrasound irradiation was developed. This method is simple, convenient and the desired compounds are produced in good to excellent yield. The bulkiness of alkoxy group (–OR) of fumaric esters did not affect significantly on the yields and reaction times. This reaction worked well on linear and nonlinear alkyl fumarates. The reaction, surprisingly, was not successful on methyl fumarate. In this case methyl fumarate has been hydrolyzed to fumaric acid under reaction conditions.

The aza-Michael addition of 1,2,3,6-tetrahydrophthalimide with symmetrical fumaric esters has been performed efficiently in a solvent-free system at 100 °C and using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base in the presence of tetrabutylammonium bromide (TBAB). The products were obtained in good to high yields within 2.5-7.0 h. This reaction worked well on linear alkyl fumarates and was not effective with nonlinear alkyl fumarates. Although the reaction was also applicable to acrylates such as n-butyl acrylate, methacrylates and crotonates were not suitable Michael acceptors for this reaction.

In an extremely fast, high efficient and novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under solventless 'dry' condition gave oximes in quantitative yield