New conversion of Friendl(a)nder reaction of 3-amino-lH-benzo[f]chromene-2-carbonitriles with cyclohexanone

Two different skeletons of heterocyclic compounds, quinoline and quinazolinone analogs could be obtained by a novel one-potsynthesis from substituted 3-amino-lH-benzo[f]chromene-2-carbonitrile derivatives and cyclohexanone in DMF in the catalyst ofanhydrous zinc chloride under reflux. A plausible mechanism was proposed.     

New synthesis of 3-amino-1H-benzo[f]chromene-2-carbonitriles

3-Amino-1H-benzo[f]chromene-2-carbonitriles were synthesized by non-catalytic reaction from Mannich bases of the naphthalene series and malononitrile. Reactive 1-benzylidene(or methylidene)naphthalen-2(1H)-ones were presumed as intermediate products.     

Oxa-[3+3] annulation of 1H-benzo[f]chromene-2-carbaldehydes and 2-naphthols: synthesis of 7aH,15H-benzo[f]benzo[5,6]chromeno[2,3-b]chromenes

Chemistry of Heterocyclic Compounds - A method for the preparation of polycondensed chromeno[2,3-b]chromenes was developed based on the formal [3+3] cycloaddition reaction between...     

Reactions of Zinc Enolates of Substituted 1-Aryl-2,2-dibromobutanones with Alkyl Esters of 3-Oxo-3H-benzo[f]chromene-2-carboxylic Acid

Zinc enolates derived from substituted 1-aryl-2,2-dibromobutanones react with alkyl 3-oxo-3H-benzo[f]chromene-2-carboxylates to form alkyl 1-aroyl-1-ethyl-2-oxo-1,9c-dihydro-3-oxacyclopropa[c]phenanthrene-1a-carboxylate as a single geometric isomer.     

One-step synthesis of substituted 2-amino-4H-chromenes and 2-amino-4H-benzo[f]chromenes. Molecular and crystal structure of 2-amino-3-cyano-6-hydroxy-4-phenyl-4H-benzo[f]chromene

Substituted 2-aminochromenes were synthesized by three-component condensation of aromatic aldehydes, derivatives of cyanoacetic acid, and phenols or naphthols. The molecular and crystal structure of 2-amino-3-cyano-6-hydroxy-4-phenyl-4H-benzo[f]chromene was established by X-ray diffraction analysis.     

One-pot,three-component synthesis and in vitro antibacterial evaluation of novel 3-amino-N-benzyl-1-aryl-1H-benzo[f]chromene-2-carboxamide derivatives

A series of novel 3-amino-N-benzyl-1-aryl-1H-benzo[f]chromene-2-carboxamides have been synthesized by the reaction of N-benzyl-2-cyanoacetamide with 2-naphthol and aromatic aldehydes in the presence of piperidine as a base. The chemical structures of all the compounds were confirmed by spectroscopic methods as well as elemental analysis. In addition, the antibacterial activities of some target compounds against Gram-negative and Gram-positive bacteria in vitro were determined. Among these compounds, 4b, 4c, 4h and 4i exhibited antibacterial effects. The advantages of the present work reaction are clean reaction, metal-free transition, environmentally friendly approach to prepare different benzo[f]chromene-2-carboxamide derivatives, good yields, low cost, readily available starting materials and in addition does not need cumbersome procedure.     

X-ray Diffraction Investigation of Ethyl 2-（2-Amino-3-ethoxycarbonyl-4H-benzo[f]chromene-4-yl） Cyanoacetate

The title compound,ethyl 2-(2-amino-3-ethoxycarbonyl-4H-benzo[f]chromene-4-yl) cyanoacetate 4,has been synthesized and its crystal structure was characterized by X-ray single-crystal diffraction.The crystal belongs to monoclinic,space group P21/n with a=12.9408(18),b=11.1870(13),c=13.8975(19),β=109.261(2)°,Z=4,C21H20N2O5,Mr=380.39,V=1899.3(4)3,Dc=1.330 g/cm3,μ=0.096 mm-1,F(000)=800,S=1.027,R=0.0535 and wR=0.1012 for 1365 observed reflections(I 2σ(I)).X-ray analysis reveals N-H…π interactions,π…π interactions and hydrogen bonds in the title molecule.     

New method for the synthesis of 4-aryl-3,4-dihydro-2H-benzo[g]chromene-2,5,10-triones

Abstract

We report herein a new method for the synthesis of 4-aryl-3,4-dihydro-2H-benzo[g]chromene-2,5,10-triones 4 that proceeds in good yields (74–86%) and mild reaction conditions between readily available 2-amino-4-aryl-5,10-dioxo-5,10-dihydro-4H-benzo[g]chromene-3-carbonitriles 1, and formic acid (88%), at reflux for 6?h. In addition, we have also studied the antioxidant activities using DPPH and total TAC methods.     

Synthesis of Some New 3-Alkylthio Derivatives of 1-Phenyl-1H-[1, 3, 4]thiadiazino[5, 6-b]quinoxalines

The synthesis of some new 3-(alkylthio)-1-phenyl-1H-[1, 3, 4]thiadiazino[5, 6-b]quinoxalines 4 have been achieved by cyclocondensation reaction of the alkyl-2-phenylhydrazinecarbodithioates 1 with 2,3-dichloroquinoxaline 2 in basic N,N-dimethylformamide.     

Novel stereoselective synthesis of 2,3-dihydro-1H-benzo[f]chromen-3-amine derivatives through a one-pot three-component reaction

A short and stereoselective novel synthesis of benzo[f]chromen-3-amine derivatives in good yields, through a three-component aromatic Betti type reaction under solvent free conditions is reported. The spontaneous reaction occurs in the absence of acid catalysts. The use of chiral 1-phenylethylamine or α,β-unsaturated aldehydes allowed us to prepare enantiopure benzo[f]chromen-3-amine derivatives with good stereoselectivity. Conformational analysis compared with the ¹H NMR data of the products obtained, allowed us to the determine the absolute configuration, which was also confirmed by X-ray analysis.     

Reactions of 3-Hydroxy-2-phenyl-1H-benzo[e]isoindol-1-one: A Route to 3-Hydroxy-/3-anilinobenzo[e]indan-1-ones and Benzo[f]phthalazin-1(2H)-ones

New hydroxy- and anilinoindanone derivatives 3 and 4 were synthesized starting from 3-hydroxybenzo[e]isoindolinone 1 via the addition of alkyllithium (s-BuLi, n-BuLi, MeLi or i-PrLi) to the carbonyl group, followed by lactam ring opening and, finally, an intramolecular cyclization leading to target compounds. The same starting material was used for the preparation of the new benzo[f]phthalazinone derivatives 12–16 through multi-step reactions. The target derivative 16 was obtained from the corresponding bromolactam 15 by the Buchwald–Hartwig amination. Structures of the obtained compounds were confirmed by the NMR spectra.     

p-Toluenesulfonic acid-catalyzed one-pot synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazolo[1,2-a]pyrimidine-3-carbonitriles under neat conditions

A simple, efficient, and green procedure for the preparation of 2-amino-4-substituted-1,4-dihydrobenzolo[4,5]imidazolo[1,2-a]pyrimidine-3-carbonitriles has been developed by multi-component condensation of 2-aminobenzimidazole with aldehydes and malononitrile in the presence of a catalytic amount of p-toluenesulfonic acid, affording excellent yields under neat conditions. The protocol avoids the use of expensive catalysts, toxic solvents, and chromatographic separation. We believe that this new environmentally metal-free procedure, combined to a solvent-free reaction, would be of importance in the search of green laboratory-scale synthesis.     

Synthesis of New 3-Aryl-1-methylbenzo[f]quinolines

Three-component condensation of 2-aminonaphthalene, acetone, and substituted benzaldehydes in alcoholic solution in the presence of concentrated hydrochloric acid gave 3-aryl-1-methylbenzo[f]quinolines. 1-Methyl-3-(nitrophenyl)benzo[f]quinolines were reduced to the corresponding amines which were converted into amides having a sulfonyl or chloroacetyl group in the aryl substituent.     

Convenient one-step synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles and 5-unsubstituted 5H-chromeno[2,3-b]pyridine-3-carbonitriles from quaternary ammonium salts

We have reported DBU catalyzed synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles in water under reflux. The attractive features of this process are mild reaction conditions, short reaction times, easy isolation of products and good yields. 5H-chromeno[2,3-b]pyridine-3-carbonitriles were obtained by refluxing excess of malononitrile and quaternary ammonium salts in ethanol in the presence of NaOH as catalyst. The mechanisms of these reactions are believed to involve the formation of the o-quinone methide intermediate.     

One-pot synthesis of 2-alkyl-7-amino-5-aryl-pyrazolo[1,5-a]pyrimidine-6-carbonitriles via a domino three-component condensation-oxidation reaction

A one-pot, domino three-component condensation reaction of an aldehyde, 3(5)-amino-5(3)-methylpyrazole and malononitrile in ethanol to give 2-alkyl-7-amino-5-aryl-pyrazolo[1,5-a]pyrimidine-6-carbonitrile in high yields at reflux condition without using any catalyst, is described.     

Efficient one-pot synthesis of 1,3-diaryl-3H-benzo[f]chromenes using ferric hydrogensulfate

<正>An efficient and easy method for one-pot three-component synthesis of l,3-disubstituted-3H-benzo[f]chromenes by the condensation of naphtol,aromatic aldehyde derivatives and phenylacetylene in the presence of ferric hydrogensulfate[Fe(HSO_4)_3], has been described.The catalyst displayed high activity which afforded the corresponding 1,3-disubstituted-3H-benzo[f]chromenes in satisfying yields.Alkyl-substituted phenols were examined and the corresponding benzopyran derivatives were synthesized in moderate yields.Heterogeneous nature of the using catalyst made it reusable for further chemical reactions.     

Base-catalyzed cyclization reaction of 2-chloroquinoline-3-carbonitriles and guanidine hydrochloride: a rapid synthesis of 2-amino-3H-pyrimido[4,5-b]quinolin-4-ones

t-BuOK-catalyzed cyclization of 2-chloroquinoline-3-carbonitriles with guanidine hydrochloride provided simple and rapid synthesis of 2-amino-3H-pyrimido[4,5-b]quinolin-4-ones in very short reaction time with good yield. Other 1,3-binucleophiles are found to react at the same rate. This methodology could be extended with their 3-formyl and 3-ester derivatives for the synthesis of pyrimido annulated quinolines.     

On triazoles XXIII [1]. The reaction of 5-amino-1,2,4-triazoles with thiacyclohexane β-oxo esters [2]

Six novel isomeric ring systems, namely the thiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[4,3-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidine and the thiopyrano[2,3-e]-1,2,4-triazolo[1,5-a]pyrimidine were synthesised. Spectroscopical evidence was given for the structure of compounds obtained.     

Convenient synthesis of substituted 3-aminothiophene-2-carbonitriles from α-acetylenic nitriles and their conversion to thieno[3,2-d]pyrimidines

Several novel 2,4,6-trisubstituted thieno[3,2-d]pyrimidines were synthesized from the hitherto unknown 3-amino-5-methyl-(or 5-phenyl)thiophene-2-carbonitriles 7 and 8 . o-Aminonitriles 7 and 8 were obtained in a single step by conjugate addition of mercaptoacetonitrile (generated in situ) to substituted acetylenic nitriles 4 and 5 and annelation of the intermediate vinylic thioethers.     

One-step synthesis of substituted 2-amino-5,6,7,8-tetrahydro-4H-benzo[b]pyrans. Molecular and crystal structure of 2-amino-3-(2-methoxyethoxycarbonyl)-4-(2-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran

Substituted 2-aminobenzo[b]pyrans were synthesized by three-component condensation of aromatic aldehydes, cyanoacetic acid derivatives, and cyclic 1,3-diketones. The molecular and crystal structure of 2-amino-3-(2-methoxyethoxycarbonyl)-4-(2-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran was established by X-ray diffraction analysis.