Intramolecular cyclizations of allyl- and propargylsilanes

Allylsilanes of type $\text{5}$ and propargylsilanes of type $\text{13}$ undergo efficient cyclizations upon treatment with EtAlCl₂ in toluene to afford stereoselectively functionalized hydrindanones of type $\text{6}$ and spiro[4,5]decanes of type $\text{14}$.     

Synthesis of novel sterically demanding carbo- and heterocyclic beta-ketoesters

We present an easy method for the synthesis of beta-ketoesters starting from various carbocyclic and heterocyclic carboxylic acids and esters. The beta-ketoester side-chain was introduced by a sequence involving alpha-deprotonation and quenching with CO(2), conversion to the corresponding acid chloride and subsequent chain elongation using deprotonated ethyl acetate.     

Sequenced cyclizations involving intramolecular capture of alkyl-oxyaminyl radicals. Synthesis of heterocyclic compounds

A cascade radical cyclization process involving oxime ethers tethered to a brominated phenyl and an activated olefin moiety is described. The generated aryl radicals using tri-n-butyltin hydride react with the CN bond to yield neutral alkyl-oxyaminyl radicals, which were then simultaneously captured by the activated double bond to provide heterocyclic systems with a pyrrolidinic nucleus.     

Synthesis and reactions of heterocyclic compounds

5-Azido-2-methylbenzthiazole, 6-azido-1, 2-dimethyl-, and 5-azido-2-methyl-1-phenylbenzimidazoles were prepared. By the reactions of these azides with alkyl halides the quaternary slats based on the cyanine dyes were obtained.     

缩杂环卓酮化合物的合成

本文报道Friedlaender反应在卓酮化学中的应用, 合成了喹啉基取代的卓酮化合物。     

异色满酮-4及其衍生物的合成IX异香豆素并杂环化合物的合成

本文通过3, 4-二氢异苯并吡喃酮-4和其β-二酮衍生物的缩合反应, 合成出3, 4-二氢异苯并吡喃并吲哚、并喹啉、并吡唑和并嘧啶类化合物, 并进一步氧化成标题化合物。所合成的新化合物均经核磁共振光谱红外光谱及元素分析证明其分子结构。     

Synthesis and reactions of azides of heterocyclic compounds

Cyanine dyes containing azido groups in the 5 or 6 position of the benzazole ring were obtained from quaternary salts of azides of benzothiazole and benzimidazole. The introduction of an azido group into the dye molecule results in a considerable bathochromic effect.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 5, pp. 640–642, May, 1974.     

Synthesis and reactions of azides of heterocyclic compounds

The reaction of 2-methyl-5- and 2-methyl-6-azidobenzothiazoles with alkyl acrylates was used to synthesize 1,2,3-triazol-2-ines, which are cleaved in the presence of bases to give the corresponding diazopropanoic acid esters. Oxidation of the triazolines leads to the correspondingtriazoles.See [1] for Communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 839–841, June, 1982.     

Ionization potentials and electron affinities of carbo- and heterocyclicπ-conjugated molecules

The correlations of the observed ionization potentials and electron affinities with the orbital energies of SCF-MO's calculated by the variable- modification of the Pariser-Parr-Pople method were examined for 30 conjugated molecules including heterocycles. A simple linear relation has been found between the ionization potential and the energy of the highest occupied SCF-MO as well as between the electron affinity and the energy of the lowest vacant SCF-MO. The ionization potential and electron affinity are estimated by using these empirical relations for 24 conjugated heteromolecules of biochemical interest.

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Zusammenfassung PPP-Rechnungen nach der variables-Methode an 30 carbo- und heterocyclischen-Systemen zeigen eine gute Korrelation der experimentellen ionisationspotentiale und Elektronenaffinitäten mit den Energien der höchsten besetzten bzw. tiefsten unbesetzten SCF-MOs. Die so erhaltenen Regressionsgeraden wurden zur Bestimmung vos Ionisationspotentialen und Elektronenaffinitäten vos 24 biochemisch interessanten Heterosystemen herangezogen.

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Résumé Examen pour 30 molécules conjuguées des corrélations entre potentiels d'ionisation et affinités électroniques expérimentales avec les énergies des orbitales moléculaires SCF de la méthode de Pariser-Parr-Pople à variable. Une relation linéaire simple a été trouvée entre le potentiel d'ionisation et l'énergie de la plus haute orbitale moléculaire occupée ainsi qu'entre l'affinité électronique et l'énergie de la plus basse orbitale vacante. Ces relations empiriques permettent d'estimer les potentiels d'ionisation et l'affinité électronique de 24 molécules conjugées d'intérêt biochimique.

     

Synthesis of heterocyclic compounds from 4-formylpyrazoles

Formylation of pyrazole and 2,5-dimethylpyrazole gave a number of pyrazole-containing aldehydes, which can be used to obtain chromenes, tetrahydrochromenes, 1,4-dihydropyrano[2,3-c]pyrazoles, pyrano[3,2-c]chromenes, thiochromeno[4,3-b]pyrans, pyrano[3,2-c]-quinolines, and thiazolo[3,2-a]pyridines.     

Copper(I)-amine metallo-organocatalyzed synthesis of carbo- and heterocyclic systems

The efficient and atom economical synthesis of 5-membered cyclic structures has been achieved through the combination of amino catalysis and metal catalysis. The discovery of a novel metallo-organocatalytic system merging the use of a catalytic copper(I) complex and a catalytic amount of cyclohexylamine allowed the room temperature preparation of a broad range of skeletons such as cyclopentanes, indanes, pyrrolidines and tetrahydrofuran, important structural cores of many biologically relevant molecules. Mechanistic studies were presented.     

Synthesis of heterocyclic compounds via nucleophilic aroylation catalyzed by imidazolidenyl carbene

Xanthones and acridones were synthesized from 3,4-difluoronitrobenzene and 2-fluorobenzaldehydes in two or three steps. The key step was nucleophilic aroylation catalyzed by imidazolidenyl carbene. The nucleophilic aroylation of 3,4-difluoronitrobenzene afforded 2,2'-difluoro-4-nitrobenzophenones. The cyclization of the difluorobenzophenones with O-nucleophile and N-nucleophile yielded 3-nitroxanthones and 3-nitroacridones, respectively. Indazole, quinolino[2,3-b]quinoxaline, and thianaphtho[2,3-b]quinoxaline derivatives were also synthesized via nucleophilic aroylation of 2,3-dichloroquinoxaline followed by cyclization with nucleophiles.     

Synthesis of heterocyclic compounds via Michael and Hantzsch reactions

Heterocycles represent the largest diversity of organic compounds with signifcant chemical, biomedical, and industrial applications. They exist in numerous natural products, dyes, and as scaffolds in diverse drugs and related pharmaceutically active substances. Substantial attention has been paid to develop various elegant methods to synthesize heterocycles. Among different strategies, Michael and Hantzsch reactions are considered as effective approaches for construction of heterocycles and their corresponding fused derivatives. This review covers this area especially in the last 10 years. The heterocyclic systems reported in this review are classified according to the kind of the heterocyclic systems.     

Synthesis of 2,4,6-trinitrophenyl derivatives of heterocyclic compounds

The preparation of 2,4,6-trinitrophenyl (picryl) derivatives of triazine, pyrimidine, thiophene, furan, thiazole, 1,3,4-oxadiazole and 1,3,4-thiadiazole is described. The picryl derivatives are prepared by the Ullmann reaction and by cyclization reactions to form the heterocyclic ring.     

Synthesis of heterocyclic compounds from o-aminobenzenethiol and ammonium thiocarbamate

The reaction of o-aminobenzenethiol with carbonyl sulfide in the presence of triethylamine afforded an alternate route for the synthesis of 2-benzothiazolinone ( 1 ) in 97–98% yield. The reaction of ammonium thiocarbamate ( 2 ) with 2-chlorocyclohexanone furnished the novel 4,5,6,7-tetrahydro-2-benzothiazolinone ( 3 ). 3-Ethoxy-2H-1,4-benzothiazin-2-one ( 7 ) was prepared by the reaction of o-aminobenzenethiol with diethyl oxalate. Possible pathways and supporting nmr, ir and mass spectra are discussed.     

Synthesis of heterocyclic azoxy compounds from C-nitroheterocyclic compounds and metal derivatives oftert-butylamine

The reaction of 3-nitropyrazole and 3(5)-nitro-1,2,4-triazole with t-BuNHMgBr gives the corresponding asymmetrical diazene oxides. Furthermore, 3(5)-(1,1-dimethylethyl)azoxy-1,2,4-triazole was also synthesized by the reaction of 1-trimethylsilyl-3(5)-nitro-1,2,4-triazole with t-BuNHLi.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1653–1654, July, 1992.     

Synthesis of heterocyclic compounds using the Nenajdenko-Shastin reaction

The use of a catalytic olefination reaction (the Nenajdenko-Shastin reaction) in the synthesis of heterocyclic compounds is discussed.     

3-Nitroacrylates as promising substrates for the construction of carbo- and heterocyclic structures

Russian Chemical Bulletin - The review analyzes and summarizes methods for the synthesis of carbo- and heterocycles based on alkyl 3-nitroacrylates that were described over the past decade. The...