三聚氯氰促进的咪唑并[1,2-a]吡啶类化合物的合成

以三聚氯氰作为反应促进剂,在室温和CH3CN作为溶剂的条件下,利用取代2-氨基吡啶、醛和烷基异腈三组分缩合,高收率地实现了一系列咪唑并[1,2-a]吡啶类化合物的合成.产物结构经1H NMR,13C NMR和元素分析等进行了表征.     

1-{2-咪唑[1,2-a]吡啶基}愈创兰烃薁的合成

以1-氯乙酰基愈创兰烃薁和取代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。     

无光敏剂参与的可见光诱导咪唑并[1,2-a]吡啶的三氟甲基化反应

发展了一个无光敏剂参与的可见光促进的咪唑并[1,2-a]吡啶衍生物的三氟甲基化新反应.该反应利用本课题组此前发展的基于硫叶立德骨架的亲电三氟甲基化试剂作为三氟甲基自由基源,反应条件温和,底物普适性好,同时兼容常见的官能团.机理研究表明该反应可被自由基捕获剂阻断.对两个反应底物及它们的1∶1混合物的紫外-可见光吸收光谱进...     

可见光催化和电化学合成在咪唑并[1,2-a]吡啶3位碳-杂键构建中的应用

咪唑并[1,2-a]吡啶是一类独特的含氮化合物,该类衍生物在农药、生物医药和光电材料等领域具有重要作用.近年来,合成功能性的咪唑并[1,2-a]吡啶已经成为有机化学家和药物化学家研究的热点,并且取得了巨大进展.其中,基于绿色化学导向的可见光催化和电催化合成官能化的咪唑并[1,2-a]吡啶,已经成为合成该类化合物的强有力...     

取代四氢咪唑并[1,2-a]吡啶酮类化合物的合成

在三乙胺催化下,α-肉桂酰基烯酮二苄硫缩醛与乙二胺反应形成α-羰基-N,N-缩烯酮类化合物,其进一步发生分子内迈克尔加成反应,以中等产率合成了3个新型的取代四氢咪唑并[1,2-a]吡啶酮类化合物,其结构经1H NMR和IR表征.对反应机理进行了初步探讨.     

8-溴-6-甲基-2-(1-吡咯烷基羰基)咪唑并[1,2-a]吡啶的合成及晶体结构

以2-氨基-5-甲基吡啶为原料,经溴代、环合、水解及酰胺化反应合成了8-溴-6-甲基-2-(1-吡咯烷基羰基)咪唑并[1,2-a]吡啶,总收率32.82％,其结构经1H-NMR和MS确证,并用X-单晶衍射法测定了其晶体结构.结果表明:待测物块状晶体a(CCDC:2039002)属三斜晶系,空间群P-1,晶胞参数a=6....     

6-卤代咪唑并[1,2-a]吡嗪-3-甲酰胺的简便合成

6-卤代咪唑并[1,2-a]吡嗪-3-甲酰胺是一类重要的抗癌新药中间体,广泛应用于淋巴癌、肺癌、皮肤癌等癌症新药的研发.以2-氨基吡嗪为起始原料,与N-卤代丁二酰亚胺发生卤代反应,与N,N-二甲基甲酰胺二甲基缩醛制备亚胺化合物,再和溴乙酸乙酯缩合成环制备6-卤代咪唑并[1,2-a]吡嗪-3-甲酸乙酯,再与氨水氨解共4步...     

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.     

氨基磺酸催化下三组分一锅法无溶剂合成苯并[4,5]咪唑并[1,2-a]嘧啶类衍生物

无溶剂条件下,用氨基磺酸催化芳香醛,2-氨基苯并咪唑和β-二羰基化合物的三组分反应,简单而方便地得到了苯并[4,5]咪唑并[1,2-a]嘧啶类衍生物.该法具有产率高,成本低廉,环境友好,适应性广简捷方便等优点.     

水相中微波辅助合成咪唑并[1,2-α]吡啶衍生物的研究

开展了水相中硝基烯烃与氨基吡啶反应生成咪唑并[1,2-α]吡啶衍生物的微波辅助合成研究。结果表明:相同反应时间,在微波辅助条件下,生成咪唑并[1,2-α]吡啶衍生物的速率较常规加热条件下增大。一系列咪唑并[1,2-α]吡啶衍生物被高效的合成出来,最高产率达到85%。产物结构经~1H NMR,~(13)C NMR及MS得到确证。该方法具有产率高、操作简单、环境友好等优点。     

Synthesis and Biological Evaluation of Novel 5,7-Diphenylimidazo[1,2-a]pyridine Derivatives

A series of novel 5,7-diphenylimidazo[1,2-a]pyridine derivatives was designed and synthesized. The in vitro cytotoxic activities of all the target compounds against human colorectal cancer（HT-29）, human lung can- cer（H460）, human gastric cancer（MKN45） and human breast cancer（MDA-MB-231） cell lines were evaluated. The pharmacological results indicated that most of the target compounds showed moderate to excellent activities against the tested cell lines. The most promising compound 4h（0.20, 0.006, 0.08, 0.021 μmol/L） was 2.6, 5.1, 3.6 and 21.9 times more active than EPC2407（0.52, 0.031, 0.29, 0.46 μmol/L） against HT-29, H460, MKN45 and MDA-MB-231 cell lines, respectively.     

Metal cation-induced multifluorescence of azacrown-substituted (tetrafluorophenyl)imidazo[1,2-a]pyridine

ortho-Azacrown-substituted (tetrafluorophenyl)imidazo[1,2-a]pyridine (2) in an acetonitrile solution emits 380 nm light in the presence of Li⁺ cation and emits 460 nm light in the presence of Zn²⁺, Mg²⁺ or H⁺ cation. In contrast, para-azacrown-substituted analogue (1) emits three different fluorescent lights responding to Li⁺, Zn²⁺ or H⁺ cation, respectively; 388 nm light to Li⁺ cation, 433 nm light to Zn²⁺ cation or 469 nm light to H⁺ cation.     

Formylation of Furyl-substituted Imidazo[1,2-a]pyridine, Imidazo[1,2-a]pyrimidine and Imidazo[2,1-b]thiazole

Vilsmeier formylation of 2-(2-furyl)-substituted imidazo[1,2-a]pyridine and imidazo[1,2-a]pyrimidine, and also 6-(2-furyl)imidazo[2,1-b]thiazole with 1 mole of reagent occurs at the free position of the imidazole ring, while with an excess of the reagent it also occurs at the position 5 of the furyl group.     

Heterocycles from Pyrazoloylhydroximoyl Chloride: Synthesis of Certain Quinoxaline,Benzothiadiazine, Benzoxadiazine,Quinazolinone, Imidazo[1,2-a]pyridine,Imidazo[1,2-a]pyrimidine,Isoxazole, Pyrazolo[3,4-d]pyridazine and Pyrrolidino[3,4-d]isoxazolin-4,6-dione Derivatives

3-Ethoxycarbonyl-5-methyl-1-(4-methylphenyl)-4-pyrazoloylhydroximoyl chloride (1) reacted with o-phenylenediamine, o-aminothiophenol, o-aminophenol and methyl anthranilate to afford 3-nitrosoquinoxaline, benzothiadiazine, benzoxadiazine, and 3-hydroxyquinazoline, respectively. Imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine and isoxazole derivatives were obtained via the reaction of 1 with 2-aminopyridine, 2-aminopyrimidine and the appropriate active methylene compounds, respectively. Pyrazolo[3,4-d]pyridazines, and pyrrolidino[3,4-d]isoxazolines derivatives were also synthesized. The structures of the newly synthesized compounds were established on the basis of spectral data and alternate synthesis whenever possible.     

Synthesis and Neurotropic Activity of New Heterocyclic Systems: Pyridofuro[3,2-d]pyrrolo[1,2-a]pyrimidines,Pyridofuro[3,2-d]pyrido[1,2-a]pyrimidines and Pyridofuro[3′,2′:4,5]pyrimido[1,2-a]azepines

Background: Neurotic disturbances, anxiety, neurosis-like disorders, and stress situations are widespread. Benzodiazepine tranquillizers have been found to be among the most effective antianxiety drugs. The pharmacological action of benzodiazepines is due to their interaction with the supra-molecular membrane GABA-a-benzodiazepine receptor complex, linked to the Cl-ionophore. Benzodiazepines enhance GABA-ergic transmission and this has led to a study of the role of GABA in anxiety. The search for anxiolytics and anticonvulsive agents has involved glutamate-ergic, 5HT-ergic substances and neuropeptides. However, each of these well-known anxiolytics, anticonvulsants and cognition enhancers (nootropics) has repeatedly been reported to have many adverse side effects, therefore there is an urgent need to search for new drugs able to restore damaged cognitive functions without causing significant adverse reactions. Objective: Considering the relevance of epilepsy diffusion in the world, we have addressed our attention to the discovery of new drugs in this field Thus our aim is the synthesis and study of new compounds with antiepileptic (anticonvulsant) and not only, activity. Methods: For the synthesis of compounds classical organic methods were used and developed. For the evaluation of biological activity some anticonvulsant and psychotropic methods were used. Results: As a result of multistep reactions 26 new, five-membered heterocyclic systems were obtained. PASS prediction of anticonvulsant activity was performed for the whole set of the designed molecules and probability to be active Pa values were ranging from 0.275 to 0.43. The studied compounds exhibit protection against pentylenetetrazole (PTZ) seizures, anti-thiosemicarbazides effect as well as some psychotropic effect. The biological assays evidenced that some of the studied compounds showed a high anticonvulsant activity by antagonism with pentylenetetrazole. The toxicity of compounds is low and they do not induce muscle relaxation in the studied doses. According to the study of psychotropic activity it was found that the selected compounds have an activating behavior and anxiolytic effects on the models of “open field” and “elevated plus maze” (EPM). The data obtained indicate the anxiolytic (anti-anxiety) activity of the derivatives of pyrimidines, especially pronounced in compounds 6n, 6b, and 7c. The studied compounds increase the latent time of first immobilization on the model of “forced swimming” (FST) and exhibit some antidepressant effect similarly to diazepam. Docking studies revealed that compound 6k bound tightly in the active site of GABA_A receptor with a value of the scoring function that estimates free energy of binding (ΔG) at −7.95 kcal/mol, while compound 6n showed the best docking score and seems to be dual inhibitor of SERT transporter as well as 5-HT_1A receptor. Conclusions: Тhe selected compounds have an anticonvulsant, activating behavior and anxiolytic effects, at the same time exhibit some antidepressant effect.     

Green procedure for highly efficient,rapid synthesis of imidazo[1,2-a]pyridine and its late stage functionalization

We unfold a rapid synthetic protocol for the preparation of imidazo[1,2-a]pyridine in cyclohexane. This methodology includes several advantages like shorter reaction time, catalyst free, broader substrate scope, and good yields of the desired products. Late stage functionalization of imidazo[1,2-a]pyridine has also been performed through C–H bond activation and C–C cross-coupling reactions.     

Construction of a Bifunctional Pd(0)-CALB@SiO2 Hybrid Catalyst for the Synthesis and Arylation of Imidazo[1,2-a]pyridine in One Pot

Herein, we describe an efficient strategy for the construction of enzyme-metal biohybrid catalyst [Pd(0)-CALB@SiO₂] via encapsulation of Candida antarctica lipase B and Pd(0) within silica. Next, the applicability of the newly constructed biohybrid was demonstrated by catalyzing the sequence of Groebke-Blackburn-Bienayme (GBB) multicomponent reaction and Suzuki-Miyaura coupling in a single-pot to produce clinically significant imidazo[1,2-a]pyridine derivatives. Interestingly, both entities, i.e., CALB enzyme and Pd(0)-metal of hybrid catalyst, exhibited good catalytic activity during this approach. Further, the generality of this protocol was explored by using differently substituted boronic acid, which gave related products in 49–87 % isolated yield. Next, the synthetic utility was proved by set-up a gram scale reaction which provided the complementary product in 81 % yield. Also, the developed biohybrid was found to be reusable up to five catalytic cycles.     

Polyethylene glycol-promoted synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives in water

Synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives were achieved using polyethylene glycol (PEG-400) as promoting reaction medium in water under catalyst-free conditions at reflux and room temperature, respectively. The structure of pyrimido[1,2-a]benzimidazole was confirmed using ¹H NMR, ¹³C NMR, DEPT, and HMBC experiments. The promising points for the present methodology are efficiency, generality, high yield, short reaction time, cleaner reaction profile, ease of product isolation, simplicity, potential of recycling reaction medium, and finally agreement with green chemistry protocols.     

Synthesis and anti-inflammatory activity of imidazo [1,2-a] pyrimidine derivatives

A series of imidazo[1,2-a]pyrimidine derivatives substituted adjacently with two aryls at positions 2 and 3 were designed and synthesized in order to improve their anti-inflammatory activities. Biological tests suggested that these compounds have antiinflammatory activities with COX-2 selectivity to some extent.