New Bisbenzimidazolin‐2‐Ylidene Salts as N‐Heterocyclic Dicarbene Precursors: Synthesis,Characterization, and Involvement in Palladium‐Catalyzed Suzuki Reactions

A new series of bis‐N‐heterocyclic carbene precursors, LHX ( 3a–d ), have been synthesized and characterized by appropriate spectroscopic techniques and microanalyses. In situ prepared Pd(OAc)₂/bis‐N‐heterocyclic carbene precursors catalysts have catalyzed unactivated aryl chlorides on the Suzuki cross‐coupling reaction under mild reaction conditions in aqueous media.     

A New Pathway to Synthesize Cyclomercurated Ferrocenylimines Containing Heterocyclic Ring

The cyclomercurated ferrocenylimines containing heterocyclic ring were prepared by the condensation of cyclomercuration of acylferrocene with the appropriate heterocyclic amine.This procedure provides an efficient method for the synthesis of cyclomerucurated ferrocenylimines containing heterocyclic ring which are difficultly synthesized by the conventional method.The reaction mechanism is proposed.     

Natural Product‐Mimetic Scaffolds with Privileged Heterocyclic Systems: Design,Synthesis, and Evaluation of Antioxidant Activity of Quinazoquinobenzothiazinones

Structurally diverse quinazolinoquinolinobenzothiazinones based on rutaecarpine structural framework with hybrid structural features of three medicinally privileged heterocyclic systems has been synthesized as natural product‐mimetic scaffolds involving the use of multi‐step reaction sequences. The synthesized quinazolinoquinolinobenzothiazinones have been evaluated for their antioxidant and radical scavenging activities.     

Synthesis, structure and properties of pyrazole type tetrakis compounds

A series of pyrazole type tetrakis compounds has been synthesized by reaction of aromatic or heterocyclic dialdehydes and pyrazolone derivatives. Structure and tautomerism of the products were investigated by spectroscopic methods and X-ray analysis. Several tetrakis compounds form inclusion complexes with solvents like alcohols, ethers, and ketones in a definite ratio via hydrogen bonds.     

Synthesis of the angular furanoxanthone,deoxydehydropsorospermin methyl ether (5,10-dimethoxy-2-isopropenyl-6H-furo[2,3-c]xanthen-6-one)

The angular isopropenylfuranoxanthone heterocyclic system, on which the anti-leukemic natural product psorospermin is based, is synthesized by the reaction of cuprous isopropenylacetylide with 4-bromo-1,5-dimethoxy-3-hydroxyxanthone.     

Pyrido[1',2':1,5]pyrazolo[4,3-b]quinolines as New Fluorescent Heterocyclic Systems for Dye-Sensitized Solar Cells

Russian Journal of General Chemistry - New fluorescent heterocyclic compounds pyrido[1',2':1,5]pyrazolo[4,3-b]quinolines have been synthesized by the reaction of...     

Synthesis of Chiral Heterocyclic Ketene N,O-Acetals

Chiral heterocyclic ketene N, O-acetals 3 were synthesized by the reaction of ketene mercaptals 2 with (R)-(-)-2-amino-1-butanol.     

Formation of the imidazolinone ring under mild conditions in the presence of sodium hydride

Substituted imidazolinones containing heterocyclic carboxylic acids as substituents and possessing herbicidal properties were synthesized by cyclization of 2-amino-2,3-dimethylbutyramide with heterocyclic ethyl dicarboxylates under mild conditions. The use of NaH as base leads to a significant increase in the reaction rate and allows the preparation of the target compounds in high yields.     

Two Novel Thermal Biradical Cyclizations of Enyne-Ketenimines: Theory,Experiment, and Synthetic Potential

Both benzocarbazoles and quinolines can be synthesized from enyne ketenimines 1 generated in situ via biradical intermediates (see reaction below). Which of the heterocyclic ring systems is formed depends on the choice of the substituent R¹ at the alkyne terminus.     

Conversion of 2-aminomethylbenzothiazoles into imidazo[5, 1-b]benzothiazoles

A number of substituted 2-aminomethylbenzothiazoles ate synthesized. The corresponding ureas or thioureas are also obtained by reaction with arylisocyanates or arylisothiocyanates. Heating the substituted ureas or thioureas at temperatures above their melting points cyclizes them to 9-substituted 2-hydroxy- or 2-mercaptoimidazo[5, 1-b]benzothiazoles, which are derivatives of a new heterocyclic system.     

Heterocondensed 1,2,3‐diazaphosphorines

The reaction of phosphorus tribromide with phenylhydrazones of heterocyclic aldehydes leads to formation of a new phosphorus‐containing heterocyclic system—heterocondensed 1,2,3‐diazaphosphorines. Properties of the phosphorus‐containing heterocyclic compounds that have been synthesized are described. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:658–664, 2001     

POCl3-mediated synthesis of 2-substituted benzimidazolyl-coumarin,benzimidazolyl-indole,and styrylbenzimidazole derivatives

2-Substituted benzimidazolyl heterocycles and styrylbenzimidazoles have been synthesized by the reaction of substituted o-phenylenediamine with different heterocyclic carboxylic acids and cinnamic acid respectively in the presence of POCl₃ as a solvent and catalyst. The proposed reaction has advantageous features of good yields, short reaction times, and operational simplicity. In addition, the scope and limitations were explored, and a plausible reaction mechanism was proposed. The synthesized molecules were characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectral data. Further, single crystals of 2-(1H-indol-2-yl)-1H-benzo[d]imidazole have been developed and structural parameters were collected from x-ray diffraction data.     

Novel synthesis of hydrazide-hydrazone derivatives and their utilization in the synthesis of coumarin, pyridine, thiazole and thiophene derivatives with antitumor activity

The reaction of cyanoacetyl hydrazine (1) with 3-acetylpyridine (2) gave the hydrazide-hydrazone derivative 3. The latter compound undergoes a series of heterocyclization reactions to give new heterocyclic compounds. The antitumor evaluation of the newly synthesized products against three cancer cell lines, namely breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) was performed. Most of the synthesized compounds showed high inhibitory effects.     

微波辅助1,4-迈克尔加成合成香豆素3-,4-并六元杂环衍生物

在微波辐射下,以1,4-二氧六环为介质,六甲基二硅基胺基钾(KHMDS)为碱使香豆素与杂环烯酮缩胺进行加成环化及脱氢芳构化反应合成多环香豆素类化合物.该法只需微波辐射20min,产率60%～87%.该法具有反应时间短,操作简便等特点.     

Synthesis of 2-(p-Toluenesulfonamido)-4-phenyl-4, 5-dihydro-1H-1, 3, 4-diazaphosphole 4-oxides

Some novel unsaturated five-membered organophosphorus heterocyclic compounds, 2-(p-toluenesulfonamido)-4-phenyl-4, 5-dihydro-1H-1, 3, 4-diazaphosphole 4-oxides 8 have been synthesized by Mannich-type reaction of p-toluenesulfonylguanidine with phenyldichlorophosphine and ketones.     

Design,Synthesis, and Antimicrobial Evaluation of some Novel Pyridine,Coumarin, and Thiazole Derivatives

Treatment of 2‐cyano‐N′‐(1‐(pyridin‐2‐yl)ethylidene)acetohydrazide 1 with aromatic/heterocyclic aldehydes 2a–f gave arylidene derivatives 3a–f . Polysubstituted pyridine derivatives 4a,b were prepared either from reaction of arylidene 3a,b with malononitrile or from reaction of acetohydrazide 1 with arylidenemalononitrile 5a,b . Cyclocondensation of acetohydrazide 1 with salicylaldehyde derivatives and acetylacetone furnished pyrido‐coumarins 6,7 and 2‐pyridone‐3‐carbonitrile 8, respectively. In addition, pyrido‐thiazoles 13 and 15 were obtained through reaction of 2‐(1‐(pyridin‐2‐yl)ethylidene)hydrazinecarbothioamide 11 with hydrazonyl chlorides and α‐haloketones, respectively. The structures of synthesized compounds were elucidated with spectral and elemental data. The antimicrobial activity of the synthesized compounds was studied.     

Reaction of phenyl-containing N-substituted 1,3-oxazolidines and 1,3-oxazinanes with triammine(tricarbonyl)chromium

Russian Chemical Bulletin - New heterocyclic compounds with phenyl chromium tricarbonyl substituents were synthesized by the reaction of triammine(tricarbonyl)chromium with phenyl-substituted...     

Microwave-assisted combinatorial synthesis of polysubstituent imidazo[1,2-a]quinoline, pyrimido[1,2-a]quinoline and quinolino[1,2-a]quinazoline derivatives

A series of unusual fused heterocyclic compound derivatives, consisting of a pyridine and a imidazole or pyrimidine core, with a bridgehead nitrogen, were successfully synthesized by a microwave-assisted, three-component domino reaction of aldehydes, enaminones, and malononnitrile. In this one-pot reaction, up to five new bonds were formed accompanied by generating the lactam group. This method has the advantages of short synthetic route, operational simplicity, increased safety for small-scale high-speed synthesis, and minimal environment impact.     

Solvent‐Free Synthesis of Heterocyclic Thioureas Using Microwave Technology

A new and rapid solvent‐free synthesis of heterocyclic thioureas in a microwave oven has been reported for the first time. Nine heterocyclic thioureas that possess biological activity have been synthesized. The reaction time is short (2–4.5 min) and gives excellent yields (82.9–95.5%).     

A convenient palladium catalyzed synthesis of symmetric biaryls, biheterocycles and biaryl chiral diamides

A series of symmetrical diamido biaryls has been synthesized in good yield by direct homocoupling of iodoarylbenzamides by palladium-catalysis. No cross product has been isolated from the reaction mixture of two different iodoarylbenzamides under similar conditions. However, only in the case of 2-iodo-N-phenylbenzamide, the intramolecularly coupled product phenanthridone has been isolated as a minor product along with the major intermolecularly coupled product. Biphenyl chiral diamides have been synthesized by this coupling method. This coupling reaction also works well with the reductive dimerization of functionalized heterocyclic compounds. Thus 6,6′-dipivaloylamino-3,3′-bipyridine and 6,6′-dimethyl-2,2′-bipyridine have been efficiently synthesized. In two cases, the X-ray crystal structures have been solved to establish the structures of symmetrical and chiral diamido biaryls and their supramolecular networks.