Chemoselective synthesis and cytotoxic activity of a series of novel benzo[1,4]oxazin-3-one derivatives

That tetraacetonitrile copper perchlorate catalyzes intramolecular amidation of arenes was found to be a new strategy for construction of nitrogen-containing heterocycles and resulted in the formation of a series of novel benzo[1,4]oxazin-3-one derivatives from N-(1,3-diphenyl-1H-1,2,4-triazol-5-yl)-2-phenoxyacetamides.This approach of heterocyclic construction proceeds in a chemoselective manner in which only benzo[1,4]oxazin-3-one derivatives were obtained by C—N bonds formation with cheap and simple copper salt catalyst under mild conditions in moderate to good yields.The biological assay of some of benzo[1,4]oxazin-3-one derivatives showed that they had moderate antiproliferative activity toward MDA-MB231 and HeLa cancer cell lines.     

FeCl3-Mediated Reaction of 1,4-Dilithio-1,3-dienes with Alkynes Affording Benzene Derivatives

Unactivated alkynes reacted with 1,4-dilithio-1,3-diene derivatives in the presence of FeCl3 affording substituted benzene derivatives via a formal[4 2] cycloaddition.     

Synthesis, structure and conformation of 1,3-difluorotetraphenyl benzene

The compound trifluoroiodomethane can be activated to react with the electron donor,1,4-dilithiotetraphenyl butadiene,by means of electron transfer catalysis (ETC).The structure of the product,1,3-difluorotetraphenyl,benzene (1),was determined by MS,NMR,and X-ray single crystal diffraction.The conformations of compound 1 and its derivatives were analysized by molecular mechanics.     

Synthesis and Insulin—sensitizing Activity of a Series of 2—Benzyl—1,3—dicarbonyl Derivatives

A series of 2-benzyl-1,3-dicabonyl derivatives was synthesized.Their insulin-sensitizing activity was evaluated in 3T3-L1 preadipocyte cells.Compounds3,26 and 27 were found to possess strong insulin-sensitizing activity in vitro and were selected for further hypoglycemic evaluation in vivo.     

Synthesis of (1H)-3,4-Dihydropyrrolo[2,1-c][1,4]oxazin-1-one Derivatives

It has been found that some acyl derivatives of 1,2,3,4-tetrahydro-1-indolizin-1-one 1and (1H)-3,4-dihydropyrrolo[1,2-a]pyrazin-1-one 2 show remarkable anti-inflammatory and analgesic activities1,2. The interest in extending the study of structure-activity relationships and search of new potent anti-inflammatory and analgesic agents led us to design and synthesize (1H)-3,4-dihydropyrrolo[2,1-c][1,4]oxazin-1-one 3 derivatives. NO 1 NNHO2 87654321ONO3 A few examples of the p…     

Solid State Oxidative Aromatization of Hantzsch 1,4-Dihydropyridines to Pyridines Using Iodobenzene Diacetate or Hydroxy(tosyloxy)iodobenzene

An easy, safe, solvent-free and effective method for oxidative aromatization of Hantzsch 1,4-dihydropyridines catalyzed by hypervalent iodine (IBD and HTIB) to corresponding pyridine derivatives in high yields within short span of time. All reactions were carried out just by grinding the two reactants.     

REACTION OF ORGAINIC-TELLURONIUM YLIDE XI.A FACILE SYNTHESIS OF DERIVATIVES OF BISCYCLOPROPANE

Some telluronium salts react easily with 1,4-bis(3-substitutedphenyl-3-oxo-1-propenyl)benzene and 1,5-disubstituted phenyl-1,4-pentadien-3-one to afford derivatives of biscyclopropanes in 61.8-88.8% yield.     

One-pot synthesis of novel pyrrolo-1,4-benzoxazines via a three- component reaction of 2-amino phenols,acetylenic esters and nitrostyrene derivatives简

A simple and efficient synthetic protocol has been developed using a one-pot, three-component reaction involving 2-amino phenols, dialkyl acetylene dicarboxylates and nitrostyrene derivatives. Utilizing this protocol, a variety of novel pyrrolo-1,4-benzoxazine derivatives were synthesized in excellent yields.     

Copper-mediated 1,4-conjugation reaction of functionalized alkylzinc iodides with derivatives of β-nitrostyrene

Functionalized alkylzinc iodides will undergo 1,4-conjugation reaction with derivatives ofβ-nitrostyrene in the presence of Cu(OAc)_2/LiCl to afford a polyfunctional nitro-compound in high yield.     

Transition-metal-free synthesis of 1,4-benzoxazepines via[4+3]-cycloaddition of para-quinone methides with azaoxyallyl cations

A formal[4+3]-cycloaddition reaction of ortho-hydroxyphenyl-substituted para-quinone methides(p-QMs)with in-situ generated azaoxyallyl cations is reported.The reaction occurs under very mild reaction conditions(transition-metal free,room temperature,cheap inorganic base)and provides a very efficient route to a series of biologically important 1,4-benzoxazepine derivatives in good to excellent yields.     

Synthesis and Stereochemistry of Some New 1,3-Dioxane Derivatives of 1,4-Diacetylbenzene

Summary.  The synthesis and stereochemistry of new 1,3-dioxane derivatives of 1,4-diacetylbenzene are reported. The anancomeric structure of these compounds, the axial orientation of the aryl group for both 1,3-dioxane rings, and the cis and trans isomerism of some of these compounds is discussed considering data of conformational analysis, NMR investigations, and single crystal X-ray diffractometry. Received September 12, 2001. Accepted (revised) November 5, 2001     

Synthesis of Benzofuro[3,2-e][1,4]diazepines

A synthesis of 4-N-oxides and of 3-hydroxy derivatives of 1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-ones and of 2,3-dihydro-1H-benzofuro[3,2-e][1,4]diazepines is described. Condensation of 2-acetyl- and 2-benzoyl-3-ethoxycarbonylaminobenzofurans with acrylonitrile gave derivatives of 1,2-dihydro- and of 1,2,3,4-tetrahydrobenzofuro[3,2-b]pyridine.     

1,4-Dithiafulvene aus der Umsetzung von 4,4-disubstituierten 1,3-Thiazol-5(4H)-thionen mit Acetylenderivaten

1,4-Dithiafulvenes, Products of the Reaction of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thiones and Acetylenic Compounds On heating in toluene, 4,4-disubstituted 1,3-thiazol-5(4H)-thiones 1 and acetylenecarboxylates or acetylenecarbonitriles 2 undergo a cyclosubstitution reaction to yield 2-methylidene-1,3-dithiol derivatives 3 (1,4-dithiafulvenes) and a nitrile. Further heating of 3a and 3b in the presence of excess 2a leads to the isomeric 2,3-dihydrothiophene-2-thiones 4a and 4b , respectively. The benzodithiafulvene 14 has been formed in a similar reaction from 1a and in situ generate benzyne.     

Highly efficient synthesis of stereodefined multisubstituted 1,4-dicyano- and 1-cyano-1,3-butadienes and their reactions with organolithium reagents

Stereodefined multisubstituted 1-cyano- and 1,4-dicyano-1,3-butadiene derivatives were obtained in excellent yields of the isolated product from their corresponding monohalo- and dihalobutadienes and CuCN. This reaction proceeded with high stereoselectivity and retention of the stereochemistry of the starting halobutadienes. A study of the utility of the thus-obtained 1-cyano- and 1,4-dicyano-1,3-butadiene derivatives was demonstrated by their reactions with organolithium reagents. 2H-Pyrrole or iminocyclopentadiene derivatives were formed in high yields from 1-cyano-4-halo-1,3-butadienes and organolithium reagents. When 1,4-dicyano-1,3-butadienes were treated with organolithium reagents followed by trapping with electrophiles, a tandem process took place to afford 2H-pyrrolyl nitriles in excellent yields. Reduction of 1,4-dicyano-1,3-butadiene derivatives with LiAlH4 showed novel reaction patterns relative to normal nitriles.     

The oxidation of 1,4-dihydropyridines

The olefinic bond of methenylbisindan-1,3-dione, 2-benzylideneindan-1, 3-dione, and its derivatives is easily reduced by many 1, 4-dihydropyridines. Under the conditions described, other functional groups are untouched. These -dicarbonyl compounds are utilized to compare the effects of substituents in 1,4-dihydropyridines on their reactivity in the hydrogen transfer reaction.     

Formation of stereodefined multiply substituted all-cis octatetraenes, tricyclo[4.2.0.0]octa-3,7-dienes and pentalenes via CuCl- or FeCl3-mediated dimerization of 1-lithiobutadienes and 1,4-dilithiobutadienes

Dimerization of 1-lithiobutadienes and 1,4-dilithiobutadienes depended remarkably on the substituents and metal halide reagents. Stereodefined multiply-substituted linear all-cis octatetraenes were prepared in moderate yields via FeCl₃-mediated dimerization of 1-lithiobutadienes, while CuCl induced the dimerization of alkyl-substituted 1,4-dilithio-1,3-dienes to form linear all-cis octatetraenes and tricyclo[4.2.0.0^2,5]octa-3,7-dienes. Interestingly, stereodefined pentalene derivatives were also obtained when 1,4-dilithio-1,3-dienes possessed both phenyl and alkyl substituents.     

Quinazolines and 1,4-benzodiazepines. XCVI. Compounds derived from benzodiazepine-2-acetic acid

1,4-Benzodiazepine-2-acetic acid derivatives were prepared and converted to compounds with a heterocyclic ring fused to the a-face of the benzodiazepine system. Representatives of pyrido[1,2-a][1,4]benzodiaze-pines, pyrimido[1,6-a][1,4]benzodiazepines and [1,3]oxazino[3,4-a][1,4]benzodiazepines are described. Some of the compounds showed marked CNS-activity as measured by the antimetrazole test which is a well established primary screening method for assessment of benzodiazepine type activity.     

Reactions of substituted (1,3-butadiene-1,4-diyl)magnesium, 1,4-bis(bromomagnesio)butadienes and 1,4-dilithiobutadienes with ketones, aldehydes and PhNO to yield cyclopentadiene derivatives and N-Ph pyrroles by cyclodialkenylation

1,4-Dilithiobutadiene derivatives 1, 1,4-bis(bromomagnesio)butadiene derivatives 2 and metallacyclic (1,3-butadiene-1,4-diyl)magnesium reagents 3 were prepared and their reactions with ketones, aldehydes, and PhNO were investigated. Multiply substituted cyclopentadienes and N-Ph pyrroles were formed by unprecedented reaction conditions. The carbonyl group of aldehydes and ketones was deoxygenated during the reaction and behaved formally as a one-carbon unit; the N==O moiety of PhNO was cleaved to afford N-Ph pyrrole derivatives. Furthermore, different reactivities among these three types of reagents 1, 2 and 3 were revealed. The 1,4-dilithium reagents 1 readily reacted with both aldehydes and ketones; the 1,4-dimagnesium reagents 2 reacted with aldehydes, but not ketones; the metallacyclopentadiene reagents of magnesium 3 showed higher reactivity and did react with ketones.     

Synthesis and Stereochemistry of Some New 1,3-Dioxane Derivatives of 1,4-Diacetylbenzene

 The synthesis and stereochemistry of new 1,3-dioxane derivatives of 1,4-diacetylbenzene are reported. The anancomeric structure of these compounds, the axial orientation of the aryl group for both 1,3-dioxane rings, and the cis and trans isomerism of some of these compounds is discussed considering data of conformational analysis, NMR investigations, and single crystal X-ray diffractometry.