Synthesis of Some Novel 5-(Arylidene)-2-imino-3(pyridin-2-yl)thiazolidin-4-one Derivatives

Treatment of 2-aminopyridine ( 1 ) with chloroacetyl chloride in dry benzene gave 2-chloro-N-(pyridin-2-yl)acetamide ( 3 ), which on further reaction with potassium thiocyanate gave 2-imino-3-(pyridin-2-yl)thiazolidin-4-one ( 4 ) as an intermediate compound for the synthesis of pyridin-2-yl substituted 2-imino-thiazolidine-4-one derivatives. Cyclocondensation reaction of ( 4 ) with a series of aromatic aldehydes gave 5-arylidene derivatives of pyridin-2-yl substituted 2-imino-thiazolidine-4-ones 5a–j . ¹ H and ¹³C NMR spectroscopy, as well as elemental analyses, were used for the identification of these new compounds.     

Palladium complex of 6-(2-hydroxy-5-methylphenyl)-3-(pyridin-2-yl)-1,2,4-triazin-5(2<Emphasis Type="Italic">H</Emphasis>)-one: Synthesis,structure, and catalytic activity

Palladium(II) complex with 6-(2-hydroxy-5-methylphenyl)-3-(pyridin-2-yl)-1,2,4-triazin-5(2H)-one was synthesized for the first time. The ligand was prepared from 3-(pyridin-2-yl)-1,2,4-triazin-5(2H)-one and 4-methylphenol via nucleophilic substitution of hydrogen (S_N^H reaction). The complex was readily soluble in basic medium, and it effectively catalyzed Mizoroki-Heck reaction.     

Reaction of 3(Z)-benzoylmethylidene-6-nitro-3,4-dihydro-2H-1,4-benzooxazin-2-one with oxalyl chloride

3(Z)-Benzoylmethylidene-6-nitro-3,4-dihydro-2H-1,4-benzooxazin-2-one reacts with (COCl)₂ as imino enol rather than enamino ketone. The reaction is accompanied by replacement of the hydroxy group by chlorine. The molecular and crystal structures of the starting 1,4-benzooxazin-2-one and its chlorinated derivative were studied by X-ray diffraction analysis.     

Synthesis,crystal structure and fluorescence of a two-dimensional coordination polymer with 1-(pyrazin-2-yl)pyridine-2(1H)-one and thiocyanate as mixed bridge ligands

A two-dimensional sheet coordination polymer, [Cd(μ-C₉H₇N₃O)(μ-NCS)₂] _n , (C₉H₇N₃O=1-(pyrazin-2-yl)pyridin-2(1H)-one), has been synthesized with 1-(pyrazin-2-yl)pyridin-2(1H)-one and thiocyanate anion as bridging ligands, and its crystal structure determined by X-ray crystallography. The crystal belongs to monoclinic system with space group P2₁ /c, and its relevant crystal parameters are: a?=?7.5392(16) Å, b?=?18.343(4) Å, c?=?10.155(2) Å, β?=?106.362(3)°, Z?=?4, V?=?1347.4(5) ų, C₁₁H₇CdN₅OS₂, D _Calcd?=?1.980, R?=?0.0516. The crystal structure reveals that both 1-(pyrazin-2-yl)pyridin-2(1H)-one and thiocyanate anion connect adjacent Cd(II) ions resulting in a two-dimensional sheet structure in the bc plane. There are weak π–π stacking interactions between adjacent pyridine rings. The coordination polymer has weaker fluorescent emission in the solid state than 1-(pyrazin-2-yl)pyridin-2(1H)-one compound, attributed to the π–π stacking interaction and the coordination effect.     

A 2D coordination polymer with 4*82 topology constructed from a new T -shaped ligand: synthesis,crystal structure and photoluminescence

A cadmium(II) coordination polymer [CdL(H₂O)] (1) (H₂L?=?3,3-bis(carboxymethyl)imidazo[1,2-a]pyridin-2-one) was synthesized under hydrothermal conditions and characterized by X-ray structure analysis. Compound 1 crystallizes in the monoclinic space group P2₁/n with a?=?11.945(2)?Å, b?=?8.0865(16)?Å, c?=?13.114(3)?Å, β?=?91.36(3)°, Z?=?4, and represents a 2D network with the 4*8² topology constructed from combination of metal centers with a T-shaped geometry and ligands with T-shaped structure simultaneously. Compound 1 also exhibits strong photoluminescence at room temperature.     

A Novel and Efficient Reaction of Imidazolidin-2-one and N-Acylbenzotriazoles: A Facile Synthesis of 1-Acylimidazolidin-2-one

Acylation of imidazolidin-2-one with readily available N-acylbenzotriazoles, in the presence of K₂CO₃, produced 1-acylimidazolidin-2-ones and N,N′-diacyl-imidazolidin-2-one in moderate to good yields. The utilization of N-acylbenzotriazoles which make the reaction simple and mild, may be especially advantageous when the corresponding acid chlorides are not stable or not easily prepared. It's also an example of the reaction of N-acylbenzotriazoles and amide.     

Synthesis of substituted 2-amino-3-cyano-7,9-dimethyl-4H-pyrano[2",3":4,5]thieno[2,3-b]pyridines

4,6-Dimethyl-2H-thieno[2,3-b]pyridin-3-one reacts with 2-aryl-1,1-dicyanoethylenes or an aromatic aldehyde/ketone (cyclohexanone and piperidone derivatives) and malononitrile to give substituted 2-amino-3-cyano-7,9-dimethyl-4H-pyrano[2",3":4,5]thieno[2,3-b]pyridines.     

A novel kind of dimmer (excimer)-induced-AIE compound 2-phenylisothiazolo[5,4-b]pyridin-3(2H)-one as high selective bisulfite anion probe

An interesting dimmer (excimer)-induced-AIE characteristic of 2-phenylisothiazolo[5,4-b]pyridin-3(2H)-one was observed. By using a ring-opening reaction, we developed a novel fluorescent probe based on sub-micron particles of 2-phenylisothiazolo[5,4-b]pyridin-3(2H)-one in water.     

Reaction of 2-methoxy-1,3,2-dioxaphosphorino[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-4(4<Emphasis Type="Italic">H</Emphasis>)-one with hexafluoroacetone

The reaction of the di-O-trimethylsilyl derivative of 2-hydroxynicotinic acid with methyl phosphodichloridite afforded 2-methoxy-1,3,2-dioxaphosphorino[4,5-b]pyridin-4(4H )-one. The NMR spectrkscopic data suggest that the reaction of the latter with hexafluoroacetone produces unstable 2-methoxy-2,5-dioxo-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyridine, which is readily transformed into 9-methyl-2,5-dioxo-4,4- bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyrid-9-inium-2-oate. The structure of the hydrolysis product of the latter, viz., 1-methyl-3-(2-hydroxy-3,3,3-trifluoro-2- trifluoromethylpropanoyl)pyridin-2-one, was established by X-ray diffraction analysis.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1640–1646, August, 2004.     

Expedient Synthesis of 6-Aryl Derivatives of 3,4-Dihydro-1,4,4a,6a-tetraaza-benzo[a]fluoren-2-one: A New Heterocyclic Framework

3,4-Dihydro-1,4,4a,6a-tetraaza-benzo[a]fluoren-2-one, a new tetracyclic heterocyclic framework, is designed through a simple and convenient synthetic sequence. Its 6-aryl derivatives are synthesized starting from 1H-indole-2-carboxylic acid. The reaction of differently substituted phenacyl bromides with 1H-indole-2-carboxylic acid and POCl₃-mediated cyclization of the resultant 1H-indole-2-carboxylic acid phenacyl ester provided 2-oxa-4a-aza-fluoren-1-one, and its sequential reaction with hydrazine and 2-chloro-acetamide furnished the desired new heterocyclic compounds 7a–f.     

2-氨基-4-羰基噻吩的Knoevenagel反应

在碳酸钾等无机碱的存在下,异硫氰酸酯和4-氯乙酰乙酸乙酯反应生成2-氨基-4-羰基-4,5-二氢噻吩-3-甲酸乙酯。该化合物显示了与醛基的反应活性,即Knoevenagel反应,本文对该噻吩化合物的Knoevenagel反应位点选择性进行了研究。运用Gaussian03程序对化合物进行了几何全优化和相应的电荷、轨道能量分析研究。     

The Use of 4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one as “Masked” α-Bromo-α'-Hydroxy Ketone in the Synthesis of Heterocyclic Systems

4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one was obtained on the basis of the readily obtainable 4-methylene-5,5-dimethyl-1,3-dioxolan-2-one. It forms 2-imidazo[1,2-a]pyridin-2-yl-2-propanol with 2-aminopyridine, 11a-hydroxy-1,1-dimethyl-3-oxo-1,5,11,11a-tetrahydro[1,3]oxazolo[3,4-a]pyrido[1,2-d]-10-pyrazinium bromide with 2-(aminomethyl)pyridine, and the corresponding derivative of 4-hydroxyoxazolidin-2-one with 2-(3,4-dimethoxyphenyl)ethylamine. The last product was converted by intramolecular amidoalkylation without isolation into 10b-(bromomethyl)-8,9-dimethoxy-1,1-dimethyl-1,5,6,10b-tetrahydro[1,3]oxazolo[3,4-a]isoquinolin-3-one.     

Syntheses,structures, and properties of four coordination polymers based on 2,7-di(pyridin-4-yl)-9H-fluoren-9-one

Four coordination polymers (CPs), [Cd(2,7-dpfo)₂(NO₃)₂(CH₃OH)]_n (1) , [Zn(2,7-dpfo)(NO₃)(CH₃COO)]_n (2) , [Co(2,7-dpfo)₂(H₂L)]_n (3) , and [Ni(2,7-dpfo)₂(H₂L)]_n (4) (where 2,7-dpfo is 2,7-di(pyridin-4-yl)-9H-fluoren-9-one and H₄L is 1,1′:4′,1′′-terphenyl-4,2′,5′,4′′-tetracarboxylic acid), were synthesized and structurally characterized. Compounds 1 – 4 were determined by elemental analyses, single crystal X-ray diffraction analyses, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analyses. Compound 1 displays a one-dimensional (1D) zigzag chain structure, while compound 2 possesses a 1D ladder chain structure. Compounds 3 and 4 are isostructural and consist of 1D chains. The solid-state luminescent properties of 1 and 2 and the magnetic properties of 3 and 4 were also investigated.     

Synthesis of 3-(3-Methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one Derivatives via a One-Pot,Three-Component Reaction

An efficient synthesis of 3-(3-methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one derivatives by the reaction of salicylaldehydes, 4-hydroxy-6-methyl-2H-pyran-2-one, and arylhydrazine in acetonitrile under reflux condition and in the presence of piperidine is reported. This three-component reaction has some advantages such as ease of handling, good yields, and easy purification. All structures were confirmed by infrared, mass, ¹H NMR, and ¹³C NMR spectroscopy.     

Synthesis and Photoisomerization of 3-Cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one

The condensation of 4-nitrobenzaldehyde with 3-cyano-4,6,6-trimethyl-5,6-dihydropyran-2-one leads to the formation of a crotonization product and a compound of the Michael adduct type. The main product of the photochemical conversion of (E)-3-cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one is the Z-isomer. Investigation of the photoisomerization of 3-cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one by the semiempirical AM1 method showed that in the ground state the E-isomer was thermodynamically more stable than the E-isomer. E-Z-photoisomerization is effected most probably through the lowest excited singlet state S₁.     

One step synthesis of 1,5-diaryl pyridin-2(1H)-ones from 2-aryl vinamidinium salts and N-aryl cyanoacetamides

A one step, direct method for the synthesis of 1,5-diaryl pyridin-2(1H)-one derivatives by condensation of 2-aryl vinamidinium salts with N-aryl cyanoacetamides has been developed. This method can conveniently provide the corresponding 1,5-diaryl pyridin-2(1H)-one derivatives with various substituents in good yields and overcome the drawbacks of existing methods such as poor substrate scope, heavy metal pollution, and low yields. The formation mechanism of the products was illustrated.     

2-Trif luoromethyl-4H-thiochromen-4-one and 2-trif luoromethyl-4H-thiochromene-4-thione: Synthesis and reactivities

2-Trifluoromethyl-4H-thiochromene-4-thione obtained from 2-trifluoromethyl-4H-thiochromen-4-one and P₂S₅ reacts with aromatic amines, hydrazine hydrate, phenylhydrazine, and hydroxylamine at the C(4) atom of the chromene ring to give the corresponding anils, azine, hydrazones, and oxime of thiochromone. 2-Trifluoromethyl-4H-thiochromen-4-one is oxidized by hydrogen peroxide in AcOH into 4-oxo-2-trifluoromethyl-4H-thiochromene 1,1-dioxide and reduced by NaBH₄ to 2-trifluoromethyl-4H-thiochromen-4-ol or cis-2-(trifluoromethyl)thiochroman-4-ol. When treated with hydrazine hydrate, thiochromen-4-one gives 3(5)-(2-mercaptophenyl)-5(3)-trifluoromethylpyrazole. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 504–509, March, 2006.     

Synthesis of azolo[a]pyridines from 5-(bromomethyl)hept-4-en-3-one and 5-bromopent-3-en-2-one derivatives

Alkyl derivatives of 1H-imidazo[1,2-a]pyridin-4-ium, 5H-pyrido[1,2-a]benzimidazol-10-ium, 1H-[1,2,4]-triazolo[4,3-a]pyridin-4-ium, and 3-methylthiazolo[3,2-a]pyridin-4-ium bromides were obtained in two stages from (4Z)-5-(bromomethyl)-2,2,6,6-tetramethylhept-4-en-3-one, 5-bromo-4-methylpent-3-en-2-one, or (3E)-5-bromopent-3-en-2-one by alkylation of 1-alkyl-1H-imidazoles, 1-alkyl-1H-benz-imidazoles, 1-methyl-1H-1,2,4-triazole, and 4-methylthiazole and subsequent cyclization of the quaternary azolium salts in the presence of bases.     

Synthesis of Novel 2-(4-Oxo-3,4- Dihydroquinazolin-2-Ylsulfinylmethyl)-3H-Quinazolin-4-One

Abstract

Condensation of 2-mercapto-3H-quinazolin-4-one (1) with chloroacetic acid gave 4-oxo-3,4-dihydroquinazoline-2-yl-sulfanyl)-acetic acid (2) that with anthranilamide (3) gave 2-(4-oxo-3,4-dihydroquinazolin-2-ylsulfanylmethyl)-3H-quinazolin-4-one (4). Oxidation of 4 with sodium hypochlorite in alkaline medium gave the novel product, 2-(4-oxo-3,4- dihydroquinazolin-2-ylsulfinyl methyl)-3H -quinazolin-4-one) (5). The entire sequences of reactions in this work have been carried out using eco-friendly solvents and green conditions.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

A simple and efficient approach for the synthesis of a novel class aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives via intramolecular nucleophilic substitution reaction

In this study, we synthesized a new series of substituted aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives (6-24) in yields ranging from 42 to 70% with an interesting mechanism that involves internal nucleophilic substitution followed by an S_N2-type nucleophilic substitution. First, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanone (3) was synthesized from the reaction of 5-methyl-1,3,4-thiadiazole-2-thiol (1) with 2-bromo-1-(4-chlorophenyl)ethanone (2) in the presence of potassium hydroxide. Then, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanol (4) was synthesized by a reduction reaction of this compound using NaBH₄. Finally, 5-methyl-3-alkyl-1,3,4-thiadiazol-2(3H)-one derivatives (6-24), which are the target compounds, were synthesized from the reaction of this compound (4), which is a secondary alcohol with various alkyl halides (5a-n) in the presence of sodium hydride (NaH). This study presents an interesting reaction mechanism related to the synthesis of aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives that is not recorded in the literature.