Studies of imidazo[1,2-a]benzimidazole derivatives. 21. Synthesis of haloketones in the imidazo[1,2-a] benzimidazole series

Methods for the synthesis of imidazo[1,2-a]benzimidazole haloketone derivatives have been investigated. It has been found that -bromoketone derivatives of this heterocycle can be prepared either by bromination of 3-acylimidazo[1,2-a]benz-imidazoles with bromine in glacial acetic acid or by acylation of 3-unsubstituted imidazo[1,2-a]benzimidazoles with haloanhydride derivatives of -bromoalkanoic acids. Treatment of imidazo[1,2-a]benzimidazoles with 3-chloropropionyl chloride results in the formation of imidazo[1,2-a]benzimidazolyl-3-propionyl chloride and bis(imidazo[1,2-a]benzimidazolyl)propan-3-one derivatives as side products. Reaction of 2-phenylimidazo[1,2-a]benzimidazoles with 3-bromopropionic acid in polyphosphoric acid gives benzocyclohepten[5,6:4,5]imidazo[1,2-a]benzimidazole derivatives.For Communication 20, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–345, March, 1986.     

Reaction of 2-methylene-2,3-dihydroindoles with acrylamide

1,3-Dihydrospiro[2H-indolo-2,2-piperidine] derivatives were obtained by the reaction of 2-methylene-2,3-dihydro-1H-indole derivatives with acrylamide in proton-containing solvents. 2-(3-Carbamoylpropyl)-3H-indolium perchlorates were formed when the 1,3-dihydrospiro[2H-indolo-2,2-piperidine] derivatives were treated with perchloric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 902–904, July, 1988.     

Investigations in the imidazole series

Cyclization of 2--oxoalkylthio- and 2--oxoaralkylthiobenzimidazoles and the reaction of 2-mercaptobenzimidazoles with -halogenoketones in the absence of bases has given a number of derivatives of thiazolo[3, 2-a]benzimidazole, cyclopentenothiazolo[3, 2-a]benzimidazole, and tetrahydrobenzothiazolo[3, 2-a]benzimidazole.For part XXXVI, see [6].     

2-Methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-5- and -7-Ones

The cyclocondensation of methylcinnamates and arylidene derivatives of Meldrums acid with 3-amino-5-methylthio-1,2,4-triazole in DMF gives 2-methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]-pyrimidin-5-ones. The reaction involving arylidene derivatives of Meldrums acid or its synthetic equivalents in ethyl acetate with a catalytic amount of pyridine gives a mixture of 2-methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidin-5- and -7-ones.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 246–251, February, 2005.     

Synthesis and spectroscopic study of arylazo derivatives of benzimidazolo[2′, 1′:2, 3]thiazolidin-4-one

The coupling of benzimidazolo[2, 1:2, 3]thiazolidin-4-one with benzenediazonium chlorides in acetic acid in the presence of sodium acetate at pH 4.5–4.0 has yielded 5-arylazo derivatives of the thiazolidone. By a study of the IR and UV spectra of the aryl derivatives of benzimidazolo[2, 1:2, 3]thiazolidin-4-one synthesized, it has been shown that the latter has the azo structure.     

The annelation of the 2-aminopyran-4-one ring to condensed thiophenes

The reaction of arylacetonitriles with the methyl ester of 3-hydroxybenzo[b]thiophene-2-carboxylic acid in the presence of a basic catalyst leads to the previously unreported 2-amino-3-arylbenzo[4,5]thieno[3,2-b]pyran-4-ones. Under the same conditions, the ethyl ester of 4,6-dimethyl-3-hydroxythieno[3,2-c]pyridine-2-carboxylic acid reacts to form derivatives of a new heterocyclic system, pyrano[2,3-4,5]-thieno[3,2-c]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1476–1478, November, 1983.     

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.     

Comparative characteristics of the electronic structures of perimidine and naphthimidazoles within the framework of the CNDO-2 (complete neglect of differential overlap) method

The 1H-naphth[1,2-d]imidazole, 3H-naphth[1,2-d]imidazole, and 1H-naphth[2,3-d]-imidazole molecules were calculated by the CNDO-2 method. The dipole moments of N-methyl derivatives of perimidine and linear naphthimidazole were measured. The -donor character of N-methyl derivatives of perimidine and naphthimidazoles with respect to 1,3,5-trinitrobenzene was also measured. The study showed that the CNDO-2 method, except for individual details associated with the distribution of the electrons, leads to the same conclusions relative to the overall pattern of the effective charges on the atoms in the perimidine and naphthimidazole molecules as the -approximation methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 692–695, May, 1979.     

Investigations in the imidazole series

2,3-Dihydro derivatives of naphth[1,2-d]imidazo[3,2-b]imidazole were synthesized by the reaction of 2-chloro-3-(-haloalkyl)naphth[1,2-d]imidazole with ammonia and primary amines and by the reaction of 2-chloro-3-(-hydroxyaIkyl)naphth[1,2-d]imidazole with ammonia and amines with subsequent cyclization of the resulting 2-amino(alkylamino, arylamino)-3-(-hydroxyalkyl)naphth[1,2-d]imidazoles under the influence of thionyl chloride or phosphorus oxychloride. Dihydro derivatives of the condensed naphth[1,2-d]imidazo[3,2-b]imidazole system have not been described in the literature.See [1] for communication LX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1127, August, 1971.     

Phenylmercury derivatives of aminomethylene- and hydroxymethylene-substituted 1-methyloxindoles, 1-indanones,and 1,3-indanediones

A number of phenylmercury derivatives of 3-hydroxymethylene- and 3-aminomethylene-substituted 1-methyloxindoles, 1-indanones, and 1,3-indanediones were synthesized. It is shown that the preferred tautomeric structures of the potentially metallotropic and prototropic hydroxymethylene keto (hydroxy vinyl aldehyde) derivatives of the indicated compounds and 3-hydroxybenzo[b]-2-formylthiophene coincide precisely. An aminomethylene structure with an N-H bond is realized for the phenylmercury derivatives of the corresponding azomethines in all cases.Communication 28 from the series Benzenoid-Quinoid Tautomerism of Azomethines and Their Structural Analogs. See [1] for communication 27.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 65–68, January, 1979.     

Imidazo[1,2-a]benzimidazole derivatives

3-Amino derivatives of 9-alkyl(benzyl)-2-arylimidazo[1,2-a]benzimidazoles, obtained by the reduction of the appropriate 3-nitro(nitroso) derivatives, are extremely unstable, and the imidazole ring opens readily resulting in conversion to 2-(-carboxybenzylamino)benzimidazoles. The reaction apparently proceeds through the intermediate formation of 2-(-cyanobenzylamino)benzimidazole, which is a tautomeric form of the 3-amino compound and can react as such to form 3-acylamino derivatives and anils. If there is a methyl group in the 3-position of the ring, the amine is quite stable and can be isolated in free form.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 673–677, May, 1971.     

Synthesis and Chemical Conversions of 2-Chloro-3-cyano-4-methylamino-5-nitropyridine

5-Cyano-6-(-dimethylamino)vinyl-1-methyl-4-pyrimidinone was synthesized by the interaction of -cyano--(N-methylamino)crotonamide with N,N-dimethylformamide diethylacetal. Recyclization of the product in alkaline medium leads to 3-cyano-4-methylamino-2-pyridone. Nitration of the latter and transformation of the nitropyridone by boiling in POCl₃ gave 2-chloro-3-cyano-4-methylamino-5-nitropyridine. This is a key compound for various transformations including the synthesis of derivatives of dipyrido[1,2-a:3,2-e]pyrimidine, thieno[2,3-b]pyridine, and (2-pyridylamino)polyene derivatives.     

5,7-Dichloro-1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-Selone: Synthesis, Crystal Structure, Solvatochromism, and Reactions with Nucleophiles

We have obtained for the first time the halo derivatives of a novel heterocyclic system, 1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-selone, by reaction of 5,7-dioxo(4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-selone with POCl₃. The crystal structure of thione confirms that we had obtained the desired compound. The electronic absorption spectra reveal an interesting solvatochromism connected with the appearance of low-intensity n transitions from selenium and sulfur atoms in the visible region of the spectrum. The chlorine atoms in the studied compounds have significant mobility in reactions with nucleophiles (amines, thiourea, azidione), which ensures that new derivatives of 1,3-dithiolo[4,5-d]pyrimidine-2-selone are obtained, and specifically 7-N,N-dialkylamino, 7-N-alkyl-N-arylamino derivatives and 7-isothiuronium salts. The 2-selones obtained can be used in synthesis of new tetrathiafulvalenes.     

Synthesis of dimethylamino derivatives of some condensed heterocycles from dimethylphosgeneimmonium chloride

Diazo coupling of indazole-3-diazonium chloride with 1-(2,4-dinitrophenyl)-3,5-bis(dimethylamino)pyrazole, obtained from dimethylphosgeneimmonium chloride, and subsequent cyclization of the azo compound lead to the formation of the dimethylamino derivatives of a new polycyclic system — benzo[h]dipyrazolo[3,2-c:3,4-e]-1,2,4-triazine. Previously unknown 3-dimethylamino derivatives of 1,2,4-triazolo-[3,4-b]benzothiazole were synthesized by reaction of dimethylphosgeneimmonium chloride with 2-hydrazinobenzothiazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 403–406, March, 1978.     

Investigation of nitrogen- and sulfur-containing heterocycles. 39. Reactions of 2-mercapto-3-ureido- and 2-mercapto-3-aminopyridines with β-halo carbonyl compounds. Synthesis of 6-oxo derivatives of pyrido[2,3-b][1,5]thiazepines

The reaction of 2-mercapto-3-ureido- and 2-mercapto-3-aminopyridines with -halo derivatives of carbonyl compounds (ketones, acids, and aldehydes) and with acrylonitrile proceeds not only via the mercapto group but also via the amino group, as a result of which S--keto (carboxy, cyano) alkyl, N,S-bis(-ketoalkyl), and N,S-diacyl derivatives of pyridine are formed. The action of acids, alkalis, and dehydrating agents on 2-S--keto (carboxy, cyano) ethyl-3-aminoureidopyridines was studied. A method for the preparation of derivatives of a new heterocyclic system, viz., 6-oxopyrido [2,3-b] [1,5] thiazepine, by the reaction of 2-mercapto-3-aminopyridines with -bromopropionic acid and subsequent treatment of 2-(-car-boxyethyl) thio-8-aminopyridines with dicyclohexylcarbodiimide was developed.See [5] for Communication 38.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–639, May, 1981.     

α-Oxides in reaction with N-H acids of the heterocyclic series

Anumber of 1-methyl-4-(2-hydroxyalkyl)-3-nitro-1,2,4-triazol-5-ones and their derivatives were obtained by reaction of 1-methyl-3-nitro1,2,4-triazol-5-one with -epoxides. The fact of intramolecular nucleophilic substitution of the nitro group in hydroxy derivatives of 3-nitro-1,2,4-triazol-5-one with cyclization to 2-methyl-3-oxo-5,6-dihydrooxazolo[3,2-b]-1,2,4-triazoline was established.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1407–1410, October, 1977.     

Derivatives of heterocyclic α-iminocarboxylic acids. 4. Reduction of N-alkoxycarbonyl derivatives of α-iminocarboxylic acids

When N-methoxycarbonyl and N-benzoxycarbonyl derivatives of methyl esters of aziridine-2-carboxylic acid, L-proline, L-thioproline, and pipecolic acid interact with NaBH₄ in tert-butanol/methanol, the products of reduction of the C-methoxycarbonyl group of the original compounds are accompanied by bicyclic urethanes and oxazolidines. Reduction of N-maleates and N-fumarates of heterocyclic -iminocarboxylic acids leads to the formation of -hydroxymethyl-N-[4-(2-oxo-2,5-dihydrofuryl)] derivatives of pyrrolidine, piperidine, 1,3-thiazolidine, and 1,4-thiazan. In the latter case, 1-aza-2-hydroxymethyl-4-oxo-5-oxa-9-thiabicyclo [5.4.0]undecene-2 is also obtained. The N-maleates and fumarates of aziridine-2-carboxylic acid are reduced anomalously by sodium borohydride, forming 2-hydroxymethyl-2-(-hydroxyethyl)-3-oxa-1-azabicyclo[3.1.0]hexanes.For Communication 3 see [2].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1567–1573, November, 1993.     

Synthesis of New Imidazo[4,5-b]pyridine Derivatives

New imidazo[4,5-b]pyridine derivatives with various substituents in the 2-position (,-unsaturated ketones, imines, ²-pyrazolines, pyrimidines, 1,2,3,4-tetrahydropyrimidines) and derivatives of the new pyrido[3',2':4,5]imidazo[1,2-d][1,2,4]triazine ring system were synthesized. Biological data for selected compounds are presented.     

Investigation of the products of the reaction of epichlorohydrin with aromatic amines

The action of hydrogen halides on 7a,8-dihydro-7H-azirino[1,2-]benz[g]indole gives 2-halomethyl-2,3-dihydro-1H-benz[g]indoles and 3-halo-1,2,3,4-tetrahydrobenzo[h]quinolines, which were converted to the corresponding N-nitroso derivatives and then to the isonitroso derivatives. 2-(Benzoxymethyl)-2,3-dihydro-1H-benz[g]indole hydrohalides were obtained by heating 1-benzoyl-2-halomethyl-2,3-dihydro-1H-benz[g]indoles. The reaction of 3-halo-1,2,3,4-tetrahydrobenzo[h]quinolines with thionyl chloride at room temperature gives 3-halo-6-chloro-1,2,3,4-tetrahydrobenzo[h]quinolines, while refluxing with thionyl chloride gives 6-chlorobenzo[h]quinoline.See [1] for communication XVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 342–346, March, 1973.