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Journal articles on the topic 'Heterocycl'

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Published: 10 March 2023

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1

Andres, C. J., Derek J. Denhart, Milind S. Deshpande, and Kevin W. Gillman. "Recent Advances in the Solid Phase Synthesis of Drug Heterocyclic Small Molecules." Combinatorial Chemistry & High Throughput Screening 2, no. 4 (August 1999): 191–210. http://dx.doi.org/10.2174/1386207302666220204193145.

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Abstract: Because of their synthetic challenge, broad range of physical I chemical properties, and diverse biological activities, heterocycles continue to be of interest to both the academic and industrial chemist. This review covers recent advances in the solid phase synthesis of drug-like heterocyclic small molecules. Syntheses which form the heterocycle on the solid phase are emphasized; syntheses in which a preformed heterocycle is functionalized on the solid support have been omitted. The majority of references are from publication year 1999. This review should be of interest to anyone involved in, or contemplating the solid phase synthesis of small molecule drug-like heterocycles, especially for combinatorial chemistry applications.

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2

Winne, Johan, Jan Hullaert, Bram Denoo, Mien Christiaens, and Brenda Callebaut. "Heterocycles as Moderators of Allyl Cation Cycloaddition Reactivity." Synlett 28, no. 18 (July 27, 2017): 2345–52. http://dx.doi.org/10.1055/s-0036-1588511.

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For the rapid elaboration of polycarbocyclic scaffolds, prevalent in many important families of terpenoid natural products, allyl cations derived from simple heterocyclic alcohols can be used as versatile reaction partners in both (4+3) and (3+2) cycloaddition pathways. Our recent progress in this area is outlined, pointing towards the untapped potential of heterocycles to act as reagents in novel or known but challenging organic transformations.1 Heterocyclic Reagents2 Cycloadditions and Allyl Cations3 Furfuryl Cations in Cycloadditions4 Heterocycle-Substituted Cations in Cycloadditions5 Mechanistic Considerations6 Conclusions and Outlook

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3

Ma, Huai-Rang, Xiao-Hong Wang, and Min-Zhi Deng. "Palladium Catalyzed Cross-Coupling Reaction of Stereodefined Cyclopropylboronic Acids with N-Heterocycl Bromides." Synthetic Communications 29, no. 14 (July 1999): 2477–85. http://dx.doi.org/10.1080/00397919908086254.

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4

Gzella, Andrzej K., Marcin Kowiel, Aneta Suseł, Magdalena N. Wojtyra, and Roman Lesyk. "Heterocyclic tautomerism: reassignment of two crystal structures of 2-amino-1,3-thiazolidin-4-one derivatives." Acta Crystallographica Section C Structural Chemistry 70, no. 8 (July 31, 2014): 812–16. http://dx.doi.org/10.1107/s2053229614015162.

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The structures of 5-(2-hydroxyethyl)-2-[(pyridin-2-yl)amino]-1,3-thiazolidin-4-one, C10H11N3O2S, (I), and ethyl 4-[(4-oxo-1,3-thiazolidin-2-yl)amino]benzoate, C12H12N2O3S, (II), which are identical to the entries with refcodes GACXOZ [Váňaet al.(2009).J. Heterocycl. Chem.46, 635–639] and HEGLUC [Behbehani & Ibrahim (2012).Molecules,17, 6362–6385], respectively, in the Cambridge Structural Database [Allen (2002).Acta Cryst.B58, 380–388], have been redetermined at 130 K. This structural study shows that both investigated compounds exist in their crystal structures as the tautomer with the carbonyl–imine group in the five-membered heterocyclic ring and an exocyclic amine N atom, rather than the previously reported tautomer with a secondary amide group and an exocyclic imine N atom. The physicochemical and spectroscopic data of the two investigated compounds are the same as those of GACXOZ and HEGLUC, respectively. In the thiazolidin-4-one system of (I), the S and chiral C atoms, along with the hydroxyethyl group, are disordered. The thiazolidin-4-one fragment takes up two alternative locations in the crystal structure, which allows the molecule to adoptRandSconfigurations. The occupancy factors of the disordered atoms are 0.883 (2) (for theRconfiguration) and 0.117 (2) (for theSconfiguration). In (I), the main factor that determines the crystal packing is a system of hydrogen bonds, involving both strong N—H...N and O—H...O and weak C—H...O hydrogen bonds, linking the molecules into a three-dimensional hydrogen-bond network. On the other hand, in (II), the molecules are linkedviaN—H...O hydrogen bonds into chains.

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5

Cui, Hai-Lei. "Recent Advances in DMSO-Based Direct Synthesis of Heterocycles." Molecules 27, no. 23 (December 2, 2022): 8480. http://dx.doi.org/10.3390/molecules27238480.

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Besides serving as a low-toxicity, inexpensive and easily accessible solvent, dimethyl sulfoxide (DMSO) has also been extensively used as a versatile reagent for the synthesis of functionalized molecules. Dimethyl sulfoxide can not only be utilized as a carbon source, a sulfur source and an oxygen source, but also be employed as a crucial oxidant enabling various transformations. The past decade has witnessed a large number of impressive achievements on the direct synthesis of heterocycles as well as modifications of heterocyclic compounds by applying DMSO as a reagent. This review summarized the DMSO-based direct heterocycle constructions from 2012 to 2022.

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6

Slivka, Mikhailo, and Mikhailo Onysko. "The Use of Electrophilic Cyclization for the Preparation of Condensed Heterocycles." Synthesis 53, no. 19 (May 19, 2021): 3497–512. http://dx.doi.org/10.1055/s-0040-1706036.

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AbstractCondensed heterocycles are well-known for their excellent biological effects and they are undeniably important compounds in organic chemistry. Electrophilic cyclization reactions are widely used for the synthesis of mono-heterocyclic compounds. This review highlights the utility of electrophilic cyclization reactions as an effective generic tool for the synthesis of various condensed heterocycles containing functional groups that are able to undergo further chemical transformations, such as nucleophilic substitution, elimination, re-cyclization, cleavage, etc. This review describes the reactions of unsaturated derivatives of different heterocycles with various electrophilic agents (halogens, arylsulfanyl chlorides, mineral acids) resulting in annulation of an additional partially saturated heterocycle. The electrophilic reaction conditions, plausible mechanisms and the use of such transformations in organic synthesis are also discussed. The review mainly focuses on research published since 2002 in order to establish the current state of the art in this area. 1 Introduction2 Electrophilic Cyclization Pathways Involving a Nitrogen Nucleophilic Center3 Electrophilic Cyclization Pathways Involving a Chalcogen Nucleophilic Center3.1 Sulfur Centers3.2 Oxygen Centers3.3 Selenium Centers4 Strategies and Mechanisms5 Conclusion

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7

Sparr, Christof, and Christian Fischer. "Configurationally Stable Atropisomeric Acridinium Fluorophores." Synlett 29, no. 16 (August 3, 2018): 2176–80. http://dx.doi.org/10.1055/s-0037-1610233.

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Arylated heterocyclic fluorophores are particularly useful scaffolds for numerous applications, such as bioimaging or synthetic photochemistry. While variation of the substitution pattern at the heterocycle and aryl groups allows dye modulation, the bond rotational barriers are also strongly affected. Unsymmetrically substituted ring systems of rotationally restricted arylated heterocycles therefore lead to configurationally stable atropisomeric fluorophores. Herein, we describe these characteristics by determining the properties and configurational stability of atropisomeric, tri-ortho-substituted naphthyl-acridinium fluorophores. A significant barrier to rotation of >120 kJ mol–1 was measured, which renders these dyes and related compounds distinct atropisomers with stereoisomer-specific properties over a broad temperature range.

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8

Luna, Isadora Silva, Rayssa Marques Duarte da Cruz, Ryldene Marques Duarte da Cruz, Rodrigo Santos Aquino de Araújo, and Francisco Jaime Bezerra Mendonça-Junior. "1,4-Dithiane-2,5-diol: A Versatile Synthon for the Synthesis of Sulfur-containing Heterocycles." Current Organic Synthesis 15, no. 8 (December 17, 2018): 1026–42. http://dx.doi.org/10.2174/1570179415666180821154551.

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Background: 1,4-Dithiane-2,5-diol (1,4-DTD) is the stable dimer of α-mercapto acetaldehyde. This commercially available ambidentade compound is characterized as having in its chemical structure one group that acts as an electrophile and another that acts as a nucleophile, this permits its use as versatile and efficient synthon in synthetic heterocycle procedures. Objective: The aim of this review is to present synthetic applications of 1,4-DTD in heterocyclic chemistry and their applicability to the synthesis of bioactive compounds. Conclusion: Gewald reactions to obtain C-4 and C-5 unsubstituted 2-amino-thiophene derivatives; sulfa- Michael/Henry and sulfa-Michael/aldol sequences to obtain polysubstituted tetrahydrothiophenes, and other heterocyclic reactions that allow synthesizing several functionalized sulfur-containing heterocycles such as thiazolidines, oxathiazinoles and thiazoles are presented and discussed. The use of such heterocyclics in subsequent reactions allows obtaining various bioactive compounds including the antiretroviral lamivudine which is one of the examples presented in this review.

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9

Munzeiwa, Wisdom A., Bernard Omondi, and Vincent O. Nyamori. "Architecture and synthesis of P,N-heterocyclic phosphine ligands." Beilstein Journal of Organic Chemistry 16 (March 12, 2020): 362–83. http://dx.doi.org/10.3762/bjoc.16.35.

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Diverse P,N-phosphine ligands reported to date have performed exceptionally well as auxiliary ligands in organometallic catalysis. Phosphines bearing 2-pyridyl moieties prominently feature in literature as compared to phosphines with five-membered N-heterocycles. This discussion seeks to paint a broad picture and consolidate different synthetic protocols and techniques for N-heterocyclic phosphine motifs. The introduction provides an account of P,N-phosphine ligands, and their structural and coordination benefits from combining heteroatoms with different basicity in one ligand. The body discusses the synthetic protocols which focus on P–C, P–N-bond formation, substrate and nucleophile types and different N-heterocycle construction strategies. Selected references are given in relation to the applications of the ligands.

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10

Geisenberger, Josef, Jürgen Erbe, Jürgen Heidrich, Ulrich Nagela, and Wolfgang Beck. "Pseudohalogenometallverbindungen, LXV [1] Synthese von Tetrazolen und Triazolen über die 1,3-dipolare Cycloaddition an die Azid-Liganden von polymeren Cobalt(III)-und Palladium(II)-Komplexen. Darstellung und Struktur von 5-TrichlormethyItetrazol / Pseudohalogeno Metal Compounds, LXV [1] Synthesis of Tetrazoles and Triazoles via 1,3-Dipolar Cycloaddition to the Azido Ligands of Polymerie Cobalt(III) and Palladium(II) Complexes. Synthesis and Structure of 5-Trichloromethyltetrazole." Zeitschrift für Naturforschung B 42, no. 1 (January 1, 1987): 55–64. http://dx.doi.org/10.1515/znb-1987-0112.

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Abstract The cycloaddition of nitriles and of dimethylacetylenedicarboxylate to the azide ligand of polymeric Schiff Base cobalt(III) and phosphine palladium(II) complexes gives the corresponding tetrazolate and triazolate complexes from which the heterocycles could be cleaved by hydrogen chloride. Usually the yields are low; if the heterocycle is soluble in ether or sublimable, yields up to 30% have been obtained. Using this method the hitherto unknown 5-trichlormethyltetrazole could be prepared which was characterized by an X-ray structural analysis. Similarly, the cyclo-addition of azido(tetraphenylporphinato)cobalt(III) with nitriles, cyclohexylisocyanide and MeO2CC≡CCO2 Me affords the corresponding complexes with heterocyclic ligands. The prepa-ration of tetraphenylporphyrinato(tricyanmethanido)cobalt(III), (TPP)CoN=CC(CN)2 , is reported.

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11

Giles, Ian D., Alan J. DeHope, Nathaniel B. Zuckerman, Damon A. Parrish, and Philip F. Pagoria. "Effect of counter-ion on packing and crystal density of 5,5′-(3,3′-bi[1,2,4-oxadiazole]-5,5′-diyl)bis(1H-tetrazol-1-olate) with five different cations." Acta Crystallographica Section E Crystallographic Communications 74, no. 4 (March 9, 2018): 505–13. http://dx.doi.org/10.1107/s205698901800364x.

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In energetic materials, the crystal density is an important parameter that affects the performance of the material. When making ionic energetic materials, the choice of counter-ion can have detrimental or beneficial effects on the packing, and therefore the density, of the resulting energetic crystal. Presented herein are a series of five ionic energetic crystals, all containing the dianion 5,5′-(3,3′-bi[1,2,4-oxadiazole]-5,5′-diyl)bis(1H-tetrazol-1-olate), with the following cations: hydrazinium (1) (2N2H5 +·C6N12O4 2−), hydroxylammonium (2) 2NH4O+·C6N12O4 2− [Pagoria et al.. (2017). Chem. Heterocycl. Compd, 53, 760–778; included for comparison], dimethylammonium (3) (2C2H8N+·C6N12O4 2−), 5-amino-1H-tetrazol-4-ium (4) (2CH4N5 +·C6N12O4 2−·4H2O), and aminoguanidinium (5) (2CH7N4 +·C6N12O4 2−). Both the supramolecular interactions and the sterics of the cation play a role in the density of the resulting crystals, which range from 1.544 to 1.873 Mg m−1. In 5, the tetrazolate ring is disordered over two positions [occupancy ratio 0.907 (5):0.093 (5)] due to a 180° rotation in the terminal tetrazole rings.

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12

Palaniappan, Saravana Priya. "Pharmacological Role of Heterocyclic Compounds in the Treatment of Alzheimer’s Disease: A Review." Journal of Phytopharmacology 11, no. 4 (August 15, 2022): 289–94. http://dx.doi.org/10.31254/phyto.2022.11412.

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Alzheimer’s disease (AD) is a multifactorial neurological disease that mainly affects the old age people. Neuropathologically, AD is characterized by low level of acetylcholine, loss of synapses and neurons in certain brain regions, accumulation of extracellular amyloid beta peptide (Aβ) and phosphorylation of intracellular tau protein. Patients with AD are characterized by various symptoms such as memory deficits, depression, cognitive dysfunction and difficult to perform daily activities. Currently available drugs for the treatment of AD are used to treat symptomatic relief at an early stage, however the prolonged usage of the drugs may cause adverse side effects. To overcome this, development of drugs produced from natural products is considered as one of the promising alternatives for the treatment of AD. Among that heterocyclic compound play a major role in the development of therapeutic drugs against various disorders. An organic compound which is cyclic or non-cyclic consists of one or more atoms in their ring structure are known as heterocyclic compounds. These heterocyclic compounds occur both in natural and synthetic form and play a major role in the metabolism of all living cells. Most of the organic compounds used as drugs have a heterocyclic core in their skeleton. Nitrogenous bases such as purines and pyrimidines present in DNA, chlorophyll, vitamins contain heterocycle in their structure. Other compounds containing heterocycles are proline, morphine, furan, vinblastine, cephalosporin, penicillin etc. This review summarizes the nomenclature, classification, and the role of heterocyclic compounds in the treatment of Alzheimer's disease.

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13

Olšovská, Jana, Karel Štěrba, Martin Slabý, and Tomáš Vrzal. "Novel method for determination of heterocyclic compounds and their impact in brewing technology." KVASNY PRUMYSL 67, no. 2 (April 15, 2021): 417–27. http://dx.doi.org/10.18832/kp2021.67.417.

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A new simultaneous method for determination of 16 heterocyclic compounds using SPE sample preparation and GC-MS determination was developed regarding increasing interest of the role of sensory active compounds in beer. LiChrolut® EN SPE columns proved to be optimal for both, a mixture of analytes with a different polarity and such complicated matrix as beer. Recoveries of individual analytes are about 100% except for three compounds (2-methylpyridine about 30%, maltol and furaneol about 50%); repeatability, uncertainty and LOQ are satisfactory for the method application. The method was used for monitoring of heterocyclic compounds formation during roasting, mashing, hop boiling and fermentation. To summarize, during roasting of malt, the concentration of oxygen heterocycle compounds (OHC) increases more rapidly in comparison with nitrogen heterocycles compounds (NHC) till a critical point where OHC starts to decrease and NHC starts to be formed sharper (with the exception of 2-acetylpyrrole which is similar to OHC). Finally, the total concentration of NHC during fermentation rapidly decreases whilst the OHC concentration is influenced by many factors, e.g., fermentation conditions and yeast strain.

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14

Shekarkhand, Marzieh, Karim Zare, Majid Monajjemi, Elham Tazikeh-Lemeski, and Masoumeh Sayadian. "Computational study of heterocyclic anticancer compounds through nbo method." Nexo Revista Científica 35, no. 01 (April 6, 2022): 367–81. http://dx.doi.org/10.5377/nexo.v35i01.13982.

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In the present study NBO method contain the HOMO and the LUMO energies are calculated for 10 different heterocycles anticancer drug using B3LYP/6-31G(d,p). Frontier molecular orbitals (HOMO and LUMO) and Molecular Electrostatic Potential map of the compound was produced by using the π stacking of structures and anticancer activity of molecules. The NBO analysis was suggested that the molecular system contains π- π interaction, strong conjugative interactions and the molecule become more polarized owing to the movement of π-electron cloud from donor to acceptor. NBO, HOMO and LUMO energies, were investigated and Anticancer activity of Aromatic Heterocyclic compounds was investigated by NBO study and result was compared with our previous study about NICS and S-NICS of these 10 anticancer drug. the HOMO/LUMO gap of the heterocycle anticancer drug is significantly different from each other. The NBO method is used in both symmetric and asymmetric molecules and provides accurate information on the aromatics of the compound, especially the heterocyclic rings. It also provides accurate information in protected areas. Molecule 8 has the highest amount of HOMO and therefore aromaticity among the studied compounds which confirms the result of molecular orbital examination.

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15

Chmovzh, Timofey N., Daria A. Alekhina, Timofey A. Kudryashev, and Oleg A. Rakitin. "Efficient Synthesis of 4,8-Dibromo Derivative of Strong Electron-Deficient Benzo[1,2-d:4,5-d’]bis([1,2,3]thiadiazole) and Its SNAr and Cross-Coupling Reactions." Molecules 27, no. 21 (October 30, 2022): 7372. http://dx.doi.org/10.3390/molecules27217372.

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An efficient synthesis of hydrolytically and thermally stable 4,8-dibromobenzo[1,2-d:4,5-d’]bis([1,2,3]thiadiazole) by the bromination of its parent heterocycle is reported. The structure of 4,8-dibromobenzo[1,2-d:4,5-d’]bis([1,2,3]thiadiazole) was confirmed by X-ray analysis. The conditions for the selective aromatic nucleophilic substitution of one bromine atom in this heterocyclic system by nitrogen nucleophiles are found, whereas thiols formed the bis-derivatives only. Suzuki–Miyaura cross-coupling reactions were found to be an effective method for the selective formation of various mono- and di(het)arylated derivatives of strong electron-deficient benzo[1,2-d:4,5-d’]bis([1,2,3]thiadiazole), and Stille coupling can be employed for the preparation of bis-arylated heterocycles, which can be considered as useful building blocks for the synthesis of DSSCs and OLEDs components.

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16

Howell, Tyler O., Aron J. Huckaba, and T. Keith Hollis. "An Efficient Synthesis of Bis-1,3-(3′-aryl-N-heterocycl-1′-yl)arenes as CCC-NHC Pincer Ligand Precursors." Organic Letters 16, no. 9 (April 15, 2014): 2570–72. http://dx.doi.org/10.1021/ol5007407.

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17

Soni, Vatsala, Meenakshi Sharma, Vandana Singh, Vaishali Soni, and Kishore D. "Comprehensive Study of Biological Aspects of Heteroring Annelated Benzothiazoles." International Journal of Science, Engineering and Management 9, no. 6 (June 13, 2022): 1–6. http://dx.doi.org/10.36647/ijsem/09.06.a001.

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Heterocyclic chemicals are chemical structures which include at least a single carbon molecule plus at least one other element, such as sulphur, oxygen, or nitrogen, within the ring structure. Benzothiazoles are discussed in terms of synthesis methodologies, structural changes, chemical reactivity, and possible pharmaceutical effectiveness. This research relied upon secondary data obtained from the sources. The qualitative method was used to provide a section of such an evaluation which looked flawless and accurate. A handy methodology strategy is used in inquiry research. Heterocyclic compounds have been widely exploited in bioorganic and medical research for medication development. Scientists are interested in such compounds because of their various physicochemical and pharmacological properties. Recognizing heterocycles is advantageous in both industrial and biological processes. Benzothiazole, a molecular heterocyclic structure, is being studied as a candidate for such creation of larger, often medicinal chemicals. It is highly durable due to its aromatic components; however, it has reactive services that offer the synthesis method. The benzothiazole ring becomes an important framework for the production of colours used throughout the identification of lanthanide metal cations in aqueous environments. This identical basic N, S heterocycle, benzothiazoles, seems to be abundant; for example, it is required essential thiamine action (vitamin B1). Thiazole compounds could also be discovered in medications such as Nosiheptide. This chemistry group is used for about simply for antibacterial purposes; its distinctive heteroring linked derivatives have attracted the curiosity of scientists due to their various biological or indeed medicinal properties.

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18

Yadav, Shailendra, Sushma Singh, and Chitrasen Gupta. "A CONCISE OVERVIEW ON HETEROCYCLIC COMPOUNDS EXHIBITING PESTICIDAL ACTIVITIES." International Journal of Advanced Research 9, no. 08 (August 31, 2021): 989–1004. http://dx.doi.org/10.21474/ijar01/13352.

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Heterocyclic compounds are numerous and diverse group of organic compounds. Heterocycles are abundantly found in nature and express various physiological properties. Heterocycles are intricately linked to all aspects of life. There are many heterocyclic compounds currently known, and the number is constantly rising owing to extensive synthetic development and their applications. Heterocyclic compounds are used significantly in a number of areas, including biochemistry and medicinal chemistry, and some others. They are predominantly synthesized in agrochemical and pharmaceutical industries due to their potential biological activities. This review article focuses on recently synthesized heterocyclic compounds and their different pesticidal activities such as antifungal, antibacterial, antiviral, nematocidal, insecticidal, acaricidal, and herbicidal.

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Zhu, Yannan, and You Huang. "Organocatalyzed [3+3] Annulations for the Construction of Heterocycles." Synthesis 52, no. 08 (February 5, 2020): 1181–202. http://dx.doi.org/10.1055/s-0039-1690810.

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Six-membered heterocyclic systems are widely distributed in many natural products and pharmaceuticals, and the construction of highly functionalized six-membered heterocyclic compounds is an important topic in modern organic synthesis. Organocatalyzed [3+3] annulations represents an important method for assembling a substantial variety of six-membered cycles that contain one or more heteroatoms. This review describes the development of organocatalyzed [3+3] annulations for the synthesis of six-membered heterocycles, including organocatalysis using secondary amines, tertiary amines, phosphines, chiral phosphoric acids and N-heterocyclic carbenes.1 Introduction2 Secondary Amine Catalyzed [3+3] Annulations2.1 Synthesis of Nitrogen Heterocycles2.2 Synthesis of Oxygen Heterocycles2.3 Synthesis of Sulfur Heterocycles3 Tertiary Amine Catalyzed [3+3] Annulations3.1 Catalysis through Multiple Hydrogen-Bonding Interactions3.2 Catalysis of Tertiary Amines as Lewis Bases4 Phosphine-Catalyzed [3+3] Annulations4.1 Synthesis of Nitrogen Heterocycles4.2 Synthesis of Oxygen Heterocycles4.3 Synthesis of Heterocycles Containing Two or More Heteroatoms5 Chiral Phosphoric Acid Catalyzed [3+3] Annulations5.1 Synthesis of Nitrogen Heterocycles5.2 Synthesis of Heterocycles Containing Two or More Heteroatoms6 N-Heterocyclic Carbene Catalyzed [3+3] Annulations6.1 Synthesis of Nitrogen Heterocycles6.2 Synthesis of Oxygen Heterocycles6.3 Synthesis of Heterocycles Containing Two or More Heteroatoms7 Conclusion and Outlook

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Niedballa, Jonas, and Thomas J. J. Müller. "Heterocycles by Consecutive Multicomponent Syntheses via Catalytically Generated Alkynoyl Intermediates." Catalysts 12, no. 1 (January 13, 2022): 90. http://dx.doi.org/10.3390/catal12010090.

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Multicomponent processes are beneficial tools for the synthesis of heterocycles. As densely substituted bifunctional electrophiles, ynones are essential intermediates by applying cyclocondensations or cycloadditions in numerous heterocycle syntheses. The respective alkynoyl intermediates are generally accessible by palladium-, copper- and palladium/copper-catalyzed alkynylation. In turn, the mild reaction conditions allow for a fast and versatile entry to functional heterocycles in the sense of consecutive multicomponent processes. This review collates and presents recent advances in accessing thirteen heterocycle classes and their applications by virtue of catalytic alkynoyl generation in diversity-oriented multicomponent syntheses in a one-pot fashion.

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Ávila, Edward E., Asiloé J. Mora, Gerzon E. Delgado, Ricardo R. Contreras, Luis Rincón, Andrew N. Fitch, and Michela Brunelli. "Structure and conformational analysis of a bidentate pro-ligand, C21H34N2S2, from powder synchrotron diffraction data and solid-state DFTB calculations." Acta Crystallographica Section B Structural Science 65, no. 5 (September 17, 2009): 639–46. http://dx.doi.org/10.1107/s0108768109027244.

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The molecular and crystalline structure of ethyl 1′,2′,3′,4′,4a′,5′,6′,7′-octahydrodispiro[cyclohexane-1,2′-quinazoline-4′,1′′-cyclohexane]-8′-carbodithioate (I) was solved and refined from powder synchrotron X-ray diffraction data. The initial model for the structural solution in direct space using the simulated annealing algorithm implemented in DASH [David et al. (2006). J. Appl. Cryst. 39, 910–915] was obtained performing a conformational study on the fused six-membered rings of the octahydroquinazoline system and the two spiran cyclohexane rings of (I). The best model was chosen using experimental evidence from 1H and 13C NMR [Contreras et al. (2001). J. Heterocycl. Chem. 38, 1223–1225] in combination with semi-empirical AM1 calculations. In the refined structure the two spiran rings have the chair conformation, while both of the fused rings in the octahydroquinazoline system have half-chair conformations compared with in-vacuum density-functional theory (DFT) B3LYP/6-311G*, DFTB (density-functional tight-binding) theoretical calculations in the solid state and other related structures from X-ray diffraction data. Compound (I) presents weak intramolecular hydrogen bonds of the type N—H...S and C—H...S, which produce delocalization of the electron density in the generated rings described by graph symbols S(6) and S(5). Packing of the molecules is dominated by van der Waals interactions.

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Shaikh, Ansar R., Mazahar Farooqui, R. H. Satpute, and Syed Abed. "Overview on Nitrogen containing compounds and their assessment based on ‘International Regulatory Standards’." Journal of Drug Delivery and Therapeutics 8, no. 6-s (December 21, 2018): 424–28. http://dx.doi.org/10.22270/jddt.v8i6-s.2156.

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Heterocyclic compounds have a role in most fields of sciences such as medicinal chemistry, biochemistry also another area of sciences. More than 90% of new drugscontain heterocycles and the interface between chemistry and biology, at which so much new scientific insight, discovery and application is taking place is crossed by heterocyclic compounds. Compounds derived from heterocyclic rings in pharmacy, medicine, agriculture, plastic, polymer and other fields.Most active heterocycles that have shown considerable biological actions as antifungal, anti-inflammatory, antibacterial, anticonvulsant, antiallergic, herbicidal, anticancer activity. There is always a strong need for new and efficient processes in synthesizing of new Heterocycles.Alum have been used as a novel catalyst in the synthesis of Schiff’s bases. Synthesized Schiff’s bases are free from use of ICH class 1 and Class 2 solvents and also free from structural alerts genotoxic impurities. This review highlights on various aspects of heterocyclic compounds with its biological activity & regulatory assessment based on the ‘International Regulatory Standards’. Keywords: Heterocycles. Nitrogen containing compounds Biological activity, History, Regulatory assessment, International Regulatory Standards

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23

Xia, Xiao-Feng, and Yan-Ning Niu. "Recent developments in the synthesis of nitrogen-containing heterocycles from β-aminovinyl esters/ketones as CC–N donors." Organic & Biomolecular Chemistry 20, no. 2 (2022): 282–95. http://dx.doi.org/10.1039/d1ob01998h.

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Lechel, Tilman, and Hans-Ulrich Reissig. "Synthesis of heterocycles via alkoxyallenes." Pure and Applied Chemistry 82, no. 9 (May 31, 2010): 1835–44. http://dx.doi.org/10.1351/pac-con-09-09-06.

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Lithiated alkoxyallenes are very versatile components for the synthesis of heterocycles such as furans, pyrroles, and 1,2-oxazines, easily allowing the preparation of natural products via these heterocyclic intermediates. A surprising three-component synthesis of N-acylated enaminones allowed the synthesis of highly functionalized 4-hydroxypyridines, 5-acetyloxazoles, and pyrimidines. All these heterocyclic products are ready for further functionalizations, in particular for palladium-catalyzed reactions, leading to libraries of new interesting heterocycles.

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Adak, Laksmikanta, and Tubai Ghosh. "Recent Progress in Iron-Catalyzed Reactions Towards the Synthesis of Bioactive Five- and Six-Membered Heterocycles." Current Organic Chemistry 24, no. 22 (December 18, 2020): 2634–64. http://dx.doi.org/10.2174/1385272824999200714102103.

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Heterocyclic compounds are the largely diverse organic molecules and find prevalent applications in the fine chemical industry, medicinal chemistry and agricultural science. They are also among the most commonly bearing frameworks in numerous drugs and pharmaceutical substances. Therefore, the development of convenient, efficient and environmentally benign methods to produce various types of heterocyclic compounds is an attractive area of research. For the synthesis and functionalization of heterocycles, enormous achievements have been attributed over the past decades. Recently, ironcatalyzed reactions have accomplished a noteworthy development in the synthesis of heterocycles. This review highlights some remarkable achievements in the iron-catalyzed synthesis of heterocyclic compounds published in the last five years.

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Howell, Tyler O., Aron J. Huckaba, and T. Keith Hollis. "ChemInform Abstract: An Efficient Synthesis of Bis-1,3-(3′-aryl-N-heterocycl-1′-yl)arenes as CCC-NHC Pincer Ligand Precursors." ChemInform 45, no. 46 (October 30, 2014): no. http://dx.doi.org/10.1002/chin.201446155.

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Gorbulenko, Natalia, Tetyana Shokol, and Volodymyr Khilya. "Isoflavonoids Modified with Azole Heterocycles with Three Heteroatoms." French-Ukrainian Journal of Chemistry 10, no. 1 (2022): 101–27. http://dx.doi.org/10.17721/fujcv10i1p101-127.

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Heterocycle modified chromones are attracting increasing attention as novel potential therapeutic agents due to their effective bioactivities and low toxicity. This review describes all strategies and versatile synthons that have been developed for the synthesis of isoflavone heterocyclic analogs containing isolated 5-member heterocyclic rings with three identical or different heteroatoms. Their biological activity is also presented.

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Ābele, E., R. Ābele, Ļ. Golomba, J. Višņevska, T. Beresņeva, and K. Rubina. "Oximes of Seven-Membered Heterocyclic Compounds Containing One Heteroatom." Latvian Journal of Chemistry 50, no. 3-4 (January 1, 2011): 205–22. http://dx.doi.org/10.2478/v10161-011-0071-7.

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Oximes of Seven-Membered Heterocyclic Compounds Containing One Heteroatom Literature data on the synthesis and structure of azepane, oxepane and thiepane oximes were reviewed. Synthesis of novel heterocycles from oximes of seven-membered heterocycles containing one heteroatom were described. Biological activity of oximes of seven-membered heterocycles with one heteroatom was also reviewed.

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Prager, RH, Y. Singh, and B. Weber. "The Chemistry of 5-Oxodihydroisoxazoles. VIII. Photolysis of 2-(Heterocyclyl)isoxazol-5(2H)-ones." Australian Journal of Chemistry 47, no. 7 (1994): 1249. http://dx.doi.org/10.1071/ch9941249.

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Photolysis of 2-( heterocyclyl )isoxazol-5(2H)-ones occurs readily at 300 nm. In alcohol the products are the corresponding 2-alkoxy-3-heterocyclylaminoacrylates, and, in the presence of 1 M trifluoroacetic acid, the corresponding imidazole annulated heterocycle . Examples are reported where the heterocycle is quinolin-2-yl (10 examples), isoquinolin-1-yl, benzoxazol-2-yl, benzothiazol-2-yl, quinazolin-1-yl and pyrimidin-2-yl.

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Ābele, E. "Oximes of Seven-Membered Heterocyclic Compounds Containing Two Heteroatoms." Latvian Journal of Chemistry 51, no. 1-2 (January 1, 2012): 83–92. http://dx.doi.org/10.2478/v10161-012-0005-z.

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Oximes of Seven-Membered Heterocyclic Compounds Containing Two Heteroatoms Literature data concerning the synthesis and structure of diazepane, oxazepane and thiazepane oximes were reviewed. Synthesis of novel heterocycles from the oximes of seven-membered heterocycles containing two heteroatoms was described. Biological activity of oximes of seven-membered heterocycles with two heteroatoms was also reviewed.

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31

Li, Chongyang, Yongli Huang, Chang Q. Sun, and Lei Zhang. "Acidic Stabilization of the Dual-Aromatic Heterocyclic Anions." Catalysts 11, no. 7 (June 24, 2021): 766. http://dx.doi.org/10.3390/catal11070766.

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Recently, we discovered that the delocalization of nitrogen lone-pair electrons (NLPEs) in five-membered nitrogen heterocycles created a second σ-aromaticity in addition to the prototypical π-aromaticity. Such dual-aromatic compounds, such as the pentazole anion, were proved to have distinct chemistry in comparison to traditional π-aromatics, such as benzene, and were surprisingly unstable, susceptible to electrophilic attack, and relatively difficult to obtain. The dual-aromatics are basic in nature, but prefer not to be protonated when confronting more than three hydronium/ammonium ions, which violates common sense understanding of acid−base neutralization for a reason that is unclear. Here, we carried out 63 test simulations to explore the stability and reactivity of three basic heterocycle anions (pentazole anion N5¯, tetrazole anion N4C1H1¯, and 1,2,4-triazole anion N3C2H2¯) in four types of solvents (acidic ions, H3O+ and NH4+, polar organics, THF, and neutral organics, benzene) with different acidities and concentrations. By quantum mechanical calculations of the electron density, atomistic structure, interatomic interactions, molecular orbital, magnetic shielding, and energetics, we confirmed the presence of dual aromaticity in the heterocyclic anions, and discovered their reactivity to be a competition between their basicity and dual aromaticity. Interestingly, when the acidic ions H3O+/NH4+ are three times more in number than the basic heterocyclic anions, the anions turn to violate acid−base neutralization and remain unprotonated, and the surrounding acidic ions start to show a significant stabilization effect on the studied heterocyclic anions. This work brings new knowledge to nitrogen aromatics and the finding is expected to be adaptable for other pnictogen five-membered ring systems.

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Li, Xianwei, Tianzhang Wang, Yu-Jing Lu, Shaomin Ji, Yanping Huo, and Bifu Liu. "Copper-catalyzed oxidative multicomponent reaction: synthesis of imidazo fused heterocycles with molecular oxygen." Organic & Biomolecular Chemistry 16, no. 39 (2018): 7143–51. http://dx.doi.org/10.1039/c8ob01532e.

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An oxidative cascade that involves multicomponent reaction comprising a terminal alkyne, 2-amino N-heterocycle, benzyl or allylic bromide with molecular oxygen, delivering densely functionalized imidazo fused heterocycles, is achieved.

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Shoji, Taku, Tetsuo Okujima, and Shunji Ito. "Development of Heterocycle-Substituted and Fused Azulenes in the Last Decade (2010–2020)." International Journal of Molecular Sciences 21, no. 19 (September 25, 2020): 7087. http://dx.doi.org/10.3390/ijms21197087.

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Azulene derivatives with heterocyclic moieties in the molecule have been synthesized for applications in materials science by taking advantage of their unique properties. These derivatives have been prepared by various methods, involving electrophilic substitution, condensation, cyclization, and transition metal-catalyzed cross-coupling reactions. Herein, we present the development of the synthetic methods, reactivities, and physical properties for the heterocycle-substituted and heterocycle-fused azulenes reported in the last decade.

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34

Hoffman, Gavin R., and Allen M. Schoffstall. "Syntheses and Applications of 1,2,3-Triazole-Fused Pyrazines and Pyridazines." Molecules 27, no. 15 (July 22, 2022): 4681. http://dx.doi.org/10.3390/molecules27154681.

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Pyrazines and pyridazines fused to 1,2,3-triazoles comprise a set of heterocycles obtained through a variety of synthetic routes. Two typical modes of constructing these heterocyclic ring systems are cyclizing a heterocyclic diamine with a nitrite or reacting hydrazine hydrate with dicarbonyl 1,2,3-triazoles. Several unique methods are known, particularly for the synthesis of 1,2,3-triazolo[1,5-a]pyrazines and their benzo-fused quinoxaline and quinoxalinone-containing analogs. Recent applications detail the use of these heterocycles in medicinal chemistry (c-Met inhibition or GABAA modulating activity) as fluorescent probes and as structural units of polymers.

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35

Llopart, Carme Cantos, Conchita Ferrer, and John A. Joule. "Lithiation of 1-arylimidazol-2(1H)-ones and 1-aryl-4,5-dihydroimidazol-2(1H)-ones." Canadian Journal of Chemistry 82, no. 11 (November 1, 2004): 1649–61. http://dx.doi.org/10.1139/v04-137.

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1-Arylimidazol-2(1H)-ones are shown to be readily lithiated, using 2 mol equiv. of n-butyllithium, on the benzene ring, ortho to the heterocycle. 1-Aryl-4,5-dihydroimidazol-2(1H)-ones also undergo metalation on the aromatic substitutuent ortho to the heterocycle, but less efficiently. 1-Aryl-3-methylimidazol-2(1H)-ones are lithiated on the heterocyclic ring and then on the benzene ring ortho to the heterocycle. No ortho-directing effect was found for 1-aryl-4,5-dihydro-3-methylimidazol-2(1H)-ones.Key words: ortho-lithation, ureas for directed ortho metalation, 1-arylimidazol-2-ones, 1-arylimidazolidin-2-ones.

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36

Zhu, Daqian, Zhouming Wu, Liyun Liang, Yameng Sun, Bingling Luo, Peng Huang, and Shijun Wen. "Heterocyclic iodoniums as versatile synthons to approach diversified polycyclic heteroarenes." RSC Advances 9, no. 57 (2019): 33170–79. http://dx.doi.org/10.1039/c9ra07288h.

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37

Mohareb, Rafat, and Hanaa Hana. "Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activity." Acta Pharmaceutica 58, no. 1 (March 1, 2008): 29–42. http://dx.doi.org/10.2478/v10007-007-0043-3.

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Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activityThe aim of this work was to synthesize steroidal heterocycles and to elucidate the potential role of these compounds as antimicrobial agents. The synthesis of steroidal heterocycles containing the pyrazole, isoxazole, thiazole, pyrane, pyridine, pyridazine, or benzopyrane ring attached to the pregnene nucleus is reported. Progesterone (1) reacts with dimethyl formamide dimethyl acetal to form enamine2. Heterocyclization of2with hydrazines, hydroxylamine, glycine, ethyl acetoacetate or cyanomethylene afforded novel steroidal heterocyclic derivatives. Thein vitroantimicrobial evaluation showed that all synthesized compounds show activity against the used strains of Gram positive bacteria and fungi.

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38

Maciejewski, Andrzej, Anna Jaworska-Augustyniak, Dariusz Radocki, Ronald G. Sutherland, and Adam Piórko. "An efficient photochemical formation of phenoxazine and phenothiazine from their respective cyclopentadienyliron complexes." Collection of Czechoslovak Chemical Communications 54, no. 8 (1989): 2171–75. http://dx.doi.org/10.1135/cccc19892171.

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The photochemical liberation of phenoxazine and phenothiazine from their cyclopentadienyliron complexes was studied in THF, methanol and dimethylsulfoxide. Quantum yields of decay of the complexes and the formation of free heterocycles have been determined to be about 1.0, independent of solvent, concentration and wavelength of light used. The ease of isolation of free heterocycles after photolysis show that this efficient way of heterocycle recovery is superior to the previously utilized pyrolytic sublimation.

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39

Zhang, Zhen-Zhen, Yongna Zhang, Hui-Xin Duan, Zhuo-Fei Deng, and You-Qing Wang. "Enantioselective (3+2) cycloaddition via N-heterocyclic carbene-catalyzed addition of homoenolates to cyclic N-sulfonyl trifluoromethylated ketimines: synthesis of fused N-heterocycle γ-lactams." Chemical Communications 56, no. 10 (2020): 1553–56. http://dx.doi.org/10.1039/c9cc09269b.

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An enantioselective (3+2) cycloaddition via N-heterocyclic carbene-catalyzed homoenolate addition to cyclic N-sulfonyl trifluoromethyl ketimines is realized, affording fused N-heterocycle γ-lactams with up to >20 : 1 dr and 94–99% ee.

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40

Ábrányi-Balogh, Péter, Aaron Keeley, György G. Ferenczy, László Petri, Tímea Imre, Katarina Grabrijan, Martina Hrast, et al. "Next-Generation Heterocyclic Electrophiles as Small-Molecule Covalent MurA Inhibitors." Pharmaceuticals 15, no. 12 (November 29, 2022): 1484. http://dx.doi.org/10.3390/ph15121484.

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Heterocyclic electrophiles as small covalent fragments showed promising inhibitory activity on the antibacterial target MurA (UDP-N-acetylglucosamine 1-carboxyvinyltransferase, EC:2.5.1.7). Here, we report the second generation of heterocyclic electrophiles: the quaternized analogue of the heterocyclic covalent fragment library with improved reactivity and MurA inhibitory potency. Quantum chemical reaction barrier calculations, GSH (L-glutathione) reactivity assay, and thrombin counter screen were also used to demonstrate and explain the improved reactivity and selectivity of the N-methylated heterocycles and to compare the two generations of heterocyclic electrophiles.

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41

Birzan, Liviu, Mihaela Cristea, Constantin C. Draghici, and Alexandru C. Razus. "Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines." Revista de Chimie 69, no. 1 (February 15, 2018): 64–69. http://dx.doi.org/10.37358/rc.18.1.6045.

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The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

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42

Kerru, Nagaraju, Lalitha Gummidi, Suresh Maddila, Kranthi Kumar Gangu, and Sreekantha B. Jonnalagadda. "A Review on Recent Advances in Nitrogen-Containing Molecules and Their Biological Applications." Molecules 25, no. 8 (April 20, 2020): 1909. http://dx.doi.org/10.3390/molecules25081909.

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The analogs of nitrogen-based heterocycles occupy an exclusive position as a valuable source of therapeutic agents in medicinal chemistry. More than 75% of drugs approved by the FDA and currently available in the market are nitrogen-containing heterocyclic moieties. In the forthcoming decade, a much greater share of new nitrogen-based pharmaceuticals is anticipated. Many new nitrogen-based heterocycles have been designed. The number of novel N-heterocyclic moieties with significant physiological properties and promising applications in medicinal chemistry is ever-growing. In this review, we consolidate the recent advances on novel nitrogen-containing heterocycles and their distinct biological activities, reported over the past one year (2019 to early 2020). This review highlights the trends in the use of nitrogen-based moieties in drug design and the development of different potent and competent candidates against various diseases.

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43

Kumar, Adarsh, Ankit Kumar Singh, Harshwardhan Singh, Veena Vijayan, Deepak Kumar, Jashwanth Naik, Suresh Thareja, et al. "Nitrogen Containing Heterocycles as Anticancer Agents: A Medicinal Chemistry Perspective." Pharmaceuticals 16, no. 2 (February 14, 2023): 299. http://dx.doi.org/10.3390/ph16020299.

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Cancer is one of the major healthcare challenges across the globe. Several anticancer drugs are available on the market but they either lack specificity or have poor safety, severe side effects, and suffer from resistance. So, there is a dire need to develop safer and target-specific anticancer drugs. More than 85% of all physiologically active pharmaceuticals are heterocycles or contain at least one heteroatom. Nitrogen heterocycles constituting the most common heterocyclic framework. In this study, we have compiled the FDA approved heterocyclic drugs with nitrogen atoms and their pharmacological properties. Moreover, we have reported nitrogen containing heterocycles, including pyrimidine, quinolone, carbazole, pyridine, imidazole, benzimidazole, triazole, β-lactam, indole, pyrazole, quinazoline, quinoxaline, isatin, pyrrolo-benzodiazepines, and pyrido[2,3-d]pyrimidines, which are used in the treatment of different types of cancer, concurrently covering the biochemical mechanisms of action and cellular targets.

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44

Huang, Pengfei, Pan Wang, Shengchun Wang, Shan Tang, and Aiwen Lei. "Electrochemical oxidative [4 + 2] annulation of tertiary anilines and alkenes for the synthesis of tetrahydroquinolines." Green Chemistry 20, no. 21 (2018): 4870–74. http://dx.doi.org/10.1039/c8gc02463d.

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Panchal, Neil B., and Vipul M. Vaghela. "Pteridine a Colored Heterocycle and its Anticancer Activity: An Overview." Oriental Journal Of Chemistry 38, no. 4 (August 31, 2022): 822–39. http://dx.doi.org/10.13005/ojc/380402.

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The objective of this work is to provide an overview of the numerous pharmacological features that are associated with the pteridine molecule. Pteridines are nitrogen-containing heterocyclic compounds that are well-known and noteworthy. Their chemical formula is C6H4N4.In recent years, pteridine's various potential uses in the field of medicinal chemistry research have garnered significant attention. In the expanding field of intensive study, Pteridine is regarded as a privileged scaffold, and the alteration created with diverse substituents around the centroid opened the way for researchers to deal with it at ease. The heterocycle, which is a fused ring, has a high pharmacological quality. A pteridine is one of the heterocycles that has attracted a lot of interest in terms of biological uses. The pteridine nucleus serves as the quintessential framework in a range of physiologically energetic chemicals and pharmacological molecules. This evaluation is necessary in order to bring to light the remarkable potential that this ring device possesses as a result of the wide variety of pharmacological effects it may perform. This research might unquestionably hasten the graph and synthesis procedures, which would ultimately yield in a wide array of therapeutically feasible medicinal options.

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46

Niu, Jingze, and Michael C. Willis. "Heterocycle-derived β-S-enals as bifunctional linchpins for the catalytic synthesis of saturated heterocycles." Organic Chemistry Frontiers 3, no. 5 (2016): 625–29. http://dx.doi.org/10.1039/c6qo00057f.

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We demonstrate how heterocycle-derived β-S-enals can be employed as bifunctional substrates in a cascade of two rhodium-catalysed C–C bond forming reactions – a hydroacylation followed by a Suzuki-type coupling – to deliver substituted heterocyclic products.

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47

Boelke, Andreas, Soleicha Sadat, Enno Lork, and Boris J. Nachtsheim. "Pseudocyclic bis-N-heterocycle-stabilized iodanes – synthesis, characterization and applications." Chemical Communications 57, no. 60 (2021): 7434–37. http://dx.doi.org/10.1039/d1cc03097c.

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48

Georghiou, Paris E. "Preface." Pure and Applied Chemistry 82, no. 9 (January 1, 2010): iv. http://dx.doi.org/10.1351/pac20108209iv.

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The 22nd International Congress on Heterocyclic Chemistry (ICHC-22) was held 2-7 August 2009 in St. John's, Newfoundland and Labrador, Canada. St. John's, the capital of Canada's youngest Province, Newfoundland and Labrador, is also Canada’s oldest and North America’s most easterly city. The Conference was chaired by Prof. Mohsen Daneshtalab (School of Pharmacy, Memorial University of Newfoundland) and was organized by the School of Pharmacy and the Chemistry Department at Memorial University of Newfoundland.Approximately 260 participants from over 30 different countries attended. The scientific program consisted of 10 plenary lectures, 19 invited lectures, 52 short communications, and 115 posters. Prof. Samuel Danishefsky (Sloan-Kettering Institute for Cancer Research, Columbia University) was honored with the 2009 ISHC Senior Award in Heterocyclic Chemistry, and Prof. John Wood (Colorado State University) was the 2009 Katritzky Junior Award winner. A special symposium entitled "Focus on heterocycles in organic synthesis today and tomorrow" was held during the Congress as a tribute to Prof. Victor Snieckus (Queen's University, Kingston) for his research accomplishments and long-time contribution to the International Society of Heterocyclic Chemistry (ISHC).The five Congress themes were:- New Methods in Heterocyclic Chemistry- Biologically Active Heterocycles (Pharmaceuticals/Agrochemicals)- Heterocyclic Natural Products and their Analogues- Applications of Heterocycles in Organic Synthesis- Heterocycles in Materials ScienceBesides the collection of 9 papers that are based on the plenary and invited lectures included in this issue of Pure and Applied Chemistry, the ICHC-22 Book of Abstracts is available online and can be downloaded for free from http://www.ichc2009.ca/abstract_book.pdf in pdf format.ICHC-23 will be held in Glasgow, Scotland, 31 July to 5 August 2011 with the following five main themes of heterocyclic chemistry: synthetic methodology, natural products and complex molecule synthesis, materials, medicinal chemistry, and nanochemistry. The conference will be chaired by Prof. Colin Suckling (University of Strathclyde).The organizers are grateful to all who contributed to a successful scientific program, especially to the speakers and to our public and private sponsors: City of St. John's, Memorial University of Newfoundland, IUPAC, Thieme, Wiley-Blackwell, Elsevier, Taiho Pharmaceutical Co., ChemRoutres Corporation, and American Diagnostica, Inc.Paris E. GeorghiouConference Editor

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Stephens, David E., Johant Lakey-Beitia, Jessica E. Burch, Hadi D. Arman, and Oleg V. Larionov. "Mechanistic insights into the potassium tert-butoxide-mediated synthesis of N-heterobiaryls." Chemical Communications 52, no. 64 (2016): 9945–48. http://dx.doi.org/10.1039/c6cc04816a.

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Zhang, Ming, Qiuhong Wang, Yiyuan Peng, Zhiyuan Chen, Changfeng Wan, Junmin Chen, Yongli Zhao, Rongli Zhang, and Ai Qin Zhang. "Transition metal-catalyzed sp3 C–H activation and intramolecular C–N coupling to construct nitrogen heterocyclic scaffolds." Chemical Communications 55, no. 87 (2019): 13048–65. http://dx.doi.org/10.1039/c9cc06609h.

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