Condensation Cyclization Reactions Research Articles

1. C2対称性を有する新規光学活性ジケトンの縮合環化連続反応を用いたguignardone 類の不斉全合成(口頭発表の部

1. C2対称性を有する新規光学活性ジケトンの縮合環化連続反応を用いたguignardone 類の不斉全合成(口頭発表の部

Triamide macrocyclic chloride receptors via a one-pot tandem reduction-condensation-cyclization reaction.

A pyridine containing triamide macrocycle and its substituted analog have been synthesized in one pot from the corresponding monomer without the use of coupling reagents. The macrocycle can selectively bind chloride ions. The ease of synthesis and chloride-binding properties of the macrocycle make it a highly attractive scaffold for ion-encapsulation, ion-transport and water purification.

Correction: Triamide macrocyclic chloride receptors via a one-pot tandem reduction-condensation-cyclization reaction.

Correction for 'Triamide macrocyclic chloride receptors via a one-pot tandem reduction-condensation-cyclization reaction' by Harekrushna Behera, et al., Org. Biomol. Chem., 2017, DOI: .

ChemInform Abstract: One‐Pot Four‐Component Synthesis of Thieno[2,3‐d]pyrimidin‐4‐amines via Sequential Gewald/Cyclocondensation Reactions.

A one-pot four-component synthesis of thieno[2,3-d]pyrimidin-4-amines via sequential Gewald/cyclocondensation reactions is described. 2-Aminothiophene-3-carbonitriles obtained from the Gewald reaction between cyclic ketones, malononitrile, and sulfur underwent a condensationcyclization reaction with benzonitriles under solvent-free conditions to afford the title compounds in excellent yields.

A convenient, simple and one-pot synthesis of dibenzoxanthenes and tetrahydrobenzoxanthenes by nanotitania-supported sulfonic acid as an efficient and highly reusable nanocatalyst

Nanotitania-supported sulfonic acid (n-TSA) as a highly powerful solid acid nanocatalyst has been successfully applied for the rapid and green synthesis of dibenzoxanthenes and tetrahydrobenzoxanthenes via one-pot condensation–cyclization reactions of aldehydes with β-naphthol, on the other hand with β-naphthol and 1,3-cyclic diketones. The ease of preparation and handling of the catalyst, operational simplicity, short reaction time, mild reaction conditions, and environmentally benign conditions are the main advantages of these protocols, which led to high yields of products, 70–96 % for dibenzoxanthenes and 65–98 % for tetrahydrobenzoxanthenes. Furthermore, the catalyst could be recycled after a simple work-up, and reused at least five times without substantial reduction in its catalytic activity, confirming the stability of the covalent bonding of acidic centers.

One‐Pot Four‐Component Synthesis of Thieno[2,3‐d]pyrimidin‐4‐amines via Sequential Gewald/Cyclocondensation Reactions

AbstractA one‐pot four‐component synthesis of thieno[2,3‐d]pyrimidin‐4‐amines via sequential Gewald/cyclocondensation reactions is described. 2‐Aminothiophene‐3‐carbonitriles obtained from the Gewald reaction between cyclic ketones, malononitrile, and sulfur underwent a condensationcyclization reaction with benzonitriles under solvent‐free conditions to afford the title compounds in excellent yields.

ChemInform Abstract: Synthesis of Oxazolidine‐2,4‐diones by a Tandem Phosphorus‐Mediated Carboxylative Condensation—Cyclization Reaction Using Atmospheric Carbon Dioxide.

AbstractOxazolidine‐2,4‐diones [(IV), (VIII), and (X)] are conveniently synthesized via title tandem reaction in one‐pot fashion using carbon dioxide under atmospheric pressure and transition‐metal free conditions.

Lewis Acid Catalyzed Condensation-Cyclization Cascade: Direct Synthesis of Di/Trifluoromethyl-1,2,3,4-tetrahydroquinazolines.

Condensed heterocycles such as quinazolines constitute the framework of many promising drugs. The great impact of the dramatic fluorine effect in pharmaceuticals prompted a great surge in the quest for fluorinated drug design resulting in over 20 % fluorine-containing drugs in the market today. Therefore, finding an efficient and cost-effective method for the direct synthesis of fluorine-tagged quinazoline systems is of great significance in the pharmaceutical arena. For the first time, a one-pot sequential condensation-cyclization reaction to form selectively the difluoro/trifluoromethylated tetrahydroquinazolines from simple components difluoro/trifluoroacetaldehyde hemiacetal and aromatic amines is reported. Our recent studies using difluoro/trifluoroacetaldehyde hemiacetal as simple and elegant difluoro/trifluoromethyl synthons and metal triflates such as gallium triflate as safe and stable Lewis acid catalysts led us to this direct synthesis protocol for the expedient and convenient synthesis of fluorinated quinazolines. DFT calculations at PCM/B3LYP/6-31++G** were carried out for evaluating a possible reaction mechanism for this cyclization. According to the DFT calculations, product stereochemistry is thermodynamically driven, favoring the cis isomer as the major product, which is also confirmed experimentally.

Cyrhetrenyl and ferrocenyl 1,3,4-thiadiazole derivatives: Synthesis, characterization, crystal structures and in vitro antitubercular activity

A new series of cyrhetrenyl and ferrocenyl 1,3,4-thiadiazoles (TDZs) were designed, synthesized and characterized. The condensation–cyclization reaction of organometallic-cyanide with the corresponding thiosemicarbazide produces the ferrocenyl-TDZs (3a–c) and cyrhetrenyl analogues (4ac). The structures of all products were inferred from their elemental analysis, 1H and 13C NMR spectra and MS. The molecular structures of 3b and 4b were confirmed using X-ray crystallography. The electronic effects of cyrhetrenyl (4a–c) and ferrocenyl (3a–c) bound directly to the thiadiazole ring have been correlated with the chemical shift of the exocyclic amine proton and 13C shift of the carbon at the 5-position. The X-ray crystal structure of 3b and 4b indicates that the rhenium compound 4b possesses a more extensive conjugated π-system. The activity of the new organometallic-TDZs was evaluated in vitro against Mycobacterium tuberculosis. The incorporation of any organometallic fragment into the thiadiazole skeleton showed a comparable but lower antitubercular activity than isoniazid.

Synthesis of oxazolidine-2,4-diones by a tandem phosphorus-mediated carboxylative condensation-cyclization reaction using atmospheric carbon dioxide.

The oxazolidine-2,4-dione motif is found frequently in biologically important compounds. A tandem phosphorus-mediated carboxylative condensation of primary amines and α-ketoesters/base-catalyzed cyclization reaction have been developed. These processes provide a novel and convenient access to various oxazolidine-2,4-diones in a one-pot fashion using atmospheric carbon dioxide and readily available substrates under very mild and transition-metal-free conditions.

ChemInform Abstract: A Facile Synthesis of 3‐Hydroxy‐3‐(trifluoromethyl)‐1H‐pyrrol‐2(3H)‐ones with Broensted Acid‐Catalyzed Condensation—Cyclization Reactions of β‐Enamino Esters and Ethyl Trifluoropyruvate.

AbstractThe reaction, when carried out under optimized conditions A), affords a mixture of the desired ring system and a condensation product.

A facile synthesis of 3-hydroxy-3-(trifluoromethyl)-1H-pyrrol-2(3H)-ones with Brønsted acid-catalyzed condensation–cyclization reactions of β-enamino esters and ethyl trifluoropyruvate

A facile synthesis of 3-hydroxy-3-(trifluoromethyl)-1H-pyrrol-2(3H)-ones based on trifluoroacetic acid-catalyzed condensation–cyclization reactions of β-enamino esters and ethyl trifluoropyruvate is described. These reactions afford a series of α-trifluoromethylated γ-lactam compounds in good to excellent yields under mild conditions. A preliminary trial of an asymmetric catalytic version with chiral BINOL-derived phosphoric acid as enantioselective catalyst was conducted and showed promising enantioselectivity of the desired product.

ChemInform Abstract: Synthesis and Characterization of Oxadisilole‐fused‐3,4‐dihydro‐2H‐naphtho[2,1‐e]‐1,3‐oxazines and 3,4‐Dihydro‐2H‐anthra[2,1‐e]‐1,3‐oxazines.

Abstract Oxadisilole-fused-3,4-dihydro-2 H -naphtho[2,1- e ]-1,3-oxazines and 3,4-dihydro-2 H -anthra[2,1- e ]-1,3-oxazines were synthesized through an eco-friendly Mannich type condensation–cyclization reaction of oxadisilole-fused-1-naphthalenol or 1-anthracenol with formaldehyde and primary amines at ambient temperature in high to excellent yields. The photophysical, electrochemical, and thermal properties of these 3,4-dihydro-2 H -anthra[2,1- e ]-1,3-oxazine derivatives were also studied.

Utilisation of Home Laundry Effluent (HLE) as a catalyst for expeditious one-pot aqueous phase synthesis of highly functionalised 4-thiazolidinones

BackgroundThe impact of global warming and associated climate changes have built up pressure to focus on the option of green chemistry over traditional one for long term sustainability of the environment. Considering the fact, for the first time, efficient HLE catalysed expeditious one-pot synthesis of highly functionalised 4-thiazolidinones has been developed.ResultsThese hybrid molecules were synthesized in good to excellent yields. The ease of work-up of the reactions less time required and mild conditions are notable features of this protocol. It was inferred that halogen containing derivatives were well suited to this condensation-cyclization reaction with varying rates to afford 4-thiazolidine derivatives. In general, the substitution on the aldehyde part was shown as a main determinant for reaction time and the product yield.ConclusionFor the first time home laundry effluent (HLE) owing to the surfactant like property has been successfully utilised as catalyst for the synthesis of a series of novel 4-thiazolidinone derivatives through one pot, three component condensation-cyclization reaction. The uniqueness of the present protocol lies in the operational simplicity, ability to reduce the demand for organic solvents, reduce the energy and carbon footprint, and meet a wide range of economic needs.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-466) contains supplementary material, which is available to authorized users.

Organometallic benzimidazoles: Synthesis, characterization and antimalarial activity

Abstract A series of ferrocenyl and cyrhetrenyl benzimidazoles were synthesized and characterized. The condensation–cyclization reaction of cyrhetrenecarbaldehyde with 1,2-phenylendiamine or 4-nitro-1,2-phenylendiamine produces only the 2-cyrhetrenyl-benzimidazoles [1-Re-(H, NO2)] whereas with the same diamines, ferrocenecarbaldehyde yields two products: 2-ferrocenyl-benzimidazole [1-Fe-(H, NO2)] and N-ferrocenylmethyl-2-ferrocenyl-benzimidazole [2-Fe-(H, NO2)]. The structures of all products were confirmed by 1H, 13C NMR spectra and MS. The molecular structure of 2-Fe-NO2 was determined by single crystal X-ray analysis. The antimalarial evaluation studies against the CQ susceptible-strain (3D7) and the CQ resistant-strain (W2) of Plasmodium falciparum revealed cyrhetrene conjugates to be most potent of the tested compounds. The presence of the nitro group at the 5-position of organometallic-benzimidazoles [1-M (M = Re, Fe)] also increases the antimalarial activity.

Synthesis and characterization of oxadisilole-fused-3,4-dihydro-2H-naphtho[2,1-e]-1,3-oxazines and 3,4-dihydro-2H-anthra[2,1-e]-1,3-oxazines

Oxadisilole-fused-3,4-dihydro-2H-naphtho[2,1-e]-1,3-oxazines and 3,4-dihydro-2H-anthra[2,1-e]-1,3-oxazines were synthesized through an eco-friendly Mannich type condensation–cyclization reaction of oxadisilole-fused-1-naphthalenol or 1-anthracenol with formaldehyde and primary amines at ambient temperature in high to excellent yields. The photophysical, electrochemical, and thermal properties of these 3,4-dihydro-2H-anthra[2,1-e]-1,3-oxazine derivatives were also studied.

Synthesis and anti-bacterial activity of novel dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones

A novel series of sulfur-containing dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones has been synthesized through an eco-friendly Mannich-type condensation cyclization reaction of 7-hydroxy-4-methyl-2-thiocoumarin or 6-chloro-7-hydroxy-4-methyl-2-thiocoumarin with formaldehyde and primary amines in water at 80–90°C for 2 h. All the synthesized compounds were screened for their in vitro anti-bacterial efficacy against two Gram-positive and three Gram-negative bacterial strains by using the disc diffusion method. The compound (8c) was found to be most potent with the zone of inhibition of 16 and 15 mm against Staphylococcus aureus ATCC 2937 and Klebsiella pneumoniae ATCC 31488, respectively.

ChemInform Abstract: Synthesis and Antibacterial Evaluation of Benzazoles Tethered Dihydro[1,3]oxazines.

AbstractA variety of novel benzazoles tethered oxazines are synthesized via three‐component one‐pot Mannich type condensation—cyclization reactions of substituted phenols or β‐naphthol with formaldehyde and benzazolylphenylamines.

Microwave-assisted green synthesis of dibenzo[a,j]xanthenes using p-dodecylbenzenesulfonic acid as an efficient Bronsted acid catalyst under solvent-free conditions

Abstract The p -dodecylbenzenesulfonic acid (DBSA) has been successfully applied as an efficient acidic catalyst for the microwave-assisted synthesis of a series of 14-aryl- or alkyl-14 H -dibenzo[ a , j ]xanthenes ( 3a-m ) via a one-pot condensation-cyclization reaction of β -naphthol with various aliphatic or aromatic aldehydes under solvent-free conditions. Operational simplicity, short reaction times, excellent yields and environmentally-benign conditions are other advantages of this protocol.

Design, synthesis and antimicrobial evaluation of novel 2-aryl-thiazolidin-4-one derivatives

Novel 2-arylthiazolidin-4-one derivatives (8a-q and 11) have been synthesized in good-to-excellent yields (70-96%) by one-pot three-component condensation-cyclization reaction of aromatic or aliphatic primary amines, aromatic aldehydes, and thioglycolic acid in polypropylene glycol at 110°C temperature. The in vitro antimicrobial activity of the synthesized 2-arylthiazolidin-4-ones was investigated against a panel of six pathogenic fungal strains, a Gram-positive and three Gram-negative bacteria. Results revealed that the compounds (8a-d) bearing 3-(4-(1H-imidazolylmethyl)phenyl)-substituent displayed significant antibacterial efficacy specifically against Klebsiella pneumoniae (minimum inhibitory concentration 12.5 μg/mL). In addition, some of the synthesized compounds have also shown antimicotic activity against Sporothrix schenckii, Trichophyton mentagrophytes, and Aspergillus fumigatus at the concentration of 50 μg/mL.Graphical abstractA series of novel 2-arylthiazolidin-4-one analogues was prepared and assessed for their in vitro antimicrobial efficacy. Some of the synthesized compounds displayed significant antibacterial efficacy against Klebsiella pneumoniae and selective antimycotic activity against Trichophyton mentagrophytes.