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Special Issue "Advances in Heterocyclic Chemistry"

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A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (30 September 2010)

Special Issue Editor

Guest Editor
Prof. Dr. Norbert Haider (Website)

Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
Fax: +43 1 4277 9551
Interests: medicinal heterocyclic chemistry; pyridazines; carbazoles; nitrogen hetarenes

Special Issue Information

Dear Colleagues,

This special issue is dedicated to the publication of the latest research results in the field of Heterocyclic Chemistry, especially focusing on the synthesis, reactivity, structure, and biological activity of heterocyclic compounds.

Prof. Dr. Norbert Haider
Guest Editor

Related Special Issue

Published Papers (10 papers)

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Research

Jump to: Review

Open AccessArticle Drug Resistance Modulation in Staphylococcus Aureus, a New Biological Activity for Mesoionic Hydrochloride Compounds
Molecules 2011, 16(3), 2023-2031; doi:10.3390/molecules16032023
Received: 25 January 2011 / Revised: 19 February 2011 / Accepted: 22 February 2011 / Published: 28 February 2011
Cited by 9 | PDF Full-text (207 KB)
Abstract
Two salts of the mesoionic compounds 1,4-diphenyl-5-(5-nitro-2-furanyl)-1,3,4-thiadiazolium-2-thiol chloride (MC-1) and 4-phenyl-5-(5-nitro-2-furanyl)-1,3,4-thiadiazolium-2-phenylamine chloride (MC-2) were synthesized utilizing 1,4-diphenyl-thiosemicarbazide and 5-nitro-2-furoyl chloride as starting materials. Their structures were characterized by IR, 1H-NMR, 13C-NMR and elemental analysis. These compounds [...] Read more.
Two salts of the mesoionic compounds 1,4-diphenyl-5-(5-nitro-2-furanyl)-1,3,4-thiadiazolium-2-thiol chloride (MC-1) and 4-phenyl-5-(5-nitro-2-furanyl)-1,3,4-thiadiazolium-2-phenylamine chloride (MC-2) were synthesized utilizing 1,4-diphenyl-thiosemicarbazide and 5-nitro-2-furoyl chloride as starting materials. Their structures were characterized by IR, 1H-NMR, 13C-NMR and elemental analysis. These compounds were analyzed for their influence on the effectiveness of norfloxacin, tetracycline, and erythromycin (standard antibiotics) against resistant strains of Staphylococcus aureus. MC-1 and MC-2, at sub-inhibitory concentrations of 16 μg/mL, favourably modulated the antibiotic activity of tetracycline by 16- and 32-fold, respectively (MIC), and that of erythromycin by 4-fold. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Open AccessArticle Chemistry of the Enaminone of 1-Acetylnaphthalene under Microwave Irradiation Using Chitosan as a Green Catalyst
Molecules 2011, 16(1), 609-623; doi:10.3390/molecules16010609
Received: 9 November 2010 / Revised: 4 January 2011 / Accepted: 6 January 2011 / Published: 17 January 2011
Cited by 9 | PDF Full-text (158 KB)
Abstract
Enaminone 1 was reacted with hydrazonoyl halides 2a-d to yield 3,4-disubstituted pyrazoles 6a-d. Coupling with arenediazonium chlorides afforded the 2-(arylhydrazono)-3-(1-naphthalenyl)-3-oxopropionaldehydes 13a-c. Compounds 13 could be utilized for the synthesis of a variety of arylpyrazoles, arylazolopyrimidines, and pyridazinones via reaction with [...] Read more.
Enaminone 1 was reacted with hydrazonoyl halides 2a-d to yield 3,4-disubstituted pyrazoles 6a-d. Coupling with arenediazonium chlorides afforded the 2-(arylhydrazono)-3-(1-naphthalenyl)-3-oxopropionaldehydes 13a-c. Compounds 13 could be utilized for the synthesis of a variety of arylpyrazoles, arylazolopyrimidines, and pyridazinones via reaction with hydrazines, aminoazoles, and active methylene derivatives, respectively. A comparative study of aforementioned reactions was carried out with chitosan as a basic ecofriendly catalyst under conventional heating as well as under pressurized microwave irradiation conditions. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
Open AccessArticle Heterocyclic Analogues of Xanthone and Xanthione. 1H-Pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones and Thiones: Synthesis and NMR Data
Molecules 2010, 15(9), 6106-6126; doi:10.3390/molecules15096106
Received: 28 July 2010 / Revised: 27 August 2010 / Accepted: 31 August 2010 / Published: 1 September 2010
Cited by 12 | PDF Full-text (197 KB)
Abstract
The synthesis of the title compounds is described. Reaction of 1-substituted 2-pyrazolin-5-ones with 5-chloro-1-phenyl-1H-pyrazole-4-carbonyl chloride or 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbonyl chloride, respectively, using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-heteroaroylpyrazol-5-ols, which were cyclized into 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones by treatment with K2CO3/DMF. The latter were converted [...] Read more.
The synthesis of the title compounds is described. Reaction of 1-substituted 2-pyrazolin-5-ones with 5-chloro-1-phenyl-1H-pyrazole-4-carbonyl chloride or 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbonyl chloride, respectively, using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-heteroaroylpyrazol-5-ols, which were cyclized into 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones by treatment with K2CO3/DMF. The latter were converted into the corresponding thiones upon reaction with Lawesson’s reagent. Detailed NMR spectroscopic investigations (1H, 13C, 15N) of the ring systems and their precursors are presented. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
Open AccessArticle Enhanced Reactivity of [Hydroxy(tosyloxy)iodo]benzene in Fluoroalcohol Media. Efficient Direct Synthesis of Thienyl(aryl)iodonium Salts
Molecules 2010, 15(3), 1918-1931; doi:10.3390/molecules15031918
Received: 3 February 2010 / Revised: 15 March 2010 / Accepted: 16 March 2010 / Published: 17 March 2010
Cited by 22 | PDF Full-text (121 KB)
Abstract
In this manuscript, we report clear evidence for the generation of aromatic cation radicals produced by using [hydroxy(tosyloxy)iodo]benzene (HTIB) in fluoroalcohol solvents such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). The single-electron-transfer (SET) oxidation ability of HTIB to give cation radicals was first [...] Read more.
In this manuscript, we report clear evidence for the generation of aromatic cation radicals produced by using [hydroxy(tosyloxy)iodo]benzene (HTIB) in fluoroalcohol solvents such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). The single-electron-transfer (SET) oxidation ability of HTIB to give cation radicals was first established by ESR and UV measurements. The reaction was broadly applied to various thiophenes, and unique thienyliodonium salts were directly synthesized by this method in excellent yields without the production of any harmful byproducts. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
Open AccessArticle Heterocyclic Analogs of Thioflavones: Synthesis and NMR Spectroscopic Investigations
Molecules 2009, 14(9), 3814-3832; doi:10.3390/molecules14093814
Received: 3 September 2009 / Revised: 11 September 2009 / Accepted: 21 September 2009 / Published: 25 September 2009
Cited by 21 | PDF Full-text (213 KB)
Abstract
The synthesis of several hitherto unknown heterocyclic ring systems derived from thioflavone is described. Coupling of various o-haloheteroarenecarbonyl chlorides with phenylacetylene gives 1-(o-haloheteroaryl)-3-phenylprop-2-yn-1-ones, which were treated with NaSH in refluxing ethanol to yield the corresponding bi- and tricyclic annelated [...] Read more.
The synthesis of several hitherto unknown heterocyclic ring systems derived from thioflavone is described. Coupling of various o-haloheteroarenecarbonyl chlorides with phenylacetylene gives 1-(o-haloheteroaryl)-3-phenylprop-2-yn-1-ones, which were treated with NaSH in refluxing ethanol to yield the corresponding bi- and tricyclic annelated 2-phenylthiopyran-4-ones. Detailed NMR spectroscopic investigations of the ring systems and their precursors are presented. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Open AccessCommunication Synthesis, ex Vivo and in Vitro Hydrolysis Study of an Indoline Derivative Designed as an Anti-Inflammatory with Reduced Gastric Ulceration Properties
Molecules 2009, 14(9), 3187-3197; doi:10.3390/molecules14093187
Received: 12 June 2009 / Revised: 7 August 2009 / Accepted: 13 August 2009 / Published: 26 August 2009
Cited by 11 | PDF Full-text (222 KB)
Abstract
The compound 1-(2,6-dichlorophenyl)indolin-2-one (1), planned as a pro-drug of diclofenac (2), was easily synthesized in 94% yield by an intramolecular reaction in the presence of coupling agent (i.e., EDC). Compound 1 showed anti-inflammatory and analgesic activity without gastro-ulcerogenic effects. The [...] Read more.
The compound 1-(2,6-dichlorophenyl)indolin-2-one (1), planned as a pro-drug of diclofenac (2), was easily synthesized in 94% yield by an intramolecular reaction in the presence of coupling agent (i.e., EDC). Compound 1 showed anti-inflammatory and analgesic activity without gastro-ulcerogenic effects. The chemical and enzymatic hydrolysis profile of the lactam derivative 1 does not indicate conversion to diclofenac (2). This compound is a new non-ulcerogenic prototype for treatment of chronic inflammatory diseases. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Open AccessArticle The Reaction of 4,5-Dichloro-1,2,3-dithiazolium Chloride with Sulfimides: A New Synthesis of N-Aryl-1,2,3-dithiazolimines
Molecules 2009, 14(7), 2356-2362; doi:10.3390/molecules14072356
Received: 26 May 2009 / Revised: 10 June 2009 / Accepted: 12 June 2009 / Published: 2 July 2009
Cited by 2 | PDF Full-text (138 KB) | HTML Full-text | XML Full-text
Abstract
N-Aryl-S,S-dimethylsulfimides 3(Ar = 4-NO2C6H4), 4 (Ar = Ph) and 5 (Ar = 4-Tol)react with Appel salt 1 to give the corresponding N-aryl-(4-chloro-5H-1,2,3-dithiazolylidene)benzenamines 8 (Ar = 4-NO2C [...] Read more.
N-Aryl-S,S-dimethylsulfimides 3(Ar = 4-NO2C6H4), 4 (Ar = Ph) and 5 (Ar = 4-Tol)react with Appel salt 1 to give the corresponding N-aryl-(4-chloro-5H-1,2,3-dithiazolylidene)benzenamines 8 (Ar = 4-NO2C6H4), 9 (Ar = Ph) and 10 (Ar = 4-Tol) in 84, 94 and 87% yields, respectively. The reaction proceeds in the absence of base and a proposed reaction mechanism is given. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Review

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Open AccessReview Recent Advance in Heterocyclic Organozinc and Organomanganese Compounds; Direct Synthetic Routes and Application in Organic Synthesis
Molecules 2010, 15(11), 8006-8038; doi:10.3390/molecules15118006
Received: 17 September 2010 / Revised: 1 November 2010 / Accepted: 4 November 2010 / Published: 8 November 2010
Cited by 5 | PDF Full-text (406 KB)
Abstract
A practical synthetic route for the preparation of 2-pyridyl and 3-pyridyl derivatives has been accomplished by utilizing a simple coupling reaction of stable 2-pyridylzinc bromides and 3-pyridylzinc bromides. The organozincs used in this study were easily prepared via the direct insertion of [...] Read more.
A practical synthetic route for the preparation of 2-pyridyl and 3-pyridyl derivatives has been accomplished by utilizing a simple coupling reaction of stable 2-pyridylzinc bromides and 3-pyridylzinc bromides. The organozincs used in this study were easily prepared via the direct insertion of active zinc into the corresponding bromopyridines. The subsequent coupling reactions with a variety of different electrophiles have afforded the corresponding coupling products. Using highly active manganese, a variety of Grignard-type organomanganese reagents have been obtained. The subsequent coupling reactions of the resulting organomanganese reagents with several electrophiles have also been accomplished under mild conditions. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
Open AccessReview Chemistry of Nitroquinolones and Synthetic Application to Unnatural 1-Methyl-2-quinolone Derivatives
Molecules 2010, 15(8), 5174-5195; doi:10.3390/molecules15085174
Received: 14 July 2010 / Revised: 28 July 2010 / Accepted: 30 July 2010 / Published: 30 July 2010
Cited by 7 | PDF Full-text (1784 KB)
Abstract
The 1-methyl-2-quinolone (MeQone) framework is often found in alkaloids and recently attention was drawn to unnatural MeQone derivatives with the aim of finding new biologically active compounds, however, low reactivity of the MeQone framework prevents the syntheses of versatile derivatives. A nitro group is [...] Read more.
The 1-methyl-2-quinolone (MeQone) framework is often found in alkaloids and recently attention was drawn to unnatural MeQone derivatives with the aim of finding new biologically active compounds, however, low reactivity of the MeQone framework prevents the syntheses of versatile derivatives. A nitro group is one of the useful activating groups for this framework that enables a concise chemical transformation. Among nitroquinolones, 1-methyl-3,6,8-trinitro-2-quinolone (TNQ) exhibits unusual reactivity favoring region-selective cine-substitutions that afford 4-substituted 1-methyl-6,8-dinitro-2-quinolones upon treatment with nucleophilic reagents. Contrary to this, 1-methyl-3,6-dinitro-2-quinolone (3,6-DNQ) does not undergo any reaction under the same conditions. The unusual reactivity of TNQ is caused by steric repulsion between the methyl group at the 1-position and the nitro group at the 8-position, which distorts the MeQone framework. As a result, the pyridone ring of TNQ loses aromaticity and acts rather as an activated nitroalkene. Indeed, the pyridone moiety of TNQ undergoes cycloaddition with electron-rich alkenes or dienes under mild conditions, whereby a new fused ring is constructed on the [c]-face of the MeQone. Consequently, TNQ can be used as a new scaffold leading to versatile unnatural MeQone derivatives. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Open AccessReview Reactivity and Synthetic Applications of 4,5-Dicyanopyridazine: An Overview
Molecules 2010, 15(3), 1722-1745; doi:10.3390/molecules15031722
Received: 28 December 2009 / Revised: 12 February 2010 / Accepted: 5 March 2010 / Published: 12 March 2010
Cited by 8 | PDF Full-text (232 KB)
Abstract
Despite the poor reputation of electron-deficient pyridazines in intermolecular Hetero Diels-Alder (HDA) reactions, 4,5-dicyanopyridazine (DCP) showed a surprising reactivity as a heterocyclic azadiene in inverse electron-demand HDA processes with different dienophiles. The use of alkenes, alkynes and enamines as 2p electron counterparts [...] Read more.
Despite the poor reputation of electron-deficient pyridazines in intermolecular Hetero Diels-Alder (HDA) reactions, 4,5-dicyanopyridazine (DCP) showed a surprising reactivity as a heterocyclic azadiene in inverse electron-demand HDA processes with different dienophiles. The use of alkenes, alkynes and enamines as 2p electron counterparts afforded dicyanocyclohexa-1,3-dienes and substituted phthalonitriles, respectively, while the use of suitable bis-dienophiles provides a general strategy for the one-pot synthesis of polycyclic carbo- and hetero-cage systemsthrough pericyclic three-step homodomino processes. HDA reactions with heterocyclic dienophiles allowed direct benzoannelation: in particular, pyrrole and indole derivatives were converted to dicyano-indoles and -carbazoles. In addition an unprecedented reactivity of DCP as a very reactive heterocyclic electrophile at the C-4 carbon was also evidenced: by changing the experimental conditions, cyanopyrrolyl- and cyanoindolyl-pyridazines were obtained through reactions of pyrrole and indole systems as carbon nucleophiles in formal SNAr2 processes where a CN group of DCP acts as leaving group. Thus, careful control of the reaction conditions allows exploitation of both pathways for the synthesis of different classes of heterocyclic derivatives. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)

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