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Special Issue "Sulfur-Nitrogen Heterocycles"

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

Deadline for manuscript submissions: closed (31 December 2004)

Special Issue Editor

Guest Editor
Prof. Tomás Torroba (Website)

Chemistry Department Faculty of Science University of Burgos Burgos
Phone: +34947258088

Published Papers (7 papers)

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Editorial

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Open AccessEditorial Sulfur-Nitrogen Heterocycles
Molecules 2005, 10(2), 318-320; doi:10.3390/10020318
Received: 15 January 2005 / Published: 28 February 2005
Cited by 22 | PDF Full-text (23 KB) | HTML Full-text | XML Full-text
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)

Research

Jump to: Editorial

Open AccessArticle 1,3-Dipolar Cycloaddition Reactions of 1-(4-Phenylphenacyl)-1,10-phenanthrolinium N-Ylide with Activated Alkynes and Alkenes
Molecules 2005, 10(2), 321-326; doi:10.3390/10020321
Received: 8 October 2004 / Revised: 4 November 2004 / Accepted: 10 November 2004 / Published: 28 February 2005
Cited by 17 | PDF Full-text (103 KB) | HTML Full-text | XML Full-text
Abstract
The 3 2 cycloaddition reaction of 1-(4-phenylphenacyl)-1,10-phenanthrolinium ylide with activated alkynes gave pyrrolo[1,2- 4a][1,10]phenanthrolines 6a-d. The "one pot" synthesis of 6a,b,d from 4, activatedalkenes, Et3N and tetrakis-pyridine cobalt (II) dichromate (TPCD) is described. Thehelical chirality of pyrrolophenanthrolines 6b-d was put [...] Read more.
The 3 2 cycloaddition reaction of 1-(4-phenylphenacyl)-1,10-phenanthrolinium ylide with activated alkynes gave pyrrolo[1,2- 4a][1,10]phenanthrolines 6a-d. The "one pot" synthesis of 6a,b,d from 4, activatedalkenes, Et3N and tetrakis-pyridine cobalt (II) dichromate (TPCD) is described. Thehelical chirality of pyrrolophenanthrolines 6b-d was put in evidence by NMRspectroscopy. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)
Open AccessArticle New Route to 3-Alkylthiazolo[3,2-a]benzimidazole Derivatives
Molecules 2005, 10(2), 327-333; doi:10.3390/10020327
Received: 29 October 2004 / Accepted: 16 December 2004 / Published: 28 February 2005
Cited by 9 | PDF Full-text (52 KB) | HTML Full-text | XML Full-text
Abstract 3-Alkyl-thiazolo[3,2-a]benzimidazole derivatives are obtained in high yieldsvia the corresponding 4-alkyl-N-3-(2-aminophenyl)-thiazoline-2-thiones which are easilyprepared from 1,2-diaminobenzene, CS2 and halogenoketones. This new route comparesadvantageously with the classical mercaptobenzimidazole routes in term of simplicity,isolated yields and availability of the starting materials. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)
Open AccessArticle Valence Topological Charge-Transfer Indices for Reflecting Polarity: Correction for Heteromolecules
Molecules 2005, 10(2), 334-345; doi:10.3390/10020334
Received: 29 March 2004 / Accepted: 10 May 2004 / Published: 28 February 2005
Cited by 3 | PDF Full-text (151 KB) | HTML Full-text | XML Full-text
Abstract
Valence topological charge-transfer (CT) indices are applied to the calculationof dipole moments μ. The μ calculated by algebraic and vector semisums of the CTindices are defined. The model is generalized for molecules with heteroatoms andcorrected for sp3-heteromolecules. The ability of [...] Read more.
Valence topological charge-transfer (CT) indices are applied to the calculationof dipole moments μ. The μ calculated by algebraic and vector semisums of the CTindices are defined. The model is generalized for molecules with heteroatoms andcorrected for sp3-heteromolecules. The ability of the indices for the description of themolecular charge distribution is established by comparing them with μ of the valence-isoelectronic series of cyclopentadiene, benzene and styrene. Two CT indices, μvec(vector semisum of vertex-pair μ) and μvecV (valence μvec) are proposed. The μvecVbehaviour is intermediate between μvec and μexperiment. The correction is produced in thecorrect direction. The best results are obtained for the greatest group. Inclusion of theheteroatom in the π-electron system is beneficial for the description of μ, owing to eitherthe role of additional p and/or d orbitals provided by the heteroatom or the role of stericfactors in the π-electron conjugation. The steric effect is almost constant along the seriesand the dominating effect is electronic. Inclusion of the heteroatom enhances μ, whichcan improve the solubility of the molecule. For heteroatoms in the same group, the ringsize and the degree of ring flattering are inversely proportional to their electronegativity. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)
Open AccessArticle The Preparation and Characterization of 5-Substituted-4-chloro-1,2,3-dithiazolium Salts and their Conversion into 4-Substituted-3-chloro-1,2,5-thiadiazoles
Molecules 2005, 10(2), 346-359; doi:10.3390/10020346
Received: 29 November 2004 / Accepted: 16 December 2004 / Published: 28 February 2005
Cited by 19 | PDF Full-text (133 KB) | HTML Full-text | XML Full-text
Abstract
A series of monosubstituted acetonitriles were treated with disulfur dichloride atroom temperature in CH2Cl2 to afford 5-substituted-4-chloro-1,2,3-dithiazolium chlorides 1.Where the 5-substituent was not a good leaving group the chloride salts were converted intothe corresponding perchlorate salts 2 which were [...] Read more.
A series of monosubstituted acetonitriles were treated with disulfur dichloride atroom temperature in CH2Cl2 to afford 5-substituted-4-chloro-1,2,3-dithiazolium chlorides 1.Where the 5-substituent was not a good leaving group the chloride salts were converted intothe corresponding perchlorate salts 2 which were sufficiently stable and soluble to provideboth 1H- and 13C-NMR and cyclic voltammetry data. Several of the dithiazolium chlorideswere converted into their corresponding 4-substituted-3-chloro-1,2,5-thiadiazoles 13 ontreatment with aqueous ammonia. Mechanisms for all reactions are proposed. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)
Open AccessArticle Synthesis and X-ray Structure of a New Pyrrolo[1,2-b]-pyridazine Derivative
Molecules 2005, 10(2), 360-366; doi:10.3390/10020360
Received: 26 November 2004 / Accepted: 16 December 2004 / Published: 28 February 2005
Cited by 8 | PDF Full-text (157 KB) | HTML Full-text | XML Full-text
Abstract
The synthesis, characterization and X-ray crystal structure of 2-(4-chloro-phenyl)-7-methylpyrrolo[1,2-b]pyridazine are reported. The compound crystallizes in thespace group P21/c (No.14) with a =3.8568(1), b = 11.0690(3), c = 26.4243(7) å, β =92.777(1)° and Z = 4. Accurate molecular parameters for the [...] Read more.
The synthesis, characterization and X-ray crystal structure of 2-(4-chloro-phenyl)-7-methylpyrrolo[1,2-b]pyridazine are reported. The compound crystallizes in thespace group P21/c (No.14) with a =3.8568(1), b = 11.0690(3), c = 26.4243(7) å, β =92.777(1)° and Z = 4. Accurate molecular parameters for the novel heterocyclic systemwere obtained from intensity data collected at 113K. The molecule assumes a planarconformation in the crystal and the packing is based on π-π stacking with interplanarspacing 3.400 å, typical of aromatic molecules with potential for displaying usefuloptical properties. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)
Open AccessArticle Synthesis of Pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates via the Hurd-Mori Reaction. Investigating the Effect of the N-Protecting Group on the Cyclization
Molecules 2005, 10(2), 367-375; doi:10.3390/10020367
Received: 23 November 2004 / Accepted: 16 December 2005 / Published: 28 February 2005
Cited by 9 | PDF Full-text (57 KB) | HTML Full-text | XML Full-text
Abstract
A route to methyl pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates as potential plant activators and inducers of systemic acquired resistance (SAR) is reported. A synthetic strategy based on cyclization of the thiadiazole ring system utilizing thionyl chloride via the Hurd-Mori protocol as key step was developed. Success [...] Read more.
A route to methyl pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates as potential plant activators and inducers of systemic acquired resistance (SAR) is reported. A synthetic strategy based on cyclization of the thiadiazole ring system utilizing thionyl chloride via the Hurd-Mori protocol as key step was developed. Success of the ring closure reaction turned out to be highly dependent on the nature of the N-protecting group of the pyrrolidine precursor. While electron donors such as alkyl gave only poor conversion to the required 1,2,3-thiadiazoles, an electron withdrawing substituent such as methyl carbamate gave superior yields. Full article
(This article belongs to the Special Issue Sulfur-Nitrogen Heterocycles)

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