Researches on imidazoles

Reaction of 1,2-dialkylbenzimidazoles with -halogenoketones followed by cyclization of the 1,2-dialkyl-3-ß-ketoalkyl(aralkyl)-benzimidazolinium halides in aqueous solution, in the presence of bases, leads to the synthesis of a number of derivatives of a new aromatic tricyclic system, 4H-pyrrolo[1,2-a]benzimidazole.For Part XXXII see [8].     

Study of reaction of 2,3,3-trimethyl-3H-indole with haloacetic acid amides. Synthesis of 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones

In the reaction of 2,3,3-trimethyl-3H-indole with -chloro- and -iodoacetamides, 1-carbamoylmethyl-2,3,3-trimethyl-3H-indolium salts are formed, which by the action of bases convert into imidazo[1,2-a]indol-2-one and 1-carbamoyl-2-methylene-2,3-dihydroindole. The latter compound can by cyclized into imidazo[1,2-a]indol-2-one by the action of acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 933–935, July, 1985.     

Unusual cleavage of phenacyl-substituted benzimidazolium salts. Synthesis of 1,4-diarylimidazoles

The action of ammonium acetate in acetic acid on 1-alkyl(aralkyl)-3-phenacylbenzimidazolium bromides leads, in addition to the formation of a new imidazole ring, to cleavage of the benzimidazole fragment of the molecule at the 1,2 bond to give 1-alkyl(aralkyl)aminoaryl-4-arylimidazoles. 1,2-Dimethyl-3-(p-nitrophenacyl)benzimidazolium bromide is converted under similar conditions to the corresponding 2-methylimidazole. 4,4-Dimethyl-2,2-bis(p-nitrophenyl)-1,1-dipyrrolo[1,2-a]benzimidazole was isolated as a side product of this reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 388–392, March, 1982.     

Investigations in the imidazole series LXXIII. Synthesis of pyrrolo[1,2-a]benzimidazole derivatives from 2-alkyl(aralkyl)benzimidazoles

The synthesis of 2-alkyl(aryl)- and 2-aryl-3-alkyl(aryl)-4-acylmethyl-substituted pyrrolo-[1,2-a]benzimidazoles was accomplished by the reaction of 2-alkyl(aralkyl)benzimidazoles with -haloketones and subsequent cyclization of the resulting 1,3-(diacylmethyl)-2-alkyl-(aralkyl)benzimidazolium halides.See [1] for communication LXXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 403–404, March, 1972.     

Research on benzimidazole derivatives

Several transformations of 1-alkyl-3-(2-propynyl)-2-iminobenzimidazolines involving the imino group and the triple bond were studied. It is shown that they are readily isomerized in the presence of bases to alienes, which are then converted to 2-methylimidazo[1,2-a]benzimidazole derivatives by intramolecular cyclization. 1-Alkyl-3-(-bromoallyl)-2-iminobenzimidazolines can be used for the synthesis of the latter.See [1] for communication XXXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–400, March, 1975.     

Research in the imidazole series. 94. Synthesis of derivatives of pyrrolo[1,2a]benzimidazolyl-4-acetic acid

Derivatives of pyrrolo[1,2a]benzimidazolyl-4-acetic add have been synthesized by quaternization of 2-alkyl(aralkyl)benzimidazolyl-1-acetic acids and their esters and amides by -bromoketones, followed by cyclization of the resulting 1,2,3-substituted benzimidazolium bromides by the action of sodium alcoholate, ammonia, amines (primary, secondary, or tertiary), or hydrazine hydrate.For Communication 93, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 29, No. 5, pp. 659–663, May, 1993.     

Synthesis of isomeric benzodipyrrolenines and their derivatives

The Fischer reaction was used to synthesize 2,3,3,5,5,6-hexamethyl-3H,5H-benzo[1,2-b5,4-b]dipyrrole and 2,3,3,7,8,8-hexamethyl-3H,8H-benzo[1,2-b3,4-b]dipyrrole from the dihydrazone obtained by the action of methyl isopropyl ketone on m-phenylenedihydrazine. Centrosymmetrical 2,3,3,6,7,7-hexamethyl-3H,7H-benzo[1,2-b4,5-b]dipyrrole was synthesized from p-phenylenediamine and methyl bromoisopropyl ketone. Mono- and diquaternary salts were obtained from the new bases. The diquaternary salts were converted to bismethylene bases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 614–617, May, 1971.     

Formation of 5-oxoindeno[1,2-b]pyran derivatives in cyclization of 1,5-diketones of the indian-1,3-dione series

Indeno[1,2-b]pyrans, including 2-methylene and 2-acetoxy derivatives of 3-ethoxy-carbonyl-4-phenyl-5-oxo-3,4-dihydroindeno[1,2-b]pyran, are formed in the cyclization of 4-(indan-1,3-dion-2-yl)-4-phenyl-2-butanone and its 3-ethoxycarbonyl derivative in acetic anhydride in the presence of sulfuric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 178–183, February, 1988.     

Polynuclear heterocyclic compounds based on the adduct of o-cinnamoylbenzoic acid and cyclohexanone

The product of addition of cyclohexanone to o-cinnamoylbenzoic acid, which has the 4-phenyl-8a-hydroxyperhydrochroman-2-spiro-3-phthalide structure, reacts with nitrogen-containing nucleophiles to give hydrogenated derivatives of oxa-(aza, thia)indolizinespirophthalide and pyrido[1,21,2]imidazo[2,3-a]-isoin-dole, as well as 4-R-1-phthalazones. An isoindolo[1,2-a]quinoline derivative and a compound with a 7,8-diaza-D-homosteroid skeleton were obtained from the latter.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1280–1285, September, 1986.     

Mössbauer and electric conductivity studies of bidentate base adducts of acetylacetonatoiron(II)

Summary Bidentate bridging base polymer complexes of acetylacetonatoiron(II) [Fe(acac)₂L]_n, where L=pyrazine(pyz), 4,4-bipyridine(bpy),trans-1,2-bis(4-pyridyl)ethylene(bpe), 1,2-bis(4-pyridyl)ethane(bpa) and 4,4-trimethylene bipyridine(tmbpy), have been prepared, characterized and oxidized by iodine to give a range of iron(III) and iron(II) complexes [Fe(acac)₂L · I_x]_n] in which the Fe^III/Fe^II ratios were established by Mössbauer spectroscopy. The electric conductivities of compressed pellets of the polysalts were obtained. The conductivities and Mössbauer parameters (I.S. and Q.S.) both change with respect to the kind of bidentate bridging bases.The conjugation of bridged ligand markedly affects the conductivity of the complexes.     

Synthesis of functionalized pyrimido[1,2-a]-benzimidazoles from (benzimidazol-2-yl)cyanamide and β-dicarbonyl compounds using nickel complexes or salts

It was found that cyclocondensation of (benzimidazol-2-yl)cyanamide with -diketones and -ketoesters proceeds in the presence of -ketoenolates or nickel(2+) acetate with the formation of 2-aminopyrimido[1,2-a]benzimidazole derivatives. Protonation (deuteration) and methylation of substituted 2-aminopyrimido[1,2-a]benzimidazoles takes place at the N¹⁰ atom, while acylation by carboxylic acid anhydrides gives the 2-acylamino derivatives exclusively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2600–2608, November, 1990.     

Synthesis and physico-chemical and biological studies on ruthenium (III) complexes with Schiff bases derived from aminocarboxylic acids

Summary Ruthenium(III) complexes of types [Ru(L)₃], [Ru(L)Cl(H₂O)₂], [Ru(L)Cl₂]_n, [Ru(L)Cl(H₂O)]_n(LH =Schiff bases derived from anthranilic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH₂=Schiff bases derived from anthranilic acid and salicylaldehyde oro-hydroxyacetophenone; LH=Schiff bases derived fromp-aminobenzoic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH₂=Schiff bases derived fromp-aminobenzoic acid and salicylaldehyde oro-hydroxyacetophenone) have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic moment and spectral (electronic, i.r. and¹H n.m.r.) data. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of crystal field theory and various parameters have been evaluated. On the basis of the electronic spectra, an octahedral geometry has been established for all these complexes except [Ru(L)Cl₂]_n. The complexes [Ru(L)Cl₂]_n are pentacoordinate and a trigonal-bipyramidal environment, D_3h, is suggested for the ruthenium(III) ion. The thermal behaviour of these complexes has also been studied by t.g., d.t.g and d.s.c techniques. Heats of reaction for the decomposition steps were calculated from the d.s.c. curves. The antifungal and antiviral activities of the complexes with Schiff bases derived from anthranilic acid were also investigated.     

Synthesis of 2-phenyl-3-(2-furyl) — and 2-phenyl-3-[β-(2-furyl)vinyl]-1,2-dihydro-naphtho[1,2-d]-1,2,4-triazines

The corresponding 2-phenyl-3-(2-furyl)- and 2-phenyl-3-[-(2-furyl)vinyl]-1,2-dihydronaphtho-[1,2-d]-1,2,4-triazines were obtained by heating Schiff bases [prepared by reaction of 1-(phenyl-azo)-2-aminonaphthalene with furfural, -(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives] in glacial acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 158–160, February, 1973.     

Bisindoles. 10. Synthesis of 1,2-(5,5′-diindolyl)ethane

A 2,2-diethoxycarbonyl derivative of a new bisindole system, viz., 1,2-(5,5-diindolyl)ethane, was obtained by cyclization of ethyl pyruvate sym-4,4-diphenyleneethanedihydrazone. 5-(-Phenylethyl)-2-ethoxycarbonylindole was also isolated in very low yield from the reaction products. Saponification of the 2,2-diethoxycarbonyl derivative gave the corresponding dicarboxylic acid, the thermal decarboxylation of which leads to the formation of 1,2-(5,5-diindolyl) ethane. The syn,syn and anti,anti forms of ethyl pyruvate sym-4,4-diphenyleneethane-dihydrazone were also obtained and characterized.See [1, 2] for Communications 8 and 9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 348–351, March, 1982.     

Effect of benzo annelation on the Chichibabin reaction

The kinetics of amination with sodium amide (the Chichibabin reaction) for six azines and five azoles and the kinetics of the piperidinolysis of 2-chloro-substituted azole systems were studied. The following orders of reactivities were established for the Chichibabin reaction: isoquinoline > phenanthridine > benzo[h]quinoline > benzo[f]quinoline > pyridine acridine and 1-methylbenzimidazole > 1-methylnaphth[2,3-d]imidazole > 1-methylperimidine > 1-methylnaphth[1,2-d]imidazole > 3-methylnaphth-[1,2-d]imidazole. The changes in the reactivities are explained by the changes in the hydride labilities of the corresponding complexes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp, 257–261, February, 1979.     

Synthesis of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane and its reaction with dibromoalkanes

4-(N-Benzoylthioureido)-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclohexane), which was synthesized from 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclohexane) and benzoyl isothiocyanate, cyclized to give 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclohexane). Reaction of the latter with 1,2-dibromoethane or 1,3-dibromopropane gave products of intramolecular dialkylation at the S and N₍₃₎ atoms.A. L. Mndzhoyan Institute of Fine Organic Chemistry, Armenian National Academy of Sciences, Erevan 375014, Armenia. Center for the Investigation of Molecular Structure, Armenian National Academy of Sciences, Erevan 375014, Armenia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, 105–109, January, 1999.     

Synthesis and transformations of 2-(2-furyl)-and 2-[β;-(2-furyl)vinyl]naphth[1,2-d]imidazoles

The corresponding 2-(2-furyl)naphth[1,2-d]imidazoles were obtained by heating Schiff bases, prepared from 1,2-naphthalenediamine and furfural and 5-bromo- and 5-nitrofurfurals, in nitrobenzene. 2-[-(2-Furyl)vinyl]naphth[1,2-d]imidazoles were synthesized by condensation of 2-methylnaphth[1,2-d]imidazole with furfural and 5-bromo- and 5-nitrofurfural. The methylation, nitration, and acetylation of the compounds obtained were studied, and the replacement of the bromine atom in the furan ring by a nitro group was also investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1557, November, 1972.     

Condensation of 1-carbamoylmethyl-2,3,3-trimethyl-3H-indolium chloride with aromatic aldehydes

The reaction of 1-carbamoylmethyl-2,3,3-trimethyl-3H-indolium chloride with various aromatic aldehydes in acetic acid and the subsequent workup of the intermediate styrylic derivatives with strong bases yielded 9a-(2-arylethenyl)-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-one derivatives. Condensation of the mentioned salt with salicylaldehyde in acidic or basic medium afforded the derivative of l-carbamoylmethylspiro[benzopyran-2,2-indole]. Alkylation of the latter compound with benzyl chloride in the presence of potassium hydroxide gave 9a-[2-(2-benzyloxyphenyl)ethenyl]-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-one.Department of Organic Chemistry, Kaunas University of Technology, LT-3028 Kaunas, Lithuania Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 761–769, June, 2000.     

Chemistry of indole

,-Unsaturated ketones form pyrimido[1,2-a]indoles with 2-aminoindole, while 1-alkyl-2-aminoindoles under these conditions are converted to the corresponding -carbolines. The structures of the compounds obtained were confirmed by alternative synthesis.See [1] for communication XIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–64, January, 1971.     

Syntheses based on dimethylpyrazoles. 9. Synthesis and spectral peculiarities of isomeric pyrazolo[3′,4′-5,6]- and-[5′,4′-5,6]-pyrimido[1,2-b]benzo[d,e]isoquinoline-4,12-diones

2-Methyl-2,4,12,13H-pyrazolo[3,4-5,6]pyrimido[1,2-b]benzo[d,e]isoquinoline-4,12-dione and its 8-nitro- and 8-amino-substituted derivatives were obtained starting from 4-amino-3-carbamoyl-1-methylpyrazole and naphthalic and 4-nitronaphthalic anhydrides. The spectral properties of the synthesized compounds were studied.See [1] for Communication 8.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 237–241, February, 1990.