A one-pot catalyst-free synthesis of functionalized pyrrolo[1,2-a]quinoxaline derivatives from benzene-1,2-diamine, acetylenedicarboxylates and ethyl bromopyruvate

• Mohammad Piltan,
• Loghman Moradi,
• Golaleh Abasi and
• Seyed Amir Zarei

Beilstein J. Org. Chem. 2013, 9, 510–515, doi:10.3762/bjoc.9.55

• ; pyrrolo[1,2-a]pyrazine; pyrrolo[1,2-a]quinoxaline; Introduction Among the various classes of heterocyclic compounds, quinoxalines, a class of N-containing heterocycles, form an important component of many pharmacologically active compounds [1][2][3][4]. For example, the quinoxaline ring is a constituent

Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

• Yan Sun,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 8–14, doi:10.3762/bjoc.9.2

• ][13][14]. Considering the above reports, and as part of our program aimed at developing new multicomponent reactions for the construction of complex heterocyclic compounds, we wish in this work to report the efficient synthesis of unprecedented cyclopentyl-fused spiro[dihydropyridine-oxindoles] by the

Features of the behavior of 4-amino-5-carboxamido-1,2,3-triazole in multicomponent heterocyclizations with carbonyl compounds

• Eugene S. Gladkov,
• Katerina A. Gura,
• Svetlana M. Sirko,
• Sergey M. Desenko,
• Ulrich Groth and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2012, 8, 2100–2105, doi:10.3762/bjoc.8.236

• ; heterocycle; microwave-assisted synthesis; multicomponent reaction; ultrasound-assisted synthesis; Introduction Multicomponent reactions (MCRs) [1][2][3][4] involving polyfunctional aminazoles as a key reagent are challenging objectives in the modern chemistry of heterocyclic compounds dealing with the

A Wittig-olefination–Claisen-rearrangement approach to the 3-methylquinoline-4-carbaldehyde synthesis

• Mukund G. Kulkarni,
• Mayur P. Desai,
• Deekshaputra R. Birhade,
• Yunus B. Shaikh,
• Ajit N. Dhatrak and
• Ramesh Gannimani

Beilstein J. Org. Chem. 2012, 8, 1725–1729, doi:10.3762/bjoc.8.197

• Quinoline aldehydes are important synthetic intermediates in the synthesis of heterocyclic compounds that are used in the manufacturing of dyes [1] and pharmaceuticals [2][3]. 3-Substituted and 2,3-di-substituted quinoline-4-carbaldehyde derivatives are used in the synthesis of immunosuppressant KF20444 [4

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives

• Zhi-Cong Geng,
• Jian Chen,
• Ning Li,
• Xiao-Fei Huang,
• Yong Zhang,
• Ya-Wen Zhang and
• Xing-Wang Wang

Beilstein J. Org. Chem. 2012, 8, 1710–1720, doi:10.3762/bjoc.8.195

• good results (up to 86% yield, >10/1 regioselectivity, >20:1 dr, 99% ee) in the presence of (S)-diphenylprolinol trimethylsilyl ether catalyst. Keywords: aza-Michael; domino; hydrazine; organocatalysis; pyrazolidine; Introduction Pyrazolidines are privileged and valuable heterocyclic compounds, which

• heterocyclic compounds have been efficiently generated by means of organocatalytic domino reactions [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69]. In 2009 and 2010, List et al. and the Brière group both reported, separately, the enantioselective synthesis of 2

Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines

• Chittaranjan Bhanja,
• Satyaban Jena,
• Sabita Nayak and
• Seetaram Mohapatra

Beilstein J. Org. Chem. 2012, 8, 1668–1694, doi:10.3762/bjoc.8.191

• important classes of structural motifs found in numerous naturally occurring and synthetic compounds. Due to a rich array of functionalities and chiral centers these motifs are widely recognized as useful building blocks for the synthesis of a broad and interesting range of biologically active heterocyclic

• compounds having antiviral, antitumor, antimicrobial, antidiabetic, sex-pheromone, diuretic, anticoagulant, anti-anaphylatic and many more activities [1][2][3][4][5][6][7][8][9]. Some representative molecules of these structural motifs are shown in Figure 1 [9][10][11][12][13][14][15][16][17][18][19][20][21

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• the physicochemical properties of imidazo[5,1-c][1,2,4]triazine-3,6-dione derivatives we determined water-solubility, log P, and pKa values for compound 25 as a representative of this new class of heterocyclic compounds. Water solubility at physiological pH of 7.4 was found to be 47 µg/mL, which is a

N-Heterocyclic carbene-catalyzed direct cross-aza-benzoin reaction: Efficient synthesis of α-amino-β-keto esters

• Takuya Uno,
• Yusuke Kobayashi and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2012, 8, 1499–1504, doi:10.3762/bjoc.8.169

• synthesis of a variety of heterocyclic compounds [2] and pharmaceutically active products [3][4][5]. In addition, they are valuable intermediates for chiral α-amino acids [6][7], including β-hydroxy-α-amino acids [8][9][10][11][12][13][14]. Consequently, significant efforts have been devoted to synthesizing

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

Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

• Workalemahu M. Berhanu,
• Mohamed A. Ibrahim,
• Girinath G. Pillai,
• Alexander A. Oliferenko,
• Levan Khelashvili,
• Farukh Jabeen,
• Bushra Mirza,
• Farzana Latif Ansari,
• Ihsan ul-Haq,
• Said A. El-Feky and
• Alan R. Katritzky

Beilstein J. Org. Chem. 2012, 8, 1146–1160, doi:10.3762/bjoc.8.128

• Workalemahu M. Berhanu Mohamed A. Ibrahim Girinath G. Pillai Alexander A. Oliferenko Levan Khelashvili Farukh Jabeen Bushra Mirza Farzana Latif Ansari Ihsan ul-Haq Said A. El-Feky Alan R. Katritzky Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• novel and practical methods for the preparation of diverse heterocyclic compounds, herein, we report our extended investigation on the efficient synthesis of spirooxindole [1,3]oxazino derivatives by means of alkylative pyridine dearomatization [18][19][20][21]. Results and Discussion Reactions of N

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• -deficient heteroaromatic azadienes are well-established for the synthesis of heterocyclic compounds, and have been previously applied to the synthesis of α-carbolines. Intramolecular IEDDA chemistry to prepare α-carbolines employing 2-N-(o-alkynylanilino)pyrimidine systems have been successful in a limited

Identification and isolation of insecticidal oxazoles from Pseudomonas spp.

• Florian Grundmann,
• Veronika Dill,
• Andrea Dowling,
• Aunchalee Thanwisai,
• Edna Bode,
• Narisara Chantratita,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 749–752, doi:10.3762/bjoc.8.85

• above, but again no incorporation could be observed. Thus, the biosynthesis via tryptamine amides, which are subsequently oxidized and cyclized to give the oxazoles, can be excluded and more experiments are needed to fully elucidate the biosynthesis of these simple heterocyclic compounds. All

A general and facile one-pot process of isothiocyanates from amines under aqueous conditions

• Nan Sun,
• Bin Li,
• Jianping Shao,
• Weimin Mo,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2012, 8, 61–70, doi:10.3762/bjoc.8.6

• for potential medical applications [3][4][5][6]. Morevoer, isothiocyanates are pivotal intermediates in organic synthesis, especially in the synthesis of various heterocyclic compounds [7][8] and unsymmetric thioureas [9][10][11][12]. Although many synthetic methods for the preparation of

Regioselectivity in the multicomponent reaction of 5-aminopyrazoles, cyclic 1,3-diketones and dimethylformamide dimethylacetal under controlled microwave heating

• Kamal Usef Sadek,
• Ramadan Ahmed Mekheimer,
• Tahany Mahmoud Mohamed,
• Moustafa Sherief Moustafa and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2012, 8, 18–24, doi:10.3762/bjoc.8.3

• naturally occurring and synthetic compounds containing quinazoline derivatives are of considerable interest in fields related to the organic and medicinal chemistry of natural products [1][2]. The quinazoline ring system represents the core skeleton of an important class of heterocyclic compounds possessing

Continuous-flow hydration–condensation reaction: Synthesis of α,β-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst

• Magnus Rueping,
• Teerawut Bootwicha,
• Hannah Baars and
• Erli Sugiono

Beilstein J. Org. Chem. 2011, 7, 1680–1687, doi:10.3762/bjoc.7.198

• and other heterocyclic compounds [61][62][63][64][65]. Consequently, the development of an efficient synthesis to obtain these valuable compounds attracted our interest. Thus, we decided to develop an efficient continuous-flow synthesis of α,β-unsaturated ketones starting from alkynes and aldehydes by

Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis

• Kristina Butković,
• Željko Marinić,
• Krešimir Molčanov,
• Biserka Kojić-Prodić and
• Marija Šindler-Kulyk

Beilstein J. Org. Chem. 2011, 7, 1663–1670, doi:10.3762/bjoc.7.196

• % yield). Keywords: [3 + 2] cycloaddition; isoindoles; nitrile imines; pyrazoles; sydnones; Introduction Sydnones belong to the group of five-membered heterocyclic compounds referred to as being "mesoionic" and have been widely studied since their discovery [1][2][3][4][5]. They can be represented as

Efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles from 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes

• Yiwen Yang,
• Chunxiang Kuang,
• Hui Jin,
• Qing Yang and
• Zhongkui Zhang

Beilstein J. Org. Chem. 2011, 7, 1656–1662, doi:10.3762/bjoc.7.195

• and its derivatives are an important class of heterocyclic compounds. As medicines, many of them display anti-inflammatory [3], antimicrobial [3], antiplatelet [4], antiallergenic [5], antifungal [6], MAP Kinase inhibitor [7], and anticancer activities [8]. As pesticides, they are used as insecticides

A novel and facile synthesis of 3-(2-benzofuroyl)- and 3,6-bis(2-benzofuroyl)carbazole derivatives

• Wentao Gao,
• Meiru Zheng and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 1533–1540, doi:10.3762/bjoc.7.180

• substituted with a carbazole unit. Hence the synthesis of such compounds is desirable [29][30]. On the other hand, the benzofuran derivatives are an important class of heterocyclic compounds that are known to possess important biological properties [31][32][33]. Especially, recent studies have shown that some

• benzofuroyl-based compounds [39][40][41][42][43]. We have recently reported the synthesis of quinolyl-substituted carbazoles [44] and benzofuranyl-substituted quinoline [45]. Thus, in light of the above findings and in the context of our ongoing work on the synthesis of new heterocyclic compounds, we found it

Directed aromatic functionalization in natural-product synthesis: Fredericamycin A, nothapodytine B, and topopyrones B and D

• Charles Dylan Turner and
• Marco A. Ciufolini

Beilstein J. Org. Chem. 2011, 7, 1475–1485, doi:10.3762/bjoc.7.171

• activity: Fredericamycin A, nothapodytine B, and topopyrones B and D. In each case, directed aromatic functionalization methodology greatly facilitated the assembly of the key molecular subunits. Keywords: alkaloids; directed aromatic functionalization; fredericamycin; heterocyclic compounds; lithiation

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

• Elena Borsini,
• Gianluigi Broggini,
• Andrea Fasana,
• Chiara Baldassarri,
• Angelo M. Manzo and
• Alcide D. Perboni

Beilstein J. Org. Chem. 2011, 7, 1468–1474, doi:10.3762/bjoc.7.170

• -azepines. Keywords: C–C coupling; gold catalysis; homogeneous catalysis; nitrogen heterocycles; rearrangement; Introduction Intramolecular transition-metal-catalyzed reactions represent one of the most challenging routes for the preparation of heterocyclic compounds [1][2][3][4][5]. Methodologies

PEG-embedded KBr₃: A recyclable catalyst for multicomponent coupling reaction for the efficient synthesis of functionalized piperidines

• Sanny Verma,
• Suman L. Jain and
• Bir Sain

Beilstein J. Org. Chem. 2011, 7, 1334–1341, doi:10.3762/bjoc.7.157

• tetrabutylammonium tribromide (TBATB) [30], bromodimethylsulfonium bromide (BDMS) [31], InCl3 [32] and L-proline/TFA [33] were reported for the one-pot syntheses of these heterocyclic compounds. However, tedious synthetic procedures, the need for high catalyst loadings, and the expense and non-recyclability of the

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents

• Paul Knochel,
• Matthias A. Schade,
• Sebastian Bernhardt,
• Georg Manolikakes,
• Albrecht Metzger,
• Fabian M. Piller,
• Christoph J. Rohbogner and
• Marc Mosrin

Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147

• cross-coupling product 40 in 79% yield (Scheme 7) [22]. 1.3 Preparation of heteroaryl zinc reagents by direct zincation of heterocyclic compounds using the new zinc base TMP2Zn·2MgCl2·2LiCl (42) The preparation of zinc reagents by a directed deprotonation was of limited use as no soluble zinc base was

Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation

• David R. Armstrong,
• Liam Balloch,
• Eva Hevia,
• Alan R. Kennedy,
• Robert E. Mulvey,
• Charles T. O'Hara and
• Stuart D. Robertson

Beilstein J. Org. Chem. 2011, 7, 1234–1248, doi:10.3762/bjoc.7.144

• direct zincation of functionalised arenes and heteroarenes [9][10]. However, common limitations have been noted for the use of this reagent with some electron poor and heterocyclic compounds which suffer from the drawback of limited regioselectivity, whilst several activated aromatic compounds bearing

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• synthesis of such a class of heterocyclic compounds has been the subject of several investigations. Among them, a multi-step synthetic pathway with final TBAF-promoted cyclization was proposed by Lepore [38] and, almost simultaneously, Poli and Prestat described a Pd-catalyzed Tsuji–Trost-type allylic