A facile one-pot synthesis of 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-<Emphasis Type="Italic">d</Emphasis>]-1,2,4-triazolo[4,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-5-ones

Abstract  The reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species. Graphical abstract        

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.     

Thieno[2,3-d]pyrimidin-4-ones 1. Condensation of 2,3-dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-7,8-dihydro-pyrrolo[1,2-a]thieno[2,3-d]pyriminidin-4(6H)-ones with aromatic aldehydes and furfural

2,3-Dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-substituted 8-arylidene-6,7-dihydro-pyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4-ones were synthesized by the reaction of 2,3-dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-7,8-dihydropyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4(6H)-ones with benzaldehyde, its 4-dimethylamino-, 3,4-dimethoxy-, and 3,4-methylenedioxy derivatives and also furfural in the presence of NaOH.     

Substituted 2-aminonicotinamides in the synthesis of pyrido[2,3-d]pyrimidin-4(1H)-ones, 2,3-dihydropyrido- [2,3-d]pyrimidin-4(1H)-ones, and 11b,12-dihydropyrido- [2',3':4,5]pyrimido[2,1-a]isoindole-5,7-diones

The reactions of 2-aminonicotinamides with triethyl orthoformate, carboxylic acids chlorides, aldehydes, and 2-formylbenzoic acid were studied. As a result pyrido[2,3-d]pyrimidin-4(1H)-ones, 2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-ones, and 5,7,11b,12-tetrahydropyrido[2',3':4,5]pyrimido- [2,1-a]isoindole-5,7-diones were obtained.     

Iminophosphorane-mediated efficient synthesis of new tricyclic 3,5-dihydro-1,2,3-triazolo[4,5-d]-1,2,4-triazolo[1,5-a]pyrimidin-9-ones

The carbodiimides 2, obtained from aza-Wittig reactions of iminophosphorane 1 with aromatic isocyanates, reacted with hydrazine to give selectively 6-amino-7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones 5. Compounds 5 were further transformed to iminophosphoranes 6 by reaction with triphenylphosphine, hexachloroethane and triethylamine. A tandem aza-Wittig reaction of iminophosphorane 6 with isocyanate or acyl chloride generated previously unreported 3,5-dihydro-1,2,3-triazolo[4,5-d]-1,2,4-triazolo[1,5-a]pyrimidin-9-ones 10 or 12 in satisfactory yield. X-ray structure analysis of 10 g verified the proposed structure and the reaction selectivity.     

Synthesis of 2,3-Dihydrothiazolo[3,2-a]pyrimidin-5-ones by a Michael-type Tandem Reaction

Although various thiazoles are known in literature for their biological and pharmacological properties only a few multi-step synthesis pathways for the preparation of thiazolo[3,2-a]pyrimidinones have been reported, which are tedious and time-consuming. An alternative synthesis pathway is described, which allows the preparation of 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-ones in a one-step process based on a Michael-type tandem reaction. By heating of 2-thiobarbituric acid with ethyl 4-bromocrotonate in ethanol at 60°C for 2 h, a 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one was obtained in 73% yield, whereas carrying out the reaction at room temperature results in the formation of an unstable unsaturated ester. The structures of both, the α,β-unsaturated ester as well as the 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one were confirmed by NMR spectroscopy. Additionally, the structure of the 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one was investigated by single-crystal X-ray analysis. The described approach offers a significant improvement over previously reported synthesis pathways because it allows the simple preparation of 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-ones with good yields in a one-step reaction.     

2-氨基噻吩并[2,3-d]嘧啶-4(3H)-酮衍生物的合成

丁醛(1)、氰乙酸乙酯、硫磺在三乙胺作用下制得2-氨基-4-乙基噻吩-3-羧酸乙酯(2), 2再与三苯基膦、六氯乙烷及三乙胺反应, 以84%的产率得到膦亚胺3. 应用膦亚胺3与芳基异氰酸酯的氮杂Wittig反应, 生成的碳二亚胺4, 再与仲胺作用得到中间体5, 而后在醇钠的催化下关环制得2-二烷氨基噻吩并[2,3-d]嘧啶-4(3H)-酮衍生物6, 产率为58%～82%.     

2-取代氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶类衍生物的合成

以2-溴丙酸甲酯、α,α-二氯甲基甲醚和胍唑为原料, 经缩合以及环化反应制得2-氨基-6-甲基-5-氧代-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶. 为了提高其在有机溶剂中的溶解性, 该化合物再同1-溴丁烷发生亲核取代反应得到了2-氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶, 然后与芳基醛和叔丁基异氰发生Ugi多组分反应, 合成了一系列具有潜在催吐活性的2-取代氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶类衍生物, 产品结构经质谱、核磁共振谱及元素分析确认.     

The synthesis of 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles,11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles and 1,2,4-triazolo[3,4-f]-1,2,4-triazino[4,5-a]indoles

This paper describes the synthesis of the previously unknown 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles (2) and 11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles (3) from 4-hydrazino-5H-pyridazino[4,5-b]indoles (1) , as well as the synthesis of 1,2,4-triazolo[3,4-f]-1,2,4-triazino-[4,5-a]indoles (10) from 2-indolecarbohydrazide (4) . Compounds 2 were obtained by acylation of compounds 1 , followed of thermal cyclization and compounds 3 by treating compounds 1 with nitrous acid. The reactions of compound 4 with formic acid or ethyl orthoformiate gave 1,2-dihydro-1-oxo-1,2,4-triazino[4,5-a]indole (6) . Treating this last compound with phosphorus oxychloride or phosphorus pentasulfide, followed by hydrazine, gave 1-hydrazino-1,2,4-triazino-[4,5-a]indole (9) . Acylation of this last compound, followed of cyclization gave compounds 10 . All the compounds were characterized by elemental analysis and ir and ¹H-nmr spectra.     

Derivatives of condensed thieno[2,3-d]-pyrimidines. 20. Synthesis of 2-substituted 5,6-dihydro-8H-pyrano[4′,3′:4,5]thieno[2,3-d]pyrimidin-4(3H)-ones and 5,6,7,8-tetrahydrobenzo-[b]thieno[2,3-d]pyrimidin-4-ones

We have developed a method for obtaining 2-substituted 3-amino-6,6-dimethyl-5,6-dihydro-8H-pyrano[4′,3′:4,5]-and 5,6,7,8-tetrahydrobenzo[b]thieno[2,3-d]pyrimidin-4(3H)-ones, converted by deamination to the corresponding dihydropyranothieno-3H-pyrimidinones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 441–444, March, 2006.     

Synthesis of new imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-one derivatives by iodocyclization of 6-alkenyl(alkynyl)-aminopyrazolo[3,4-d]pyrimidin-4(5H)-ones

6-Allyl(diallyl, prop-2-yn-1-yl)amino-1-R-pyrazolo[3,4-d]pyrimidin-4(5H)-ones reacted with iodine to give angularly fused 8-iodomethyl-7,8-dihydro-1-R-imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-ones which were treated with sodium acetate to obtain 8-methylidene-1-R-7,8-dihydroimidazo[1,2-a]pyrazolo-[4,3-e]pyrimidin-4(6H)-ones as a result of elimination of hydrogen iodide. 8-Methylidene-1-R-7,8-dihydroimidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-ones were converted into 8-methyl-1-R-imidazo[1,2-a]pyrazolo-[4,3-e]pyrimidin-4(5H)-ones on heating to the melting point. 8-Methylidene-1-phenyl-7,8-dihydroimidazo-[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-one underwent isomerization into linearly fused 6-methyl-1-phenyl-1,8-dihydro-4H-imidazo[1,2-a]pyrazolo[3,4-d]pyrimidin-4-one on heating in sulfuric acid.     

Synthesis of 8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine

8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine has been synthesized by the interaction of 6-tert-butyl-3-hydrazino-1,2,4-triazolo[3,4-c]-1,2,4-triazin-5-one with formic acid. The conditions of carrying out the reaction are discussed. Spectral characteristics are given.     

Microwave assisted synthesis of 2,3-dihydro-4H-benzo[4,5]thiazolo[3,2-a]furo[2,3-d]pyrimidin-4-ones and 6,7-dihydro-5H-furo[2,3-d]thiazolo[3,2-a]pyrimidin-5-ones using Mn(OAc)3

2-Hydroxy-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-4-one 2a and 7-hydroxy-5H-thiazolo[3,2-a]pyrimidin-5-one 2b, were obtained in high yields under mild conditions from the cyclization reactions of bis-(2,4,6-trichlorophenyl) malonate and 2-aminobenzothiazole or 2-aminothiazole, respectively. A new class of compounds, 2,3-dihydro-4H-benzo[4,5]thiazolo[3,2-a]furo[2,3-d]pyrimidin-4-ones and 6,7-dihydro-5H-furo[2,3-d]thiazolo[3,2-a]pyrimidin-5-ones, were synthesized via the microwave assisted radical addition of compounds 2a and 2b to various alkenes using manganese(III) acetate. A preliminary acetylcholine esterase (AchE) inhibition test of compound 4e showed excellent (92%) inhibitory potential, comparable with the standard drug Donapezil®.     

A Solution-Phase Parallel Synthesis of 5-Substituted 3,6-Dihydro-7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones

5‐Substituted 7H‐1,2,3‐triazolo[4,5‐d]pyrimidin‐7‐ones ( 4 ) were rapidly prepared by a solution‐phase parallel synthetic method, which includes aza‐Wittig reaction of iminophosphorane ( 1 ) with phenyl isocynate to give carbodiimide ( 2 ) and subsequent reaction of 2 with various amine and alcohols in the presence of catalytic amount of sodium alkoxide in a parallel fashion.     

Synthesis of thieno[2,3-e]-1,2,4-triazines

3-Methylmercapto-5-oxo-6-vinyl- and 2-methyl-3-mercapto-5-oxo-6-vinyl-2,5-dihydro-1,2,4-triazines were readily converted into the corresponding thieno[2,3-e]-1,2,4-triazine in one step by the action of phosphorus pentasulfide in pyridine. 4-Methyl-3-mercapto-5-oxo-4,5-dihydro-1,2,4-triazine is only converted into the 5-thioxo analog and no thiophene ring product was obtained under the same conditions. Thieno[2,3-e]-1,2,4-triazines were also more efficiently obtained by the action of phosphorus petnasulfide in pyridine on the appropriate 6-acylmethyl-3-mercapto-5-oxo-2,5-dihydro-1,2,4-triazine.     

Solid-phase synthesis of pyrido[2,3-d]pyrimidin-7-ones

A novel solid-phase method for the synthesis of 4-methyl-pyrido[2,3-d]pyrimidin-7-one compounds with two diversity points is described. The polymer supported methylsulfonyl derivatives A₃, achieved by coupling compound G with different resin-bound amines A₁ followed by oxidation with MCPBA, are substituted with several amines R₁R₂NH. Final cleavage affords 126 compounds having formula H in good yield and purity.     

Synthesis of imidazo[4,5-a]acridones and imidazo[4,5-a]acridines as potential antibacterial agents

Abstract  

New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl₃. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug.     

The synthesis of substituted pyrazino[2,3-d]-1,2,4-triazolo[4,3-b]pyridazines

The synthesis of 1,2,4-triazolo[4,3-b]pyridazines and the unknown ring system, pyrazino[2,3-d]-1,2,4-triazolo[4,3-b]pyridazine, has been achieved. The preparation of the new tricyclic 1,2,4-triazole was accomplished first by ring closure of the triazole ring followed by formation of the pyrazine ring. Substitution of the pyrazino[2,3-d]-1,2,4-triazolo[4,3-b]pyridazine ring system was carried out in order to provide information of its reactivity and to provide a variety of interesting compounds for biological testing.     

A convenient synthesis of trisubstituted pyrido[2,3-d]pyrimidin-7-ones

A novel, highly efficient and scalable route for the synthesis of trisubstituted pyrido[2,3-d]pyrimidin-7-ones was developed. The target compounds were synthesized in five steps from readily available reagents in about 40% overall yield.