Novel syntheses of hexahydro-1H-pyrrolo[1,2-a]ĭmidazoles and Octahydroimidazo[1,2-a]pyridines

1-Phenyl-5-(benzotriazol-1-yl)hexahydro-1H-pyrrolo[1,2-a]?midazole (18) and 1-phenyl-5-benzotriazolyloctahydroimidazo[1,2-a]pyridine (27) were readily prepared from succindialdehyde or glutaraldehyde, benzotriazole, and N-phenylethylenediamine. Synthons 18 and 27 reacted with Grignard reagents, allylsilanes, silyl ethers, and triethyl phosphite to produce 1-phenyl-5-substituted-hexahydro-1H-pyrrolo[1,2-a]?midazoles 20a-f, 22, 24a,b, and 25 and 1-phenyl-5-substituted-octahydroimidazo[1, 2-a]pyridines 28a-e, 32, 33a,b, and 34 in good to excellent yields. The configurations of 20, 22, 24, and 25 were determined to be cis isomers by NOE experiment, while the configurations and conformations of 28a-e, 32, 33a,b, and 34 were elucidated by (1)H-(1)H COSY and (1)H-(13)C COSY.     

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.     

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.     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 5. Azo coupling of dipyrrolo[1,2-a;2′,1′-c]pyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2′,1′-c]pyrazines

We have synthesized a series of previously unreported azo dyes via the azo coupling of alkyl substituted dipyrrolopyrazines with aryldiazonium chloride. For this type of substrate where one or both -positions of the pyrrole rings of the molecules are not occupied by substituents, electrophilic attack was found to occur initially at carbon atom C₍₃₎.For communication 4 see [1]M. V. Lomonosov State University, Moscow 119899, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 236–240, February, 1999.     

Synthesis of Substituted Pyrido[1,2-a]benzimidazoles by Ruthenium-Catalyzed C−H Bond Activation and Tandem Cyclization of 2-Arylimidazo[1,2-a]pyridines with Iodonium Ylides

Ruthenium-catalyzed C−H bond activation and tandem cyclization of 2-arylimidazo[1,2-a]pyridines with iodonium ylides proceed efficiently. For the first time, the easily available iodonium ylides and inexpensive ruthenium complex were employed to synthesize pyrido[1,2-a]benzimidazole derivatives in good yields under simple and easy-to-operate conditions. Several primary mechanism investigations and synthetic applications involving gram-scale preparation, derivatization reactions and the transformation of iodonium ylide generated in situ have also been conducted.     

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.     

One-pot synthesis of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives via the three-component reaction of 1,2-diamines,ethyl pyruvate and α-bromo ketones

A simple synthetic protocol has been developed involving the three-component reaction between 1,2-diamines, ethyl pyruvate and a-bromo ketones in the presence of Fe Cl3 as a catalyst. A number of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives were synthesized in excellent yields using this protocol.     

2-吡啶基咪唑并[1,2-a]吡啶的水中合成

2-乙酰基吡啶1经溴化反应后得到2-(2-溴乙酰基)吡啶氢溴酸盐2,2在水中与NaHCO3发生中和反应生成2-(2-溴乙酰基)吡啶,不经分离直接于水中和2-氨基吡啶衍生物3a-3h反应生成2-吡啶基咪唑并[1,2-a]吡啶4a-4h.采用核磁共振谱仪、红外光谱仪及质谱仪表征了产物的结构.结果表明,利用该方法可以在温和的反应条件下高产率得到目标产物,且方法操作简便、对环境友好.     

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     

Unexpected Recyclization of 1H-δ-Carbolines to Pyrrolo[1,2-a]indoles

When 1H-2-methyl-1-p-nitrophenyl-3-ethoxycarbonylpyrido[3,2-b]indole (1) is heated in alcoholic solutions of ammonia, we observe a previously unknown recyclization leading to formation of 2-alkoxycarbonyl-3-methyl-9-p-nitrophenylimino-9H-pyrrolo[1,2-a]indoles (3,6).     

Synthesis of derivatives of the new heterocyclic system pyrimido[4′,5′:4,5]pyrimido[1,2-a]benzimidazole

3-Phenyl-5-methyl(phenyl)-1H,3H-pyrimido[4,5:4,5]pyrimido[1,2-a]benzimi-dazole-2,4-diones were obtained by the cyclization of N-phenyl-N-[3-ethoxycar-bonyl-4-methyl(phenyl)pyrimido [1,2-a]benzimidazol-2-yl]ureas by the action of potassium carbonate. 2-Methyl-5-phenyl-1H-pyrimido[4,5:4,5]pyrimido[1,2-a]benzimidazol-4-one was obtained by the reaction of N-3-ethoxycarbonyl-4-phenylpyrimido[1,2-a]benzimidazol-2-yl]-N,N-dimethylacetamidine with ammonium acetate in ethanol. The synthesized compounds are members of a new heterocyclic system. The molecular and crystal structure of the solvate of 3-phenyl-5-methyl-1H,3H-pyrimido[4,5:4,5] pyrimido[1,2-a]benzimidazole-2,4-dione with two molecules of DMF was studied by x-ray crystallographic analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2587–2592, November, 1991.     

咪唑并[1,2-a]吡啶化合物绿色合成的研究进展

咪唑并[1,2-a]吡啶化合物是由五元和六元稠和的氮杂环化合物,在多种天然产物中被发现,表现出广泛的药理学活性,具有重要的研究意义和广阔的医药应用前景,因此有关于此类化合物的多样性的合成策略被不断报道.近年来,绿色化学是当代化学的热门方向之一,科学家们对绿色合成越来越重视,不断开发出各种绿色合成方案,其中一锅"多组分"反应、微波反应和固相合成这几种绿色、高效的合成方法一直是研究热点,就从这三类绿色合成的方法对咪唑[1,2-a]吡啶类化合物近几年绿色合成的研究进展加以概括总结.     

吡咯并[1,2-a]喹喔啉类化合物合成研究进展

吡咯并[1,2-a]喹喔啉类化合物是广泛存在于天然产物和生物活性分子中一类重要的含氮杂环化合物.因而,吡咯并[1,2-a]喹喔啉骨架,特别是取代的吡咯并[1,2-a]喹喔啉的合成具有重要理论和实际意义.较全面总结近几十年里吡咯并[1,2-a]喹喔啉和4,5-二氢吡咯并[1,2-a]喹喔啉类化合物的合成研究进展,对该领域所存在的问题和局限性进行了总结并对今后的发展作出展望.     

A convenient synthesis of 2-aryl substituted benzo[f] [1,2,4]triazolo[1,5-a]azepine derivatives

A convenient synthetic pathway to 2-aryl-5,6-dihydro-4H-benzo[f][1,2,4]triazolo[1,5-α]azepine derivatives 7 was developed. The synthesis was based on the cycloaddition of the 1,2,3,4-tetrahydronaphthalene a-acetoxy azo compounds 3 with Ar-CN in the presence of AlCl3 and the consecutive ring enlargement.     

Synthesis of a new heterocyclic system of 2-amino-3-cykanO-5h-4,5-dihydropyrido[3′,2′:4,5]-pyrrolo[1,2-a]indole

Alkylatio of 2-piperidinomethylene-2H-pyrrolo[1,2-a]indole-3,9-dione with dimethyl sulfate, followed by hydrolysis of the intermediate immonium salts. yielded 2-formyl derivatives, the reaction of which with substances possessing on active methylene unit leads to the formation of 2-substituted vinyl-3-oxo-9-alkoxypyrrolo[1,2-aindoles. Cyclization of the 9-methoxy derivative yielded a new heterocyclic system of 2-amino-3-cyano-5H-4,5-dihydropyrodol[32:4,5]pyrroloindoledione-4,11.Center for the Chemistry of Drugs, S. Ordzhonikidze All-Russian Scientific Research Institute Moscow119021 Translated from Khimiya Geterotsiklicheskikh Soedinenii.No. 8, pp, 919–925, August, 1994. Orginally article submitted June 22, 1994.     

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.     

Dipyrrolo[1,2-a; 2',1'-c]pyrazines. 2. Electrophilic substitution in dipyrrolo[1,2-a; 2′,1′-c]pyrazines: protonation,trifluoroacetylation, acetylation

A number of alkyl-substituted dipyrrolo[l,2-a; 2,1-cIpyrazines have been synthesized and investigated to determine their behavior in reactions of protonation, trifluoroacetylation, and acetylation. The experimental results correlate well with the calculated data in most cases.For communication 1, see [1].M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp, 1566–1572, November, 1995 Original article submitted September 13, 1995.     

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...     

Synthesis of 11H-Indeno[1,2-b]quinolines via the Friedliinder Reaction

The nine new 11H-indeno[1,2-b]quinolines were synthesized in high yield with sodium ethoxide as a catalyst via the Friedlander condensation reaction, The possible reaction mechanism was proposed.     

手性磷酸催化合成多取代吡咯并[1,2-a]吲哚

以联萘二酚骨架的手性磷酸催化吲哚苄基醇和3-吲哚丙烯酸酯发生环加成反应,产生三个连续的手性中心.当使用3,3'-位被α-萘取代的联萘二酚骨架手性磷酸为催化剂时,反应的效果最佳,产率最高达91%以上,非对映选择性为9∶1~20∶1,对映选择性为62%~92%.