2-取代吲哚的染料敏化光氧化反应

2-苯基吲哚 (1a) 在甲醇中的染料敏化光氧化反应给出2-苯基-2-(2'-苯基-3'-吲哚基)二氢吲哚-3-酮 (2a) 和2-甲氧基-2-苯基二氢吲哚-3-酮 (4a), 相应N-甲基取代产物由1-甲基-2-苯基吲哚 (1b) 的类似反应获得。发现反应产物分布随吲哚 (1) 的浓度和介质酸度的变化而变化。对反应机理进行了推测, 其中当1a的反应在乙腈中进行时, 分离到了相应的反应中间体: 2-苯基-3H-吲哚-3-酮 (3a)。     

2-芳基吲哚的敏化光氧化偶合反应

本文研究了十七种2-芳基吲哚(1a-1q)在甲醇-乙酸介质中的亚甲基蓝(MB)敏化光氧化反应, 发现有十五种吲哚(1a-1o)以85%-95%的产率给出2,2'-二芳基-[2,3'-联-1H-吲哚]-3(2H)-酮(2a-2o), 而2-(4-硝基苯基]吲哚(1p)和2-联苯基吲哚(1q)则分别生成2-甲氧基-2-(4-硝基苯基)-1,2-二氢-3H-吲哚-3-酮(7p)和2-联苯基-4H-3,1-苯并恶嗪-4-酮(11q), 其中7p在分离过程中失去甲醇分子给出2-(4-硝基苯基)-3H-吲哚-3-酮(10p)。     

[2,3′-联-1H-吲哚]-3(2H)-酮类化合物的单重态氧反应

[2,3’-联-1H-吲哚]-3(2H)-酮衍生物(1a～1c)在甲醇中的单重态氧反应给出溶剂捕捉产物4,后者在分离过程中脱去甲醇分子生成5。考察了标题化合物分子中二氢吲哚酮结构单元以及吲哚结构单元在单重态氧反应中的作用。并探讨了反应机理。     

[2, 3'-联-1H-吲哚]-3(2H)-酮类化合物的单重态氧反应

[2, 3'-联-1H-吲哚]-3(2H)-酮衍生物(1a~1c)在甲醇中的单重态氧反应给出溶剂捕捉产物4, 后者在分离过程中脱去甲醇分子生成5。考察了标题化合物分子中二氢吲哚酮结构单元以及吲哚结构单元在单重态氧反应中的作用, 并探讨了反应机理。     

2-苯基吲哚单重态氧反应机理

本文比较了在甲醇介质下, 2-苯基吲哚(1)单重态氧反应中的捕捉反应以及2-苯基-3H-吲哚-3-酮(4)的亲核加成反应特征。结果显示, 在1的单重态氧反应中, 捕捉反应主要发生于两性离子(2)阶段, 而4并非导致捕捉产物的重要中间体。根据上述事实, 结合有关反应溶剂极性效应的研究结果, 对反应机理进行了探讨。     

3-仲氨基氧杂环丁烷-3-腈衍生物的合成

以仲胺、氧杂环丁-3-酮和三甲基氰硅烷为原料,无水甲醇为溶剂,无需催化剂,一步反应合成目标化合物3-仲氨基氧杂环丁烷-3-腈衍生物(1a～1d),产物结构经¹H NMR、¹³C NMR和ESI-MS表征。并以异吲哚啉、氧杂环丁-3-酮和三甲基氰硅烷的反应为模型反应,考察影响产物1a收率的主要因素,优化反应条件为:物料摩尔比为n(异吲哚啉)∶n(氧杂环丁-3-酮)∶n(三甲基氰硅烷)=2.0∶1∶2.5;反应溶剂为无水甲醇,在65℃反应6h,在此反应条件下,化合物1a收率78.3%。化合物1a与苯基溴化镁在四氢呋喃中室温反应5h,可得到2-(3-苯基氧杂环丁烷-3-基)异吲哚啉(4)和[3-(异吲哚啉-2-基)氧杂环丁烷-3-基](苯基)甲酮(5),收率分别为40.1%和31.5%。     

在微波作用、无催化剂的条件下合成3-芳基亚甲基-1，3-二氢-2H-吲哚-2-酮类化合物

用DMF作溶剂，无催化剂、微波辐射的条件下，使吲哚-2-酮(1)和醛、酮(2)发 生缩合反应，合成了3-芳基亚甲基-1，3-二氢-2H-吲哚-2-酮类化合物，时间短、 收率高。     

吡啶并吲哚盐的结构及波谱中的取代基效应

前文报道了2,3,3-三甲基-3 H-吲哚高氯酸盐(1)与1.5-二(4-取代苯基)-1,4-戊二烯-3-酮在异戊醇介质中反应,合成了6-(4-取代苯乙烯基)-8-(4-取代苯基)-10,10-二甲基-10 H-吡啶并[1,2-a]吲哚高氯酸盐(4a～g,其中取代基为苯基和硝基的未见报道),但产物     

1-(1-乙基-1H-5-吲哚基)-2-苯基-1,2-二酮缩合成1,2,4-三嗪类化合物反应

报道了一种1-(1-乙基-1H-5-吲哚基)-2-苯基-1,2-二酮与氨基胍碳酸氢盐缩合生成互为同分异构体的两种1,2,4-三嗪的反应,并通过运用目标定向合成和核磁的方法,研究了1,2-二酮苯环上不同取代基对反应产品比例的影响.反应总收率为40%~81%,且当不对称1,2-二酮苯环上无取代基时,其生成的同分异构体6-(1-乙基-1H-5-吲哚基)-5-苯基-3-氨基-1,2,4-三嗪(2a)和5-(1-乙基-1H-5-吲哚基)-6-苯基-3-氨基-1,2,4-三嗪(4a)比例为40∶60;当苯环上取代基为吸电子基时,6-(1-乙基-1H-5-吲哚基)-5-(4-硝基苯基)-3-氨基-1,2,4-三嗪(2b)和5-(1-乙基-1H-5-吲哚基)-6-(4-硝基苯基)-3-氨基-1,2,4-三嗪(4b)比例为63∶37;当苯环上取代基为供电子基时,绝大部分生成2系列构型结构.     

含三氟甲基的螺[环丙烷-1,3'-吲哚啉]-2'-酮和螺[环丙烷-1,2'-茚]-1',3'-二酮衍生物的高立体选择性简易合成

采用3-(4-三氟甲基苯亚甲基)吲哚啉-2-酮和2-(4-三氟甲基苯亚甲基)-1H-茚-1,3(2H)-二酮分别与鉮盐在二氯甲烷中,碳酸钾或氟化钾存在下反应,可高产率、高立体选择性地得到以反式构型为主的含三氟甲基的3'-螺环丙基取代的氧化吲哚和2'-螺环丙基取代的茚二酮衍生物.产物相对构型经X射线单晶衍射或1H-1H NOESY谱确定.还从反应机理的角度对产物构型做了解释.     

Synthesis and reactions of 11H‐benzo[b]pyrano[3,2‐f]indolizines an pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolines

2‐Methyl‐3H‐indoles 1 cyclize with two equivalents of ethyl malonate 2 to form 4‐hydroxy‐11H‐benzo[b]pyrano[3,2‐f]indolizin‐2,5‐diones 3, whereas 2‐mefhyl‐2,3‐dihydro‐1H‐indoles 9 give under similar conditions regioisomer 8‐hydroxy‐5‐methyl‐4,5‐dihydro‐pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolin‐7,10‐diones 10 . The pyrone rings of 3 and 9 can be cleaved either by alkaline hydrolysis to give 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 4 or 5‐acetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo‐[3,2,1‐ij]quinolin‐4‐ones 11 , respectively. Chlorination of 3 and 9 with sulfurylchloride gives under subsequent ring opening 7‐dichloroacetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 5 or 5‐dichloracetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 12 . The dichloroacetyl group of 5 can be reduced with zinc to 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 7. Treatment of the acetyl compounds 4, 7 and 11 with 90% sulfuric acid cleaves the acetyl group and yields 8‐hydroxy‐10H‐pyrido[1,2‐a]‐indol‐6‐ones 6 and 8 , and 6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 13 . Reaction of dichloroacetyl compounds 12 with sodium azide yields 6‐hydroxy‐2‐methyl‐5‐(1H‐tetrazol‐5‐ylcarbonyl)‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 14 via intermediate geminal diazides.     

An Efficient Method for the Synthesis of Laquinimod

Laquinimod, 5‐chloro‐1,2‐dihydro‐N‐ethyl‐4‐hydroxy‐1‐methyl‐2‐oxo‐N‐ phenyl‐3‐quinoline carboxamide, is an oral drug in clinical trials for the treatment of multiple sclerosis. An efficient synthetic method for laquinimod from 2‐amino‐6‐chlorobenzoic acid via four steps was established. The overall yield of laquinimod is up to 82% as compared with 70% reported in literature. It has also been demonstrated that green reagent dimethyl carbonate is not suitable for the N‐methylation of 5‐chloroisatoic anhydride owing to the ring‐cleavage reaction induced by the generated methanol. The ring‐cleavage by‐products were isolated and characterized by ¹H‐NMR and ¹³C‐NMR. In addition, in the study of laquinimod derivatives, we found that 5‐chloro‐1,2‐dihydro‐N‐ethyl‐4‐hydroxy‐1‐methyl‐2‐oxo‐N‐phenyl‐3‐quinoline carboxamide (laquinimod) was obtained in much higher yield than 7‐chloro‐1,2‐dihydro‐N‐ethyl‐4‐hydroxy‐1‐methyl‐2‐oxo‐N‐phenyl‐3‐quinoline carboxamide under the same reaction conditions, and it is possibly attributed to a neighboring group effect.     

Synthesis of Some Heterocyclic Compounds from 1H‐Indole‐2,3‐Dione: A Direct One‐Pot Synthesis of Spiro Indolone Derivatives

Some spiro indolone derivatives 5_a,b and 6 were synthesized through one‐pot synthesis via the ternary condensation of 1H‐indole‐2,3‐dione 1 , 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one 2 and active methylenes, namely malononitrile, ethyl cyanoacetate 4_a,b and pyrazolone 2 , respectively. The same derivatives can be obtained via other methods, through reactions of 3‐[3‐methyl‐5‐oxo‐1‐phenyl‐1,5‐dihydro‐pyrazol‐(4Z)‐ylidene]‐1,3‐dihydro‐indol‐2‐one 3 with the corresponding active methylenes. Reaction of 3 with amines and with ethyl vinyl ether was studied.     

Stress degradation of edaravone: Separation,isolation and characterization of major degradation products

In the present study the International Conference on Harmonization‐prescribed stress degradation was carried out to study the degradation profile of edaravone. To establish a Quality by Design (QbD)‐assisted stability‐indicating assay, the reaction solutions in which different degradation products were formed were mixed. Plackett Burman and central composite design were used to screen and optimize experimental variables to resolve edaravone and its impurities with good peak symmetry using an RP C₁₈ column. The method was validated according to International Conference on Harmonization guidelines. Seven unknown and two known degradation products were identified and characterized by LC‐MS/MS. Two major degradation products formed under thermal degradation were isolated and characterized as 4‐(4,5‐dihydro‐3‐methyl‐5‐oxo‐1‐phenyl‐1H‐pyrazol‐4‐yl‐4‐(4,5‐dihydro‐5‐hydroxy‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐one and 3‐hydroxy‐dihydro‐thiazolo[1‐(2‐methyl‐buta‐1,3dienyl)‐1‐phenylhydrazine]5‐one. The degradation pathways of degradants were proposed based on m/z values.     

A convenient route to pyridones,pyrazolo[2,3‐a]pyrimidines and pyrazolo[5,1‐c]triazines incorporating antipyrine moiety

Condensation of 4‐aminoantipyrine with ethyl acetoacetate, ethyl benzoylacetate, and ethyl cyanoacetate furnished the corresponding ethyl 3‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)aminoacrylate and 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide derivatives. The aminoacrylates derivatives react with acetonitrile and sodium hydride to give 2‐amino‐6‐methyl‐1‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)‐4‐pyridone. Reaction of the cyanoacetamide derivative with dimethylformamide‐dimethylacetal (DMF‐DMA) afforded 2‐cyano‐N‐[1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐pyrazol‐4‐yl]‐2‐(N,N‐dimethylamino)methylene acetamide in high yield. Treatment of the latter with 5‐aminopyrazole derivatives afforded the corresponding pyrazolo[2,3‐a]pyrimidines. 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide also reacts with heterocyclic diazonium salts to give the corresponding pyrazolo[5,1‐c]‐1,2,4‐triazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:508–514, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20046     

Syntheses,Characterization, and Antibacterial Activities of Four New Schiff Base Compounds Derived from 1‐Phenyl‐3‐methyl‐4‐benzoyl‐2‐pyrazolin‐5‐one

Four new Schiff bases were designed and synthesized. 5‐Methyl‐4‐(4‐aminophenylamino‐phenyl‐methylene)‐2‐phenyl‐2,4‐dihydro‐pyrazol‐3‐one (compound 1 ) and 5‐methyl‐4‐(2‐aminophenylamino‐phenyl‐methylene)‐2‐phenyl‐2,4‐dihydro‐pyrazol‐3‐one (compound 2 ) were synthesized by interaction of 1‐phenyl‐3‐methyl‐4‐benzoyl‐2‐pyrazolin‐5‐one (PMBP) with o‐ and p‐phenylenediamine, respectively; 4,4′‐(1,2‐phenylenebis(azanediyl)bis(phenylmethanylylidene))bis(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐one) (compound 3 ) and 5‐methyl‐4‐(phenyl(2‐((3‐phenylallylidene)amino)phenylamino)methylene)‐2‐phenyl‐2,4‐dihydro‐pyrazol‐3‐one (compound 4 ) were synthesized by interaction of compound 2 with PMBP and cinnamaldehyde in an ethanolic medium, respectively. The molecular structures of the title compounds were first characterized by single‐crystal X‐ray diffraction, mass spectrometry, and elemental analysis. The title compounds were tested for antibacterial activity (Escherichia coli, Staphylococcus aureus, and Bacillus subtilis) by disk diffusion method.     

Convenient Synthesis of Piperazine Substituted Quinolones

A series of 1‐[(4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonyl]‐4‐(substituted) piperazines 3a–c and methyl 2‐[(4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonylamino] alkanoates 5a–d has been developed by the direct condensation of ethyl [4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydro‐3‐quinoline] carboxylate 2 with N ¹‐monosubstituted piperazine hydrochlorides or amino acid ester hydrochloride in the presence of triethyl amine. The quinolone amino acid esters 5a–d were the key intermediate for the preparation of a series of 1‐[2‐((4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonylamino)alkylcarbony]‐4‐substituted piperazine derivatives 8–11 (a‐d) via azide coupling method with amino acid ester hydrochloride.