Molecules

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

by Walid Fathalla, Michal Čajan and

Pavel Pazdera

Molecules 2001, 6(6), 557-573; https://doi.org/10.3390/60600557 - 31 May 2001

Cited by 36 | Viewed by 6761

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

by

Geetha Gopalakrishnan

, N. D. Pradeep Singh and V. Kasinath

Molecules 2001, 6(6), 551-556; https://doi.org/10.3390/60600551 - 31 May 2001

Cited by 5 | Viewed by 7407

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

by Klaus Martens, Anke Scheunemann, Kerstin Drexler,

Heinz Dehne

, Helmut Reinke and Manfred Michalik

Molecules 2001, 6(6), 540-550; https://doi.org/10.3390/60600540 - 31 May 2001

Cited by 1 | Viewed by 7626

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

by

Edgardo N. Durantini

Molecules 2001, 6(6), 533-539; https://doi.org/10.3390/60600533 - 31 May 2001

Cited by 12 | Viewed by 8595

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

by

Fu An Wang

, Jiqin Zhu, Jianchi Song, Shengli Zhai and Lei Wang

Molecules 2001, 6(6), 528-532; https://doi.org/10.3390/60600528 - 31 May 2001

Cited by 5 | Viewed by 8155

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

by

A. M. El-Agrody

, M. S. Abd El-Latif, N. A. El-Hady, A. H. Fakery and A. H. Bedair

Molecules 2001, 6(6), 519-527; https://doi.org/10.3390/60600519 - 31 May 2001

Cited by 174 | Viewed by 12333

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

by Kamal A. Kandeel and

Ahmed S. A. Youssef

Molecules 2001, 6(6), 510-518; https://doi.org/10.3390/60600510 - 31 May 2001

Cited by 11 | Viewed by 7138

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

by

Francisco Torrens

Molecules 2001, 6(6), 496-509; https://doi.org/10.3390/60600496 - 31 May 2001

Cited by 6 | Viewed by 10308

Abstract

A method (POLAR) for the calculation of the molecular polarizability is presented. It uses the interacting induced dipoles polarization model. As an example, the method is applied to Sc_n and C_n (fullerene and one-shell graphite) model clusters. On varying the number [...] Read more.

A method (POLAR) for the calculation of the molecular polarizability is presented. It uses the interacting induced dipoles polarization model. As an example, the method is applied to Sc_n and C_n (fullerene and one-shell graphite) model clusters. On varying the number of atoms, the clusters show numbers indicative of particularly polarizable structures. The are compared with reference calculations (PAPID). In general, the Sc_n calculated (POLAR) and C_n computed (POLAR and PAPID) are less polarizable than what is inferred from the bulk. However, the Sc_n calculated (PAPID) are more polarizable than what is inferred. Moreover, previous theoretical work yielded the same trend for Si_n, Ge_n and Ga_nAs_m small clusters. The high polarizability of the Sc_nclusters (PAPID) is attributed to arise from dangling bonds at the surface of the cluster. Full article

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Open AccessShort Note

(3(5) Phenylpyrazol-5(3)-yl)-2-benzoylmethyl Benzimidazole

by Noureddine Hammou Ahabchane, Joseph Téné Ghomsi and

El Mokhtar Essassi

Molecules 2001, 6(6), M231; https://doi.org/10.3390/M231 - 25 May 2001

Viewed by 3946

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

by Hai-Yang Liu, Chi-Fong Luo, Kuo-Shen Chuang and

Wen-Jwu Wang

Molecules 2001, 6(6), M230; https://doi.org/10.3390/M230 - 25 May 2001

Cited by 1 | Viewed by 3953

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

by

F. Matloubi Moghaddam

and O. Khakshoor

Molecules 2001, 6(6), M229; https://doi.org/10.3390/M229 - 25 May 2001

Cited by 1 | Viewed by 3072

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

by

M. Dakir

, E. Lassaba, A. Chekroun and A. Benharref

Molecules 2001, 6(6), M228; https://doi.org/10.3390/M228 - 25 May 2001

Viewed by 3137

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

by

M. Dakir

, E. Lassaba and A. Benharref

Molecules 2001, 6(6), M227; https://doi.org/10.3390/M227 - 25 May 2001

Cited by 1 | Viewed by 3234

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

by Christoph Michel, Davood Habibi and

Michael Schmittel

Molecules 2001, 6(6), M226; https://doi.org/10.3390/M226 - 25 May 2001

Viewed by 2901

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

by Christoph Michel, Davood Habibi and

Michael Schmittel

Molecules 2001, 6(6), M225; https://doi.org/10.3390/M225 - 25 May 2001

Cited by 4 | Viewed by 2938

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)

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3-Trimethylsilanylethynyl-[1,10]phenanthroline

by Christoph Michel, Davood Habibi and

Michael Schmittel

Molecules 2001, 6(6), M224; https://doi.org/10.3390/M224 - 25 May 2001

Cited by 5 | Viewed by 2968

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

by

M. Daoubi

and A. Benharref

Molecules 2001, 6(6), M223; https://doi.org/10.3390/M223 - 25 May 2001

Viewed by 3139

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)

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(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

by

M. Daoubi

, A. Benharref and Diego. M. Cortes

Molecules 2001, 6(6), M222; https://doi.org/10.3390/M222 - 25 May 2001

Viewed by 3787

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)

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(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 [7,4,0,0^4,8] Tridecane

by

M. Daoubi

, A. Benharref and M. Pierrot

Molecules 2001, 6(6), M221; https://doi.org/10.3390/M221 - 25 May 2001

Viewed by 3110

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

by

David C. Forbes

, Charles O. Gaston, Derrick L. Lewis, Doug W. Morrison and Mary C. Smith

Molecules 2001, 6(6), M220; https://doi.org/10.3390/M220 - 25 May 2001

Viewed by 3504

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)

by

Györgyi Kovács

, Zoltán Kele, Péter Forgó and Lajos Kovács

Molecules 2001, 6(6), M219; https://doi.org/10.3390/M219 - 25 May 2001

Cited by 2 | Viewed by 3841

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

by Boyan I. Iliev and

Ivo C. Ivanov

Molecules 2001, 6(6), M218; https://doi.org/10.3390/M218 - 25 May 2001

Cited by 2 | Viewed by 2992

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

by

Edmont V. Stoyanov

and Ivo C. Ivanov

Molecules 2001, 6(6), M217; https://doi.org/10.3390/M217 - 25 May 2001

Viewed by 2568

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

by

Edmont V. Stoyanov

and Ivo C. Ivanov

Molecules 2001, 6(6), M216; https://doi.org/10.3390/M216 - 25 May 2001

Viewed by 2955

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)

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(R,S)-N-[(2-Oxocyclohexyl)methyl]-1-butanaminium Chloride

by

Edmont V. Stoyanov

and Ivo C. Ivanov

Molecules 2001, 6(6), M215; https://doi.org/10.3390/M215 - 25 May 2001

Viewed by 3156

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

by

Abdullah Mohamed Asiri

Molecules 2001, 6(6), M214; https://doi.org/10.3390/M214 - 25 May 2001

Viewed by 3683

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)

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3-(2-Nitrophenyl)-2-(4-nitrophenyl)-4-thiazolidinone

by

Abdullah Mohamed Asiri

Molecules 2001, 6(6), M213; https://doi.org/10.3390/M213 - 25 May 2001

Cited by 2 | Viewed by 3728

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)

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3-Cyano-2-(2,5-dimethoxybenzalamino)-4-5-tetramethylenethiophene

by

Abdullah Mohamed Asiri

Molecules 2001, 6(6), M212; https://doi.org/10.3390/M212 - 25 May 2001

Viewed by 3591

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)

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2,4-Dimethyl-3-phenyl-[2'-methyl-3'-chloro]-7-chloro-8-methyl-1,3-diaza-2,4-diboranaphtalene Tricarbonylchromium Complexes

by B. Abouhamza,

S. Allaoud

and A. Karim

Molecules 2001, 6(6), M211; https://doi.org/10.3390/M211 - 25 May 2001

Cited by 3 | Viewed by 3388

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

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