Molecules

64 KiB

Open AccessArticle

Application of the Solid-Phase Julia–Lythgoe Olefination in Vitamin D Side-Chain Construction

by Jo N. D'herde and Pierre J. De Clercq

Molecules 2006, 11(8), 655-660; https://doi.org/10.3390/11080655 - 26 Aug 2006

Cited by 5 | Viewed by 7602

An example of the Julia–Lythgoe attachment of the vitamin D side chain to a solid-phase linked Inhoffen–Lythgoe diol derived CD-ring fragment is reported. Full article

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57 KiB

Open AccessArticle

Efficient Ce(NO₃)₃·6H2O-Catalyzed Solvent-Free Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

by Mehdi Adib, Khadijeh Ghanbary, Manizheh Mostofi and Mohammad Reza Ganjali

Molecules 2006, 11(8), 649-654; https://doi.org/10.3390/11080649 - 23 Aug 2006

Cited by 60 | Viewed by 10987

Abstract

Cerium(III) nitrate hexahydrate efficiently catalyzes the three-component Biginelli reaction under solvent-free conditions of an aldehyde, a β-keto ester or β- diketone and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)- ones or –thiones in excellent yields. Full article

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100 KiB

Open AccessArticle

Formal Synthesis of the ACE Inhibitor Benazepril·HCl via an Asymmetric Aza-Michael Reaction

by Luo-Ting Yu, Ji-Ling Huang, Ching-Yao Chang and Teng-Kuei Yang

Molecules 2006, 11(8), 641-648; https://doi.org/10.3390/11080641 - 23 Aug 2006

Cited by 16 | Viewed by 13360

Abstract

A formal enantioselective synthesis of benazepril·HCl (4), an anti- hypertensive drug, is reported. Our synthesis employed an asymmetric aza-Michael addition of L-homophenylalanine ethyl ester (LHPE, 1) to 4-(2-nitrophenyl)-4-oxo- but-2-enoic acid methyl ester (6) as the key step to prepare (2S,3’S)-2-(2-oxo-2,3,4,5- tetrahydro-1H-benzo[b]azepin-3-ylamino)-4-phenylbutyric acid ethyl [...] Read more.

A formal enantioselective synthesis of benazepril·HCl (4), an anti- hypertensive drug, is reported. Our synthesis employed an asymmetric aza-Michael addition of L-homophenylalanine ethyl ester (LHPE, 1) to 4-(2-nitrophenyl)-4-oxo- but-2-enoic acid methyl ester (6) as the key step to prepare (2S,3’S)-2-(2-oxo-2,3,4,5- tetrahydro-1H-benzo[b]azepin-3-ylamino)-4-phenylbutyric acid ethyl ester (8), which is the key intermediate leading to benazepril·HCl (4). Full article

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326 KiB

Open AccessReview

Development of Fluorous Lewis Acid-Catalyzed Reactions

by Akihiro Yoshida, Xiuhua Hao, Osamu Yamazaki and Joji Nishikido

Molecules 2006, 11(8), 627-640; https://doi.org/10.3390/11080627 - 23 Aug 2006

Cited by 16 | Viewed by 11676

Abstract

Organic synthetic methodology in the 21st century aims to conform to the principles of green sustainable chemistry (GSC) and we may expect that in the future, the realization of GSC will be an important objective for chemical industries. An important aim of synthetic [...] Read more.

Organic synthetic methodology in the 21st century aims to conform to the principles of green sustainable chemistry (GSC) and we may expect that in the future, the realization of GSC will be an important objective for chemical industries. An important aim of synthetic organic chemistry is to implement waste-free and environmentally-benign industrial processes using Lewis acids as versatile as aluminum choride. A key technological objective of our work in this area has been to achieve a “catalyst recycling system that utilizes the high activity and structural features of fluorous Lewis acid catalysts”. Thus, we have developed a series of novel fluorous Lewis acid catalysts, namely the ytterbium(III), scandium(III), tin(IV) or hafnium(IV) bis(perfluoroalkanesulfonyl)amides or tris(perfluoro- alkanesulfonyl)methides. Our catalysts are recyclable and effective for acylations of alcohols and aromatics, Baeyer-Villiger reactions, direct esterifications and transesterifications in a fluorous biphasic system (FBS), in supercritical carbon dioxide and on fluorous silica gel supports. Full article

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90 KiB

Open AccessArticle

Synthesis of Conformationally Constrained Aryl- or Heteroarylpiperazinyl Derivatives of Selected Imides as 5-HT1A Receptor Ligands

by Jerzy Kossakowski, Mariola Krawiecka and Bożena Kuran

Molecules 2006, 11(8), 615-626; https://doi.org/10.3390/11080615 - 23 Aug 2006

Cited by 9 | Viewed by 6482

Abstract

The preparation of a number of cyclic imide 5-HT_1A receptor ligandderivatives has been described. Their structures were conformationally constrained byintroducing rigid linkers containing unsaturated bonds or aromatic benzene rings. Thesecompounds are expected to possess anxiolytic and antidepressant activity. Full article

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77 KiB

Open AccessArticle

Epibatidine Alkaloid Chemistry: 5. Domino-Heck Reactions of Azabicyclic and Tricyclic Systems

by Çigdem Yolacan, Emine Bagdatli, Nüket Öcal and Dieter E. Kaufmann

Molecules 2006, 11(8), 603-614; https://doi.org/10.3390/11080603 - 16 Aug 2006

Cited by 33 | Viewed by 7607

Abstract

Palladium-catalyzed hydroarylations and additional domino reactions of aza- bicyclic and tricyclic norbornene derivatives were investigated and a series of new epibatidine analogues were synthesized. Full article

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48 KiB

Open AccessCommunication

One-Pot Synthesis of 5-Arylidene-2-Imino-4-Thiazolidinones under Microwave Irradiation

by Souad Kasmi-Mir, Ayada Djafri, Ludovic Paquin, Jack Hamelin and Mustapha Rahmouni

Molecules 2006, 11(8), 597-602; https://doi.org/10.3390/11080597 - 10 Aug 2006

Cited by 49 | Viewed by 10147

Abstract

A rapid and easy solvent free one-pot synthesis of 5-arylidene-2-imino-4- thiazolidinones by condensation of the thioureas with chloroacetic acid and an aldehyde under microwave-irradiation is described. Full article

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265 KiB

Open AccessArticle

Synthesis and Molecular Structures of Two [1,4-bis(3-pyridyl)-2,3-diazo-1,3-butadiene]-dichloro-Zn(II) Coordination Polymers

by Gene-Hsiang Lee and Hsin-Ta Wang

Molecules 2006, 11(8), 589-596; https://doi.org/10.3390/11080589 - 10 Aug 2006

Cited by 4 | Viewed by 8257

Abstract

Two novel coordination polymers with 3D metal-organic frameworks (MOFs) have been synthesized by reacting 1,4-bis(3-pyridyl)-2,3-diazo-1,3-butadiene (L) with zinc dichloride. Both compounds have the same repeating unit consisting of a distorted tetrahedral Zn(II) center coordinated by two chlorides and two pyridyl nitrogen atoms of [...] Read more.

Two novel coordination polymers with 3D metal-organic frameworks (MOFs) have been synthesized by reacting 1,4-bis(3-pyridyl)-2,3-diazo-1,3-butadiene (L) with zinc dichloride. Both compounds have the same repeating unit consisting of a distorted tetrahedral Zn(II) center coordinated by two chlorides and two pyridyl nitrogen atoms of two bridging bismonodentate L ligands, however, different structural conformations have been found, one forming a helical chain and the other producing a square-wave chain. The intermolecular C−H···Cl hydrogen bonds in 1 and 2 play important roles in the formation of three-dimensional coordination polymers. Compound 1 crystallized in an orthorhombic space group Pna21 with a = 7.9652(3), b = 21.4716(7), c = 8.2491(3)Å, V = 1410.81(9) Å 3 and Z = 4. Compound 2 crystallized in a monoclinic space group P21/n with a = 9.1752(3), b = 14.5976(4), c = 10.3666(3) Å , β = 98.231(2)°, V = 1374.16(7) Å 3 and Z = 4. Full article

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43 KiB

Open AccessCommunication

1,4-Benzodiazepine N-Nitrosoamidines: Useful Intermediates in the Synthesis of Tricyclic Benzodiazepines

by Santos Fustero, Javier González and Carlos Del Pozo

Molecules 2006, 11(8), 583-588; https://doi.org/10.3390/11080583 - 09 Aug 2006

Cited by 21 | Viewed by 13528

Abstract

1,4-Benzodiazepine N-nitrosoamidines have been used as scaffolds for the preparation of different tricyclic derivatives. Replacement of the N-nitrosoamidine moiety through treatment with the nucleophiles acetylhydrazine, aminoacetaldehyde dimethylacetal and 1-amino-2-propanol, followed by an acid-catalyzed cyclization step, afforded triazolo and imidazobenzodiazepines 1, 6, and 7, [...] Read more.

1,4-Benzodiazepine N-nitrosoamidines have been used as scaffolds for the preparation of different tricyclic derivatives. Replacement of the N-nitrosoamidine moiety through treatment with the nucleophiles acetylhydrazine, aminoacetaldehyde dimethylacetal and 1-amino-2-propanol, followed by an acid-catalyzed cyclization step, afforded triazolo and imidazobenzodiazepines 1, 6, and 7, respectively, in good yields. When acetylhydrazine is used as a nucleophile, the overall process provides an alternative route to alprazolam (1b) and triazolam (1c), respectively. Full article

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Molecules, Volume 11, Issue 8 (August 2006) – 9 articles , Pages 583-660

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