Synthesis of novel isoxazolyl bis-thiazolo[3,2-a]pyrimidines

A new synthetic strategy for the synthesis of novel 3-(3-(3-methyl-4-nitroisoxazol-5-yl)-2-phenyl-1-(5,7-diaryl-7H-thiazolo[3,2-a]pyrimidin-3-yl)propyl)-5,7-diaryl-7H-thiazolo[3,2-a] pyrimidines(7a-i) analogues is described.Reaction of 3-(2(3-methyl-4-nitroisoxazole-5-yl)-1-phenylethyl)pentane-2,4-dione(3) with two moles of thiourea in presence of iodine and CuO afforded 4-(1-(2-aminothiazol-4-yl)-3-(3-methyl-4-nitroisoxazol-5-yl)-2-aryl propyl-thiazol-2-amine(5).Compound 5 on reaction with two moles of chalcone(6) furnished novel 3-(3-(3-methyl-4-nitroisoxazol-5-yl)-2-phenyl-1-(5,7-diaryl-7H-thiazolo[3,2a]pyrimidin-3-yl)propyl)-5,7-diaryl-7H-thiazolo[3,2-a] pyrimidines(7a-i).     

新型环烷烯并嘧啶并噻唑-3-酮类化合物的合成

以环戊酮、环庚酮为起始原料合成的环烷烯并[1,2-d]嘧啶-2-硫酮(2)与氯乙酸、芳香醛反应, 合成具有潜在抗癌活性的稠合杂环化合物5-芳基-2,8-二芳亚甲基-2,3,6,7-四氢-5H,8H-环戊烯并[1,2-d]噻唑并[3,2-a]嘧啶-3-酮(3)以及5-芳基-2,10-二芳亚甲基-2,3,6,7,8,9-六氢-5H,10H-环庚烯并[1,2-d]噻唑并[3,2-a]嘧啶-3-酮(4). 3和4的结构经¹H NMR, IR, MS分析确认.     

An efficient synthesis of novel pyridothieno-fused thiazolo[3,2-a]pyrimidinones via Pictet–Spengler reaction

An efficient method for the synthesis of novel pyrido[3',2':4',5']thieno[3',2':2,3]pyrido [4,5:d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives (5) has been developed using a Pictet-Spengler reaction between 2-(3-aminothieno[2,3-b]pyridin-2-yl)thiazolo[3,2-a] pyrimidin-5-one (3), which could be obtained from the condensation of 7-(chloromethyl)-5H-thiazolo[3,2-a]pyrimidin-5-one (1) with 3-cyanopyridine-2-thione (2) via Thorpe-Ziegler isomerization, and aromatic aldehydes under NH₂SO₃H as catalysis in good yields.     

Rearrangement of thiazolo[3,2-a]pyrimidines into triazolo[4,3-a]pyrimidines induced by C=N bond reduction

Chemistry of Heterocyclic Compounds - Triazolo[4,3-a]pyrimidines were prepared by the reduction of 5,6,7-trisubstituted 2-(arylhydrazinylidene)-5H-[1,3]thiazolo[3,2-a]- pyrimidin-3(2H)-ones with...     

Some chemical properties of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones

We have studied the reaction of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with amines, alkylating reagents, and hydrogen peroxide. We have shown that the presence of an aryl substituent at the 2 position of [1,3-thiazino[3,2-a]benzimidazol-4-ones has a substantial effect on the direction of the reactions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 445–452, March, 2006.     

One-Pot Synthesis of Novel Spiro Pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine Derivatives

In a one-pot synthesis, 1′-methyl-2,3″-dioxo-5″-aryl-1,2,5a″,7″,8″,9a″-hexahydro-5″H,6″H-dispiro[indole-3,2′-pyrrolidine-3′,2″-pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine]-4′-carboxylic acid methyl ester was prepared via the sequential reaction of 4-aryl-octahydro-pyrano[2,3-d]pyrimidine-2-thione, dimethyl acetylenedicarboxylate (DMAD), and a mixture of isatin and sarcosine. All the novel spiro compounds, in moderate yields, were characterized thoroughly by infrared, NMR, mass spectromentry, and elemental analysis together with x-ray crystallographic analysis.     

MgO nanopowders catalyzed synthesis of pyrano[4,3-d]thiazolo[3,2-a]pyrimidine derivatives

A cubic phase of pure MgO nanopowders was prepared in an aqueous solution containing freshly squeezed orange juice with pulp and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared (FT-IR) spectroscopic techniques. The catalytic potential of MgO nanopowders was evaluated in preparation of pyrano[4,3-d]thiazolo[3,2-a]pyrimidine and chromeno[4,3-d]thiazolo[3,2-a]pyrimidines derivatives using the three simple methods including thermal, ultrasonic irradiation, and high-speed ball milling (HSBM) technique under solvent-free conditions. All products were successfully formed in high yields.     

Regioselective Synthesis of 3-Benzylthiazolo[3,2-a]pyrimidones and 3-Benzyl-thiazolo[3,2-c]pyrimidones Through Palladium-Catalyzed Heteroannulation of Acetylenic Compounds

Abstract

The reaction of 2-(prop-2-ynylsulfanyl)pyrimidone 1 with various iodobenzenes in the presence of a palladium catalyst leads to regioselective cyclization to 3-benzylthiazolo [3,2-a] pyrimidones 3. The reaction of 4-(prop-2-ynylsulfanyl) pyrimidone 5 with various iodobenzenes in the same condition give the corresponding 3-benzylthiazolo[3,2-c]pyrimidones 6.     

Utility of a Pyrimidin-2-Thione Derivative in Synthesis of New Fused Thiazolo[3,2-a]pyrimidines

A pyrimidin-2-thione derivative 2 was prepared and treated with 1,2-dibromoethane, chloroacetic acid and ethyl chloroacetate to give the alkylation products 3,4,9,5, respectively. Furthermore, the reaction of 2 with acrylonitrile and hydrazine hydrate yielded the pyrimidino[2,1-b]thiazine derivative 7, and [1,2,4]-triazolo[4,3-a]pyrimidine 8. Compound 9 was used as the key starting material for synthesis of thiazolo[3,2-a]pyrimidine and pyrano[2′,3′ :4,5]thiazolo[3,2-a]pyrimidine derivatives 10–13, through the reaction with ethyl acetate, malononitrile, hydrazine hydrate, β-aroylacrylic acid, and chalcone, respectively. Treatment of compound 5 with 3,5-dibromo-2-aminobenzoic acid in refluxing butanol gave the 3,1-benzoxazinone derivative 6. The structure assignment of the new compounds is based on chemical and spectroscopic evidence.     

海洋生物碱2,3-二羟基-10-溴吲哚[3,2-a]咔唑的简易合成

2,3-二羟基-10-溴吲哚[3,2-a]咔唑(1)是一种从海绵体中提取的具有多种潜在生物活性的天然海洋生物碱.本文作者以3,6-二溴吲哚(2)与5,6-二乙酰氧基吲哚(3)为原料,经过酸催化偶联、分子间成环两步关键反应构建吲哚[3,2-a]咔唑母核;所构建的吲哚[3,2-a]咔唑母核在碱性条件下水解脱去酚羟基上的酯基,即得到目标化合物1,总收率为48%.     

Hexahydrobenzothiazolo[3,2-a]pyridinium salts

Salts of hexahydrobenzothiazolo[3,2-a]pyridine are obtained by exchange reactions. Anions are placed in the order [(NC)₂CCHC(CN)₂]- > ClO₄ ^–>I₃ ^–>Br^– according to the ability to displace each other. X-ray structural and spectroscopic studies establish the cis-attachment of the thiazolidine and cyclohexane rings in the hexahydrobenzothiazolo [3,2-a]pyridinium salts studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1682–1688, December, 1988.     

Convenient synthesis and anticancer evaluation of novel pyrazolyl-thiophene,thieno[3,2-b]pyridine,pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine derivatives

The newly synthesized 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was utilized as a precursor for the synthesis of pyrazolyl-thiophene derivative, which undergoes cyclization upon treatment with benzaldehyde derivatives to provide pyrazolo[3,4-d]thieno[3,2-b]pyridines. Basic treatment of pyrazolyl-thiophene derivative with phenyl isothiocyanate followed by subsequent addition of chloroacetone and/or ethyl bromoacetate yielded the thiazolylidene-pyrazolyl thiophenes. In addition, the building block 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was converted into the corresponding thieno[3,2-b]pyridine compounds through its reactions with (DMF-DMA) and/or heating in sodium ethoxide. Moreover, the reaction of 7-hydroxy-5-oxo-N-phenyl-2-(phenylamino)-4,5-dihydrothieno[3,2-b]pyridine-3-carboxamide with 2-arylidenemalononitrile produced the new annulated pyrano[2,3-d]thieno[3,2-b]pyridines. The prepared thiophene-based compounds were evaluated against HepG2, PC3, and MCF-7 cancer cells, and normal fibroblast cell (WI38). The pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine compounds substituted with chlorophenyl group presented promising cytotoxic activities against HepG2 cancer cell line without any human toxicity. Docking study for the synthesized thiophene compounds delivered valuable insights about the binding interactions with the crystal structure of NS5B enzyme with PDB ID (4TLR).     

Convenient Synthesis of Fluorine-Containing 2-Aryl-5H-[1,3,4]thiadiazolo[3,2-a]quinazolin-5-ones

Russian Journal of Organic Chemistry - An efficient synthetic approach to new fluorine-containing [1,3,4]thiadiazolo[3,2-a]quinazolin-5-ones has been developed on the basis of intramolecular...     

Synthesis and Crystal Structure of 1-（4-Fluorophenyl）-2-hexylthiobenzo[4,5]-furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5（1H）-one

The crystal structure of the title compound 1-(4-fluorophenyl) -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H) -one(C23H21FN4O2S,Mr = 436.5) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 13.9854(3) ,b = 17.2678(4) ,c = 18.1828(5) ,β = 99.364(2) °,V = 4332.58(18) 3,Z = 4,Dc = 1.338,F(000) =1824,μ = 0.185 mm-1,MoKa radiation(λ = 0.71073) ,R = 0.0538 and wR = 0.1162 for 4728 observed reflections with I > 2σ(I) . X-ray diffraction analysis reveals the fused rings of benzo[4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a] pyrimidin-5(1H) -one system are nearly coplanar. The crystal packing is mainly stabilized by weak intermolecular C-H···O hydrogen bond and π-π interactions.     

Synthesis of heterocyclic compounds possessing the 4H-thieno[3,2-b]pyrrole moiety

A series of novel heterocyclic combinatorial libraries containing 4H-thieno[3,2-b]pyrrole, thieno[2',3':4,5]-pyrrol[1,2-d][1,2,4]triazine and thieno[2',3':4,5]pyrrolo[1,2-a]pyrazine heterocyclic moieties were obtained by parallel solution-phase synthesis. Key steps include different reactions of initial alkyl 4H-thieno[3,2-b]-pyrrole-5-carboxylates, such as alkylation with alkylating agents; transformation of the carboxylate group into different reactive functionalities, followed by reactions with electrophilic species; intramolecular cyclizations; and amide bond formation. Simple manual techniques for parallel reactions were coupled with easy purification procedures to give high-purity final products.     

Dakin-West trick in the design of novel 2-alkyl(aralkyl) derivatives of oxazolo[3,2-a]pyridines

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of further utilization of this strategy is illustrated by preparation of unknown 2-benzylimidazo[1,2-a]pyridine from the salt I and ammonia.     

Synthesis and antiallergy activity of [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one derivatives. II. 6-Alkyl- and 6-cycloalkylalkyl derivatives.

A series of 6-alkyl- or 6-(cycloalkylalkyl)-[1,3,4]thiadiazolo[3,2- a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-ones 1b--o was synthesized from the corresponding 1,3,4-thiadiazol-5-amines 3b--o and the antiallergic activities of the products were evaluated. Among the compounds 6-(2-cyclohexylethyl)- [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one 1h, whose X-ray crystallographic stereostructure is shown, was found to be a promising new antiallergic agent, which has low toxicity and dual activity as a leukotriene D4 receptor antagonist and as an orally active mast cell stabilizer.     

Unusual sulfamate indoles and a novel indolo[3,2-a]carbazole from Ancorina sp

Four new indoles, ancorinolates A-C and bis-ancorinolate B, which contain sulfamate and sulfate groups, were isolated from the aqueous extract of the sponge Ancorina sp. In addition, ancorinazole, an indolo[3,2-a]carbazole also possessing sulfamate and sulfate groups, was isolated from two separate New Zealand collections of Ancorina sp. Ancorinazole is the first indolo[3,2-a]carbazole described as a natural product. Ancorinolates A (1) and C (3) showed weak HIV-inhibitory activity in the XTT-based, anticytopathicity assay.     

Studies with Polyfunctionally Substituted Heterocycles: New Synthesis of Pyrido[5′, 4′:2,3][1,3,4]oxadiazolo[3,2-a]pyridine; Pyridazine; 1,3,4-Oxadiazote; and Pyrazolo[1,5-a]Pyrimidine Derivatives

Cyanoacetohydrazide 1a reacts with 2-arylhydrazoketons 2a,b and 3a,b in refluxing ethanol to yield pyrido[5′,4′:2,3][1,3,4]oxadiazolo[3,2-a]pyridine and pyridazine derivatives; in the absence of solvent pyrazolo[1,5-a]pyrimidine derivatives were obtained. The reaction of 2a,b and 3a,b will) benzoylhydrazine afforded 1,3,4-oxadiazole and pyrazole derivatives.     

Electrophilic substitution of furo[3,2-c] pyridine

Furo[3,2-c] pyridine (I) was nitrated to give 2-nitrofuro[3,2-c]pyridine (II). Bromination and chlorination of I gave, respectively, 2,3-dibromo-2,3-dihydrofuro[3,2-c]pyridine (III) and 2,3-dichloro-2,3-dihydrofuro[3,2-c]pyridine (IV). Oxidation of I with hydrogen peroxide afforded furo[3,2-c]pyridine 5-oxide (V) which was converted to I by phosphorus trichloride and to 4-chlorofuro[3,2-c]pyridine (VI) by phosphorus oxychloride.