2-取代苯并噻吩类化合物合成研究进展

2-取代苯并噻吩广泛的存在于天然产物中,独特的分子结构使其表现出了较高的药理和生物活性,常被用于药物化学和材料化学中。已有多种具有苯并噻吩骨架药物用于临床,故具有极高的研究价值。本文结合国内外学者对这方面的相关研究,重点对2-苯基苯并噻吩、2-酰基苯并噻吩和2-氨基苯并噻吩类化合物的合成方法进行了综述。     

Efficient Synthesis of a Benzo[b]furan Building Block

Unexpected difficulty in the conversion of a bromobenzofuran to the corresponding formylbenzofuran led us to develop a new synthesis for 5-formylbenzo[b]furan-2-carbonitrile (1).     

Concise Synthesis of 6-Cyanobenzo[b]furan,a Useful Building Block

A new three-step synthesis of 6-cyanobenzo[b]furan (6) was developed, starting from commercially available 6-hydroxybenzo[b]furan-3-one (18). Key steps in this process were the first step, which was the reductive dehydration of 18 to produce 6-hydroxybenzo[b]furan (19), and the last step, which converted the aryl triflate 20 to the aryl cyanide 6 in a palladium-catalyzed cross-coupling protocol. Overall yield for this new synthesis was 49%.     

2-(2,6-二烷氧基苯基)苯并呋喃衍生物的合成

以焦性没食子酸、4-羟基苯甲醛和酚为原料, 以邻碘代苯酚与苯乙炔衍生物的Sonogashira偶联及其连串化反应生成苯并呋喃环为关键步骤, 设计合成了一系列2-(2 ,6 -二烷氧基苯基)苯并呋喃衍生物, 并对产物进行了¹H NMR, ¹³C NMR, MS等表征.     

Simple,Convenient, and Efficient Synthesis of 2-Aryl-substituted Benzo[b]furans

A simple, convenient, and efficient one-pot method for the preparation of benzofuran is reported. Sonogashira coupling reaction of aryl iodides with 2-methyl-3-butyn-2-ol was used as an acetylene source in the presence of Pd(PPh₃)₂Cl₂ and CuI. Deprotection of the acetylene moiety in the same pot using a strong base and the second Sonogashira coupling/cyclization of and substituted o-iodophenols led to the formation of the appropriate benzo[b]furans. These protocols also can be used in the synthesis of natural products and indoles.     

Iron-Catalyzed Synthesis of 2-Arylbenzo[b]furans

An iron-catalyzed procedure was employed to achieve both the Sonogashira cross-coupling and intramolecular o-arylation of o-iodophenols and aryl acetylenes/1-substituted-2-trimethylsilyl acetylenes. A variety of 2-arylbenzo[b]furans were synthesized in moderate to good yields under the catalysis of 5% FeCl₃ and 10% 1,10-phenanthroline.     

2-取代芳基苯并呋喃类化合物的合成

以香草醛和丙二酸为原料,经Knoevenagel缩合、酯化、仿生氧化偶联、DDQ脱氢、还原和氧化等反应合成了3种新的2-取代芳基苯并呋喃类化合物,其结构经1H NMR,IR和MS表征。两分子阿魏酸甲酯仿生氧化偶联为它的二聚体是合成的关键步骤。     

2-芳基苯并[b]呋喃衍生物的生物活性与合成策略

2-芳基苯并呋喃是一类广泛存在于植物中的化合物,具有良好的抗病毒、抗肿瘤、抗真菌、抗氧化等生物活性,一直以来都引起人们的广泛关注.综述了近年来2-芳基苯并呋喃类化合物的研究进展,重点介绍其生物活性和合成方法,尤其是苯并呋喃环的构建方法.     

2-取代芳基苯并呋喃类化合物生物活性及合成研究进展

综述了近十几年来报道的具有良好生物活性的2-芳基苯并呋喃类化合物, 以及这一类化合物结构骨架的构建与合成方法.     

Facile Synthesis of 2-Substituted Benzo[b]thiophen-3-ols in Water

A facile synthesis of 2-substituted benzo[b]thiophen-3-ols in a simple reaction system is reported with water as the only media. Density functional theory (DFT) investigations suggest two pathways comparable in energetics: A neutral pathway with concerted C-C bond formation and hydrogen transfer and an anionic pathway with anion attack to the carbonyl group. Studies indicate that water plays crucial mechanistic roles in both cases.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

(苯并呋喃-2-酰基)二茂铁衍生物的合成与表征

氯乙酰基二茂铁(1)与水杨醛或取代水杨醛在聚乙二醇-400作相转移催化剂条件下,使Williamson反应与Knoevenagel反应在一锅内完成,以40.2%～70.0%的总收率得到了由羰基相连的二茂铁与苯并呋喃组成的结构新颖的闭环产物(苯并[b]呋喃-2-酰基)二茂铁衍生物2a～2n.通过IR,1HNMR,MS和元素分析确认了所合成新化合物2a～2n的结构.     

新型2-苯甲酰基苯并呋喃类似物的合成

以水杨醛与2-溴-4’-氟苯乙酮为原料,经取代和分子内缩合反应合成了中间体2-苯甲酰基苯并呋喃(1);在碱性条件下,1分别与咪唑,N-甲基哌嗪和二乙胺等反应,合成了6个新型的2-苯甲酰基苯并呋喃含氮类似物,收率63%~82%,其结构经1H NMR,13C NMR,IR和HR-MS表征。     

Synthesis and Biological Activities of Novel Anthranilic Diamides Analogues Containing Benzo[b]thiophene

A series of novel anthranilic diamides analogues containing benzo[b]thiophenyl ring was designed and synthesized. Their structures were characterized by melting points, ¹H nuclear magnetic resonance(¹H NMR) and high-resolution mass spectrometry(HRMS). The bioassay tests indicate that their insecticidal activities were weak to moderate. Antibacterial tests indicate that some of the compounds showed favourable activity in vitro against Physalospora piricola, Alternaria solani, Cercospora arachidicola, Gibberella sanbinetti and Phytophthora infestans at a dosage of 50 mg/L.     

金催化的炔烃羟基化反应: 合成2取代苯并呋喃化合物

本文报道了一种以邻炔基苯酚为原料,通过金催化的炔烃羟基化反应合成2取代苯并呋喃的方法. 该方法可以在温和的条件下快速以高产率得到各种2取代苯并呋喃. 关键前体邻炔基苯酚可以很容易由Sonogashira 反应制备.     

1-(2-苯并呋喃酰基)愈创兰烃薁的合成

在路易斯酸作用下, 以氯乙酰氯为酰基化试剂, 对愈创兰烃薁进行了酰化反应研究, 将氯乙酰化产物与水杨醛在温和反应条件下进行缩合, 以较好的收率、高选择性地得到1-(2-苯并[b]呋喃酰基)兰烃薁类衍生物, 其结构经1H NMR, IR及元素分析等得以证实.     

Synthesis of Some New Benzo[b][1,4]diazepine Based Heterocycles

Preparation of 4‐chloro‐3H‐benzo[b][1,4]diazepine‐2‐carbaldehyde 5 , which is used as a key intermediate in the synthesis of chalcones derivatives, via its condensation with some aromatic acetophenone derivatives under ethanol piperidine condition was described. Also illustrated was the reaction of such chalcones with available nucleophilics and reagents of active methylene group to afford new series of fused and isolated pyrazoles, isoxazolines pyrimidines, pyridines, triazolo[1,5‐a]pyrimidines, benzo[1,4]oxa(thia)zepines, and pyrido[1,2‐a]benzimidazoles incorporating 4‐chloro‐3H‐benzo[b][1,4]diazepine moiety, which have a potential pharmaceutical interest. Furthermore, condensation reaction of 4‐chloro‐3H‐benzo[b][1,4]diazepine‐2‐carbaldehyde with aromatic amine derivatives to afford the Schiff's bases was described. The C═N double bond of the latter compounds has been reacted with chloroketene to give β‐lactams and with sulfanylacetic acid to give the 2‐(4‐oxo‐1,3‐thiazolidinyl)‐substituted derivative. The structures of the newly prepared compounds were established by elemental analysis, IR, MS, and ¹H NMR spectral analysis.     

I2-Promoted Intramolecular Oxidative Cyclization of Butenyl Anilines: A Facile Route to Benzo[b]azepines

A metal-free approach for the synthesis of seven-membered N-heterocycles has been developed by the I₂-promoted intramolecular cross-coupling/annulation of butenyl anilines. This cyclization reaction involves C−H activation and C−C bond formation and exhibits good functional group tolerance. A series of benzo[b]azepine derivatives are obtained in moderate to good yields.     

Ring-contraction from benzo[b][1,4]thiazines to benzo[d]thiazolines induced by oxygen

An unexpected ring-contraction from benzo[b]pyrazino[1,2-d][1,4]thiazine-1,4-diones (6) to benzo[4,5]thiazolo[3,2-a]pyrazine-1,4-diones (7) has been developed. The preliminary mechanistic studies showed the transformation contained two independent steps: the first step is the formation of a Michael adduct upon the addition of the protic solvent, in the presence of base, to the C-2-C-3 double bond of compound 6, and the second step is a ring-contraction induced by oxygen via the migration of sulfur atom from C-2 to C-3 position. And its scope is also studied.     

Synthesis,Reactions, and Characterization of 6-Amino-4-(Benzo[b]Thiophen-2-YL)-2-Thioxo-1, 2-Dihydropyridine-3, 5-Dicarbonitrile

Abstract

Benzothiophene -2- carbaldehyde 1 reacted with 2-cyanoethanethioamide 2 in 1:2 molar ratios to give the corresponding 6-amino-4-(benzo[b]thiophen-2-yl)-2-thioxo-1, 2-dihydropyridine-3,5-dicarbonitrile 6. The synthetic potentiality of compound 6 was investigated via its reaction with active halogen-containing reagents to afford the corresponding thieno[2,3-b]pyridine derivatives 11a,b, 14, 16, and 19. Also, compound 6 reacted with hydrazine hydrate to give the pyrazolo[3,4-b]pyridine derivative 21. Compound 21 condensed with 4-(2-thienyl)benzaldehyde to afford pyrazolo[3,4-b]pyridine derivative 23. Structural elucidation of all the newly synthesized heterocyclic compounds was based on elemental analyses, IR, ¹H NMR, and mass spectra.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.