A novel synthesis of benzofuran and related compounds. I. The vilsmeier reaction of phenoxyacetonitriles

A novel synthesis of 2-benzofurancarboxylic acid derivatives by the Vilsmeier reaction of phenoxyacetonitriles is described.     

A novel reaction of vilsmeier reagent with 2,1-benzisoxazoles

Vilsmeier reagent reacts with 2,1-benzisoxazoles affording N-formanilides in high yields.     

The reaction of acetals with aliphatic nitro compounds. 1. The synthesis of α-nitrosuccinic esters

Conclusions A preparative method was developed for esters of -nitro--alkoxy--arylpropionic acids and substituted -nitrosuccinic acids from a nitroacetate ester and acetals of aromatic aldehydes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 639–641, March, 1980.     

Formation of benzofuran and 2H-chromene structures in one reaction. A novel synthesis of 2H-chromene derivatives

Heating the morpholinal of nitrosalicylic aldehyde with methyl propiolate in acetonitrile in the presence of Cul affords an equimolar mixture of 2-methoxycarbonylmethyl-3-morpholino-5-nitrobenzofuran and 3-methoxycarbonyl-2-morpholino-6-nitro-2H-chromene, the structures of which were determined by X-ray analysis. Only the 2H-chromene mentioned above was obtained in the absence of Cul and solvent.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1222–1228, May, 1996.     

A novel one-pot three-component synthesis of benzofuran derivatives via Strecker reaction: Study of antioxidant activity

Abstract

A three-component Strecker-type reactions was applied for the synthesis of benzofuran derivatives through the reaction of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-yl)-1-ethanone (euparin), primary amines and trimethylsilyl cyanide (TMSCN) in the presence of catalytic amount of ZnO-nanorods (ZnO-NR) and piperidine in acetonitrile at room temperature. The method has proved to be synthetically simple, and effective with high atom economy and yield. The catalyst also revealed significant reusability. Moreover, the antioxidant activity and free radical scavenging capacity of the newly synthesized such as 4a, 4c, 6a and 6c was screened using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays and compared with hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). These compounds exhibit good DPPH radical scavenging and ferric reducing antioxidant power (FRAP) assays.     

Studies on quinoline derivatives and related compounds. III. A novel pyridine synthesis to give substituted 1,4-dihydro-4-oxonicotinic acids

A variety of 5-mono- and 5,6-disubstituted 1,4-dihydro-4-oxonicotinates were prepared by a novel pyridine synthesis which involves thermal cyclisation of enaminomethylenemalonates 9. The intermediates 9 were readily prepared through a few steps from commercially available starting materials.     

Research on heterocyclic compounds. XLII. The vilsmeier reaction in the synthesis of imidazo[1,2‐a]pyrimidine derivatives

The Vilsmeier reaction on imidazo[1,2‐a]pyrimidine ring is reported. The 3‐formyl derivative obtained is oxidized to yield the corresponding carboxylic acid.     

The synthesis and properties of dichloroheptafluoropropyltripyridinechromium(III) and some related compounds

The reaction between C₃F₇I and CrCl₂(CH₃CN)₂ in the presence of pyridine allows the isolation of C₃F₇CrCl₂py₃ together with a CrICl₂-pyridine complex. Similar complexes can be prepared using 2,2′-bipyridyl, 2,2′,2″-terpyridyl and 1,10-phenanthroline. The latter complexes are resistant to hydrolysis whereas C₃F₇CrCl₂py₂ is rapidly hydrolysed to a pentafluoroalkyl aquo species.     

Synthesis of dimethyl acetals. diethyl acetals. and cyclic acetals catalyzed by aminopropylated silica gel hydrochloride (APSG-HCL)

The aminopropylated Silica-Gel hydrochloride (APSG.HCl) proved to be an efficient catalyst for the rapid conversion of carbonyl compounds in the corresponding acetals with high yields and in mild and selective conditions. In addition to the obvious advantages offered by heterogeneous catalysis, the present method results very useful when the presence of a weakly-acidic function chemically bonded on the catalyst surface (alkyl ammonium salt). is necessary (compounds which contains functions unstable in acidic media).     

Straightforward synthesis of gem-phosphonate-phosphate containing compounds via one-pot reaction of thioesters with diethyl phosphite

A convenient straightforward, three step, one-pot reaction of diethyl phosphite with thioesters in the presence of catalytic amounts of potassium tert-butoxide in toluene or DMF as solvent provided various phosphonate-phosphate containing compounds in excellent yields.     

The first synthesis of cyclopropanone acetals from the reaction of Fischer carbene complexes with ketene acetals

The reaction of iso-propoxy stabilized Fischer carbene complexes with ketene acetals gives moderate to excellent yields of cyclopropanone acetals when carried out under a carbon monoxide atmosphere. This is in contrast to the known reaction of methoxy substituted complexes which give cyclic ortho esters under the same conditions. A mechanism is proposed which involves a branch point between the two products as the zwitterionic intermediate resulting from nucleophilic addition of the ketene acetal to the carbene carbon. A 1,3-migration of the methoxyl group to the cationic center leads to the ortho ester and a ring closure by backside attack leads to the cyclopropanone acetal. A double-labeling experiment shows that the 1,3-migration occurs by an intramolecular process that is proposed to involve a bridging oxonium ion. The effect of the isopropoxy group is thus interpreted to be to sterically hinder the formation of a bridged oxonium ion.     

Enynones in organic synthesis. III. A novel synthesis of phenols

Enynones are converted to phenols by an acid catalyzed process which can be controlled to give either of two regioisomeric series of products.     

Rhenium-catalyzed reaction of carbonyl compounds with ketene silyl acetals

It was found that rhenium complex is an effective catalyst for the reaction of carbonyl compounds with ketene silyl acetals. A wide range of β-silyloxy esters is obtained by the treatment of carbonyl compounds with ketene silyl acetals in the presence of a catalytic amount of ReBr(CO)₅ in moderate to good yields.