Regioselective synthesis of benzo[<Emphasis Type="Italic">g</Emphasis>]- and benzo[<Emphasis Type="Italic">f</Emphasis>]quinolines by reaction of chalcones with naphthalen-2-amine

Reactions of 4- and 4′-substituted chalcones with naphthalen-2-amine afforded isomeric benzo[g]- and benzo[f]quinoline derivatives. Depending on the substituent in the initial chalcone, the cyclization follows two pathways through different intermediates. The product structure was confirmed by IR, ¹H and ¹³C NMR, and mass spectra and X-ray analysis.     

A simple and clean procedure for the synthesis of polyhydroacridine and quinoline derivatives: reaction of Schiff base with 1,3-dicarbonyl compounds in aqueous medium

A clean and simple synthesis of benzo[c]acridine, benzo[a]acridine, pyrido[2,3-c]acridine and benzo[f]quinoline derivatives was accomplished in good to excellent yields via the reaction of Schiff base with 1,3-dicarbonyl compounds in aqueous medium catalyzed by TEBA. The structures were characterized by ¹H NMR, IR and elemental analysis, and confirmed by X-ray diffraction study.     

A novel method for the synthesis of tetrahydrobenzo[a]-xanthen-11-one derivatives using cerium(III) chloride as a highly efficient catalyst

Cerium(III) chloride is found to be an highly efficient catalyst for the addition of aldehydes, β-naphthol and cyclic 1,3-dicarbonyl compounds/Meldrum's acid via a multicomponent reaction. The easy availability of starting materials, novel and eco-friendly procedure makes this strategy more useful for the preparation of tetrahydrobenzo[a]-xanthen-11-one, and benzo[f]chromen-3-one derivatives.     

Synthesis of benzo[<Emphasis Type="Italic">f</Emphasis>]quinoline derivatives by three-component condensation of tetronic acid with naphthalen-2-amine and formaldehyde

New derivatives of benzo[f]furo[3,4-b]quinoline, spiro[benzo[f]quinoline-2,3′-furan], and benzo[f]-quinoline-2-carboxylic acid were synthesized with high selectivity by three-component condensation of tetronic acid with naphthalen-2-amine and formaldehyde.     

Condensation of fluorine-substituted benzaldehydes with amines and cyclic ketones

Condensation of fluorine-containing benzaldehydes with naphthalen-2-amine or quinolin-6-amine and cyclic ketones (cyclopentanone, cyclohexanone, and 4-methylcyclohexanone) gave new fluorine-containing derivatives of cyclopenta[c]benzo[f]quinoline, benzo[a]phenanthridine, and cyclopenta[a]- and benzo[a]-[4,7]phenanthroline. Intermediate products, 2-[(fluorophenyl)(2-naphthylamino or quinolin-6-ylamino)methylidene] cyclohexanones, dihydrobenzo[f]quinolines, and dihydro-4,7-phenanthrolines, were isolated.     

Green Method for the Synthesis of Benzo[f]pyrimido[4,5-b]quinoline Derivatives Catalyzed by Iodine in Aqueous Media

A convenient one-pot synthesis of benzo[f]pyrimido[4,5-b]quinoline derivatives is described via three-component reaction of benzaldehydes, naphthalen-2-amine, and barbituric acid at room temperature in aqueous media catalyzed by iodine. Compared with other methods, this three-component reaction used a green solvent, gave good yields, and was operationally simple.     

One-pot synthesis of benzoquinoline and coumarin derivatives using Meldrum’s acid in three-component reactions

A series of 1-aryl-1,2-dihydrobenzo[f]quinolin-3(4H)-one derivatives and 4-aryl-7,7-dimethyl-5-oxo-3,4,5,6,7,8-hexahydrocoumarin derivatives have been synthesized by one-pot multicomponent reaction of Meldrum’s acid with benzaldehyde, naphthalene-2-amine, or cyclohexanedione in PEG-400. The method has the advantages of mild reaction conditions, good yields, and easy processing, and is environmentally benign.     

Catalyst-free rapid synthesis of benzo[4,5]imidazo[1,2-a]-pyrimidine-3-carboxamides via four-component coupling in one pot

A new class of fused tricyclic benzo[4,5]imidazo[1,2-a]-pyrimidine-3-carboxamide derivatives was synthesized via an environmentally benign one pot sequential four-component condensation reaction of an amine, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, an aldehyde and 1H-benzo[d]imidazol-2-amine without using catalyst in good yields.     

Is samoquasine A indeed benzo[f]phthalazin-4(3H)-one? Unambiguous, straightforward synthesis of benzo[f]phthalazin-4(3H)-one and its regioisomer benzo[f]phthalazin-1(2H)-one

In search for the structural elucidation of samoquasine A, a natural product isolated from the seeds of Annona squamosa L., two benzo[f]phthalazinone isomers have been synthesized. The synthetic pathway followed to build up these skeletons is based on the combination of two Suzuki reactions on a pyridazinone precursor and a ring closure reaction via a condensation reaction. ¹H NMR data of the synthesized compound allowed to establish that the structure of the natural product samoquasine A is not benzo[f]phthalazin-4(3H)-one, as previously suggested.     

Efficient method for the synthesis of 2-(3-arylbenzo[f]quinolin-2-yl)ethanol derivatives through an unusual ring-opening of THF-involved reaction

An efficient synthesis of 2-(3-arylbenzo[f]quinolin-2-yl)ethanol derivatives by an unusual THF-involved reaction of aromatic aldehyde and naphthalen-2-amine promoted by iodine has been demonstrated with good yields. The ring-opening of THF reaction is proposed in the possible mechanism.     

Reaction of the zinc enolate derived from 1,1-dibromo-3,3-dimethylbutan-2-one with 3-aryl-2-cyanopropenoic acid amides and esters and 2-oxochromene-3-carboxamides

Zinc enolate derived from 1,1-dibromo-3,3-dimethylbutan-2-one reacts with 3-aryl-2-cyanoprop-2-enamides and aryl 3-aryl-2-cyanoprop-2-enoates to give the corresponding derivatives of 3-aryl-2-(2,2-dimethylpropanoyl)-1-cyanocyclopropane-1-carboxylic acid as a single stereoisomer with cis arrangement of the hydrogen atoms at the cyclopropane ring. The reactions of the same zinc enolate with 3-morpholinocarbonyl-2H-chromen-2-one and 2-morpholinocarbonyl-3H-benzo[f]chromen-3-one lead to formation of 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,7b-dihydrocyclopropa[c]chromen-2-one and 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,9c-dihydrobenzo[f]cyclopropa[c]chromen-2-one, respectively as a single stereoisomer.     

水介质中三组分一锅合成1-芳基苯并[f]喹啉衍生物

以芳醛、2-萘胺和Meldrum酸为原料, 以水为溶剂, 在回流条件下以三乙基苄基氯化铵为催化剂通过三组分一锅反应, 合成了一系列的1-芳基苯并[f]喹啉衍生物. 该方法具有反应条件温和、产率较高(79%～87%)、环境友好等优点. 产物的结构通过熔点, IR, ¹H NMR和元素分析表征.     

Vicinal acetylenic derivatives of 2-amino-1,4-naphthoquinone as key precursors of heterocyclic quinones

The Pd-catalyzed reaction between 3-acetylamino-2-bromo-1,4-naphthoquinones and Cu^I acetylides prepared in situ gave 3-acetylamino-2-alkynyl-1,4-naphthoquinones, which were transformed into benz[f]indole-4,9-dione and benzo[g]quinoline-5,10-dione derivatives.     

Iodine-Catalyzed Synthesis of 3-Arylbenzoquinoline Derivatives by Three-Component Reactions

A mild, efficient, and general method for the synthesis of benzo[f]quinoline derivatives via three-component reaction of arylaldehyde, naphthalen-2-amine, and acetone or acetophenone is described using iodine as catalyst. The features of this procedure are mild reaction conditions, high yields, and operational simplicity.     

Iodine-catalyzed synthesis of pyrazolo[4,3-f]quinoline derivatives via a highly regio-selective Povarov reaction

A highly regio-selective Povarov reaction of an aromatic aldehyde, 1H-indazol-5-amine, and methyl 3-oxobutanoate catalyzed by iodine is described. This novel reaction selectively gave 3H-pyrazolo[4,3-f]quinolin-9-yl acetates, in high yield, rather than 3H-pyrazolo[4,3-f]quinoline-8-carboxylate derivatives. This procedure has the advantages of mild reaction conditions, high yields, metal-free catalyst, and high regio-selectivity.     

Enantioselective construction of biaryl part in the synthesis of stegane related compounds

A Pd-mediated intramolecular aryl-aryl coupling reaction of phenyl benzoate derivatives were examined to form benzo[c]chromen-6-ones, and then enantioselective lactone-opening reaction with a borane-oxazaborolidine combination was carried out. The resulting biphenyl was transformed into a key intermediate for the stegane related compounds. The absolute configuration of the biphenyl is also discussed.     

Synthesis of polycyclic mixed phenothiazine-phenoxazine organic dyes

A convenient synthesis of new polycyclic mixed phenothiazine-phenoxazine compounds is described. The cross-coupling of 2,4-diaminothiophenol with 2,3-dichloro-1,4-naphthoquin one at room temperature gave reddish brown 10-amino-6-chlorobenzo[a]phenoxazin-5-one which was converted into a benzoxazinophenothiazin-12-amine in 58% yield via reaction with 2-aminothiophenol under anhydrous basic conditions. A three-component one-pot synthesis improved the yield of benzoxazinophenothia-12-amine to 81% a in shorter time compared to two steps reactions. The synthesis of new azomethine derivatives of benzo[a]benzo[5,6] [1,4] oxazino [3,2-c] phenothiazin-12-amine with extended conjugations and excellent yields were also reported. The structural assignments of the prepared compounds were established by combine Ultraviolet-Visible, Fourier Transform Infrared, ¹H and ¹³C Nuclear Magnetic Resonance Spectroscopies, Mass Spectrometry and elemental analytical data. The ease of preparations in high yields and their intense colourations make these compounds applicable as dyestuffs.     

3-(4-fluorophenyl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-4-carbaldehyde in the synthesis of aza-and diazaphenanthrene derivatives

Condensation of 3-(4-fluorophenyl)-1H-pyrazole-4-carbaldehyde with 2-naphthyl-or 6-quinolylamine and CH-acids (acetone, acetophenone, cyclic mono-and β-diketones) provided new derivatives of benzo[f]quinoline, benzo[a]phenanthridine, benzo[a]acridine, and 4,7-phenanthroline. The arising in the course of the reaction [3-(4-fluorophenyl)-1H-pyrazole-4-ylmethylene]-2-naphthyl-(or 6-quinolyl)amines, [3-(4-fluorophenyl)-1H-pyrazole-4-ylmethylene]-1,3-indandione, and octahydro-1,8-xanthenedione derivatives were isolated.     

Strontium triflate catalyzed one-pot condensation of β-naphthol, aldehydes and cyclic 1,3-dicarbonyl compounds

An efficient one-pot condensation of β-naphthol, aldehydes, and cyclic 1,3-dicarbonyl compounds has been achieved with strontium triflate as a catalyst, thus a variety of 8,9,10,12-tetrahydrobenzo[a]xanthen-11-one or 8,9-dihydrobenzo-[f]cyclopenta[b]chromen-10(11H)-one derivatives were prepared in good yields.     

A highly selective method for the synthesis of 1,3-diarylbenzo[f]quinoline derivatives catalyzed by silver triflate

Abstract  

The three-component reactions of aromatic aldehydes, naphthalen-2-amine, and phenylacetylene catalyzed by AgOTf in toluene selectively gave 1,3-diarylbenzo[f]quinolines in high yields. This procedure provides an efficient method for the synthesis of benzo[f]quinolines under mild reaction conditions and with high yields, high selectivity, and operational simplicity.