Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• acid (13) and malononitrile (14) all containing active methylene groups, which initiated a domino reaction (Scheme 2). The Knoevenagel reaction of the formyl group in rac-5 and the active methylene groups of 12–14 afforded the intermediates rac-6a–c (Scheme 1), which underwent regioselective [1,5

• (−5.51). [5-Nitro-2-(2-phenyl-2,3-dihydro-1,4-benzoxazepin-4(5H)-yl)benzylidene]propanedinitrile (7c): To the stirred solution of rac-5 (100 mg, 0.27 mmol) in chloroform (5 mL), anhydrous MgSO4 (150 mg, 1.25 mmol) and malononitrile (130 mg, 1.97 mmol) were added and the mixture was refluxed for 10 h

A simple copper-catalyzed two-step one-pot synthesis of indolo[1,2-a]quinazoline

• Chunpu Li,
• Lei Zhang,
• Shuangjie Shu and
• Hong Liu

Beilstein J. Org. Chem. 2014, 10, 2441–2447, doi:10.3762/bjoc.10.254

• aryl halides with active methylene compounds such as ethyl acetoacetate, malononitrile, cyanoacetate and their equivalents [8][9][10][11][12][13][14][15]. Copper-catalyzed domino reactions have also been used in the synthesis of nitrogen-containing compounds [16][17][18][19][20]. Ma et al reported a

• derivatives by reduction and PCC oxidation [33]. Initially, N-(2-iodophenyl)acetamide (1a), malononitrile (2a) and 2-iodobenzaldehyde (3a) were chosen as model substrates to optimize reaction conditions including the catalysts, bases and solvents under argon atmosphere. Based on the previous work [22], four

• organic chemistry and medicinal chemistry. Experimental General procedure for the synthesis of indolo[1,2-a]quinazolines 4a–4q A dry sealed tube was charged with a magnetic stirrer, substituted N-(2-iodophenyl)acetamide (100 mg for each example, 0.38 mmol), malononitrile or 2-sulfonylacetonitriles (0.46

Facile synthesis of 1H-imidazo[1,2-b]pyrazoles via a sequential one-pot synthetic approach

• András Demjén,
• Márió Gyuris,
• János Wölfling,
• László G. Puskás and
• Iván Kanizsai

Beilstein J. Org. Chem. 2014, 10, 2338–2344, doi:10.3762/bjoc.10.243

• [1,2-b]pyrazole library in sequential one-pot protocol utilizing four components such as hydrazine hydrate, ethoxymethylene substituted malononitrile or ethyl cyanoacetate derivatives, isocyanides and aldehydes. Results and Discussion In the initial stage, a model GBB-3CR was performed between 5

• envisage a sequential one-pot access to 1H-imidazo[1,2-b]pyrazole species through the in situ microwave-assisted formation of 1a followed by a GBB-3CR. A comparative study for the optimum synthesis of 6 revealed that the cyclocondensation of ethoxymethylene malononitrile (4a) with hydrazine (5) under

• sequential one-pot GBB method has been extended by means of ethyl 2-cyano-3-ethoxyacrylate (4b), (1-ethoxyethylidene) malononitrile (4c) and ethyl (E)-2-cyano-3-ethoxycrotonate (4d). Application of these starting materials in the optimized protocol with a slight modification (elevated temperature was

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• )4], β-CD and γ-CD, bromobenzene (Br–Ph), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) were purchased from (Sigma-Aldrich) and used as received. Malononitrile (Merck), tetrabutylammonium perchlorate (TBAP) for electrochemical analysis (99.0%) (Fluka) were used without further purification

• ]. Synthesis of 2,7-dibromo-9,9-(dicyanomethylene)fluorene (1): 2,7-dibromo-9,9-(dicyanomethylene)fluorene was prepared by a condensation reaction between 2,7-dibromofluoren-9-one with malononitrile at 110 °C in DMSO according to a literature method [13][33][34]. Synthesis of bis(4-bromophenyl)(4-methylphenyl

Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives

• Akshay Kumar and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2014, 10, 929–935, doi:10.3762/bjoc.10.91

• time of 6 days (Table 5, entry 13). The R absolute configuration of Michael adducts was assigned by comparing the HPLC chromatograms of Michael adducts with that reported in the literature [23][24]. Next, we studied the multicomponent version of this reaction. Acetone, isatin and malononitrile react in

• involves the initial formation of isatylidenemalononitrile by Knoevenagel condensation of isatin with malononitrile followed by the addition of acetone to provide Michael adduct 4a. Thus, catalyst 1a also finds its successful application in the multicomponet version of this reaction without compromising

Towards allosteric receptors – synthesis of β-cyclodextrin-functionalised 2,2’-bipyridines and their metal complexes

• Christopher Kremer,
• Gregor Schnakenburg and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 814–824, doi:10.3762/bjoc.10.77

• : carbon, red: oxygen, blue: nitrogen, yellow: sulfur, white: hydrogen). MALDI mass spectrum (sample prepared from a 1:1 mixture of CuPF6 and 2 in benzene/acetonitrile (1:1) using DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile) as matrix). Aromatic region of the 1H NMR spectra

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• -propenylidene]malononitrile (DCTB) as supporting matrix. UV–vis spectra were measured using a Lambda 25 Perkin Elmer Spectrometer. EPR spectra were obtained on a Bruker EMX EPR spectrometer. Cyclic voltammetry Cyclic voltammetric studies were carried out using an Autolab PGSTAT20 potentiostat, using a three

Organobase-catalyzed three-component reactions for the synthesis of 4H-2-aminopyrans, condensed pyrans and polysubstituted benzenes

• Moustafa Sherief Moustafa,
• Saleh Mohammed Al-Mousawi,
• Maghraby Ali Selim,
• Ahmed Mohamed Mosallam and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2014, 10, 141–149, doi:10.3762/bjoc.10.11

• malononitrile with benzaldehyde and cyclic ketones [11] (Scheme 2). In contrast, MW-irradiation-promoted reactions of ketones, aldehydes and malononitrile are known to afford polysubstituted benzenes 3 (Scheme 3) [12]. Elnagdi et al. reported [13] that reaction of alkyl azenyl carbonitrile with arylidene

• malononitrile afforded benzo-fused azenes. Based on these studies several surveys were published during the last decade [10][14][15][16][17][18][19]. Results and Discussion Very recently we reported that the reaction of dimethylacetylene dicarboxylate (DMADC) with benzylidenemalononitrile afforded 2-amino-4H

• -pyran 9 and that the yield of the process can be improved if equimolar amounts of DMADC, benzylidenemalononitrile and malononitrile are used [20]. Similar observations have been made in previous studies of these reactions using 1-methylimidazole [21]. Recently we observed that 2-amino-4H-pyran 9 can be

Investigating the continuous synthesis of a nicotinonitrile precursor to nevirapine

• Ashley R. Longstreet,
• Suzanne M. Opalka,
• Brian S. Campbell,
• B. Frank Gupton and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2013, 9, 2570–2578, doi:10.3762/bjoc.9.292

• dimethyl acetal (DMF-DMA) [34]. Previous attempts to synthesize the nicotinonitriles via enamines resulted in poor yields due to dimerization of the starting alkylidene malononitrile [35][36][37]. A high yield enamine approach allows us to begin the synthesis from the commodity chemicals (acetone and

• malononitrile) and bypass the pyridone intermediate used in the original CAPIC synthesis (Scheme 2a) by effecting the ring closure under Pinner reaction conditions (Scheme 2b) [14]. We set out to investigate the possibility of performing a continuous synthesis of 2-bromo-4-methylnicotinonitrile starting from

• acetone and malononitrile (Scheme 3) using the Vapourtec R series reactor system [38]. The batch synthesis commences with a Knoevenagel reaction condensing malononitrile and acetone catalyzed by aluminum oxide producing isopropylidenemalononitrile (4) [39][40]. The penultimate enamine 5 results by

The chemistry of amine radical cations produced by visible light photoredox catalysis

• Jie Hu,
• Jiang Wang,
• Theresa H. Nguyen and
• Nan Zheng

Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234

• . König and coworkers showed that the same aza-Henry reaction can be catalyzed by the organic dye Eosin Y to afford the aza-Henry product 18 (Scheme 5) [67]. In addition to nitroalkanes, dialkyl malonates and malononitrile can be used as pronucleophiles to provide β-diester amine 19 and α-aminonitrile 20

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• with malononitrile (156) and [18F] labeling of 157 (Scheme 12) [101][102]. Compound 152 bound to synthetic Aβ1-40 fibrils with high affinity

Synthesis of functionalized spiro[indoline-3,4’-pyridines] and spiro[indoline-3,4’-pyridinones] via one-pot four-component reactions

• Li-Juan Zhang,
• Qun Wu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 846–851, doi:10.3762/bjoc.9.97

• malononitrile afforded the functionalized spiro[indoline-3,4’-pyridine] derivatives in good yields. Similar reactions with ethyl cyanoacetate successfully afforded the functionalized spiro[indoline-3,4’-pyridines] and spiro[indoline-3,4’-pyridinones] as the main products according to the structures of the

• [12][13][14][15][16][17][18][19][20][21][22][23]. Recently, Perumal and we have both developed an efficient synthetic procedure for functionalized spiro[indoline-3,4’-pyridines] by domino reactions of in situ generated β-enamino esters, isatin and malononitrile with triethylamine as the base catalyst

• reactions of arylamines, methyl propiolate, aromatic aldehydes and malononitrile (ethyl cyanoacetate) and successfully developed a facile synthetic procedure for functionalized spiro[indoline-3,4’-pyridines] and spiro[indoline-3,4’-pyridinones]. Results and Discussion The efficient formation of

New simple synthesis of ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thiones: Direct formation from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles

• Qiuping Ding,
• Yuqing Lin,
• Guangni Ding,
• Fumin Liao,
• Xiaoyan Sang and
• Yi-Yuan Peng

Beilstein J. Org. Chem. 2013, 9, 460–466, doi:10.3762/bjoc.9.49

• excellent 90% yield (Table 2, entry 15). However, it was found that reactants 2-(2-aminobenzylidene)malononitrile (1s) and ethyl 3-(2-aminophenyl)-2-cyanoacrylate (1t) were not workable under the standard conditions (Table 2, entries 19 and 20). The 2-(2-thioxo-2,4-dihydro-1H-benzo[d][1,3]thiazin-4-yl

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• . The enolates and their equivalents involved in the reactions discussed in this article were derived from ketones, nitroalkanes, malononitrile and α,β-unsaturated compounds. Keywords: acetophenone; chromane; enolates; malononitrile; Michael addition; salicylaldehyde; Introduction The chromane

• used. Chromane derivatives from the reactions of salicylaldehyde and enolate equivalents derived from malononitrile and its derivatives The one-pot reaction of salicylaldehyde and malononitrile has proved to be an efficient method for the synthesis of 2-iminochromene derivatives. In general such

• synthetic procedures involve a Knoevenagel condensation followed by intramolecular cyclization. In a detailed study directed towards understanding the pathway of the reaction of salicylaldehyde (5) and malononitrile (20), Costa and co-workers reported the efficient synthesis of 2-iminochromene 21 in 90

Organocatalytic asymmetric addition of malonates to unsaturated 1,4-diketones

• Sergei Žari,
• Tiiu Kailas,
• Marina Kudrjashova,
• Mario Öeren,
• Ivar Järving,
• Toomas Tamm,
• Margus Lopp and
• Tõnis Kanger

Beilstein J. Org. Chem. 2012, 8, 1452–1457, doi:10.3762/bjoc.8.165

• . Products of that reaction can be used as precursors of biologically active compounds. Padmaja et al. have reported that racemic heterocyclic compounds derived from the Michael addition of malonates and malononitrile to unsaturated 1,4-diketones possess antimicrobial and antifungal properties [14][15

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• involve the reactions of β-ketonitriles, malononitrile, alkylidenemalononitriles and their derivatives with hydrazines, as well as some novel miscellaneous methods. Keywords: alkylidenemalononitriles; 5-aminopyrazoles; hydrazines; β-ketonitriles; malononitriles; Review The 5-aminopyrazole system

• to give hydrazide resin 40, which on further treatment with 2-(1-ethoxyethylidene)malononitrile in ethanol-CH2Cl2 (v/v 1:1) mixture at room temperature for 5 h provided resin bound 5-aminopyrazole 41. Resin 41 was easily cleaved with isopropylamine to give crude 42, which was diazotized with 4 M HCl

• reacted with N-aryl-2-oxo-2-phenylethanehydrazonoyl bromides 58 to yield 3,7-bis(arylazo)-6-methyl-2-phenyl-1H-imidazo[1,2-b]pyrazoles 59 (Scheme 14). 2. Reaction of malononitrile and its derivatives with hydrazines Malononitrile (60) and its derivatives have been shown to react smoothly with hydrazines

A new and facile synthetic approach to substituted 2-thioxoquinazolin-4-ones by the annulation of a pyrimidine derivative

• Nimalini D. Moirangthem and
• Warjeet S. Laitonjam

Beilstein J. Org. Chem. 2010, 6, 1056–1060, doi:10.3762/bjoc.6.120

• derivatives of 1,3-diarylthiobarbituric acids (DTBA) with active methylene compounds, such as malononitrile and ethyl cyanoacetate, in presence of ZnCl2 has been developed. Keywords: benzenoid; ethylcyanoacetate; malononitrile; pyrimidine; 2-thioxoquinazolin-4-ones; Introduction Quinazolines and derivatives

• active methylene compounds, such as, malononitrile and ethylcyanoacetate. Results and Discussion DTBA are among the simplest synthetic intermediates and can be easily prepared in a one-pot reaction by treating 1,3-diaryl thioureas with malonic acid in the presence of acetyl chloride. DTBA undergoes

• a pyrimidine ring. Thus, treatment of 1 with malononitrile in presence of NH4OAc with ZnCl2 as catalyst in refluxing acetic acid gives the corresponding 2-thioxoquinazolin-4-ones 2 in 78–85% overall yields (Scheme 1). During the optimization of the cyclization of ethoxymethylene derivatives of DTBA

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• material acenaphthylene-1,2-dione undergoes a Knoevenagel condensation with malononitrile to give mono-adduct 2. Compound 2 was originally synthesized by Junek et al. [38]. However, no detailed NMR data were reported. In a second step, cyclization with anhydrous K2CO3 converted 2 to 1 in a good yield. In

• Chemie (Burghausen, Germany). 2-(2-Oxo-2H-acenaphthylene-1-ylidene)-malononitrile (2) Compound 2 was synthesized as described earlier [34]. Acenaphthene-1,2-dione (2.00 g, 11 mmol) and malononitrile (0.73 g, 11 mmol) were dissolved in 40 mL of CH3CN and refluxed for 3 h. After cooling, the orange

• -Oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile (1) 2-(2-Oxo-2H-acenaphthylene-1-ylidene)-malononitrile (2) (0.80 g, 3.5 mmol) and K2CO3 (48 mg, 0.35 mmol) in 5 mL of CH3CN were refluxed for 1 h. After cooling, the yellow-orange precipitate was filtered off and washed several times with CH3CN to yield 1

Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

• Monika Gupta,
• Rajive Gupta and
• Medha Anand

Beilstein J. Org. Chem. 2009, 5, No. 68, doi:10.3762/bjoc.5.68

• Monika Gupta Rajive Gupta Medha Anand Department of Chemistry, University of Jammu, Jammu 180 006, India 10.3762/bjoc.5.68 Abstract The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in

• water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions. Keywords: ethyl cyanoacetate; hydroxyapatite supported caesium carbonate; Knoevenagel condensation; malonic acid; malononitrile; Introduction An area of recent intense

• caesium carbonate (HAP–Cs2CO3) and its effective application to the Knoevenagel condensation between different aromatic aldehydes and malononitrile or ethyl cyanoacetate or malonic acid by stirring in water at 80–100 °C. The products were obtained in high yield and purity. Results and Discussion

An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

• Rajeshwar Reddy Sagyam,
• Ravinder Buchikonda,
• Jaya Prakash Pitta,
• Himabindu Vurimidi,
• Pratap Reddy Padi and
• Mahesh Reddy Ghanta

Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66

• condensation reactions, such as the condensation of oxazolo[3,2-b]pyridazinium perchlorates with malononitrile, ethyl cyanoacetate and ethyl malonate in the presence of sodium ethoxide [15]; the condensation of 1,4,7-triketones with hydrazine followed by dehydrogenation [16]; the condensation of cyanoacetic

The tert- amino effect in heterocyclic chemistry: Synthesis of new fused pyrazolinoquinolizine and 1,4-oxazinopyrazoline derivatives

• Dipak Prajapati and
• Kalyan Jyoti Borah

Beilstein J. Org. Chem. 2007, 3, No. 43, doi:10.1186/1860-5397-3-43

• malononitrile and cyanoacetamide followed by cyclisation using anhydrous zinc chloride. Background The N-phenyl-3-substituted 5-pyrazolone derivatives are organic compounds that have been known since 1883; they are very useful as intermediates for pharmaceuticals and are used as anti-inflammatory agents and

2-Arylhydrazononitriles as building blocks in heterocyclic synthesis: A novel route to 2-substituted- 1,2,3-triazoles and 1,2,3-triazolo[4,5-b]pyridines

• Saleh M. Al-Mousawi and
• Moustafa Sh. Moustafa

Beilstein J. Org. Chem. 2007, 3, No. 12, doi:10.1186/1860-5397-3-12

• cyclized into the corresponding oxadiazole 4 on refluxing in acetic anhydride. When refluxed in DMF in presence of piperidine, the corresponding 1,2,3-triazoleamine 5 was formed. The latter was acylated to 6 by addition of acetic anhydride while treatment of 5 with malononitrile gave the 1,2,3-triazolo

• al, [14] and the possibility that the really formed product is the 5-amino-1,2,4-triazole 7. We decided to investigate further the chemical reactivity pattern of the cyclized product (Scheme 1) to support our conclusion. Compound 5 was reacted with malononitrile in refluxing DMF to yield the