Synthesis of 1-｛ Imidazo[ 1,2-a ] pyridin-2-yl ｝ guaiazulenes

以1-氯乙酰基愈创兰烃奠和取代2-氨基吡啶为原料,一锅法合成了一系列未见文献报道的1-{2-咪唑[1,2-a]吡啶基}愈创兰烃薁衍生物,收率47％ ～ 74％,其结构经1H NMR,IR和元素分析表征.     

Synthesis of 11-aryl-11H-indeno[1′,2′:4,5]imidazo[1,2-a]pyridines via dehydrative cyclization of aryl(2-arylimidazo[1,2-a]pyridin-3-yl)methanols

A series of 11-aryl-11H-indeno[1′,2′:4,5]imidazo[1,2-a]pyridines was obtained via AlCl₃-promoted, dehydrative cyclization of the corresponding aryl(2-arylimidazo[1,2-a]pyridin-3-yl)methanols in moderate to good yields. The synthesized compounds can be considered as conformationally restricted, privileged aza-heterocyclic scaffold bearing triarylmethane analogs.     

“On-water” one-pot four-component synthesis of novel 1H-furo[2,3-c]pyrazole-4-amine derivatives

Research on Chemical Intermediates - A catalyst-free, simple and green protocol has been accomplished for the synthesis of novel 1H-furo[2,3-c]pyrazole-4-amines in a one-pot four-component domino...     

Intramolecular Ullmann-type C−N coupling for the synthesis of substituted benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridines

An efficient CuI catalyzed intramolecular Ullmann-type C−N coupling reaction is described here. Newly substituted 1H-benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridine-1,3,5(2H, 11H)-trione has been easily synthesized from ortho halogenated N-substituted pyrrolo[3,4-c]pyridine-1,3,6(5H)-triones in presence of CuI catalyst and K₂CO₃ base without any ligand. This procedure is based on intramolecular Ullmann-type reaction and provides a proficient method of making fused tetracyclic heterocycles.     

Synthesis,Reactions, and Antiviral Activity of 1-(1H-Pyrazolo[3,4-b]pyridin-5-yl)ethanone and Pyrido[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazine Derivatives

1-(3-Amino-6-methyl-4-pyridin-3-yl-1H-pyrazolo[3,4-b]pyridin-5-yl)ethanone (3) was obtained in very pure state and used as a good starting material for the present study. It diazotized to give the corresponding diazonium salt 9 and also reacted with phenyl isothiocyanate to give the corresponding thiourea derivative 4. Compound 4 was used for the preparation of thiazole derivatives 5–8 via the reaction with active halogen-containing compounds. On the other hand, compound 9 coupled with several active –CH₂- containing compounds to afford the corresponding triazine derivatives 10–17. Considering the data from IR, ¹ H NMR, mass spectra, and elemental analyses, the chemical structures of the newly synthesized heterocyclic compounds were elucidated. Cytotoxicity, anti-HSV1, and anti-HAV-MBB activity were evaluated for the newly synthesized heterocyclic compounds.     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 1. Quantum-chemical study of dipyrrolo[1,2-a; 2′,1′-c]pyrazines in electrophilic substitution reactions

The semiempirical quantum-chemical method PM3 has been used in a study of the electronic and spatial structure of dipyrrolo[l , 2-a; 2,1-cjpyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2,1-cjpyrazines, and also their reactivities in electrophilic substitution reactions (protonation, acylation).M. V. Lomonosov Moscow State University, Moscow 119899 Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1559–1565, November, 1995. Original article submitted September 13, 1995     

Synthesis of (1H)-3,4-Dihydropyrrolo[2,1-c][1,4]oxazin-1-one Derivatives

It has been found that some acyl derivatives of 1,2,3,4-tetrahydro-1-indolizin-1-one 1and (1H)-3,4-dihydropyrrolo[1,2-a]pyrazin-1-one 2 show remarkable anti-inflammatory and analgesic activities1,2. The interest in extending the study of structure-activity relationships and search of new potent anti-inflammatory and analgesic agents led us to design and synthesize (1H)-3,4-dihydropyrrolo[2,1-c][1,4]oxazin-1-one 3 derivatives. NO 1 NNHO2 87654321ONO3 A few examples of the p…     

Novel synthesis of tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones via decarboxylative cyclization reaction of α-amino acids and α-ketoamides

An efficient and practical method was developed for the synthesis of tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones based on the decarboxylative cyclization reaction of α-ketoamides and proline. In most cases, tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones were obtained with perfect diastereoselectivity to give trans-isomer in excellent yield.     

Rapid and efficient one-pot microwave-assisted synthesis of 2-phenylimidazo[1,2-a]pyridines and 2-phenylimidazo[1,2-a]quinoline in water–PEG-400

An effective, expeditious, environmentally benign one-pot synthesis of 2-phenylimidazo[1,2-a]pyridines and 2-phenylimidazo[1,2-a]quinoline from easily available starting materials as aromatic carbonyl compound, 2-amino pyridine, succinamide, and in situ generated α-iodo acetophenone in combination with green solvent PEG-400 and water (2:1) under microwave irradiation. The newly developed protocol with excellent yield of product in very short time of reaction by avoiding the use of lachrymatric α-chloro and α-bromocarbonyl compounds, volatile, toxic organic and hazardous solvents, reagents is the advantage of this research work. The final products were confirmed by their characterization data such as ¹H NMR, ¹³C NMR, high resolution mass spectrometry (HRMS) and were compared with its reported method.     

Synthesis and Structure of 2-(1Н-Indol-1-yl)-6-ferrocenyl-4-(2-chloroimidazo[1,2-a]pyridin-3-yl)pyrimidine

A 2,4,6-trisubstituted pyrimidine including a 2-(1H-indol-1-yl) substituent was synthesized by the reaction of 1-ferrocenyl-3-(2-chloroimidazo[1,2-a]pyridin-3-yl)propanone with 2,5-dimethoxytetrahydrofuran. The structure of the synthesized compound was confirmed by IR and ¹Н NMR spectroscopy, and X-ray diffraction analysis. It has been shown that the ferrocene-containing compounds synthesized in the present work all demonstrate intramolecular charge transfer which is evidenced by the observation of the corresponding absorption bands with λ ^abs_max > 480 nm. The oxidation potential of ferrocene (E ^Fc_ox ) in all the compounds is higher than 700 mV.

     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 4. Aminomethylation of alkyl substituted dipyrrolo[1,2-a; 2′,1′-c]pyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2′,1′-c]pyrazines

We have studied the aminomethylation reaction of alkyl substituted dipyrrolo[1,2-a; 2,1-c]pyrazines and their 5,6-dihydro analogs using different aminomethylating agents. Use of alkoxydialkylaminomethanes (aminoacetals) as Mannich reagents leads to the highest yields of the aminomethylated dipyrrolopyrazines. The compounds prepared have been studied by mass spectrometry.For Communication 3, see [1].M. V. Lomonosov State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 949–957, July, 1998.     

Multicomponent reactions of pyridines, α-bromo carbonyl compounds and silylaryl triflates as aryne precursors: a facile one-pot synthesis of pyrido[2,1-a]isoindoles

Multicomponent reactions (MCRs) involving pyridines, α-bromo ketones, and silylaryl triflates as aryne precursors were investigated. The reactions could also be extended to isoquinoline or α-bromo ethyl acetate. Substituted pyrido[2,1-a]isoindoles or isoindolo[2,1-a]isoquinolines could be obtained from this routine, which may have potential applications in antitumor drugs and fluorescent material fields.     

A new convenient four-component synthesis of 6-amino-2H, 4H-pyrano[2,3-c]pyrazole-5-carbonitriles and one-pot synthesis of 6 ′-amino-5-cyano-1,2-dihydrospiro-[(3H)-indole-3,4 ′-(4 ′H)-pyrano[2,3-c]pyrazol]-2-ones

A new convenient method for the synthesis of 6-amino-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitriles, namely, four-component condensation of carbonyl compounds (aromatic aldehydes, heterocyclic ketones), malononitrile, β-keto esters, and hydrazine hydrate in ethanol in the presence of triethylamine as a catalyst, which occurs selectively, is developed. One-pot two-step modification of this method is proposed for the synthesis of spiro[(3 H)-indole-3,4 ′-(4′H)-pyrano[2,3-c]pyrazol]-2-ones.     

Synthesis of Angular [1,2,5]Oxadiazolo[3,4-b]pyrazino-[1′,2′ : 1,2]pyrrolo[2,3-e][1,4]diazepine by Stepwise Reaction of Pyrrolo[1,2-a]pyrazinetrione with 3,4-Diaminofurazan

Russian Journal of Organic Chemistry - Diaminofurazan reacted with 8-benzoyl-2-phenyl-3,4-dihydropyrrolo[1,2-a]pyrazine-1,6,7(2H)- trione to give addition product of the amino group to the double...     

Novel Synthesis of Benzo[a]quinolizines (Pyrido[2,1-a]isoquinolines) by [3+3]-Cyclocondensation of 1-Alkyl-3,4-dihydroisoquinolines with β-Ketoesters

Benzo[a]quinolizines (pyrido[2,1-a]isoquinolines) were synthesized via heterocyclization of 1-alkyldihydroisoquinoline Schiff bases with -ketoesters.     

Cyclization of alk-4-ynals with o-diaminoarenes as a selective one-pot synthesis of arylmethylidene-substituted 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles and 7,8-dihydro-6H-pyrrolo[1’,2’:1,2]imidazo[4,5-b]pyridines

Russian Chemical Bulletin - A one-pot synthesis of arylmethylidene-substituted 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles based on the reaction of alk-4-ynals with 1,2-diaminobenzenes in DMSO at...     

Synthesis of Dispiro[indoline-3,3′-pyrrolo[2,1-a]isoquinoline-1′,2′′-thiazolo[3,2-a]pyrimidine] Derivatives via Cycloaddition Reactions

Russian Journal of General Chemistry - The 1,3-dipolar cycloaddition reaction of ethyl (Z)-2-(2-methoxy-2-oxoethylidene)-7-methyl-3-oxo-5-aryl-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate...     

四氢咪唑并[2',1':2,3]噻吩并[5,4-c]哌啶衍生物的合成及抗肿瘤活性

以4-哌啶酮为原料,经过胺基保护、缩合、环合、脱保护等步骤,设计合成了一系列新型的5,6,7,8-四氢咪唑并[2',1':2-3]噻吩并[5,4-c]哌啶类化合物。通过核磁共振波谱仪(~1H NMR、~(13)C NMR)、质谱(MS)和元素分析确证了其结构。对其体外活性研究发现,该类化合物对乳腺癌细胞MCF-7具有一定的抑制活性,其中化合物5a的抑制活性最为显著,半数抑制浓度(IC_(50))值达到了8.6μmol/L。为此类化合物的抗肿瘤活性研究提供了参考。     

Selective synthesis and optical properties of diimidazo[1,2-a:5′,1′-c]quinoxaline derivatives

Novel diimidazo[1,2-a:5′,1′-c]quinoxaline derivatives were synthesized by a Pd-catalyzed intramolecular coupling reaction of 1,2-bis(2-iodo-1H-imidazol-1-yl)benzene. This method was applied to the selective introduction of an aryl substituent at the 10 position by the addition of a boronic ester. Moreover, a stepwise introduction of the aryl substituent could be achieved by the further coupling reaction at the 3 position. Focused on the optical properties, a more efficient substituent effect at the 10 position was obtained compared with the analogous structure, diimidazo[1,2-a:2′,1′-c]quinoxaline derivatives. In addition, we revealed that the diimidazo[1,2-a:5′,1′-c]quinoxaline skeleton potentially has an electron-donating character on the optical properties by introducing an electron-withdrawing substituent.