Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• reactions butylene oxide was used as a base precursor, phenylsilane was the reducing reagent, and the reactions were performed using microwave irradiation (MWI). Subsequently, Werner et al. reported the scope and limitations of such microwave-assisted catalytic Wittig reactions using tributylphosphine

Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells

• John A. Love,
• Shu-Hua Chou,
• Ye Huang,
• Guilllermo C. Bazan and
• Thuc-Quyen Nguyen

Beilstein J. Org. Chem. 2016, 12, 2543–2555, doi:10.3762/bjoc.12.249

• 3 was obtained through lithium–halogen exchange with n-BuLi followed by addition of trimethyltin chloride. Segments 2 and 3 were cross-coupled using a microwave-assisted Stille reaction to afford the target p-SIDT(FBTThCA8)2. The thermal transitions of p-SIDT(FBTThCA8)2 were evaluated by

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• ; copper; cyclic voltammetry; DFT; microwave-assisted synthesis; multicomponent reactions; palladium; phenothiazines; thiophenes; Introduction Oligothiophenes [1][2][3][4][5][6][7][8] have adopted a dominating role among functional π-electron systems [9]. In particular, they have received attention as

Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes

• Jimena E. Díaz,
• María C. Mollo and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2016, 12, 2026–2031, doi:10.3762/bjoc.12.190

• -2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA) esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a chloroformic solution of ethyl polyphosphate (PPE). The use of

• ][26][27][28], indoles and 3,4-dihydroisoquinolines [23][29]. Microwave-assisted organic reactions proceed in general faster, with higher yields and more efficiently than those performed under conventional heating [30][31][32][33][34][35][36][37][38]. This technology has found interesting applications

• of conventional heating [17]. In previous work, we reported the microwave-assisted synthesis of 5 to 8 membered cyclic amidines by cyclodehydration of N-aryl-N´-acyl-1,n-alkanediamines (n = 2–5) promoted by polyphosphoric acid (PPA) esters PPE and PPSE (Scheme 1, reaction 1) [41][42][43]. In this

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• at 110 °C for 10 min in aqueous medium. In both cases, the desired α,β-unsaturated ketone 2 were isolated in similar yields (see Table 1). It is worth mentioning here that the microwave-assisted reaction was performed in aqueous medium, an environmentally benign solvent. The other advantage of this

• ion. Conclusion Novel 4′-azulenyl-substituted terpyridines were efficiently synthesized following the Kröhnke methodology. The azulenylchalcone intermediates were conveniently synthesized using grind or microwave-assisted aldol condensation procedures. The target terpyridine compounds exhibit

• experiments. Microwave-assisted reactions were performed with a BIOTAGE Initiator reactor. X-ray diffraction measurements were performed on a STOE IPDS II diffractometer, operating with Mo Kα (λ = 0.71073 Å) X-ray tube with graphite monochromator. The structures were solved by direct methods and refined by

Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

• Kkonnip Son and
• Seong Jun Park

Beilstein J. Org. Chem. 2016, 12, 1780–1787, doi:10.3762/bjoc.12.168

• times (generally overnight) to obtain the desired products [1][2][3][4][5][6][7][8][9][10][11][12]. For example, these cyclization methods involve procedures such as microwave-assisted heating with NaOMe [1] and H2N-Ar [6] at 150–160 °C, refluxing with HC(OEt)3 [3] and xylene [4][5][8], stirring at 100

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• Chemistry, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany 10.3762/bjoc.12.146 Abstract A practical method was elaborated for the synthesis of (aminomethylene)bisphosphine oxides comprising the catalyst- and solvent-free microwave-assisted three-component condensation of primary amines

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• -EDOT (Scheme 1). We very recently reported the synthesis of the same polymer structures by the microwave-assisted direct arylation polycondensation, but it should be noted that the soluble 2,7-Cbz-EDOT could not be obtained due to undesired side reactions [37]. In contrast, the conventional Stille

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• isoindolin-1-one-3-phosphonates. A microwave-assisted Kabachnik–Fields reaction toward isoindolin-1-ones. The synthesis of 3-arylmethyleneisoindolin-1-ones through a Horner–Wadsworth–Emmons reaction of Kabachnik–Fields reaction products. An efficient one-pot method for the synthesis of ethyl (2-alkyl- and 2

A cross-metathesis approach to novel pantothenamide derivatives

• Jinming Guan,
• Matthew Hachey,
• Lekha Puri,
• Vanessa Howieson,
• Kevin J. Saliba and
• Karine Auclair

Beilstein J. Org. Chem. 2016, 12, 963–968, doi:10.3762/bjoc.12.95

• propylacrylamide (10c) and pentylacrylamide (10d). The trans-isomer was the only one detected by 1H NMR of the crude reaction mixture in all cases. In the hope of further improving the yield of the reaction, a microwave reactor was employed. Indeed, a number of literature reports have demonstrated that microwave

• -assisted cross-metathesis reactions were complete in a fraction of the time required for the thermal process and provided a cleaner reaction [24][25][26][27]. In the cases of 2-vinylpyridine (10b) and pentylacrylamide (10d), not only did the reaction mixture appear cleaner by TLC, but a dramatic increase

Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

• Camilla Matassini,
• Stefania Mirabella,
• Andrea Goti,
• Inmaculada Robina,
• Antonio J. Moreno-Vargas and
• Francesca Cardona

Beilstein J. Org. Chem. 2015, 11, 2631–2640, doi:10.3762/bjoc.11.282

• assignments 2D spectra were measured (COSY, HSQC, NOESY, and NOE as necessary). Small scale microwave-assisted syntheses were carried out in a microwave apparatus for synthesis (CEM Discover) with an open reaction vessel and external surface sensor. IR spectra were recorded with a BX FTIR Perkin-Elmer system

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• size, N-substituents, and counterions [67]. In 2010, we have further optimized the microwave-assisted synthesis of SIMes·HCl to turn it into a convenient, laboratory-scale preparation [68]. With the latest implementation of our protocol, which uses an 80 mL glass vessel in a monomodal microwave reactor

• -step synthesis of SIDip·HCl (also known as SIPr·HCl) initially reported by Arduengo et al. closely matched the one defined for SIMes·HCl in terms of experimental conditions and yields [43]. Likewise, our microwave-assisted cyclization performed equally well when applied to N,N'-bis(2,6

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• and alkyne derivatives to further interconnect by microwave-assisted click reaction. Azidocorroles/porphyrins Azidocorrole 1 [9] was obtained by the condensation of the corresponding meso-mesityl-substituted dipyrromethane with 4-azidobenzaldehyde in the presence of a catalytic amount of

Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles

• Kandasamy Rajaguru,
• Arumugam Mariappan,
• Rajendran Suresh,
• Periasamy Manivannan and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2015, 11, 2021–2028, doi:10.3762/bjoc.11.219

• construction of other heterocyclic systems. Experimental General A CEM Discover microwave synthesizer (Model No: 908010) operating at 180/264 V and 50/60 Hz with microwave power maximum level of 300 W and microwave frequency of 2455 MHz was employed for the microwave-assisted experiments. Nuclear Magnetic

Aerobic addition of secondary phosphine oxides to vinyl sulfides: a shortcut to 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides

• Svetlana F. Malysheva,
• Alexander V. Artem’ev,
• Nina K. Gusarova,
• Nataliya A. Belogorlova,
• Alexander I. Albanov,
• C. W. Liu and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 1985–1990, doi:10.3762/bjoc.11.214

• ][20] as well as transition metal catalysts [21][22][23]. Also, examples of the microwave-assisted [24][25] and photoinduced [26] addition are described. Recently, on example of secondary phosphines [27] as well as secondary phosphine sulfides [28] and selenides [29], it has been disclosed that the

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• ] have demonstrated an intramolecular Diels–Alder (IMDA) reaction followed by a RCM–ROM–CM cascade was found to be useful to assemble a linear triquinane framework. Microwave assisted IMDA reaction of cyclopentadiene derivative 210 performed in chlorobenzene at 201 °C under 310 psi pressure gave the

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• ) Microwave assisted synthesis: NH4BF4, (EtO)3CH, 160 °C [47]. Proposed ring-closure mechanism for 1-Cl, 2-Cl, 3-Cl and 4-Cl. Comparison of various preparations of the benzannulated NHCs: 1-Cl, 2-Cl, 3-Cl and 4-Cl, and of 1-BF4, 3-BF4 and 4-BF4. Supporting Information Supporting Information File 275: CIF

Synthesis of icariin from kaempferol through regioselective methylation and para-Claisen–Cope rearrangement

• Qinggang Mei,
• Chun Wang,
• Zhigang Zhao,
• Weicheng Yuan and
• Guolin Zhang

Beilstein J. Org. Chem. 2015, 11, 1220–1225, doi:10.3762/bjoc.11.135

• [15]. The 11-step synthesis of icaritin, starting from 2,4,6-trihydroxyacetophenone via microwave-assisted Claisen rearrangement reaction as the key step, was succeeded with an overall yield of 23% [16]. In view of the long synthetic routes, tedious work-up and harsh reaction conditions, an

Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties

• Rupert G. D. Taylor,
• Joseph Cameron,
• Iain A. Wright,
• Neil Thomson,
• Olena Avramchenko,
• Alexander L. Kanibolotsky,
• Anto R. Inigo,
• Tell Tuttle and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1148–1154, doi:10.3762/bjoc.11.129

• ]dithiolylidene) [15] as a core and appending heterocyclic arms through microwave assisted Stille couplings. It is worth noting that the tetrabromo-dithienoTTF core is still prepared via a triethyl phosphite-mediated homocoupling, but in this divergent route valuable heterocyclic groups can be introduced at the

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• alkyne by oxidative amidation using carbon tetrachloride with propargylamine. The microwave-assisted click-conjugation was performed on a solid phase upon completion of the DNA synthesis (Scheme 4). Lönnberg and co-workers prepared a thymidine modified at the 4’-position with an azidomethyl group to

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• ; diazonium salts; Matsuda–Heck reaction; microwave-assisted synthesis; stilbenes; Introduction Diazonium salts are known as one of the most valuable building blocks in organic synthesis [1]. Today, their most common use is the construction of carbon–carbon bonds in palladium-catalyzed reactions. Starting

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• phenanthridines in excellent yields (>92%). The radical inhibitor 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) was applied to stop the transformation by a single electron transfer process. Intriguing combination of irradiation techniques (combined microwave-assisted and photochemical) offered a new route toward

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

• 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

• protocol was then adopted to synthetize a series of 1H-imidazo[1,2-b]pyrazoles from selected aldehydes 2a–j and isocyanide building blocks 3a–d (Table 2). Following the microwave-assisted rapid formation of 1a, the one-pot GBB reactions were completed during 10–60 min in yields of 23–83%. Unfortunately

• necessary for the microwave assisted preformation of pyrazole intermediates 1b–d) afforded highly functionalized 1H-imidazo[1,2-b]pyrazole analogues 46–51 in yields of 54–79% (Table 3). Conclusion We have described here the development of a de novo and facile one-pot, two-step GBB method. The established

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach

• Barbara Palka,
• Angela Di Capua,
• Maurizio Anzini,
• Gyté Vilkauskaité,
• Algirdas Šačkus and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2014, 10, 1759–1764, doi:10.3762/bjoc.10.183

• is presented. Hence, microwave-assisted treatment of 5-chloro-1-phenyl-3-trifluoromethylpyrazole-4-carbaldehyde with various terminal alkynes in the presence of tert-butylamine under Sonogashira-type cross-coupling conditions affords the former title compounds in a one-pot multicomponent procedure

• all obtained products. Keywords: microwave-assisted reactions; multicomponent reactions; NMR (1H; 13C; 15N; 19F); Sonogashira coupling; trifluoromethylpyrazoles; Introduction Fluorine-containing compounds play an important role in medicinal and pharmaceutical chemistry as well as in agrochemistry [1