Molecules

Research

Jump to: Review

8 pages, 184 KiB

Open AccessArticle

One-Pot and Efficient Synthesis of Triazolo[1,2-a]indazole-triones via Reaction of Arylaldehydes with Urazole and Dimedone Catalyzed by Silica Nanoparticles Prepared from Rice Husk

by Hooshang Hamidian, Samieh Fozooni, Asadollah Hassankhani and Sayed Zia Mohammadi

Molecules 2011, 16(11), 9041-9048; https://doi.org/10.3390/molecules16119041 - 26 Oct 2011

Cited by 42 | Viewed by 7438

Abstract

A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions [...] Read more.

A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

12 pages, 211 KiB

Open AccessArticle

Microwave-Assisted Improved Synthesis of Oxazolidin-2-ones, Oxazolidine-2-thiones and Thiazolidine-2-thione Chiral Auxiliaries

by Rosmarbel Morales-Nava, Mario Fernández-Zertuche and Mario Ordóñez

Molecules 2011, 16(10), 8803-8814; https://doi.org/10.3390/molecules16108803 - 20 Oct 2011

Cited by 23 | Viewed by 8692

Abstract

A microwave assisted method for the synthesis of some typical 4-substituted oxazolidinone chiral auxiliaries used in asymmetric synthesis is reported in this work. Under these conditions, treatment of (S)-phenylalaninol, (S)-phenylglycinol, (S)-valinol and (1S, 2R [...] Read more.

A microwave assisted method for the synthesis of some typical 4-substituted oxazolidinone chiral auxiliaries used in asymmetric synthesis is reported in this work. Under these conditions, treatment of (S)-phenylalaninol, (S)-phenylglycinol, (S)-valinol and (1S, 2R)-norephedrine with ethyl carbonate or carbon disulfide under the appropriate and specific microwave reaction conditions, led to an efficient synthesis of some oxazolidin-2-ones, oxazolidine-2-thiones and thiazolidine-2-thiones. The methodology reported in this paper provides these chiral auxiliaries with improved yields and a remarkable reduction on the reaction times, particularly in the case of thiazolidine-2-thiones, as compared with the conventional methods. All the auxiliaries prepared here show spectroscopic data in full agreement with those previously reported in the literature. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

12 pages, 226 KiB

Open AccessArticle

Efficient Microwave-Assisted Synthesis of Ionic Esterified Amino Acids

by Ricardo Cerón-Camacho, Jorge Aburto, Luisa E. Montiel, Eugenio A. Flores, Frisia Cuellar and Rafael Martínez-Palou

Molecules 2011, 16(10), 8733-8744; https://doi.org/10.3390/molecules16108733 - 19 Oct 2011

Cited by 9 | Viewed by 6350

Abstract

In this work, an efficient microwave-assisted methodology for the esterification of unprotected α-amino acids is described. Ionic esterified amino acids were synthesized in satisfactory yields in a facile one-pot solventless protocol from unprotected amino acids and alcohols under acid catalysis (MsOH or p [...] Read more.

In this work, an efficient microwave-assisted methodology for the esterification of unprotected α-amino acids is described. Ionic esterified amino acids were synthesized in satisfactory yields in a facile one-pot solventless protocol from unprotected amino acids and alcohols under acid catalysis (MsOH or p-TsOH) to afford the pure products after a simple work-up procedure. This procedure can also be extended to the preparation of long and short chain alkyl and benzyl esters. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

13 pages, 511 KiB

Open AccessArticle

Microwave Assisted Organic Synthesis (MAOS) of Small Molecules as Potential HIV-1 Integrase Inhibitors

by Stefania Ferro, Sara De Grazia, Laura De Luca, Rosaria Gitto, Caterina Elisa Faliti, Zeger Debyzer and Alba Chimirri

Molecules 2011, 16(8), 6858-6870; https://doi.org/10.3390/molecules16086858 - 11 Aug 2011

Cited by 7 | Viewed by 6633

Abstract

Integrase (IN) represents a clinically validated target for the development of antivirals against human immunodeficiency virus (HIV). In recent years our research group has been engaged in the stucture-function study of this enzyme and in the development of some three-dimensional pharmacophore models which [...] Read more.

Integrase (IN) represents a clinically validated target for the development of antivirals against human immunodeficiency virus (HIV). In recent years our research group has been engaged in the stucture-function study of this enzyme and in the development of some three-dimensional pharmacophore models which have led to the identification of a large series of potent HIV-1 integrase strand-transfer inhibitors (INSTIs) bearing an indole core. To gain a better understanding of the structure-activity relationships (SARs), herein we report the design and microwave-assisted synthesis of a novel series of 1-H-benzylindole derivatives. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

11 pages, 250 KiB

Open AccessArticle

Microwave Assisted Synthesis of Novel Functionalized Hydantoin Derivatives and Their Conversion to 5-(Z) Arylidene-4H-imidazoles

by Sukanta Kamila, Haribabu Ankati and Edward R. Biehl

Molecules 2011, 16(7), 5527-5537; https://doi.org/10.3390/molecules16075527 - 29 Jun 2011

Cited by 10 | Viewed by 6587

Abstract

2-(Alkyl-1-yl)-1H-imidazol-5(4H)-ones 5a–n were synthesized via nucleophilic substitution of the methylsulfanyl group of the corresponding 2-(methylthio)-1H-imidazol-5(4H)-ones 3a–c with suitably substituted secondary amines. The starting 2-thioxo- imidazolidin-4-ones 2a,2b were prepared by condensation of thiohydantoin and [...] Read more.

2-(Alkyl-1-yl)-1H-imidazol-5(4H)-ones 5a–n were synthesized via nucleophilic substitution of the methylsulfanyl group of the corresponding 2-(methylthio)-1H-imidazol-5(4H)-ones 3a–c with suitably substituted secondary amines. The starting 2-thioxo- imidazolidin-4-ones 2a,2b were prepared by condensation of thiohydantoin and benzo[b]-thiophene-3-carbaldehyde or benzofuran-3-carbaldehyde under microwave irracdiation (MW) conditions. 2-Methylthio derivatives 3a–c were prepared by treatment of 2a–b with methyl iodide in the presence of aqueous sodium hydroxide. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

21 pages, 298 KiB

Open AccessArticle

Microwave Assisted Synthesis of Some New Fused 1,2,4-Triazines Bearing Thiophene Moieties With Expected Pharmacological Activity

by Hosam A. Saad, Mohamed M. Youssef and Mosselhi A. Mosselhi

Molecules 2011, 16(6), 4937-4957; https://doi.org/10.3390/molecules16064937 - 15 Jun 2011

Cited by 72 | Viewed by 8239

Abstract

Rapid and efficient solvent-free synthesis of 4-amino-3-mercapto-6-[2-(2-thienyl)vinyl]-1,2,4-triazin-5(4H)-one 1 under microwave irradiation is described. Some new fused heterobicyclic nitrogen systems such as 1,2,4-triazino[3,4-b][1,3,4]thiadiazinones, 1,3,4-thiadiazolo[2,3-c][1,2,4]triazinone and pyrazolo[5,1-c]-[1,2,4]triazine-7-carbonitrile, have been synthesized by treatment of 1 with bifunctional oxygen [...] Read more.

Rapid and efficient solvent-free synthesis of 4-amino-3-mercapto-6-[2-(2-thienyl)vinyl]-1,2,4-triazin-5(4H)-one 1 under microwave irradiation is described. Some new fused heterobicyclic nitrogen systems such as 1,2,4-triazino[3,4-b][1,3,4]thiadiazinones, 1,3,4-thiadiazolo[2,3-c][1,2,4]triazinone and pyrazolo[5,1-c]-[1,2,4]triazine-7-carbonitrile, have been synthesized by treatment of 1 with bifunctional oxygen and halogen compounds, CS₂/KOH and malononitrile via heterocyclization reactions, in addition to some uncondensed triazines. Structures of the products have been deduced from their elemental analysis and spectral data (IR, ¹H-NMR, ¹³C-NMR). Select new synthesized compounds were screened as anticancer agents, with some showing activity as cytotoxic agents against different cancer cell lines. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

11 pages, 197 KiB

Open AccessArticle

Microwave Assisted Synthesis and Unusual Coupling of Some Novel Pyrido[3,2-f][1,4]thiazepines

by Rasha M. Faty, Mohamed M. Youssef and Ayman M.S. Youssef

Molecules 2011, 16(6), 4549-4559; https://doi.org/10.3390/molecules16064549 - 31 May 2011

Cited by 15 | Viewed by 7418

Abstract

3-Amino-3-thioxopropanamide (1) reacted with ethyl acetoacetate to form 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide (2), which reacted with α-haloketones 3 to produce 2,3-disubstituted-8-hydroxy-6-methyl-2H,5H-pyrido[3,2-f]-[1,4]thiazepin-5-ones 4a-c. Benzoylation of 4c led to the formation of the dibenzoate derivative 9. Compounds 4a-c could be prepared stepwise [...] Read more.

3-Amino-3-thioxopropanamide (1) reacted with ethyl acetoacetate to form 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide (2), which reacted with α-haloketones 3 to produce 2,3-disubstituted-8-hydroxy-6-methyl-2H,5H-pyrido[3,2-f]-[1,4]thiazepin-5-ones 4a-c. Benzoylation of 4c led to the formation of the dibenzoate derivative 9. Compounds 4a-c could be prepared stepwise through the formation of S-alkylated derivatives 10a-c. Compounds 2, 4a-c, 9 and 10a-c were prepared using microwave as a source of heat, and gave better yields in shorter times than those achieved by traditional methods. Coupling of 4a-c with arenediazonium chlorides proceeded unusually to give the 6-hydroxy-4-methyl-2-(arylazo)thieno[2,3-b]pyridin-3(2H)-one ring contraction products 14. Structures of the newly synthesized compounds were proven by spectral and chemical methods. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Scheme 1

11 pages, 300 KiB

Open AccessArticle

Microwave-Assisted and Efficient Solvent-free Knoevenagel Condensation. A Sustainable Protocol Using Porous Calcium Hydroxyapatite as Catalyst

by Siham Mallouk, Khalid Bougrin, Abdelaziz Laghzizil and Rachid Benhida

Molecules 2010, 15(2), 813-823; https://doi.org/10.3390/molecules15020813 - 4 Feb 2010

Cited by 65 | Viewed by 12699

Abstract

A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products are obtained in and high yields after short reaction times. [...] Read more.

A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products are obtained in and high yields after short reaction times. The effects of the specific surface of porous calcium hydroxyapatite and microwave activation are discussed. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

8 pages, 510 KiB

Open AccessArticle

Application of the Molecular Combing Technique to Starch Granules

by Hua Li, Zhong-Dong Liu, Liu Boxiang, Jian-Hui Chen, You-Ning Sun, Xiao-Ling Lv, Ze-Sheng Zhang, Pin Sun, Pin Zhang and Yang-Li Wang

Molecules 2009, 14(10), 4079-4086; https://doi.org/10.3390/molecules14104079 - 12 Oct 2009

Cited by 2 | Viewed by 11730

Abstract

The molecular combing technique was used to dissociate the nanostructural units of starch granules from the starch fragments after a gelatinization process. With the help of atomic force microscopy (AFM), we observed that some nanostructural chains were just flowing out of the granules. [...] Read more.

The molecular combing technique was used to dissociate the nanostructural units of starch granules from the starch fragments after a gelatinization process. With the help of atomic force microscopy (AFM), we observed that some nanostructural chains were just flowing out of the granules. It proves that there are substantive nanostructural units in the starch granules, a phenomenon not previously observed, so these nanostructural units were defined as suspected intermediates. Furthermore, we conclude that blocklets of starch granules are formed through twisting or distortion of nanochains. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

11 pages, 438 KiB

Open AccessArticle

Microwave-Assisted Synthesis and Crystal Structure of Oxo(diperoxo)(4,4'-di-tert-butyl-2,2'-bipyridine)-molybdenum(VI)

by Tatiana R. Amarante, Filipe A. Almeida Paz, Sandra Gago, Isabel S. Gonçalves, Martyn Pillinger, Alírio E. Rodrigues and Marta Abrantes

Molecules 2009, 14(9), 3610-3620; https://doi.org/10.3390/molecules14093610 - 16 Sep 2009

Cited by 23 | Viewed by 14348

Abstract

The oxodiperoxo complex MoO(O₂)₂(tbbpy) (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine) was isolated from the reaction of MoO₂Cl₂(tbbpy) in water under microwaveassisted heating at 120 ºC for 4 h. The structure of the oxodiperoxo complex was [...] Read more.

The oxodiperoxo complex MoO(O₂)₂(tbbpy) (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine) was isolated from the reaction of MoO₂Cl₂(tbbpy) in water under microwaveassisted heating at 120 ºC for 4 h. The structure of the oxodiperoxo complex was determined by single crystal X-ray diffraction. The Mo^VI centre is seven-coordinated with a geometry which strongly resembles a highly distorted bipyramid. Individual MoO(O₂)₂(tbbpy) complexes are interdigitated along the [010] direction to form a column. The crystal structure is formed by the close packing of the columnar-stacked complexes. Interactions between neighbouring columns are essentially of van der Waals type mediated by the need to effectively fill the available space. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

16 pages, 270 KiB

Open AccessArticle

Microwave-Assisted Solvent-Free Acetylation of Cellulose with Acetic Anhydride in the Presence of Iodine as a Catalyst

by Jing Li, Li-Ping Zhang, Feng Peng, Jing Bian, Tong-Qi Yuan, Feng Xu and Run-Cang Sun

Molecules 2009, 14(9), 3551-3566; https://doi.org/10.3390/molecules14093551 - 11 Sep 2009

Cited by 150 | Viewed by 18460

Abstract

In this work an optimization of the solvent-free acetylation of cellulose with acetic anhydride under microwave heating with iodine as a catalyst was performed. The optimized parameters included the microwave irradiation power from 300 W to 800 W, the reaction time between 5 [...] Read more.

In this work an optimization of the solvent-free acetylation of cellulose with acetic anhydride under microwave heating with iodine as a catalyst was performed. The optimized parameters included the microwave irradiation power from 300 W to 800 W, the reaction time between 5 to 40 min, the reaction temperature from 80 to 130 °C, and the amount of iodine from 1 to 15 mol%. The extent of the acetylation was measured by yield and the degree of substitution (DS), which was determined by a back-titration method. Acetylated cellulose was characterized by FT-IR, CP/MAS ¹³C-NMR, WRXD, and thermogravimetric analysis. The results showed that within the range of catalyst amounts studied, the DS increased as the amount of iodine used increased, however, it was barely affected by microwave output. It was also found that the reaction time and temperature had an active influence on the extent of acetylation, however, this did not mean that at the higher temperature a better acetylation of cellulose would be obtained. The optimal reaction time and temperature found in this work were 30 min and 130 °C. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

14 pages, 324 KiB

Open AccessArticle

Fast and Green Microwave-Assisted Conversion of Essential Oil Allylbenzenes into the Corresponding Aldehydes via Alkene Isomerization and Subsequent Potassium Permanganate Promoted Oxidative Alkene Group Cleavage

by Thi X. Thi Luu, Trinh To Lam, Thach Ngoc Le and Fritz Duus

Molecules 2009, 14(9), 3411-3424; https://doi.org/10.3390/molecules14093411 - 3 Sep 2009

Cited by 37 | Viewed by 16318

Abstract

Essential oil allylbenzenes from have been converted quickly and efficiently into the corresponding benzaldehydes in good yields by a two-step “green” reaction pathway based on a solventless alkene group isomerization by KF/Al₂O₃ to form the corresponding 1-arylpropene and a subsequent [...] Read more.

Essential oil allylbenzenes from have been converted quickly and efficiently into the corresponding benzaldehydes in good yields by a two-step “green” reaction pathway based on a solventless alkene group isomerization by KF/Al₂O₃ to form the corresponding 1-arylpropene and a subsequent solventless oxidation of the latter to the corresponding benzaldehyde by KMnO₄/CuSO₄·5H₂O. The assistance by microwave irradiation results in very short reaction times (<15 minutes). The green conversion of eugenol (4-allyl-2-methoxyphenol) into vanillin (4-hydroxy-3-methoxybenzaldehyde) has been carried out in a similar way, requiring however two additional microwave-assisted synthetic steps for acetylation of the hydroxy group prior to the oxidation reaction, and for the final deacetylation of vanillin acetate (4-acetoxy-3-methoxybenzaldehyde) by KF/Al₂O₃ under solvent-free conditions, respectively. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

9 pages, 233 KiB

Open AccessArticle

Cross-Cyclotrimerization with Two Nitriles as a Synthetic Pathway to Unsymmetrically 3,3’-Disubstituted bis(Tetrahydroisoquinolines)

by Aneta Kadlčíková and Martin Kotora

Molecules 2009, 14(8), 2918-2926; https://doi.org/10.3390/molecules14082918 - 10 Aug 2009

Cited by 18 | Viewed by 10631

Abstract

Microwave assisted CpCo(CO)₂ catalyzed cross-cyclotrimerizations of 1,7,9,15-hexadecatetrayne with two different nitriles to give unsymmetrically substituted bis(tetrahydroisoquinolines) was studied. The reaction proceeded with a range of alkyl and aryl nitriles with reasonable isolated yields. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

14 pages, 211 KiB

Open AccessArticle

Efficient Microwave Assisted Syntheses of 2,5-Diketopiperazines in Aqueous Media

by Lemuel Pérez-Picaso, Jaime Escalante, Horacio F. Olivo and María Yolanda Rios

Molecules 2009, 14(8), 2836-2849; https://doi.org/10.3390/molecules14082836 - 31 Jul 2009

Cited by 47 | Viewed by 12727

Abstract

Aqueous in situ one-pot N-Boc-deprotection-cyclization of Nα-Boc-dipeptidyl-tert-butyl and methyl esters under microwave irradiation afforded 2,5-diketopiperazines (DKPs) in excellent yields. This protocol is rapid, safe, environmentally friendly, and highly efficient, and showed that the tert-butoxy moiety is also an excellent leaving group [...] Read more.

Aqueous in situ one-pot N-Boc-deprotection-cyclization of Nα-Boc-dipeptidyl-tert-butyl and methyl esters under microwave irradiation afforded 2,5-diketopiperazines (DKPs) in excellent yields. This protocol is rapid, safe, environmentally friendly, and highly efficient, and showed that the tert-butoxy moiety is also an excellent leaving group for these cyclizations. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

7 pages, 224 KiB

Open AccessArticle

Extraction with SPME and Synthesis of 2-Methyl-6-vinylpyrazine by a ‘One Pot’ Reaction Using Microwaves

by Norma Robledo, Jaime Escalante and René Arzuffi

Molecules 2009, 14(6), 2160-2166; https://doi.org/10.3390/molecules14062160 - 15 Jun 2009

Cited by 4 | Viewed by 10944

Abstract

A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a ‘one pot’ reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound [...] Read more.

A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a ‘one pot’ reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound was separated and identified using GC/MSD (gas chromatography/mass spectrometry detector). Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

10 pages, 152 KiB

Open AccessArticle

Synthesis of γ-Nitro Aliphatic Methyl Esters Via Michael Additions Promoted by Microwave Irradiation

by Jaime Escalante and Francisco D. Díaz-Coutiño

Molecules 2009, 14(4), 1595-1604; https://doi.org/10.3390/molecules14041595 - 21 Apr 2009

Cited by 18 | Viewed by 13611

Abstract

A simple and efficient protocol has been developed for the direct synthesis of γ-nitrobutyric acid methyl esters under microwave irradiation. This methodology reduces reaction times from days to minutes, compared to conventional conditions. Additionally, these conditions increased yields and provided cleaner reactions. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

8 pages, 117 KiB

Open AccessCommunication

Phosphotungstic Acid: An Efficient, Cost-effective and Recyclable Catalyst for the Synthesis of Polysubstituted Quinolines

by Minoo Dabiri and Sahareh Bashiribod

Molecules 2009, 14(3), 1126-1133; https://doi.org/10.3390/molecules14031126 - 12 Mar 2009

Cited by 37 | Viewed by 12406

Abstract

Phosphotungstic acid (H₃PW₁₂O₄₀) was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

9 pages, 72 KiB

Open AccessArticle

Microwave Assisted Reactions of Some Azaheterocylic Compounds

by Gheorghita Zbancioc, Vasilichia Bejan, Marian Risca, Costel Moldoveanu and Ionel I. Mangalagiu

Molecules 2009, 14(1), 403-411; https://doi.org/10.3390/molecules14010403 - 15 Jan 2009

Cited by 32 | Viewed by 15299

Abstract

A fast, general, environmentally friendly and facile method for preparation of five- and six-membered ring diazaheterocylic salts under microwave irradiation is presented. The N-alkylation reactions of imidazole, pyrimidine, pyridazine and phthalazine have been studied. The microwaves remarkably accelerated these N-alkylations, the [...] Read more.

A fast, general, environmentally friendly and facile method for preparation of five- and six-membered ring diazaheterocylic salts under microwave irradiation is presented. The N-alkylation reactions of imidazole, pyrimidine, pyridazine and phthalazine have been studied. The microwaves remarkably accelerated these N-alkylations, the reaction times decreased dramatically, the reaction conditions were milder, the consumed energy decreased considerably and the amount of solvents used was reduced substantially. Consequently, the microwave assisted alkylation of N-containing heterocycles could be considered eco-friendly. In some cases, under MW irradiation the yields are also higher. A comparative study of microwave vs. classical conditions (liquid solvents) has been done. Twelve new diazaheterocylic salts of potential practical interest were obtained. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

7 pages, 151 KiB

Open AccessArticle

Dodecatungstophosphoric Acid (H₃PW₁₂O₄0), Samarium and Ruthenium (ІІІ) Chloride Catalyzed Synthesis of Unsaturated 2-Phenyl-5(4H)-oxazolone Derivatives under Solvent-free Conditions

by Ahmad Momeni Tikdari, Samieh Fozooni and Hooshang Hamidian

Molecules 2008, 13(12), 3246-3252; https://doi.org/10.3390/molecules13123246 - 18 Dec 2008

Cited by 33 | Viewed by 10999

Abstract

We found that dodecatungstophosphoric acid (H₃PW₁₂O₄0), samarium and ruthenium(III) chloride act as efficient catalysts for synthesis of unsaturated 2-phenyl-5(4H)oxazolone derivatives under solvent-free conditions. The key features of the reported protocols are short reaction times, high yields of [...] Read more.

We found that dodecatungstophosphoric acid (H₃PW₁₂O₄0), samarium and ruthenium(III) chloride act as efficient catalysts for synthesis of unsaturated 2-phenyl-5(4H)oxazolone derivatives under solvent-free conditions. The key features of the reported protocols are short reaction times, high yields of products, ambient conditions and simple workup. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Graphical abstract

Review

Jump to: Research

24 pages, 440 KiB

Open AccessReview

MAOS and Medicinal Chemistry: Some Important Examples from the Last Years

by Nailton M. Nascimento-Júnior, Arthur E. Kümmerle, Eliezer J. Barreiro and Carlos A. M. Fraga

Molecules 2011, 16(11), 9274-9297; https://doi.org/10.3390/molecules16119274 - 7 Nov 2011

Cited by 23 | Viewed by 7146

Abstract

This review aims to highlight microwave-assisted organic synthesis as applied to medicinal chemistry in the last years, showing some reactions performed under microwave irradiation for the synthesis of distinct structurally molecules of biological interest, divided into the following groups: antineoplastics, anti-inflammatory, antimicrobial agents, [...] Read more.

This review aims to highlight microwave-assisted organic synthesis as applied to medicinal chemistry in the last years, showing some reactions performed under microwave irradiation for the synthesis of distinct structurally molecules of biological interest, divided into the following groups: antineoplastics, anti-inflammatory, antimicrobial agents, antivirals, agents for the treatment of neglected diseases and central nervous system-acting prototypes. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

37 pages, 532 KiB

Open AccessReview

Microwave Multicomponent Synthesis

by Helmut M. Hügel

Molecules 2009, 14(12), 4936-4972; https://doi.org/10.3390/molecules14124936 - 1 Dec 2009

Cited by 122 | Viewed by 15226

Abstract

In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules [...] Read more.

In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achieved over the last five years. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Microwave Assisted Synthesis

Share This Special Issue

Special Issue Editor

Benefits of Publishing in a Special Issue

Published Papers (21 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI