One‐pot Combinatorial Synthesis of Benzo[4,5]imidazo‐[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one Derivatives

A series of novel fused tetracyclic benzo[4,5]imidazo[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and 1H‐benzo[d]imidazol‐2‐amine in glacial acetic acid. This protocol features mild reaction conditions, high yields and short reaction time.     

Synthesis of Novel 1H‐Imidazol[1,2‐a]Indeno[2,1‐e]Pyridine‐6(5H)‐Ones Derivatives via a One‐Pot Four‐Component Condensation Reaction

1H‐imidazol[1,2‐a]indeno[2,1‐e]pyridine‐6(5H)‐ones derivatives were synthesized in a one‐pot four‐component condensation of corresponding aldehydes, 1,3‐indandione, diamine, and nitro ketene dithioacetal using KAl(SO₄)₂·12H₂O (alum) as nontoxic, reusable, inexpensive and easily available catalyst in good to excellent yields. This green protocol provides a powerful entry into fused polycyclic structures related to bioactive heterocycles.     

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.     

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.     

Efficient Synthesis of Pyrrolo[2,1‐a]isoquinoline and Pyrrolo[1,2‐a]quinoline Derivatives via One‐pot Two‐step Metal‐catalyzed Three‐component Reactions

A sequential one‐pot two‐step reaction for efficient synthesis of pyrrolo[2,1‐a]isoquinoline and pyrrolo[1,2‐a]quinoline derivatives in good yields has been successfully developed. The reaction included firstly Cu‐catalyzed three‐component reaction of isoquinoline (quinoline), acetylenedicarboxylate and alkynylbenzene and then Pd‐catalyzed intramolecular C(sp)‐C(sp²) coupling reaction of initially formed 1‐alkenyl‐2‐alkynyl‐1,2‐dihydroisoquinoline (1,2‐dihydroquinoline).     

One‐pot Synthesis of Benzamidonaphtho[2,1‐b]furans and Benzamidobenzo[b]furans as Novel Polycyclic Heteroaromatic Compounds

An operationally simple, green and efficient procedure for one‐pot synthesis of novel polycyclic heteroaromatic compounds such as benzamidonaphtho[2,1‐b]furans and benzamidobenzo[b]furans has been developed from the reaction of arylglyoxals, benzamide, and phenols. The reactions were mediated with low amounts of yttrium nitrate hexahydrate as a suitable Lewis acid catalyst without using solvent.     

Synthesis,Structure and Biological Activities of Novel 2‐(Trifluoromethyl)‐ 6‐arylimidazo[2,1‐b][1,3,4]‐thiadiazole (bis‐)Mannich Base Derivatives Containing Substitutedpiperazine Moiety

A convenient and practicable method for the synthesis of the novel 2‐(trifluoromethyl)‐6‐arylimidazo[2,1‐b][1,3,4]‐thiadiazole (bis‐)Mannich base derivatives containing various substitutedpiperazine motif has been developed based on the fused‐heterocycle intermediate. The new structures were identified through melting points, ¹H NMR, ¹³C NMR, ¹⁹F NMR, elemental analysis (or HRMS) and X‐ray single‐crystal diffraction. The pesticidal bioassays showed that some of compounds exhibited good fungicidal activities against Cercospora arachidicola, Physalospora piricola and Rhizoctonia cereali at 50 mg/L; some of them displayed favourable insecticidal activities against oriental armyworm (Mythimna separata Walker) at 200 mg/L, particularly, Vk and Vm with mortality rate of 75% and 80% respectively, could be considered as new insecticidal lead compounds for further structural optimization.     

An Expedient Synthesis of Novel Derivatives of Pyrido[2,3‐d]pyrimidines Using Magnetically Supported ZrO2 Nanocatalyst

An efficient synthesis of pyrido[2,3‐d]pyrimidine derivatives via one‐pot multicomponent reactions of 6‐amino‐2‐(alkylthio)pyrimidin‐4(3H)‐one, 3‐cyanoacetylindole and arylaldehydes using [Fe₃O₄@ZrO₂] as magnetically recyclable nanocatalyst is reported. This protocol furnished the desired products in good to excellent yields (70–93 %) and lower reaction times. The catalyst could be easily and efficiently separated from the final product solution by an external magnet and be reused in 5 consecutive runs without any significant activity decrease.     

Hypervalent Iodine(III) Sulfonate Mediated Synthesis of 6‐Arylimidazo[2,1‐b]thiazoles in Liquid PEG‐400

PEG‐400[poly(ethylene glycol‐400)] is used as reaction medium in the one‐pot synthesis of 6‐arylimidazo[2,1‐b]thiazoles by reaction with aryl ketones, hypervalent iodine(III) sulfonate and 2‐aminothiazole. Significant rate enhancements and improved yields have been observed.     

Synthesis of Novel Isoindolo[2,1‐a]quinazolinedione Derivatives Containing a 1,2,3‐Triazole Ring System

A synthesis of isoindolo[2,1‐a]quinazolinedione derivatives, coupled with a 1,2,3‐triazole ring system, via the reaction of isatoic anhydride, HC?CCH₂NH₂, and 2‐formylbenzoic acid is described, which led to the formation of the isoindolo[2,1‐a]quinazoline‐5,11‐dione scaffold having a C?C bond that participated in a click reaction with various organic azides.     

Synthesis of Novel Phthalazino[1,2‐b]quinazolinedione Derivatives: Efficient and Practical Reaction of 2‐Amino‐N′‐Arylbenzohydrazides and 2‐Formylbenzoic Acids

This work reported the synthesis of novel phthalazino[1,2‐b]quinazolinedione derivatives through the reaction of 2‐amino‐N′‐arylbenzohydrazides and 2‐formylbenzoic acids in the presence of TsOH in EtOH under reflux conditions.     

Synthesis of Novel Pyrazino[2,1‐a]isoindolediones via Intramolecular Hydroamination of 2,3‐Dihydro‐3‐oxo‐2‐(prop‐2‐yn‐1‐yl)‐1H‐isoindole‐1‐carboxamides

Novel derivatives of pyrazino[2,1‐a]isoindolediones were synthesized through 6‐exo‐dig intramolecular hydroamination of 2,3‐dihydro‐3‐oxo‐2‐(prop‐2‐yn‐1‐yl)‐1H‐isoindole‐1‐carboxamides followed by 1,3‐H shift, in the presence of sodium hydride in DMF at 80°. All products were obtained in good yields (60 – 80%) within short reaction time (40 – 60 min).     

纳米TiO_2催化一锅法合成喹唑啉酮并酞嗪酮及3-酰胺基异吲哚酮并喹唑啉酮类化合物

以纳米TiO_2为催化剂,靛红酸酐、2-甲酰基苯甲酸、不同芳香肼或酰肼类化合物为原料,在乙醇/水溶液为溶剂的条件下一锅法合成,高产率得到6个喹唑啉酮并酞嗪酮类化合物及10个3-酰胺基取代的异吲哚酮并喹唑啉酮类化合物.该方法简洁高效,反应条件温和,为喹唑啉酮并杂环类化合物的合成提供了一条新途径.     

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.     

Novel Stereoselective Synthesis of Densely Functionalized 2H‐Indeno[2,1‐b]furans

An easy access to densely functionalized 2H‐indeno[2,1‐b]furans is presented starting from triphenylphosphine, dialkyl acetylenedicarboxylates, alcohols (propargyl alcohol, 2,2,2‐trichloroethanol, and methanol), and ninhydrin. The stereochemistry of dimethyl 8‐oxo‐8a‐(2,2,2‐trichloroethoxy)‐8,8a‐dihydro‐2H‐indeno[2,1‐b]furan‐2,3‐dicarboxylate was established by single‐crystal X‐ray structure determination. The reaction is completely stereoselective.     

Synthesis and Structure of Novel Thieno[2, 3‐d]Pyrimidine Derivatives Containing 1, 3, 4‐Oxadiazole Moiety

The reaction of 5‐(1‐pyrrolyl)‐4‐methyl‐2‐phenylthieno[2, 3‐d]pyrimidine carbohydrazide 5 with CS₂ in the presence of pyridine afforded the 6‐(2, 3‐dihydro‐2‐mercapto‐1, 3, 4‐oxadiazol‐5‐yl)‐4‐methyl‐5‐(1‐pyrrolyl)‐2‐phenylthieno[2, 3‐d]pyrimidine 6 , which reacted with methyl iodide in the presence of sodium methoxide to yield the 6‐(2‐methylthio‐1, 3, 4‐oxadiazol‐5‐yl)‐4‐methyl‐5‐(1‐pyrrolyl)‐2‐phenyl‐thieno[2, 3‐d]pyrimidine 7. The 6‐(2‐substituted‐1, 3, 4‐oxadiazol‐5‐yl)‐2‐phenylthieno[2, 3‐d]pyrimidine derivatives 9, 11 and 13 were obtained by the condensation of 6‐(2‐methylthio‐1, 3, 4‐oxadiazol‐5‐yl)‐2‐phenylthieno[2, 3‐d]pyrimidine 7 with appropriate secondary amines. The structure of the new compounds was substantiated from their IR, UV‐vis spectroscopy, ¹H NMR, mass spectra, elemental analysis and X‐ray crystal analysis.     

Rearrangement of 2—Benzothiazolylthioacetyl hidrazide in Ethanol Solution of Potassium Hydroxide：Synthesis of s—Triazolo[3,4—b] benzothiazol—3—thiol and Its Derivatives

A novel rearrangement reaction about 2-benzothiazolylthioacetyl hydrazide (1) to produce s-triazolo[3,4-b] benzothiazol-3-thiol (3) in the presence of KOH and CS2 was described.Other way to synthesize 3 from 2-benzothiazolyl-hydrazine (2) under the same condition was compared and the Mannich reaction of compound 3 was reported too.Their structures were established by elemental analyses,IR,^1H nmr and MS spectra.     

Synthesis of Derivatives of Pyrido[4,3‐d]pyrimidin‐4(3H)‐one via an Iminophosphorane

A series of new, 2‐substituted 3‐aryl‐8,9,10,11‐tetrahydro‐5‐methyl[1]benzothieno[3′,2′ : 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones, compounds 5a – q , were designed and synthesized via the aza‐Wittig reaction as the key step. The iminophosphorane 1 reacted with phenyl isocyanate (or 4‐chlorophenyl isocyanate) to the carbodiimide 4 , which was cyclized to 5 upon addition of different amines, EtOH, or phenols in the presence of a catalytic amount of EtONa or K₂CO₃ (Schemes 1 and 2). The structures of compounds 5 were confirmed by IR, ¹H‐ and ¹³C‐NMR, EI‐MS, elemental analyses, and, in the case of 5l , by single‐crystal X‐ray diffraction (Figure).     

A Simple One-pot Synthesis of Indeno[2,1-f]quinolin-3-one Derivatives under Microwave Irradiation

A series of new indeno[2,1‐f]quinolin‐3(2H)‐one derivatives were synthesized by a reaction of aromatic aldehyde with Meldrum's acid (2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione) and 9H‐fluoren‐2‐amine under microwave irradiation without catalyst in glacial acetic acid. This reaction has notable advantages of short reaction time, high yield and convenient operation.