Research

90 KiB

Open AccessShort Note

8,9-24,25-Diepoxy-Eupho-lanostan-3,4-olactone

by N. El Aouad, A. Benharref and J.-P. Lavergne

Molecules 2000, 5(12), M172; https://doi.org/10.3390/M172 - 25 Dec 2000

Viewed by 3094

To a mixture of 0.8 g (4.7 mmol) of metachloroperbenzoique acid (mCPBA) and 1.58g (18.8mmol) of sodium hydrogenocarbonate (NaHCO₃) in 15 ml of dichloromethane was added 1 g (2.35 mmol) of 1 in 5 ml of CH₂Cl₂.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

95 KiB

Open AccessShort Note

5-[o-(1-L-Phenylalanylamino)ethoxyl]phenyl-10,15,20-triphenylporphyrin

by Hai-yang Liu, Xi-ming Hu, Xiao Ying, Zhong-ping Yao, Jin-wang Huang and Liang-nian Ji

Molecules 2000, 5(12), M173; https://doi.org/10.3390/M173 - 25 Dec 2000

Viewed by 4514

Abstract

5-[o-(2-bromo-1-ethoxy)]phenyl-10,15,20-triphenylporphyrin (1) was prepared according to published method [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

88 KiB

Open AccessShort Note

3-Chloro-5-methoxy-1-benzo[b]thiophene-2-sulphonamide

by Gerard P. Moloney

Molecules 2000, 5(12), M174; https://doi.org/10.3390/M174 - 25 Dec 2000

Viewed by 2901

Abstract

As part of a research programme targeting novel molecules as potential anti-inflammatory agents we synthesised 3-Chloro-5-methoxy-1-benzo[b]thiophene-2-sulphonylamide base on the reported anti-inflammatory activity of the structurally related molecule 3-Isopropoxy-5-methoxy-N-(1H-1,2,3,4-tetraazol-5-yl)-1-benzothiophene-2-carboxamide [1,2].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

90 KiB

Open AccessShort Note

2,4-Dinitrophenylhydrazine-benzo-9-crown-3

by A. Moghimi, M. Faal Rastegar and M. Ghandi

Molecules 2000, 5(12), M175; https://doi.org/10.3390/M175 - 25 Dec 2000

Cited by 1 | Viewed by 3366

Abstract

In the course of our recent studies on the synthesis, solid phase structure, solution and solid phase ¹³C CPMAS [1], and its application in Ion Selective Electrodes [2] of the smallest benzo crown ether, Benzo-9-Crown-3, B9C3, we accomplished the synthesis of B9C3 [...] Read more.

In the course of our recent studies on the synthesis, solid phase structure, solution and solid phase ¹³C CPMAS [1], and its application in Ion Selective Electrodes [2] of the smallest benzo crown ether, Benzo-9-Crown-3, B9C3, we accomplished the synthesis of B9C3 derivative 3.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

89 KiB

Open AccessShort Note

(u,l,l,u)-3,5-Diethyl-2,4,6-triphenyltetrahydropyran-2,4-diol

by Rolf Söllner, Thomas Koy and Michael Schmittel

Molecules 2000, 5(12), M176; https://doi.org/10.3390/M176 - 25 Dec 2000

Viewed by 4223

Abstract

The experimental procedure follows a novel protocol developed recently by us [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

89 KiB

Open AccessShort Note

2-(4-Biphenyl-1-yl)-1,3-diazaspiro[4,5]dec-1-en-4-thione

by Milos Sedlak and Jirí Hanusek

Molecules 2000, 5(12), M177; https://doi.org/10.3390/M177 - 25 Dec 2000

Cited by 5 | Viewed by 2601

Abstract

The title compound was prepared from imidazolinone 1 whose synthesis as well as ¹H and ¹³C NMR spectra were published previously [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

90 KiB

Open AccessShort Note

2-Carbomethoxynor-31-lanosten-2-enol

by M. Daoubi, A. Benharref and M. Pierrot

Molecules 2000, 5(12), M178; https://doi.org/10.3390/M178 - 25 Dec 2000

Viewed by 3321

Abstract

To sodium hydride (0.3g, 12.7 mmole) carefully washed with anhydrous benzene under nitrogen (to eliminate mineral oil from the commercial product) [1], was added (0.8 ml, 8.43 mmole) of dimethylcarbonate (freshly distilled) in dry benzene (20 ml).[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

200 KiB

Open AccessShort Note

bis[(N-Benzyloxycarbonyl)-(2R)-amino-4-methylpentyl]disulfide

by Jean-Marc Poudrel and Peter Karuso

Molecules 2000, 5(12), M179; https://doi.org/10.3390/M179 - 25 Dec 2000

Viewed by 3260

Abstract

Disulfides that mimic the pentapeptide Phe-D-Leu-Gly-D-Leu-Phe can be obtained in high yield from the corresponding thioacetate via the intermediate mercaptan by prolonged standing in alkali [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

90 KiB

Open AccessShort Note

bis[(N-Benzyloxycarbonyl)-(2S)-amino-4-methylpentyl]disulfide

by Jean-Marc Poudrel and Peter Karuso

Molecules 2000, 5(12), M180; https://doi.org/10.3390/M180 - 25 Dec 2000

Viewed by 2797

Abstract

Disulfides that mimic the pentapeptide Phe-Leu-Gly-Leu-Phe can be obtained in high yield from the corresponding thioacetate via the intermediate mercaptan by prolonged standing in alkali [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

94 KiB

Open AccessShort Note

A New Xanthone from Swertia decora

by Huai Xiao, Zenai Chen, Guangming Liu, Jinfu Qian and Yang Lu

Molecules 2000, 5(12), M181; https://doi.org/10.3390/M181 - 25 Dec 2000

Cited by 3 | Viewed by 4490

Abstract

Members of genus Swertia (Gentianaceae) have been the source of many active xanthones.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

89 KiB

Open AccessShort Note

N-Benzotriazol-1-yl-methyl-1,2,3,4-tetrahydro-b-carboline

by Ann Lam and Naseem Peerzada

Molecules 2000, 5(12), M182; https://doi.org/10.3390/M182 - 25 Dec 2000

Viewed by 3412

Abstract

Katritzky's well-established chemistry of benzotriazole [1] was applied to the synthesis of 1,2,3,4- tetrahydro-b-carboline, which have been traditionally prepared by Pictet-Spengler condensation², Fischer cyclisation and other methods³.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

87 KiB

Open AccessShort Note

5-(Indol-3-yl)barbituric acid

by Abdullah Mohamed Asiri

Molecules 2000, 5(12), M183; https://doi.org/10.3390/M183 - 25 Dec 2000

Cited by 1 | Viewed by 4097

Abstract

5-(Indol-3-yl)barbituric acid 3 was prepared by knovenagel condensation of indol-3-carboxaldehyde 1 and barbituric acid 2 in ethanol using piperidine as a base [1,2].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

84 KiB

Open AccessShort Note

E-(4-Methylbenzylidene)succinic anhydride

by Abdullah Mohamed Asiri

Molecules 2000, 5(12), M184; https://doi.org/10.3390/M184 - 25 Dec 2000

Viewed by 3500

Abstract

The title compound was obtained by dehydration of the corresponding diacid 1 (12.1 g, 55 mmol) by boiling in acetyl chloride (50 ml) for four hours.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

88 KiB

Open AccessShort Note

1,4-Bis(2',4',6'-trimethylphenylethynyl)benzene

by Laura Jeffries and Eric Bosch

Molecules 2000, 5(12), M185; https://doi.org/10.3390/M185 - 25 Dec 2000

Viewed by 2566

Abstract

The experimental procedure follows the general synthesis of arylalkynes reported by Sonogashira [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

89 KiB

Open AccessShort Note

2-Methyl-5-methylmercapto-3-dimethylsulfoxymethine-7-phenyl-1,2,4-triazepine

by My. Y. Ait Itto, A Hasnaoui, A. Riahi and A. Huet

Molecules 2000, 5(12), M186; https://doi.org/10.3390/M186 - 25 Dec 2000

Cited by 3 | Viewed by 3146

Abstract

All the following operations were performed under an inert atmosphere using standard vacuum line techniques. Trimethyloxosulfonium iodide (2, 0.73 g, 3.3 mmol) [1] was suspended in anhydrous DMSO (6 mL) and sodium hydride (80 % suspension in mineral oil, 0.1 g, [...] Read more.

All the following operations were performed under an inert atmosphere using standard vacuum line techniques. Trimethyloxosulfonium iodide (2, 0.73 g, 3.3 mmol) [1] was suspended in anhydrous DMSO (6 mL) and sodium hydride (80 % suspension in mineral oil, 0.1 g, 3.3 mmol) was added at room temperature.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

91 KiB

Open AccessShort Note

8a,9a-Epoxy Nor-31-lanosten-3-one

by M. Daoubi, A. Benharref, E. Kossareva and M. Pierrot

Molecules 2000, 5(12), M187; https://doi.org/10.3390/M187 - 25 Dec 2000

Viewed by 2997

Abstract

To the epoxide 1 (1 g, 2.32 mmol) in acetone (50 ml) [1] was added dropwise at 0°C a solution of CrO₃ (0.7 g, 7 mmol) in acetone (20 ml).[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

92 KiB

Open AccessShort Note

8a,9a-Epoxy Nor-31-lanosten-3,4-olactone

by M. Daoubi, A. Benharref, E. Kossareva and M. Pierrot

Molecules 2000, 5(12), M188; https://doi.org/10.3390/M188 - 25 Dec 2000

Cited by 2 | Viewed by 3077

Abstract

To a mixture of (0.85 g, 4.9 mmol) of metachloroperoxybenzoic acid (mCPBA) [1,2] and (1.63 g, 19.6 mmol) of sodium hydrogenocarbonate (NaHCO₃) in 20 ml of dichloromethane was added (1 g, 2.42 mmol) of 1 in 10 ml of CH₂Cl₂.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

92 KiB

Open AccessShort Note

2-Carbomethoxy-8a,9a-epoxy Nor-31-lanosten-3-enol

by M. Daoubi, A. Benharref, A. Kenz and M. Pierrot

Molecules 2000, 5(12), M189; https://doi.org/10.3390/M189 - 25 Dec 2000

Viewed by 3048

Abstract

To sodium hydride (0.34 g, 13.96 mmole) carefully washed with anhydrous benzene under nitrogen (to eliminate mineral oil from the commercial product) [1], was added 0.8 ml (9.27 mmol) of dimethylcarbonate (freshly distilled) in dry benzene (20 ml).[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

86 KiB

Open AccessShort Note

8-Dihydro-3-methyl-7-amino-[1,2,4]triazino[3,4-b][1,3,4]thiadiazine

by Majid M. Heravi, Ghadir Rajabzadeh, Mohammad Rahimizadeh, Mehdi Bakavoli and Mitra Ghassemzadeh

Molecules 2000, 5(12), M190; https://doi.org/10.3390/M190 - 25 Dec 2000

Viewed by 3322

Abstract

8-Dihydro-3-methyl-7-amino-[1,2,4]triazino[3,4-b][1,3,4]thiadiazine 2 was prepared by the cyclocondensation of 4-amino-6-methyl-3-thio-1,2,4-triazin-5-one 1 with chloro-acetonitrile in the presence of triethylamine in refluxing CH₃CN.[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

92 KiB

Open AccessShort Note

E,E-1-(4-Bromophenyl)-5-(3-indolyl)-1,4-pentadien-3-one

by Gang-Chun Sun, Rui-Yun Guo, Jian-Qiang Qu, Liu-Fang Wang, Jun-Biao Chang and Rong-Feng Chen

Molecules 2000, 5(12), M191; https://doi.org/10.3390/M191 - 25 Dec 2000

Viewed by 4315

Abstract

3-(1-Butenone-3)indole 1 was prepared by previously published method [1].[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

87 KiB

Open AccessShort Note

24,31-Epoxy-24-methyl-elemo-lanost-8,9-ene-3-ol

by N. El Aouad, A. Benharref and R. Gree

Molecules 2000, 5(12), M192; https://doi.org/10.3390/M192 - 25 Dec 2000

Viewed by 3492

Abstract

To a solution of 1g (2.27 mmol) of 1 in 40ml of chloroform at room temperature was added 0.55g (2.27 mmol) of meta-chloroperbenzoic acid (mCPBA).[...] Full article

(This article belongs to the Section Molbank Section of Molecules, 1997-2001)

59 KiB

Open AccessArticle

Synthesis of 1-(2'-Deoxy-ß-D-ribofuranosyl)-1H-imidazo[4,5-d]-pyridazine-4,7(5H,6H)-dione: A Potential Building Block for Antisense Applications

by Huan-Ming Chen and Ramachandra S. Hosmane

Molecules 2000, 5(12), 1187-1193; https://doi.org/10.3390/51201187 - 15 Dec 2000

Cited by 7 | Viewed by 6458

Abstract

Synthesis of the title compound,1-(2'-deoxy-b-D-ribofuranosyl)-1H-imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione (1), is reported. It was synthesized in five steps, commencing with methyl 1-(b-D-ribofuranosyl)imidazo-4,5-dicarboxylate (2). The 3',5'-hydroxyl groups of 2 were protected with a bis-silylating agent to form 3, which was then converted into the corresponding 2'-thionocarbonate derivative 5. [...] Read more.

Synthesis of the title compound,1-(2'-deoxy-b-D-ribofuranosyl)-1H-imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione (1), is reported. It was synthesized in five steps, commencing with methyl 1-(b-D-ribofuranosyl)imidazo-4,5-dicarboxylate (2). The 3',5'-hydroxyl groups of 2 were protected with a bis-silylating agent to form 3, which was then converted into the corresponding 2'-thionocarbonate derivative 5. The reduction of the latter with tri-n-butyltin hydride (to form 6), followed by silyl deprotection with tetra-nbutylammonium fluoride, afforded 7. Treatment of the latter with hydrazine hydrate yielded the target nucleoside 1. Full article

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Scheme 1

93 KiB

Open AccessArticle

Synthesis Of Some Novel Silver-Cysteamine Complexes

by Davood Habibi, Ezat Ghaemi and Davood Nematollahi

Molecules 2000, 5(12), 1194-1200; https://doi.org/10.3390/51201194 - 15 Dec 2000

Cited by 8 | Viewed by 6840

Abstract

The aim of this research was to synthesize some new silver-cysteamine complexes of potential biological interest. Reactions were carried out between silver nitrate and cysteamine (2-aminoethanethiol hydrochloride) under different conditions of pH and mole ratios of the metal (silver) to the ligand (cysteamine). [...] Read more.

The aim of this research was to synthesize some new silver-cysteamine complexes of potential biological interest. Reactions were carried out between silver nitrate and cysteamine (2-aminoethanethiol hydrochloride) under different conditions of pH and mole ratios of the metal (silver) to the ligand (cysteamine). Some novel silver-cysteamine complexes were made, and after characterization of the complexes by cyclic voltammetry, pH measurements, and microanalysis, it is now obvious that the mole ratio of the metal to the ligand in complexes is about four to three. Full article

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Figure 1

260 KiB

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 2: Reactions on Nitrogen Atom

by W. Fathalla, M. Čajan and P. Pazdera

Molecules 2000, 5(12), 1210-1223; https://doi.org/10.3390/51201210 - 15 Dec 2000

Cited by 26 | Viewed by 7450

Abstract

The regioselectivity on a cyclic thioamide group towards different electrophiles was studied on the model compound 4-methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo [4,3-a]quinazolin-5-one 1. The examined compound 1 reacts with alkyl halides, amines in the presence of formaldehyde, acyl halides and compounds having activated double bonds to afford [...] Read more.

The regioselectivity on a cyclic thioamide group towards different electrophiles was studied on the model compound 4-methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo [4,3-a]quinazolin-5-one 1. The examined compound 1 reacts with alkyl halides, amines in the presence of formaldehyde, acyl halides and compounds having activated double bonds to afford the N-substituted derivatives 2, 3 and 6. The regioselective reactions on nitrogen atom are due to strong Coulombic attraction. The reaction of 1 with amines in the presence of hydrogen peroxide afforded the aminolysis product 4. Compounds 1-6 were identified by FTIR, 1H NMR, 13C NMR, and mass spectroscopy. Full article

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Figure 1

165 KiB

Open AccessArticle

Chemistry of Substituted Quinolinones. Part VI. Synthesis and Nucleophilic Reactions of 4-Chloro-8-methylquinolin-2(1H)-one and its Thione Analogue

by Mostafa M. Ismail, Mohamed Abass and Mohamed M. Hassan

Molecules 2000, 5(12), 1224-1239; https://doi.org/10.3390/51201224 - 18 Dec 2000

Cited by 33 | Viewed by 11308

Abstract

The synthesis of 4-chloro-8-methylquinolin-2(1H)-one and its thione analogue is described. Some nucleophilic substitution reactions of the 4-chloro group were carried out to get new 4-substituted 2-quinolinones and quinolinethiones, such as 4-sulfanyl, hydrazino, azido and amino derivatives, which are of important synthetic [...] Read more.

The synthesis of 4-chloro-8-methylquinolin-2(1H)-one and its thione analogue is described. Some nucleophilic substitution reactions of the 4-chloro group were carried out to get new 4-substituted 2-quinolinones and quinolinethiones, such as 4-sulfanyl, hydrazino, azido and amino derivatives, which are of important synthetic use. The structure of the new compounds was established by their elemental analysis, IR and ¹H-NMR spectra. Also the mass fragmentation pattern of some products is discussed. Full article

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31 KiB

Open AccessArticle

An Efficient Synthesis of 5-Alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones Catalyzed by KSF Montmorillonite

by Haixia Lin, Jinchang Ding, Xianten Chen and Ziyi Zhang

Molecules 2000, 5(12), 1240-1243; https://doi.org/10.3390/51201240 - 18 Dec 2000

Cited by 49 | Viewed by 5852

Abstract

A mild and efficient catalytic method for synthesis of 5-alkoxycarbonyl-4-aryl-3,4- dihydropyrimidin-2(1H)-ones using KSF montmorillonite as catalyst is described. Full article

68 KiB

Open AccessArticle

Improvement of a Critical Intermediate Step in the Synthesis of a Nitroxide-Based Spin-Labeled Deoxythymidine Analog

by Jeannine H. Powell, Edward M. Johnson II and Peter M. Gannett

Molecules 2000, 5(12), 1244-1250; https://doi.org/10.3390/51201244 - 18 Dec 2000

Cited by 12 | Viewed by 7512

Abstract

Methods to reduce the carboxylic acid moiety in 3-carboxy-2,2,5,5-tetramethylpyrrolin-1-oxyl to an alcohol as an intermediate toward the corresponding aldehyde have been explored and an improved method has been developed. Full article

43 KiB

Open AccessArticle

Facile and Stereoselective Synthesis of Non-Racemic 3,3,3-Trifluoroalanine

by Marcello Crucianelli, Natalia Battista, Pierfrancesco Bravo, Alessandro Volonterio and Matteo Zanda

Molecules 2000, 5(12), 1251-1258; https://doi.org/10.3390/51201251 - 18 Dec 2000

Cited by 11 | Viewed by 7105

Abstract

A highly stereoselective enantiodivergent synthesis of non-racemic 3,3,3-trifluoroalanine 7 is reported. The methodology is based on the reduction, by 9-BBN or DIBAH, of the chiral sulfinimine 3 derived from ethyl trifluoropyruvate, followed by acidic hydrolysis of the resulting diastereomeric sulfinamides 4 and 5. [...] Read more.

A highly stereoselective enantiodivergent synthesis of non-racemic 3,3,3-trifluoroalanine 7 is reported. The methodology is based on the reduction, by 9-BBN or DIBAH, of the chiral sulfinimine 3 derived from ethyl trifluoropyruvate, followed by acidic hydrolysis of the resulting diastereomeric sulfinamides 4 and 5. Full article

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Scheme 1

79 KiB

Open AccessArticle

An Efficient Synthetic Strategy for the Preparation of Nucleic Acid-Encoded Peptide and Protein Libraries for In Vitro Evolution Protocols

by Markus Kurz, Guannan Kuang and Peter A. Lohse

Molecules 2000, 5(12), 1259-1264; https://doi.org/10.3390/51201259 - 18 Dec 2000

Cited by 4 | Viewed by 6727

Abstract

We describe an improved synthetic strategy for the preparation of nucleic acid encoded peptide and protein libraries. A solid-phase format was used to prepare and purify a novel type of mRNA-template for in vitro mRNA-protein fusion synthesis. The present protocol simplifies and accelerates [...] Read more.

We describe an improved synthetic strategy for the preparation of nucleic acid encoded peptide and protein libraries. A solid-phase format was used to prepare and purify a novel type of mRNA-template for in vitro mRNA-protein fusion synthesis. The present protocol simplifies and accelerates the preparation of fusion libraries and should prove most useful for in vitro protein evolution procedures which involve repetitive cycles of fusion library preparation and selection. Full article

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Figure 1

224 KiB

Open AccessArticle

Relative Reactivities of Activated Carboxylic Acids in Amide-Forming Reactions Employed for the Synthesis of Tetraphenylporphyrin Libraries

by Kendra L. Dombi and Clemens Richert

Molecules 2000, 5(12), 1265-1280; https://doi.org/10.3390/51201265 - 18 Dec 2000

Cited by 8 | Viewed by 8524

Abstract

Presented here is a method for rapidly testing the reactivity of carboxylic acids in amide-forming reactions. For this, a mixture of two acids, one a reference compound, and one acid whose reactivity is unknown, are coupled to an aminoacylated tetrakis(paminophenyl) porphyrin under typical [...] Read more.

Presented here is a method for rapidly testing the reactivity of carboxylic acids in amide-forming reactions. For this, a mixture of two acids, one a reference compound, and one acid whose reactivity is unknown, are coupled to an aminoacylated tetrakis(paminophenyl) porphyrin under typical peptide coupling conditions. The product distribution in the resulting library is analyzed via MALDI-TOF mass spectrometry to reveal the relative reactivity. This rapid reactivity test requires sub-nanomole quantities of acids, does not involve cleavage from a support or any potentially biasing work-up, and is automatable. Thus, it is well suited for testing building blocks for combinatorial syntheses. Further, it is demonstrated that step-wise coupling can produce near-statistically distributed libraries of porphyrins when acids of very different reactivity are employed. Full article

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Figure 1

46 KiB

Open AccessArticle

Synthesis of Some Fused Pyrazoles and Isoxazoles

by Venkatapuram Padmavathi, Boggu Jagan Mohan Reddy, Akula Balaiah, Katta Venugopal Reddy and Dandu Bhaskar Reddy

Molecules 2000, 5(12), 1281-1286; https://doi.org/10.3390/51201281 - 18 Dec 2000

Cited by 54 | Viewed by 7577

Abstract

The α-keto methylene group in 3,5-diaryl-2-cyclohexenones 2 and 3,5-diarylcyclohexanones 8 have been used to obtain fused pyrazoles and isoxazoles. The new compounds were characterized by IR and ¹H-NMR spectral data. Full article

25 KiB

Open AccessArticle

Synthesis of α-Hydroxyacetosyringone

by Fernando Echeverri, Winston Quiñones, Fernando Torres, Mario Duque and Rosendo Archbold

Molecules 2000, 5(12), 1287-1290; https://doi.org/10.3390/51201287 - 19 Dec 2000

Cited by 1 | Viewed by 5969

Abstract

A phytoalexin from papaya fruit has been synthesized in four steps; this procedure involved a Pummerer- type reaction. Full article

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Scheme 1

111 KiB

Open AccessArticle

Synthesis and Photochemical Cyclization of a Novel Enyne-Carbodiimide

by Michael Schmittel, David Rodríguez and Jens-Peter Steffen

Molecules 2000, 5(12), 1372-1378; https://doi.org/10.3390/51201372 - 20 Dec 2000

Cited by 13 | Viewed by 6135

Abstract

The triplet sensitized cyclization of enyne-carbodiimide 4 leads to efficient formation of indoloquinoline 5 with concomittant loss of a methyl group. The efficient loss of the methyl group was explained using AM1 semiempirical calculations. Full article

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Figure 1

155 KiB

Open AccessArticle

The Relationship between Redox Potentials and Torsional Angles in 4,4’-Dimethyl N, N’-Alkylidene 2,2’-Bipyridinium Salts

by Yijun Wang and Wenyuan Zhao

Molecules 2000, 5(12), 1379-1385; https://doi.org/10.3390/51201379 - 20 Dec 2000

Cited by 4 | Viewed by 6544

Abstract

The redox potentials of 4,4’-dimethyl-N’N’-alkylidene bridged 2,2’-bipyridinium salts derivatives (DBPAs) can be controlled by changing the N, N’-alkylidene bridge length which changes the conformation of the DBPAs.. In this paper, the torsional angles between the two pyridine rings and the molecular energy of [...] Read more.

The redox potentials of 4,4’-dimethyl-N’N’-alkylidene bridged 2,2’-bipyridinium salts derivatives (DBPAs) can be controlled by changing the N, N’-alkylidene bridge length which changes the conformation of the DBPAs.. In this paper, the torsional angles between the two pyridine rings and the molecular energy of DBPAs are calculated using a PC based software package (AccuModel 1.2). The relationship between torsional angle and N, N’-alkylidene bridge length is discussed. The molecular energy of DBPAs can also be related to the torsional angles (or N, N’-alkylidene bridge size). Some DBPAs had been synthesized and their redox potentials measured. The difference in potential between ethylene and propylene bridged DBPAs is large enough to make a organic diode through bilayer modified electrode. Full article

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Figure 1

76 KiB

Open AccessArticle

Study of Stereoselectivity in Organometallic Additions to 1,2-O-Isopropylidene-O-R-α-D-xylopentodialdo-1,4-furanose

by Tibor Gracza and Peter Szolcsányi

Molecules 2000, 5(12), 1386-1398; https://doi.org/10.3390/51201386 - 21 Dec 2000

Cited by 17 | Viewed by 7969

Abstract

Diastereofacial selectivity of the addition of organometallic reagents to 1,2-Oisopropylidene-O-R-α-D-xylopentodialdo-1,4-furanoses (6) was studied. Full article

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Scheme 1

132 KiB

Open AccessArticle

Substitution Effects on Reactivity of N-Acyl-2-amino-2-desoxyglucopyranoses. Quantum Chemical Study

by Aušra Vektariene, Arvydas Juodviršis and Gytis Vektaris

Molecules 2000, 5(12), 1399-1407; https://doi.org/10.3390/51201399 - 21 Dec 2000

Viewed by 8150

Abstract

Quantum mechanical calculations were carried out to study the molecular geometry and electronic structure of 2-amino-2-desoxyglucopyranose (AG) and the Nacetyl-, N-ethanoyl-, series of N-phthalimidoalkanoyl-AG. The total charge density, electrostatic potential, spatial distribution and positions of HOMO and LUMO of N-acyl-AGs with respect to [...] Read more.

Quantum mechanical calculations were carried out to study the molecular geometry and electronic structure of 2-amino-2-desoxyglucopyranose (AG) and the Nacetyl-, N-ethanoyl-, series of N-phthalimidoalkanoyl-AG. The total charge density, electrostatic potential, spatial distribution and positions of HOMO and LUMO of N-acyl-AGs with respect to their substitutes yield information on the reactivity of the molecules. Full article

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91 KiB

Open AccessArticle

Halogeno Aldol Reaction of Ethyl Vinyl Ketone and Aldehydes Mediated by Titanium Tetrachloride

by Han-Xun Wei, Subramanian Karur and Guigen Li

Molecules 2000, 5(12), 1408-1416; https://doi.org/10.3390/51201408 - 22 Dec 2000

Cited by 8 | Viewed by 8566

Abstract

A three-component halogeno aldol reaction has been developed by using titanium tetrachloride as the halogen source as well as the Lewis acid mediator. The dehydration and elimination of hydrogen chloride were inhibited by conducting the reaction at 0 °C in dichloromethane or at [...] Read more.

A three-component halogeno aldol reaction has been developed by using titanium tetrachloride as the halogen source as well as the Lewis acid mediator. The dehydration and elimination of hydrogen chloride were inhibited by conducting the reaction at 0 °C in dichloromethane or at room temperature with a shortened reaction time. Seven examples were examined, giving good to high yields (61 - 92%) and modest stereoselectivity (syn/anti: 2.2/1.0 - 8.4/1.0). Full article

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407 KiB

Open AccessArticle

High-level Computational Study of the Site-, Facial- and Stereoselectivities for the Diels-Alder Reaction Between o-Benzoquinone and Norbornadiene

by Davor Margetic, Martin R. Johnston and Ronald N. Warrener

Molecules 2000, 5(12), 1417-1428; https://doi.org/10.3390/51201417 - 22 Dec 2000

Cited by 14 | Viewed by 9449

Abstract

Ab initio and DFT quantum chemical calculations have been applied to a study of the Diels-Alder reaction of o-benzoquinone as diene and norbornadiene as dienophile. Transition states for the different reactions are located and activation energies estimated. The prefered exo-π-facial selectivity [...] Read more.

Ab initio and DFT quantum chemical calculations have been applied to a study of the Diels-Alder reaction of o-benzoquinone as diene and norbornadiene as dienophile. Transition states for the different reactions are located and activation energies estimated. The prefered exo-π-facial selectivity and exo,endo-stereoselectivity exhibited in this cycloaddition are readily predicted using RHF/3-21G or higher levels of calculations. Differences between experimentally observed results and calculations may be explained by the postulation of a second, nonconcerted biradical mechanism leading to formation of hetero Diels-Alder products. Full article

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117 KiB

Open AccessArticle

Synthesis and Antimicrobial Activity of Some New Benzimidazole Derivatives

by Afaf H. El-masry, H. H. Fahmy and S. H. Ali Abdelwahed

Molecules 2000, 5(12), 1429-1438; https://doi.org/10.3390/51201429 - 22 Dec 2000

Cited by 367 | Viewed by 22707

Abstract

Reaction of 3-(2-methylbenzimidazol-1-yl)propanoic acid hydrazide (1) with CS₂/KOH gave oxadiazole 2 which underwent Mannich reaction to give 3. Compound 2 was treated with hydrazine hydrate to give triazole 4 which was treated with both aldehydes and acetic anhydride to give 5 [...] Read more.

Reaction of 3-(2-methylbenzimidazol-1-yl)propanoic acid hydrazide (1) with CS₂/KOH gave oxadiazole 2 which underwent Mannich reaction to give 3. Compound 2 was treated with hydrazine hydrate to give triazole 4 which was treated with both aldehydes and acetic anhydride to give 5 and 6, respectively. Carbohydrazide 1 was reacted with ethyl acetoacetate, acetylacetone and aldehydes to give 7, 8 and 9, respectively. Cyclocondensation of 9 with thioglycolic and thiolactic acids gave 10 and 11, respectively. Some of these compounds showed potential antimicrobial activities. Full article

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Review

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78 KiB

Open AccessReview

Synthesis of Jasmonoides from Furan Derivatives

by Janusz Nowicki

Molecules 2000, 5(12), 1201-1209; https://doi.org/10.3390/51201201 - 15 Dec 2000

Cited by 2 | Viewed by 9181

Abstract

This paper presents applicability of commonly available furan derivatives, like 2-methyl furan, furaldehyde and 5-methylfuraldehyde in syntheses of jasmanoides. Full article

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343 KiB

Open AccessReview

Hydroxyquinones: Synthesis and Reactivity

by Spyros Spyroudis

Molecules 2000, 5(12), 1291-1330; https://doi.org/10.3390/51201291 - 20 Dec 2000

Cited by 96 | Viewed by 20242

Abstract

Quinones having hydroxy groups directly attached to the quinone ring constitute a very interesting class of quinoid compounds. A great number of hydroxyquinones are found in nature and the majority of them exhibit unique biological activity. Their syntheses and their main reactivity patterns [...] Read more.

Quinones having hydroxy groups directly attached to the quinone ring constitute a very interesting class of quinoid compounds. A great number of hydroxyquinones are found in nature and the majority of them exhibit unique biological activity. Their syntheses and their main reactivity patterns are reviewed in this paper. Full article

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286 KiB

Open AccessReview

Organic Iodine(I, III, and V) Chemistry: 10 Years of Development at the Medical University of Warsaw, Poland

by Lech Skulski

Molecules 2000, 5(12), 1331-1371; https://doi.org/10.3390/51201331 - 20 Dec 2000

Cited by 48 | Viewed by 10665

Abstract

This review reports some novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium halides and, for comparison, potassium halides. All these new results were [...] Read more.

This review reports some novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium halides and, for comparison, potassium halides. All these new results were obtained in our laboratory over the past decade (1990-2000). A full list of our papers dealing with the organic iodine(I, III and V) chemistry, covering exlusively the aromatic derivatives, is also provided. Full article

231 KiB

Open AccessReview

Cyclohexenonic Long-Chain Fatty Alcohols as Neuronal Growth Stimulators

by Bang Luu, José-Luis González De Aguilar and Céline Girlanda-Junges

Molecules 2000, 5(12), 1439-1460; https://doi.org/10.3390/51201439 - 22 Dec 2000

Cited by 34 | Viewed by 9930

Abstract

Neurotrophic factors play an important role in the development and maintenance of neurons, thus providing a suitable therapeutic approach for the treatment of neurodegenerative diseases. However, their clinical use has revealed problematic because of a number of technical and biological disadvantages. Among the [...] Read more.

Neurotrophic factors play an important role in the development and maintenance of neurons, thus providing a suitable therapeutic approach for the treatment of neurodegenerative diseases. However, their clinical use has revealed problematic because of a number of technical and biological disadvantages. Among the different strategies proposed to overcome such difficulties, the search for non-peptide substances with neurotrophic potential is giving promising results. Here we will expose major findings in this field, drawing special attention to cyclohexenonic long-chain fatty alcohols, a novel family of compounds that promote neuronal survival and neurite outgrowth. Full article

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Other

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375 KiB

Open AccessMeeting Report

Meeting Reports and Abstracts: Symposium on Applications of Porphyrins in Medicine and the Fourth School for Young Scientists on the Chemistry of Porphyrins and Related Compounds Ivanovo 2000

by Oleg A. Golubchikov and Tatjana A. Ageeva

Molecules 2000, 5(12), 1461-1514; https://doi.org/10.3390/51201461 - 31 Dec 2000

Cited by 2 | Viewed by 5465

Abstract

The Fourth School for Young Scientists on Chemistry of Porphyrins and Related Compounds Ivanovo 2000 and the Symposium "Application of Porphyrins in Medicine" were held at the facilities of Ivanovo State University of Chemistry and Technology and the Institute of the Solution Chemistry [...] Read more.

The Fourth School for Young Scientists on Chemistry of Porphyrins and Related Compounds Ivanovo 2000 and the Symposium "Application of Porphyrins in Medicine" were held at the facilities of Ivanovo State University of Chemistry and Technology and the Institute of the Solution Chemistry of the Russian Academy of Sciences in Ples (Ivanovo region, Russia) from August 21 to August 27, 2000. About a hundred lecturers and young scientists from Russia, Belarus, Ukraine, Italy and Poland took part in the various sessions of the School and Symposium. The main centers (Moscow, Ivanovo, St-Petersburg, etc.) and directions of porphyrin investigation were well represented by Russian lecturers. The School program included lectures on synthesis, physico-chemical, coordination and application properties of porphyrins, phthalocyanines and related macroheterocyclic compounds. [...] Full article

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23 KiB

Open AccessNew Book Received

Thermodynamics and Kinetics for the Biological Sciences. By Gordon G. Hammes

by Shu-Kun Lin

Molecules 2000, 5(12), 1515-1516; https://doi.org/10.3390/51201515 - 31 Dec 2000

Viewed by 4649

Abstract

Gain a working knowledge of thermodynamics and kinetics with a minimum of mathematics—a guide for individuals in the biological sciences[...] Full article

9 KiB

Open AccessNew Book Received

Physical Biochemistry: Principles and Applications. By David Sheehan

by Shu-Kun Lin

Molecules 2000, 5(12), 1517; https://doi.org/10.3390/51201517 - 31 Dec 2000

Cited by 1 | Viewed by 8051

Abstract

An accessible and easy-to-read text for students requiring a broad overview of the key techniques used to characterise the structure and function of complex biomacromolecules such as proteins and DNA.[...] Full article

23 KiB

Open AccessNew Book Received

Combinatorial Chemistry. By Willi Bannwarth and Eduard Felder

by Shu-Kun Lin

Molecules 2000, 5(12), 1518-1519; https://doi.org/10.3390/51201518 - 31 Dec 2000

Viewed by 3912

Abstract

As we enter the new millennium, combinatorial chemistry is providing significant impetus to new innovations in synthetic chemistry.[...] Full article

23 KiB

Open AccessNew Book Received

Carbohydrates in Chemistry and Biology. By Ernst, Beat / Hart, Gerald W. / Sinaÿ, Pierre

by Shu-Kun Lin

Molecules 2000, 5(12), 1520-1521; https://doi.org/10.3390/51201520 - 31 Dec 2000

Viewed by 4644

Abstract

Carbohydrate Chemistry and Glycobiology have witnessed a rapid expansion during the last few years with the development of numerous new, imaginative and efficient syntheses which provide further insight into structures and biological interactions of glycoconjugates.[...] Full article

24 KiB

Open AccessNew Book Received

Lewis Acids in Organic Synthesis. By Yamamoto, Hisashi

by Shu-Kun Lin

Molecules 2000, 5(12), 1522-1523; https://doi.org/10.3390/51201522 - 31 Dec 2000

Viewed by 4519

Abstract

The use of Lewis acids in organic synthesis, especially in catalysis is one of the most rapidly developing fields in synthetic organic chemistry.[...] Full article

25 KiB

Open AccessNew Book Received

Pharmaceuticals: Classes, Therapeutic Agents, Areas of Application. By McGuire, John L.

by Shu-Kun Lin

Molecules 2000, 5(12), 1524-1525; https://doi.org/10.3390/51201524 - 31 Dec 2000

Viewed by 4006

Abstract

The pharmaceutical industry - an important segment of the chemical industry - is technologically prolific.[...] Full article

10 KiB

Open AccessNew Book Received

Molecular Diversity in Drug Design. Edited by Philip M. Dean

by Shu-Kun Lin

Molecules 2000, 5(12), 1526-1527; https://doi.org/10.3390/51201526 - 31 Dec 2000

Viewed by 3861

Abstract

This book focuses on the theoretical problems associated with molecular diversity as it is being applied in the pharmaceutical industry.[...] Full article

10 KiB

Open AccessNew Book Received

Advanced Organic Chemistry. Part A: Structure and Mechanisms. Fourth Edition. by Francis A. Carey

by Shu-Kun Lin

Molecules 2000, 5(12), 1528-1529; https://doi.org/10.3390/51201528 - 31 Dec 2000

Cited by 6 | Viewed by 6133

Abstract

Since its original appearance in 1977, Advanced Organic Chemistry has found wide use as a text providing broad coverage of the structure, reactivity and synthesis of organic compounds.[...] Full article

10 KiB

Open AccessNew Book Received

Synthetic Organic Sonochemistry. Jean-Louis Luche

by Shu-Kun Lin

Molecules 2000, 5(12), 1530-1531; https://doi.org/10.3390/51201530 - 31 Dec 2000

Cited by 1 | Viewed by 4099

Abstract

The use of ultrasound in chemistry – sonochemistry – has grown spectacularly in recent years, resulting in a significant body of empirical research.[...] Full article

9 KiB

Open AccessNew Book Received

Progress in Drug Research. By Jucker, E.

by Shu-Kun Lin

Molecules 2000, 5(12), 1532; https://doi.org/10.3390/51201532 - 31 Dec 2000

Viewed by 3734

Abstract

*Editor's Note: The brief summary and the contents of the books are reported as provided by the author or the publishers.[...] Full article

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Molecules, Volume 5, Issue 12 (December 2000) – 54 articles , Pages 1187-1532, Articles M172-M192

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