4-hydroxy-2-quinolones 151. Reaction of 4-chloro-3-ethoxycarbonyl-2-oxo-1,2-dihydroquinolines with p-toluenesulfonylhydrazide

The reaction of ethyl 4-chloro-1-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylate with p-toluene-sulfonylhydrazide at room temperature in the system DMSO/K₂CO₃ gives 5-methyl-2-(toluene-4-sulfonyl)-1,2-dihydro-5H-pyrazolo[4,3-c]quinoline-3,4-dione, alkylation of which using ethyl iodide gives the 1N-substituted derivative. For Communication 150 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 59-66, January, 2009.     

6,7-Dimethoxy-3,4-dihydroisoquinolin-1(2<Emphasis Type="Italic">H</Emphasis>)-ylidenoacetonitrile in some fusion reactions

6,7-Dimethoxy-3,4-dihydroisoquinolin-1-ylacetonitrile in the enamine form readily reacts with acyl iso(thio)cyanates affording in high yields 1,2-fused oxo- and thioxodihydropyrimidoisoquinolines and thiouracyloisoquinolines. The reaction of the enamine with primary amines of diverse classes in the presence of 2 equiv of formaldehyde resulted in 1,2-fused N-substituted tetrahydropyrimidinoisoquinolines whose yields depended on the basicity and sterical accessibility of the reagent. Fused 5-hydroxyindolo-, dioxopyrrolo-, pyrroloisoquinolines formed in medium yields in the one-stage reactions of the enamine with p-benzoquinone, oxalyl chloride, and β-nitrostyrene respectively. The reaction of 1-cyanomethyl-6,7-dimethoxydihydroisoquinoline with acrylonitrile leads to the formation of 1,2-fused iminopyridinoisoquinoline easily hydrolysable to pyridine derivative and readily reacting by the amidine group with aroyl chlorides and arylsulfonyl chlorides.     

Synthesis of 1-substituted 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones

1-R-9,9,9a-Trimethyl-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones and the corresponding 2-methylene-2,3-dihydroindoles were obtained by the reaction of 2,3,3-trimethyl-3H-indole with a number of N-substituted chloroacetic acid amides and subsequent reaction of the resulting quaternary salts with bases. The kinetics of intramolecular cyclization of 1-(N-alkylcarbamoylethyl)-2-methylene-2,3-dihydroindoles under the influence of acetic acid were studied. Under the influence of strong protic acids 1-R-imidazo[1,2-a]indol-2-ones undergo decyclization and are converted to 3H-indolium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1485–1489, November, 1986.     

Intramolecular Schmidt reaction of tert-butyl 3-(3-azidopropyl)-4-oxopiperidine-1-carboxylate as a synthetic route to saturated fused aza heterocycles

Treatment of the title compound with trifluoroacetic acid induced intramolecular Schmidt reaction with formation of a saturated fused heterocyclic system, tert-butyl 5-oxo-2,3,4,5,7,8,9,9a-octahydro-1H-pyrrolo[1,2-a][1,4]-diazepine-2-carboxylate. The latter was reduced with lithium tetrahydridoaluminate, and subsequent treatment with hydrogen chloride in dioxane gave 2,3,4,5,7,8,9,9a-octahydro-1H-pyrrolo[1,2-a][1,4]-diazepine dihydrochloride which is a promising intermediate product for the synthesis of N-substituted diazepines with a fused pyrrole ring.     

A new synthesis of p-hydroxy phenylglycine and some analogues from p-benzoquinone

[reaction: see text] A new route to p-hydroxy phenylglycine and N-substituted analogues has been developed starting from p-benzoquinone. 1,2-Addition of methyl lithioacetate to p-benzoquinone and subsequent quenching of the oxygen anion with methyl chloroformate, followed by an elimination-addition reaction with an appropriate amine, resulted in the desired amino acid derivatives. A diastereoselectivity of 60% was achieved using 8-phenylmenthyl acetate as the chiral auxiliary.     

Base-induced rearrangements of N-substituted 3-arylaminoisoxazol-5(2H)-ones to 2-arylaminoimidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridines

New N-substituted derivatives of 2-substituted 3-phenylamino-and 3-(1-naphthyl)aminoisoxazol-5(2H)-ones were synthesized. The reaction of isoxazolones with 2-chloro-5-nitropyridine gave the corresponding isoxazolones with a nitropyridyl group substituted on N-2. Their rearrangements produced ethyl 2-arylaminoimidazo[1,2-a]pyridine-3-carboxylates in the presence of triethylamine. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 751–757, May, 2008.     

Synthesis of 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane) derivatives

The reaction of4-acylamino-3-cyano-1,2-dihydrospiro(naphthalene-2,1-cyclohexanes) with hydrogen chloride yields 2-substituted 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes). It was found that when the latter are condensed with methyl iodide, N-alkylation takes place exclusively. Alkylation with ethyl iodide in analogous conditions yields a mixture of O- and N-substituted products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 658–661, May, 1992.     

The chemistry of 3-azaisotoic anhydrides. Synthesis and reactions of polyaza heterocycles

The preparation of a variety of N-substituted 3-azaisatoic anhydrides 3 and 8 is described. These anhydrides reacted with thiopseudoureas to give interesting bicyclic, tricyclic, and tetracyclic heterocycles many of which are new ring systems. One such heterocycle, the imidazo[1,2-a]pyrido[2,3-d]pyrimidine ring system, was studied further with respect to alkylation and reduction reactions. Alkylation of 12h occurred on the nitrogen in the central B ring, whereas, in the reduced species 33 , alkylation took place in the C ring. The reaction of 3-azaisatoic anhydrides with carbanions was also investigated. Reactions occur with anions generated from nitromethane, diethylmalonate, ethyl nitroacetate, ethyl isocyanate, and ethyl o-fluorobenz-oylacetate.     

Synthetic transformations of higher terpenoids: XXIII. Synthesis of diterpenoid-based dihydroisoindolones

Vilsmeier-Haak reaction of phlomisoic acid methyl ester gave a mixture of 15- and 16-formyllabdanoids. In addition, methyl 2-formyldodecahydrophenanthro[1,2-b]furan-6-carboxylate was isolated, and its structure was determined by X-ray analysis. Reductive amination of 16-formyllabdanoid with benzylamine or α-amino acid methyl esters led to the formation of labdanoid furfurylamines which reacted with maleic anhydride to produce N-substituted 4-oxo-10-oxa-3-azatricyclo[5.2.1.0^1,5]dec-8-ene-6-carboxylic acids. Acylation of labdanoid furfurylamines with (E)-but-2-enoyl chloride afforded the corresponding unsaturated amides which were converted into 10-oxa-3-azatricyclo[5.2.1.0^1,5]dec-8-en-4-ones via intramolecular Diels-Alder reaction. Treatment of the oxa adducts with boron trifluoride-diethyl ether complex gave dihydroisoindol-1-one derivatives containing a diterpene fragment.     

Synthesis of N′-substituted 4-amino piperidines with a shielded nitrogen atom

A method was developed for the synthesis of N-substituted 2,2,6,6-tetramethyl- and 1,2,-2.6,6-pentamethyl-4-aminopiperidines starting from triacetoneamine cyanohydrin through the corresponding aminonitriles with subsequent reductive decyanation. The peculiarities of salt formation from N-substituted 4-aminopiperidines with a shielded nitrogen atom are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1672–1678, December, 1971.     

Copper-catalyzed synthesis of 2-sulfenylindoles from indoline-2-thiones and aryl iodides

A novel and efficient method for synthesis of 2-sulfenylindole via copper-catalyzed coupling reaction of indoline-2-thiones with aryl iodides has been developed. A series of N-substituted and N-free 2-sulfenylindole were obtained in high yields. Furthermore, the method was employed to synthesis of benzothieno[2,3-b]indoles from indoline-2-thiones with 1,2-diiodobenzene in the presence of CuI and Pd(OAc)₂ as catalysts.     

Stereoselective pyrroline-ring formation through the cyclization of conjugated azomethine ylides at the periphery of pyrido[1,2-a]pyrimidine system

The thermal reaction of N-benzyl-N-[3-(N-substituted imino)methyl-4-oxo-4H-pyrido[1,2-a]pyrimidin-2-yl]amino acid esters, generated from aldehyde esters and primary amines, provides 2,3-dihydropyrido[1,2-a]pyrrolo[2,3-d]pyrimidin-4(1H)-one derivatives effectively and stereoselectively. Therein, the stereoselective generation of conjugated azomethine ylides from the imine esters and their cyclization is essential for the pyrroline-ring formation.     

The preparation of N-substituted aminomethylidenebisphosphonates and their tetraalkyl esters via reaction of isonitriles with trialkyl phosphites and hydrogen chloride. Part 1

The reaction of isonitriles with trialkyl phosphites in the presence of hydrogen chloride gives tetraalkyl N-substituted aminomethylidenebisphosphonates via N-methylideneaminium (isonitrilium) salts. Hydrolysis or dealkylation of these tetraalkyl esters gives N-substituted aminomethylidenebisphosphonic acids in high yields.     

Phosphorylation of Benzimidazole-2-thiones by Chloroethynylphosphonate

The reaction of chloroethynylphosphonates with N-substituted benzimidazole-2-thiones proceeded chemo- and regioselectively with the formation of cyclic zwitterions, namely alkyl (9H-benzo[4,5]imidazo[2,1-b]-thiazol-3-yl-4-ium)phosphonates. Chemo- and regioselective reaction of N-unsubstituted benzimidazole-2-thione with chloroethynylphosphonates led to the production of linear Z-1,2-bis(1H-benzimidazol-2-ylsulfanyl)-ethenylphosphonates.     

Reaction of methyl thiocarbamate with nonsubstituted malonyl dichloride. Effect of conditions on reaction direction

The reaction of methyl thiocarbamate with malonyl dichloride at low temperatures provides an N-substituted thiocarbamate, whereas prolonged boiling in high-boiling solvents gives rise to 4-hydroxy-2-(methylsulfanyl)-6H-1,3-oxazin-6-one that was also prepared by treatment of the N-substituted thiocarbamate with malonyl chloride in toluene and chlorobenzene.     

N-取代吩噻嗪和DDQ的电荷转移络合作用

具有盼嘤酸化学结构的化合物有广泛的用途I‘－＼其中吩嘤埃衍生物在医学上用作抗精神病药物特别受到药理学家们的注意，发现其药理作用与其分子提供电子的能力有关卜‘」但是我们应该注意到，作为抗精神病药物的吩嚷嚷衍生物，其吩座爆分子的氮原子都连有一个叔胺基链问，例如氯丙障（I）和奋乃静（11）．而我们知道，胺类特别是叔胺类有强的提供电子的能力＊；在上述的药物分子中是主要的提供电子因素，因此以这类化合物作为给体研究其供电子能力，是不能实际反映吩嘤嗓分子本身的给电子能力的．吩嘤噪类属于二苯并杂环化合物，分子中既…     

Reaction of organozine reagents derived from dialkyl 2,2-dibromomalonates and methyl 4,4-dibromo-3-oxoalkanoates with 2-oxochromene-3-carboxamides

Organozinc compounds obtained by treatment of dialkyl 2,2-dibromomalonates with zinc reacted with N-substituted 2-oxochromene-3-carboxamides to give dialkyl 1a-R-carbamoyl-2-oxo-1a,7b-dihydro-2H-cyclopropa[c]chromene-1,1-dicarboxylates or alkyl 2-R-1,3,4-trioxo-2,3-dihydro-1H,9bH-chromeno[3′,4′:1,3]-cyclopropa[1,2-c]pyrrole-9c-carboxylates. Reactions of N-substituted 2-oxochromene-3-carboxamides with zinc enolates derived from methyl 4,4-dibromo-3-oxoalkanoates led to the formation of the corresponding 9c-alkyl-2-R-2,3-dihydrochromeno[3′,4′:1,3]cyclopropa[1,2-c]pyrrole-1,3,4-triones.     

Cyclopropanation of 2-arylmethylidenemalononitriles,alkyl 3-aryl-2-cyanoprop-2-enoates,and N-substituted 3-aryl-2-cyanoprop-2-enamides with bromine-containing zinc enolates

Zinc enolates derived from 2,2-dibromoindan-1-one and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one reacted with 2-arylmethylidenemalononitriles, alkyl 3-aryl-2-cyanoprop-2-enoates, and N-substituted 3-aryl-2-cyanoprop-2-enamides to give, respectively, 3-aryl-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-2-dicarbonitriles, 3-aryl-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2,2-dicarbonitriles, alkyl 3-aryl-2-cyano-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-carboxylates, alkyl 3-aryl-2-cyano-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxylates, and N-substituted 3-aryl-2-cyanol-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxamides as a single diastereoisomer. The stereoconfiguration of the products was determined by ¹H and ¹³C NMR spectroscopy.     

An easy one-step photocatalytic synthesis of 1-aryl-2-alkylbenzimidazoles by platinum loaded TiO2 nanoparticles under UV and solar light

One-pot synthesis of disubstituted benzimidazoles from N-substituted 2-nitroanilines or 1,2-diamines with 3-12 nm-sized platinum particles loaded on the TiO₂ using solar and UV-A light is described. 1-Aryl-2-alkylbenzimidazoles from 2-nitrodiphenylamines are formed by combined redox photocatalytic reaction, condensation and catalytic dehydrogenation on Pt-TiO₂. In case of diamines, this reaction is proceeded by Pt-TiO₂ assisted photocatalytic oxidation of an alcohol and a catalytic dehydrogenation of the intermediate on the surface of platinum nanoparticles. In both cases product formation was achieved by tandem photocatalytic and catalytic reactions on Pt-TiO₂.     

Intramolecular Ullmann-type C−N coupling for the synthesis of substituted benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridines

An efficient CuI catalyzed intramolecular Ullmann-type C−N coupling reaction is described here. Newly substituted 1H-benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridine-1,3,5(2H, 11H)-trione has been easily synthesized from ortho halogenated N-substituted pyrrolo[3,4-c]pyridine-1,3,6(5H)-triones in presence of CuI catalyst and K₂CO₃ base without any ligand. This procedure is based on intramolecular Ullmann-type reaction and provides a proficient method of making fused tetracyclic heterocycles.