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Molecules, Volume 6, Issue 6 (June 2001) – 29 articles , Pages 496-573, Articles M211-M231

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Open AccessArticle
Regioselectivity of Electrophilic Attack on 4-Methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo[4,3-a]quinazolin-5-one. Part 1: Reactions at the Sulfur Atom
Molecules 2001, 6(6), 557-573; https://doi.org/10.3390/60600557 - 31 May 2001
Cited by 34 | Viewed by 5092
Abstract
The regioselectivity of the model compound 4-methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo[4,3-a]quinazolin-5-one (3) towards different electrophiles was studied. Compound 3 reacts with alkyl and aryl halides to give the corresponding S-substituted derivatives. The reaction of the model thioamide with acyl halides proceeds by the formation of kinetically controlled [...] Read more.
The regioselectivity of the model compound 4-methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo[4,3-a]quinazolin-5-one (3) towards different electrophiles was studied. Compound 3 reacts with alkyl and aryl halides to give the corresponding S-substituted derivatives. The reaction of the model thioamide with acyl halides proceeds by the formation of kinetically controlled S-acyl derivatives followed by a transacylation reaction to give the N2-acyl derivatives as thermodynamically controlled products. Theoretical DFT computational studies supported the explanation of these results. The synthesized compounds were characterized by FTIR, 1H-NMR, 13C-NMR, and mass spectroscopy. Full article
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Open AccessArticle
Photomediated Transformation of Salannin, a Tetranortriterpenoid from Azadirachta indica A. Juss
Molecules 2001, 6(6), 551-556; https://doi.org/10.3390/60600551 - 31 May 2001
Cited by 5 | Viewed by 5297
Abstract
Photolysis of Salannin (1), an important bioactive compound from Azadirachta indica A.Juss (Neem), affords Δ17-isosalanninolide (2), a hitherto unknown compound, along with isosalanninolide (3) and salanninolide (4). A probable mechanism has been suggested. While the mechanism of formation of 2 involves [...] Read more.
Photolysis of Salannin (1), an important bioactive compound from Azadirachta indica A.Juss (Neem), affords Δ17-isosalanninolide (2), a hitherto unknown compound, along with isosalanninolide (3) and salanninolide (4). A probable mechanism has been suggested. While the mechanism of formation of 2 involves both a [4+2] cycloaddition and a [1,3] sigmatropic shift in the furan and D-rings, respectively, formation of 3 and 4 involves the decomposition of an ozonoide-like peroxide intermediate. Full article
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Open AccessArticle
Alkylation of Zwitterionic Thiooxalic Acid Derivatives
Molecules 2001, 6(6), 540-550; https://doi.org/10.3390/60600540 - 31 May 2001
Cited by 1 | Viewed by 6019
Abstract
The new S-alkyl thiooxal-1-hydrazono-2-amidrazonium halides 2-4 were synthesized by reaction of the corresponding zwitterionic thiooxalic acid derivatives 1 with alkyl halides in methanol. The structures of compounds 4b and 4d were proven by X-ray structural analysis. Both compounds form an interesting intermolecular network [...] Read more.
The new S-alkyl thiooxal-1-hydrazono-2-amidrazonium halides 2-4 were synthesized by reaction of the corresponding zwitterionic thiooxalic acid derivatives 1 with alkyl halides in methanol. The structures of compounds 4b and 4d were proven by X-ray structural analysis. Both compounds form an interesting intermolecular network of hydrogen bonds in the solid state. Full article
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Open AccessArticle
Synthesis of 5-(4-X-Phenyl)-10,15,20-tris(Substituted Phenyl) Porphyrins Using Dipyrromethanes
Molecules 2001, 6(6), 533-539; https://doi.org/10.3390/60600533 - 31 May 2001
Cited by 11 | Viewed by 5781
Abstract
5-(4-X-Phenyl)-10,15,20-tris(substituted phenyl) porphyrins (4-6) were synthesized from meso-(substituted phenyl) dipyrromethanes (1-3), which in turn were prepared in yields of 75-92 %. This synthetic pathway was compared with the binary mixed aldehyde and pyrrole condensation method. The reported dipyrromethane approach is advantageous for [...] Read more.
5-(4-X-Phenyl)-10,15,20-tris(substituted phenyl) porphyrins (4-6) were synthesized from meso-(substituted phenyl) dipyrromethanes (1-3), which in turn were prepared in yields of 75-92 %. This synthetic pathway was compared with the binary mixed aldehyde and pyrrole condensation method. The reported dipyrromethane approach is advantageous for porphyrins substituted by –OCH3 (4) and -F (6) groups (12-14 %), while the yield of porphyrins bearing –N(CH3)2 (5) groups was similar (~0.3 %) by both methods. Full article
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Open AccessArticle
Synthesis of Bis (2,2,6,6-tetramethyl-4-piperidinyl) Maleate
Molecules 2001, 6(6), 528-532; https://doi.org/10.3390/60600528 - 31 May 2001
Cited by 3 | Viewed by 6738
Abstract
Bis (2,2,6,6-tetramethyl-4-piperidinyl) maleate is a key intermediate for the synthesis of new types of hindered amine light stabilizers (HALS), so new synthetic routes to this compound are desirable. Through an orthogonal design and follow-up single factor experiments optimal reaction conditions were determined for [...] Read more.
Bis (2,2,6,6-tetramethyl-4-piperidinyl) maleate is a key intermediate for the synthesis of new types of hindered amine light stabilizers (HALS), so new synthetic routes to this compound are desirable. Through an orthogonal design and follow-up single factor experiments optimal reaction conditions were determined for synthesizing bis (2,2,6,6-tetramethyl-4-piperidiny) maleate using dimethyl maleate, 2,2,6,6-tetramethyl-4-piperidinol and zeolite supported tetraisopropyl titanate as catalyst. Under the selected conditions, the reaction rate and the yield are high, the selectivity is good, the catalyst can be recycled, and there are fewer wastes. The product was characterized and quantitatively analyzed by elemental analysis, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy and ion suppression chromatography. Full article
Open AccessArticle
Heteroaromatization with 4-Hydroxycoumarin Part II: Synthesis of Some New Pyrano[2,3-d]pyrimidines, [1,2,4]triazolo[1,5-c]pyrimidines and Pyrimido[1,6-b]-[1,2,4]triazine Derivatives
Molecules 2001, 6(6), 519-527; https://doi.org/10.3390/60600519 - 31 May 2001
Cited by 154 | Viewed by 9033
Abstract
A variety of novel [1,2,4]triazolo[1,5-c]pyrimidine-13-ones (4a-f) and (5b-d) could be obtained via reaction of 9-amino-7-(4’-chlorophenyl)-8,9-dihydro-8-imino-6H,7H-[1]benzopyrano[3`,4`:5,6]pyrano[2,3-d]pyrimidine-6-one (3) with a variety of reagents. Pyrano[2,3-d]pyrimidine-6-ones 5a, 8a-c and pyrimido[1,6-b][1,2,4]-triazine-3,14-dione (6) were also prepared. The antimicrobial activity of some of the synthesized compounds was tested. Full article
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Open AccessArticle
Reactions of 5-Aroylmethylene-3-benzyl-4-oxo-2-thioxo-1,3-thiazolidines with Nitrile Oxides
Molecules 2001, 6(6), 510-518; https://doi.org/10.3390/60600510 - 31 May 2001
Cited by 11 | Viewed by 5566
Abstract
E,Z-5-Aroylmethylene-3-benzyl-4-oxo-2-thioxo-1,3-thiazolidines (3a-c) react with 4-methoxy and 4-chlorophenylnitrile oxides (4a and b) in pyridine solution to afford one or more of the following compounds: Z-3, Z-2,4-dioxo analogues 5 and 3,6-diaryl-1,4,2,5-dioxadiazines (6a-b). The interconversion route is discussed and the structures of all of the synthesised [...] Read more.
E,Z-5-Aroylmethylene-3-benzyl-4-oxo-2-thioxo-1,3-thiazolidines (3a-c) react with 4-methoxy and 4-chlorophenylnitrile oxides (4a and b) in pyridine solution to afford one or more of the following compounds: Z-3, Z-2,4-dioxo analogues 5 and 3,6-diaryl-1,4,2,5-dioxadiazines (6a-b). The interconversion route is discussed and the structures of all of the synthesised compounds are proven by microanalytical and spectral data. Full article
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Open AccessArticle
Molecular Polarizability of Sc and C (Fullerene and Graphite) Clusters
Molecules 2001, 6(6), 496-509; https://doi.org/10.3390/60600496 - 31 May 2001
Cited by 6 | Viewed by 7509 Show Figures

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Open AccessShort Note
(3(5) Phenylpyrazol-5(3)-yl)-2-benzoylmethyl Benzimidazole
Molecules 2001, 6(6), M231; https://doi.org/10.3390/M231 - 25 May 2001
Viewed by 3016
Abstract
The compound 3, which exists in tautomeric equilibria between enamine (form A) and methylene imine (form B) as schown in scheme 1, was prepared by addition of the 3,3-dimercapto-1-phenyl-prop-2-ene-1-one 2 to 3-N-(2-aminophenylamino)-5-phenylpyrazole 1 [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
2, 9-Diphenylamino-1,10-phenanthroline
Molecules 2001, 6(6), M230; https://doi.org/10.3390/M230 - 25 May 2001
Cited by 1 | Viewed by 2946
Abstract
2,9-Dichloro-1,10-phenanthroline was prepared by a previously published method [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
4-Phenyl-2,2'-bis(phenylsulfonyl)butane
Molecules 2001, 6(6), M229; https://doi.org/10.3390/M229 - 25 May 2001
Viewed by 2451
Abstract
During our investigation of the chemistry of bis-gemdiphenylsulphinyl and sulfonyls [1], we have prepared the 4-phenyl-2,2'-bis (phenylsulfonyl)butane from the corresponding thioketal by dimethyldioxirane oxidation [2].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(1S,2S,3R,6R,7R)-Epoxy-himachal-7-ol
Molecules 2001, 6(6), M228; https://doi.org/10.3390/M228 - 25 May 2001
Viewed by 2507
Abstract
To a mixture of lithium aluminium hydride (0,16 g, 4 mmol) in dry ether (50 mL) [1] was added a solution of (10 mL) of epoxide 1 [1,2] (1 g, 4 mmol) in dry ether dropwise at room temperature.[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(1S,6S)-Tetrazolo [1,5-g]-7-Aza-trans-himachal-2-ene
Molecules 2001, 6(6), M227; https://doi.org/10.3390/M227 - 25 May 2001
Viewed by 2696
Abstract
To a solution of 1 (2 g, 9.7 mmol) [1] in trifluoroacetic acid (15 mL) was added by portions during 30 min (1 g, 0.016 mole) sodium azoture [2,3] at -10 °C.[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
3-(4-Iodo-phenylethynyl)-[1,10]phenanthroline
Molecules 2001, 6(6), M226; https://doi.org/10.3390/M226 - 25 May 2001
Viewed by 2282
Abstract
The experimental procedure follows a protocol developed by Sonogashira [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
3-Ethynyl-[1,10]phenanthroline
Molecules 2001, 6(6), M225; https://doi.org/10.3390/M225 - 25 May 2001
Cited by 4 | Viewed by 2325
Abstract
The experimental procedure follows a protocol developed by Eaborn [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
3-Trimethylsilanylethynyl-[1,10]phenanthroline
Molecules 2001, 6(6), M224; https://doi.org/10.3390/M224 - 25 May 2001
Cited by 5 | Viewed by 2334
Abstract
The experimental procedure follows a protocol developed by Sonogashira [1] and recently used for the preparation of macrocyclic phenanthrolines.[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
2-Formyl nor-31-lanosten-3-enol
Molecules 2001, 6(6), M223; https://doi.org/10.3390/M223 - 25 May 2001
Viewed by 2543
Abstract
To a solution of 1 [1] (1 g, 2.25 mmol) in 50 mL of dry benzene held under nitrogen, was added 0.5 mL of ethyl formate [2] (distilled from phosphorus pentoxide) followed by a solution of (0.45 g, 8.33mmol) of sodium in 35 [...] Read more.
To a solution of 1 [1] (1 g, 2.25 mmol) in 50 mL of dry benzene held under nitrogen, was added 0.5 mL of ethyl formate [2] (distilled from phosphorus pentoxide) followed by a solution of (0.45 g, 8.33mmol) of sodium in 35 mL of absolute methyl alcohol.[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(1S,4R,5R,8R,9S,12R,13S),12-(1S-Hydroxyethyl)-13-(N-benzyl-2-carboxamido Ethyl)-5-(1,5-dimethylhexyl)-1,9-epoxy-4,8,13-trimethyl Tricyclo [7,4,0,0,4,8] Tridecane
Molecules 2001, 6(6), M222; https://doi.org/10.3390/M222 - 25 May 2001
Viewed by 2820
Abstract
A mixture 1 [1] (1 g, 2.25 mmol) and benzylamine [2] as a solvent was refluxed for 3 hours.[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(1S,4R,5R,8R,9S,12R,13S) 12-(1S-Hydroxyethyl)-13-(3-hydroxypropyl)-5-(1,5-dimethylhexyl)-1,9-epoxy-4,8,13 Trimethyl Tricyclo [7,4,0,04,8] Tridecane
Molecules 2001, 6(6), M221; https://doi.org/10.3390/M221 - 25 May 2001
Viewed by 2543
Abstract
A mixture of 1 (1 g, 2.25 mmol) and lithium aluminium hydride (0.34 g, 8.94 mmol) in 40 mL of THF was refluxed for 12 h. Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
1-Diazo-2-(2-quinolinyl)-2-ethanone
Molecules 2001, 6(6), M220; https://doi.org/10.3390/M220 - 25 May 2001
Viewed by 2918
Abstract
Diazoketone 2 was prepared using 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) as coupling reagent allowing for the efficient transfer of diazomethane to commercially available carboxylic acid 1 [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
2-Bromo-3-ethylthiazolium Tetrafluoroborate (BET)
Molecules 2001, 6(6), M219; https://doi.org/10.3390/M219 - 25 May 2001
Cited by 1 | Viewed by 2758
Abstract
Recent progress in peptide synthesis resulted in the elaboration of novel coupling agents. One successful approach involves the application of thiazolium salts, e.g. 2-bromo-3-ethyl-4-methylthiazolium tetrafluoroborate (BEMT) [1-3].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
4-Morpholino-2-oxo-2H-chromene-3-carbaldehyde
Molecules 2001, 6(6), M218; https://doi.org/10.3390/M218 - 25 May 2001
Cited by 1 | Viewed by 2317
Abstract
The title compound 3 has been allegedly prepared earlier [1] by refluxing the same starting materials 1 and 2 in ethanol for 10 min. Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(+)-(1R)-N1-{[(1R,1S)-2-Oxocyclohexyl]methyl}-1-phenyl-1-ethanaminium Chloride
Molecules 2001, 6(6), M217; https://doi.org/10.3390/M217 - 25 May 2001
Viewed by 2013
Abstract
The Mannich bases of cyclohexanone with benzylamine and 3,4-methylenedioxybenzylamine hydrochlorides have been prepared in moderate yields using aqueous formaldehyde solution [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(R,S)-N-[(2-Oxocyclohexyl)methyl]-2-phenyl-1-ethanaminium Chloride
Molecules 2001, 6(6), M216; https://doi.org/10.3390/M216 - 25 May 2001
Viewed by 2421
Abstract
The Mannich bases of cyclohexanone with benzylamine and 3,4-methylenedioxybenzylamine hydrochlorides have been prepared in moderate yields using aqueous formaldehyde solution [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
(R,S)-N-[(2-Oxocyclohexyl)methyl]-1-butanaminium Chloride
Molecules 2001, 6(6), M215; https://doi.org/10.3390/M215 - 25 May 2001
Viewed by 2293
Abstract
The Mannich bases of cyclohexanone with benzylamine and 3,4-methylenedioxybenzylamine hydrochlorides have been prepared in moderate yields using aqueous formaldehyde solution [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
2-Mercapto-5-(2'-isopropyl-5'-methylphenoxymethyl)-1,3,4-triazole
Molecules 2001, 6(6), M214; https://doi.org/10.3390/M214 - 25 May 2001
Viewed by 3181
Abstract
The triazole derivative 2 was prepared from 4-[2'-isopropyl-5'-methylphenoxyacyl]thiosemicarbazide 1 by heating under reflux with aqueous NaOH [1,2].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
3-(2-Nitrophenyl)-2-(4-nitrophenyl)-4-thiazolidinone
Molecules 2001, 6(6), M213; https://doi.org/10.3390/M213 - 25 May 2001
Cited by 2 | Viewed by 3185
Abstract
The 4-thiazolidinone 3 was prepared from the Schiff base 1 thioglycolic acid 2 [1,2]. Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
3-Cyano-2-(2,5-dimethoxybenzalamino)-4-5-tetramethylenethiophene
Molecules 2001, 6(6), M212; https://doi.org/10.3390/M212 - 25 May 2001
Viewed by 3039
Abstract
3-Cyano-2-(2,5-dimethoxybenzalamino)-4-5-tetramethylenethiophene was prepared by condensation of 2-amino-3-cyano-4,5-tetramethylenethiophene 1 and 2,5-dimethoxybenzaldehyde 2 [1,2].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
Open AccessShort Note
2,4-Dimethyl-3-phenyl-[2'-methyl-3'-chloro]-7-chloro-8-methyl-1,3-diaza-2,4-diboranaphtalene Tricarbonylchromium Complexes
Molecules 2001, 6(6), M211; https://doi.org/10.3390/M211 - 25 May 2001
Cited by 2 | Viewed by 2477
Abstract
All reactions were carried out under dry nitrogen using Schlenk techniques. 2,4–Dimethyl-3-phenyl-[2’-methyl-3’-chloro]-7-chloro-8-methyl-1,3-diaza-2,4-diboranaphtalene tricarbonylchromium complexes were obtained by a classical method [1].[...] Full article
(This article belongs to the Section Molbank Section of Molecules, 1997-2001)
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