Induced circular dichroism spectra of cyclobuta [1,2-b: 3,4-b′]-diquinoxaline

The induced circular dichroism (i.c.d.) and absorption spectra of the -cyclodextrin (-c.d.) complex with cyclobuta [1,2-b: 3,4-b]diquinoxaline (I) have been measured. The linear dichroism (l.d.) spectra of I in stretched polyethylene sheet have been also measured. The absorption bands of I have been assigned by using the observed spectra and the results of CNDO/S CI calculations. The i.c.d. spectra of the first absorption band have shown the Cotton-effect at high concentrations. This fact indicates that the -c.d. complex with I forms dimers at high concentrations.     

Synthesis of fluorantheno[1,2-b]thiophene and fluorantheno[3,2-b]thiophene,isosteres of benzofluoranthenes

The total syntheses of fluorantheno[1,2-b]thiophene and fluorantheno[3,2-b]thiophene are reported. The common cyclobutanone intermediate which was obtained by [2 + 2] addition of fluorenylidene ketene with 2,3-dihydrothiophene underwent regioselectively α or β ring opening to lead to linear or angular PAC skeleton molecules under desired conditions. 2,3-Dichloro-5,6-dicyanobenzoquinone was applied for aromatization to achieve the formation of PAC's. These two isosteres exhibit very similar uv/visible spectra to benzo[a] and [b]fluoranthenes respectively. Spectroscopic data used for their structural assignments is also discussed.     

The synthesis of naphtho[1,2-b]thiophene and all of the eight isomers of monomethylnaphtho[1,2-b]thiophene

The synthesis of naphtho[1,2-b]thiophene and all of the eight monomethylnaphtho[1,2-b]thiophene isomers is described.     

Benzo[f]isoindole analogs II. Thieno[3,4-b]quinoxaline

The transient existence of thieno[3,4-b]quinoxaline ( 2d ) as a product of dehydration of 1,3-dihydrothieno[3,4-b]quinoxaline 2-oxide ( 5 ) was demonstrated by trapping experiments with N-phenylmaleimide and dimethyl acetylenedicarboxylate. Attempts to isolate 2d from reaction mixtures arising from dehydration of 5 and from dehydrogenation of 1,3-dihydro-thieno[3,4-b]quinoxaline ( 8 ) were unsuccessful.     

Benzo[1,2-d: 3,4-d'] diimidazole derivatives

The structure and tautomerism of 2-amino-3, 6-dimethyl-, and 2-amino-3,6,7-trimethylbenzo[1,2-d: 3,4-d']diimidazoles were studied by means of IR and UV spectroscopy. It was found that they exist in the amino form in the crystalline state and in methanol solution.See [1] for communication III.Translated from Khimiya GeterotsiklicheskikhSoedinenii, No. 6, pp. 807–809, June, 1973     

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides in the synthesis of 2,3-dihydronaphtho- and naphtho[1,2-b]thiophenes

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1629–1633, December, 1989.     

Synthesis of pyrido[3,4-b]pyrano[3,4-b]indoles

The synthesis of some pyrido[3,4-b]pyrano[3,4-b]indoles ( 3 ) from 3-hydroxy-4-(3-indolyl)piperidines ( 6 ) is reported.     

Derivatives of benzo[5,6]cyclohepta[1,2-b]thiophene. Synthesis of 2,3,7,8-tetrahydro-3-oxothieno[1,2-b]cyclohepta[5,6,7-de]isoquinoline and 1,2,3,7,8,11b-hexahydro-3-oxothieno[1,2-b]cyclohepta[5,6,7-de]isoquinoline

The synthesis of the title compounds was carried out by cyclization via isocyanate of (E)-4,5-dihydro-10H-benzo[5,6]cyclohepta[1,2-b]-thiophene-10-ylideneacetic acid and 4,5-dihydro-10H-benzo[5,6]cyclohepta[1,2-b]-thiophene-10-ylacetic acid respectively, which were obtained by the Wadsworth-Emmons modification of the Wittig reaction of 4,5-dihydro-10H-10-oxobenzo[5,6]cyclohepta[1,2-b]thiophene and triethyl phosphonacetate. The structures of these new compounds are described.     

New heterocyclic systems. Benzo[4,5]cyclohepta[1,2-b]pyrrole and benzo[5,6]cyclohepta[1,2-f]pyrrolizidine derivatives

The synthesis of the polycyclic pyrrole acetic acids 9e, 13e and 13g by multistep processes from 1-bromo-4-phenylbutan-2-one ( 6c ) is reported. An instance of the use of the 2-chloroethyl moiety as a pyrrole nitrogen protecting group is described. The α-methylaminoketone ( 6e ) was synthesised by a novel two step process from 6c and methyl N-methylformimidate ( 12 ).     

Synthesis of 3,4-alkoxythieno[2,3-b]thiophene derivatives. The first block copolymer associating the 3,4-ethylenedioxythieno[2,3-b]thiophene (EDOThT) unit with 3,4-ethylenedioxythiophene (EDOT) moieties

The synthesis of 3,4-alkoxythieno[2,3-b]thiophene derivatives has been developed from the readily accessible dimethyl or diethyl 3,4-dihydroxythieno[2,3-b]thiophenedicarboxylates. The yields for the dialkoxy derivatives were strongly dependent both on the base and the alkylating agent used for the nucleophilic substitutions. A trimer associating the new 3,4-ethylenedioxy-thieno[2,3-b]thiophene unit with 3,4-ethylenedioxythiophene moieties has been synthesized and electropolymerized.