Sequential approach to the synthesis of 'U and Z' shaped polycyclic heteroarenes

The synthesis of three new classes of heteroarenes, built through the sequential fusion of naphthalene, benzo/naphtho[b]oxepine and thiochromene rings with pyran and pyrimidine ring systems to give 'U and Z' shaped structural frameworks is reported. The methodology is based on the synthesis of pyran fused intermediates, 1-methylthio-3-oxo-5,6-dihydro-3H-benzo[f]chromene-2-carbonitrile (3), 4-methylthio-2-oxo-5,6-dihydro-2H-benzo/naphtho[b]pyrano[2,3-d]oxepine-3-carbonitriles (10, 20) and 4-methylthio-2-oxo-2,5-dihydrothiochromeno[4,3-b]pyran-3-carbonitriles (15) from the reaction of 2-tetralone, benzo/naphtho[b]oxepin-5-ones and thiochromen-4-ones with methyl 2-cyano-3,3-dimethylthioacrylate respectively. Further condensation of intermediates 3, 10, 20 and 15 with amidines led to the formation of tetracyclic 'U' shaped 4-amino-2-aryl-7,8-dihydro-5-oxo-5H-naphtho[2,1-b]pyrimido[4,5-d]pyrans (8) and 'Z' shaped 4-amino-2-aryl-5-oxo-12,13-dihydro-5H-benzo/naphtho[b]oxepino[5,4-b]pyrimido[4,5-d]pyrans (12, 22) and 4-amino-2-aryl-5-oxo-5,12-dihydrothiochromeno[4,3-b]pyrimido[4,5-d]pyrans (17). Compound 12f forms a chain of dimers through N-HO interactions as indicated by the X-ray structure analysis, and the quantum chemical calculations performed at the MP2 level indicate that this interaction energy is 10 kJ mol(-1).     

4-Oxo-3,4-dihydroquinazolinyl- and Benzimidazolylacetonitriles in Annelation Reactions of a Haloquinoline Ring

The interaction of 4-oxo-3,4-dihydroquinazolinyl- and benzimidazolylacetonitriles with 2,6-dihalobenzaldehydes leads to 3-(2,6-dihalophenyl)-2-(4-oxo-3,4-dihydro-2-quinazolinyl)acrylonitriles and 2-(1H-benzo[d]imidazol-2-yl)-3-(2,6-dihalophenyl)acrylonitriles respectively. As a result of intramolecular cyclization of these nitriles 4-halo-12-oxo-12H-quino[2,1-b]quinazoline-6-carbonitriles and 4-halobenzo[4,5]imidazo[1,2-a]quinoline-6-carbonitriles respectively are formed.     

Synthesis of 12-aryl-1-oxo-1,2,3,4,5,12-hexahydroindolo-[2,1-b]quinazoline-6-carbonitriles by recyclization of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles

A general and convenient method for the synthesis of 12-aryl-1-oxo-1,2,3,4,5,12-hexahydroindolo[2,1-b]quinazoline-6-carbonitriles was proposed. The method is based on the recyclization of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles. The structure of 12-(3-methoxyphenyl)-8-methyl-1-oxo-1,2,3,4,5,12-hexahydroindolo[2,1-b]quinazoline-6-carbonitrile was studied by X-ray diffraction analysis.     

Synthesis and Properties of 7-Acetyl-8-aryl-9-cyano-3-hydroxy-6-methyl-3,4-dihydro-2H,8H-pyrido[2,1-<Emphasis Type="Italic">b</Emphasis>][1,3]thiazines

7-Acetyl-8-aryl-2-(1-chloro-2-hydroxy-3-propyl)thio-9-cyano-6-methyl-1,4-dihydropyridines were obtained by treatment of 1,4-dihydropyridine-2(3H)-thiones with epichlorohydrin in the presence of sodium bicarbonate. When treated with NaOMe, these compounds are readily intramolecularly alkylated with formation of 7-acetyl-8-aryl-3-hydroxy-9-cyano-6-methyl-3,4-dihydro-2H,8H-pyrido[2,1-b]-[1,3]thiazines. We have studied amination of 2-(1-chloro-2-hydroxy-3-propyl)thio-1,4-dihydropyridines and acylation of 3-hydroxy-3,4-dihydro-2H,8H-pyrido[2,1-b][1,3]thiazines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1394–1399, September, 2005.     

Condensed isoquinolines 32. Synthesis of 4H-thieno-[3′,2′:5,6]-and-[2′,3′: 5,6]pyrimido-[1,2-b]isoquinolines and 6,12-dihydro-5H-isoquino-[2,3-a]quinazoline-5,12-dione derivatives

Treatment of 2-(4-oxo-3,4-dihydrothieno[2,3-d]-and-[3,2-d]pyrimidin-2-ylmethyl)benzoic acids and 2-(4-oxo-3,4-dihydro-2-quinazolinylmethyl)benzoic acid with acetic anhydride gave thieno[3′,2′:5,6]-and-[2′,3′:5,6]pyrimido[1,2-b]isoquinoline-4,11-diones and isoquino[2,3-a]quinazoline-5,12-dione respectively. NMR spectroscopy showed that an intramolecular acylation of the above acids occurs at the atom N-1 of the pyrimidinone part of the bicycle. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1053–1061, July, 2008.     

Synthesis of 3-aryl-5-methylpyrrolidino[1,2 b]pyrazoles

The sequential conversion of 5-hydroxy-5-methyl-4-oxo-3-arylpyrrolidino [1,2-b]pyrazoles to 5-methyl-5-chloro4-oxo-, 4-hydroxy-5-methyl-5-chloro-, and 5-methyl-4-oxo-3-arylpyrrolidino[1,2-b]pyrazoles and the HuangMinlon reduction of the last afforded 3-aryl-5-methylpyrrolidino[1,2-b]pyrazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 49–51, January, 1994.     

Synthesis of some new types of 3-coumarinyl-substituted pyrazolopyrimidines and imidazothiazoles

The treatment of 3-[3-(dimethylamino)-1-oxo-2-propenyl]chromen-2-ones with 3-amino-4-cyanopyrazole gives 7-(2-oxo-2H-chromen-3-yl)pyrazolo[1,5-a]pyrimidine-3-carbonitriles. The reaction of 3-(2-bromoacetyl)coumarins with 2-amino-4-(methoxycarbonylmethyl)thiazole and 2-amino-4-methylthiazole gives methyl 2-(6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b]thiazol-3-yl)acetate and 3-(2-methylimidazo[2,1-b]thiazol-6-yl)-2H-chromen-2-ones, respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 465–471, March, 2008.     

Condensed isoquinolines 25. Alkylation of 6,11-dihydro-13H-isoquino[3,2-<Emphasis Type="Italic">b</Emphasis>]quinazolin-13-one

Interaction of 6,11-dihydro-13H-isoquino[2,3-b]quinazolin-13-one with alkylating agents occurs at two positions depending on their nature and the reaction conditions-at C₍₆₎ or N₍₅₎. Fusion with methyl tosylate leads to 5-methyl-13-oxo-6,13-dihydro-11H-isoquino[3,2-b]quinazolin-5-ium salts, while interaction with benzyl halides in the presence of i-PrONa gave 6-benzyl-and 6,6-dibenzyl-6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-ones. Alkylation with olefins led to two types of products. In the case of maleinimides and maleic acid anhydride Michael adducts at C₍₆₎ were formed and in the case of cyanocinnamic acid esters the reaction was accompanied by intramolecular acylation at N₍₅₎ to give 1-aryl-3,9-dioxo-3H,9H,11H-benzo[5,6][1,8]naphthyridino[1,8-ab]quinazoline-2-carbonitrile. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.11, 1698–1708, November 2007.     

Reactions of 5-nitrospiro[benzimidazole-2,1′-cyclohexane] 1,3-dioxide with nucleophiles

Reactions of 5-nitrospiro[benzimidazole-2,1′-cyclohexane] 1,3-dioxide with aliphatic amines and sodium hydroxide resulted in removal of one N-oxide oxygen atom and formation of 4-alkylamino- or 4-hydroxy-substituted 5-nitrospiro[benzimidazole-2,1′-cyclohexane] 1-oxides, respectively. The title compound reacted with ammonia and methylamine in the presence of MnO₂ with conservation of both N-oxide moieties, and the products were 4-amino- and 4-methylamino-5-nitrospiro[benzimidazole-2,1′-cyclohexane] 1,3-dioxides. The reactions with aromatic amines were accompanied by removal of both N-oxide oxygen atoms with formation of N-aryl-5-nitrospiro[benzimidazole-2,1′-cyclohexane]-4-amines. In the reactions of 5-nitrospiro-[benzimidazole-2,1′-cyclohexane] 1,3-dioxide with sodium azide and aromatic amine hydrochlorides nucleophilic replacement of the 5-nitro group by azido or arylamino occurred, in the first case both N-oxide fragments being conserved. The reactions with aromatic amine hydrochlorides afforded N-aryl-5-nitrospiro[benzimidazole-2,1′-cyclohexan]-4-amine 1-oxides. Treatment of 5-nitrospiro[benzimidazole-2,1′-cyclohexane] 1,3-dioxide with sodium cyanide led to the formation of 5-oxo-3,5-dihydrospiro[benzimidazole-2,1′-cyclohexane]-4-carbonitrile 1-oxide.     

An efficient de novo synthesis of partially reduced phenanthrenes through C-C insertion

An efficient and novel approach to the synthesis of highly congested 3-alkyl-, 4-alkyl-, 3-aryl-, 3,4-dialkyl-, 4-alkyl-3-aryl-, and 3,4-diaryl-9,10-dihydro-1-sec-aminophenanthrene-2-carbonitriles has been delineated through the base-catalyzed ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by carbanion derived in situ from various ketones in moderate to good yields. 9,10-Dihydrophenanthrenes with and without substituent in the bay region are efficiently and regioselectively synthesized by using propanal and acetyltrimethylsilane as a source of carbanion. Even the synthesis of bisphenanthrenes has been achieved by the ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by 2-acetylphenanthrene in moderate yield. Highly substituted 3-amino-1-sec-amino-5,6-dihydrophenanthrene-2,4-dicarbonitriles have also been prepared from the reaction of 2-oxobenzo[h]chromene and malononitrile.     

Five-membered 2,3-dioxoheterocycles: LVIII. Reaction of methyl 1-Aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrol-2-carboxylates with substituted 1-methyl-3,4-dihydroisoquinolines. New approach to the synthesis of steroid 13-azaanalogs

Methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with substituted 1-methyl-3,4-dihydroisoquinolines with the formation of substituted 3-oxo-2,3,5,6-tetra-hydropyrrolo[2,1-a]-isoquinoline-2-spiro-2′-(1-aryl-3-aroyl-4-hydroxy-5-oxo-2,5-dihydro-1H-pyrroles). A new approach was developed to the synthesis of 13-azagonanes, substituted benzo[f]pyrrolo[2,1-a]isoquinoline-9-spiro-2′-pyrroles.     

Condensed isoquinolines 26. Oxidation reactions of 6,11-dihydro-13H-isoquino-[3,2-<Emphasis Type="Italic">b</Emphasis>]quinazolin-13-one derivatives

Oxidation of the hydrobromide of 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one with dimethyl sulfoxide leads to 11-hydroxy-11H-isoquino[3,2-b]quinazoline-6,13-dione, and with hydrogen peroxide to the hydrobromide of 2-[(4-oxo-3,4-dihydro-2-quinazolinyl)carbonyl]benzoic acid. Salts of 5-and 6-alkyl-substituted isoquino[3,2-b]quinazolines are readily oxidized on boiling in nitrobenzene, which leads to aromatization of the isoquino[3,2-b]quinazoline system to 5-methyl-13-oxo-5H,13H-isoquino[ 3,2-b]quinazolinium perchlorate and 6-benzyl-13H-isoquino[3,2-b]quinazolin-13-one. The structures of the dehydrogenation products were established from ¹H NMR and UV spectra. The interaction of the obtained compounds with NaBH₄ has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1833–1840, December, 2007.     

Synthesis of spiro(benzo[h]quinazoline-5,1′-cyclohexane) derivatives

3-p-Methoxyphenyl-4-oxo-2-mercapto-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-4,1 -cyclohexane) wassynthesized by the reaction of 4-amino-3-ethoxycarbonvl-1, 2-dihydrospiro(naphthalene-2,1 '-cyclohexane) (1) with p-methoxyphenvl isothiocyanate without separation of the thioureido derivative. Amino ester 1 is transformed byacetamide and formamideinto 2-methyl-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1 -cyclohexane) and 4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane (11), respectively. Alkylation of quinazoline 11 with methyl iodide results in formation of 3-methyl-4-oxo-3, 4, 5, 6-tetrahydro-spiro (benzo[h]quinazoline-5,1 -cyclohexane). Amino ester 1 reacts with caprolactam with formation of 2, 3 pentamethylene-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane). 4-Ethoxymethyleneamino-3-ethoxy-carbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclohexane) was synthesized by the reaction of amino ester 1 with o-formic ester, and was converted into 3-amino-4-oxo-3, 4,5, 6-tetrahydro-spiro(benzo[h]quinazoline-5,1-cyclohexane) (VIII) by hydrazine hydrate. Aminoquinazoline VIII is acylated by acid chlorides with formation of 3-acylamino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes) and forms 3-benzyl-ideneamino-4-oxo-3,4,5,6-teirahydrospiro(benzo[h]quinazoline-5,1-cyclohexane) with benzaldehyde.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 530–533, April, 1996     

Synthesis of 2,3-disubstituted 4-oxo-3,4,5,6-tetrahydrospiro-(benzo[h]quinazoline-5,1′-cyclopentanes)

3-Substituted 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclopentanes) were obtained by the reaction of 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclopentane) with methyl, phenyl, and benzyl isothiocyanates and cyclization of the obtained thioureas. Condensation of the products with various halides gave 2,3-substituted 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclopentanes). The reaction of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclopentane) with 1,2-dibromoethane and 1,3-dibromopropane led to 6-oxo-7,8-dihydrospiro(benzo[h]thiazolidino[2,3-b]quinazoline-7,1-cyclopentane) and 7-oxo-8,9-dihydrospiro(benzo[h]-perhydrothiazino[2,3-b]quinazoline-8,1-cyclopentane) respectively.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 663–667, May, 2000.     

Synthesis of new spiro compounds containing a carbamate group

1,3-Dipolar cycloaddition to methyl 4-[2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)-1-oxoethyl]-phenylcarbamate of diazomethane in chloroform-diethyl ether and of 3,4-dimethoxybenzonitrile oxide generated from the corresponding aldehyde oxime by the action of N-chlorobenzenesulfonamide sodium salt (Chloramine B) in boiling ethanol gave, respectively, methyl 4-(2-oxo-1′,5′-dihydro-1H-spiro[indole-3,4′-pyrazol]-3′-ylcarbonyl)phenylcarbamate and methyl 4-[3′-(3,4-dimethoxyphenyl)-2-oxo-1H,4′H-spiro[indole-3,5′-isoxazol]-4′-ylcarbonyl]phenylcarbamate. The condensation of methyl 4-[2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)-1-oxoethyl]phenylcarbamate with hydrazine hydrate in ethanol afforded methyl 4-(2-oxo-1,2,2′,4′-tetrahydrospiro[indole-3,3′-pyrazol]-5′-yl)phenylcarbamate.     

Synthesis of 6′-carbamoylmethylthio-5′-cyano-1′,4′-dihydro-3,4′-bipyridine-3′-carboxylic and 6′-carbamoylmethylthio-5′-cyano-1′,4′-dihydro-4,4′-bipyridine-3′-carboxylic esters and investigation of their stability. 2. Esters of 6′-carbamoylmethyl-thio-5′-cyano-1′,4′-dihydro-4,4′-bipyridine-3-carboxylic acids

The stability of solutions of esters of 6′-carbamoylmethylthio-5′-cyano-2′-methyl-1′,4′-dihydro-4,4′-bipyridine-3′-carboxylic acids was investigated by HPLC. The corresponding esters of 6′-carbamoylmethylthio-5′-cyano-4,4′-bipyridine-3′-carboxylic acids,esters of 8-cyano-5-methyl-3-oxo-7-(4-pyridyl)-2,3-dihydro-7H-thiazolo-[3,2-a]pyridine-6-carboxylic acids, methyl 3-amino-2-carbamoyl-6-methyl-4-(4-pyridyl)-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylate, and methyl 3-amino-2-carbamoyl-6-methyl-4-(4-pyridyl)-thieno[2,3-b]pyridine-5-carboxylate were synthesized as standard compounds (typical impurities). Analysis by HPLC was realized under the conditions of reverse-phase chromatography. It was established that solutions of the investigated compounds (with mixtures of acetonitrile with phosphate buffer, having pH values of not less than 3 and not more than 5, as solvents) are stable for one month when the solutions are stored in a place protected against light. It is also necessary to use chromatographic systems in which the aqueous components have pH 3–5 during determination of the purity of the esters of 6′-carbamoylmethylthio-5′-cyano-2′-methyl-1′,4′-dihydro-4, 4′-bipyridine-3′-carboxylic acid by HPLC in order to separate the analyzed sorbates and their typical impurities more completely. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 841–848, June, 2007.     

Reaction of diketene with cyanothioacetamide: A convenient and regioselective method for the preparation of new 4(1H)-pyridone derivatives

The reaction of diketene with cyanothioacetamide in dry dioxane in the presence of triethylamine gives triethylammonium 3-cyano-6-methyl-4-oxo-1,4-dihydro-2-pyridinethiolate. The regioselective S-alkylation of this thiolate is a convenient method for the preparation of substituted 4(1H)-pyridones and also derivatives of thiazolo[3,2-a]pyridine and thieno[2,3-b]pyridine. The action of 2-amino-1,1,3-tricyanopropene on this thiolate leads to its transformation into a new heterocyclic system, namely, 5H-pyrido[2′,3′:4,5]thiopyrano[2,3-b]pyridine; treatment with iodine yields the oxidation product, namely, the corresponding bis(2-pyridyl) disulfide. The structure of isopropyl (3-cyano-6-methyl-4-oxo-1,4-dihydro-2-pyridinyl)thioacetate was confirmed by X-ray diffraction structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 716–725, May, 2007.     

Synthesis of new pyrrolo-[3,4-c]isoxazole, pyrrolo[2,3-d]-[1,2,3]triazole, triazolo[4,5-c]-pyridazine, and dipyrrolo-[3,2-b:3′,4′-d]pyran derivatives

New pyrrolo[3,4-c]isoxazole derivatives were synthesized from the key intermediates 4-cyanopyrrolidin-3-ones in two steps. Pyrrolo[2,3-d][1,2,3]triazoles and triazolo[4,5-c]pyridazine were obtained from 2-arylhydrazono-4-cyano-1-(4′-methoxyphenyl)-3-oxopyrrolidines by refluxing with phenylhydrazine in either ethanol or glacial acetic acid. Aldol self-condensation of 1-aryl-4-cyanopyrrolidin-3-ones afforded dipyrrolo-[3,2-b:3′, 4′-d]pyran derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1841–1848, December, 2007.     

Synthesis and structure of 3-allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles

3-Allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles were synthesized via [3,3]-sigmatropic rearrangement of 4-aryl-7,7-dimethyl-5-oxo-2-(prop-2-yn-1-ylsulfanyl)-1,4,5,6,7,8-hexahydroquinoline-3-carbonitriles. The structure of 3-allenyl-7,7-dimethyl-4-(2-nitrophenyl)-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinolin-3-carbonitrile was determined by X-ray analysis.     

Chemistry of Acyl(imidoyl)ketenes: IX. Synthesis and Thermolysis of 3-Aroyl-8-chloro-1,2-dihydro-4<Emphasis Type="Italic">H</Emphasis>-pyrrolo[2,1-<Emphasis Type="Italic">c</Emphasis>][1,4]benzoxazine-1,2,4-triones

Reactions of 3-Z-aroylmethylene-6-chloro-3,4-dihydro-2H-1,4-benzoxazine-2-ones with oxalyl chloride afford 3-aroyl-8-chloro-1,2-dihydro-4H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones and Z-3-(2-aryl-2-chlorovinyl)-6-chloro-2H-1,4-benzoxazine-2-ones. Aroyl(imidoyl)ketenes generated by decarbonylation of pyrrolobenzoxazinetriones undergo dimerization through [4+2]-cycloaddition to form 4-aroyl-3-aroyloxy-2-(2-oxo-2H-1,4-benzoxazin-3-yl)-1H, 5H-pyrido[2,1-c][1,4]benzoxazine-1,5-diones.